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Non starting 318i M40 (fuel issues, I think)

Posted by Flyboy 
Many thanks for your help guys, I really do appreciate it, honestly I do, I would be lost without the generosity of the good folk like you all.
I promised a little tutorial on the job for what it is worth, for someone who may want to change a cam belt in the future and be intimidated by the job, but mostly to try and give a little back to this great little corner of the world wide web, for all it has given me.
So, with that said, I did take lots and lots of pics as I progressed through the job, I am going to go through those pics with a fine tooth comb and see if I can spot anything that was different before, to what it is now (loose plug.....)
Although I find it hard to accept, there is a little niggle in the back of my brain that tends to agree with Rick, that I must have dislodged something somewhere, but I really don't see how, and I have done a cam belt job on this car countless times, I can do it with my eyes closed, but as Rick points out, all was perfect before I tore into it, that won't go away out of my brain, and I have redone the whole job in my head over and over trying to pinpoint something, but nothing sticks out.
Will let you know if I find anything on the photos.

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E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.
Ok just spent the last 5 hours studying 80 photos of the cam job, and everything seems fine, I can not find anything that was not as it was before I started.

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E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.
It runs, but not well :-(
Ok, I managed to get it to run and keep running, even took it for a test drive around the neighbourhood.
I spent the day at work going over everything, pouring through the manual trying to make sense of it all, I was sort of leaning towards fuel pressure problems because of the flooding, I would consider a bunch of other things, but my mind would keep returning to the flooding.
Then a guy told me a story, a few years ago they built a 'stroker' motor and had the same problem, car was running perfect before they did the work, after dropping the motor back in, straight away they had issues with it flooding, turned out the fuel pressure regulator was toast, they replaced it and all was well.
I thought about it for a while, how could be fine and on the next start it is no good, "What Changed????".........seemingly nothing, the car was parked.
Then the penny dropped, in both cases the vacum created in the intake manifold had changed, it had increased, in his case by incresing the stroke of the engine, and in my case, by the increased valve lift with the new cam and rockers, enabling the pistons to draw more air.

The fuel pressure regulator, as we know is the little black canister connected to the end of the injection rail and controls the flow of fuel back to the tank, thus the fuel pressure.
It works with a diaphram in the canister that is manipulated by manifold suction via the tube that connects it to the manifold near the throttle butterfly.
Now what if the thing was old and the diaphram was on its last legs, maybe, just maybe, the increased vacum in the intake may just be stong enough to rupture the diaphram.

So with this in mind, as soon as I got home, I figured I would put it to the test and see, so While enlisting the help of the better half to sit in the car and crank it, I, armed with clamp in hand, rigged the clamp onto the fuel delivery pipe just before it connects to the injectors and screwed the clamp down to block off fuel flow, then slowly and gradually opened the clamp, thus restricting fuel flow and changing it at will, manual fuel pressure if you like.
It worked and the car fired up, I set the clamp, thus the fuel flow to a point where the motor kept running, it took a few trial and error trys but I got it.
Now this is where it gets wierd, after leaving the car to run for about five minutes, I slowly removed the clamp.....and the car kept on running on its own without the clamp.

But unfortunatly not out of the woods, the car now hunts at idle, not badly, about 500rpm between 1000 and 500 rpm.
It also has a huge flat spot straight off idle, you have to gently apply gas to get through it, if you crack the throttle open fast from idle it will stumble and die.
Out on the drive it lacks power, you need quite a bit more throttle to get away from a standstill and is very sluggish on acceleration. As you back off the accelerator it dies immidiatly, like you turned off the key, if you try and hold a steady speed at about half throttle setting it surges badly, but goes away if you go back to full throttle, but serious lack of power.
And lastly, if you turn it off and then try and restart the motor, you need full throttle to start, then it cranks longer than normal and slowly takes, exactly like a flooded motor.

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E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.
Well, you may very well be onto something here. What happens when you disconnect the vacuum line and suck? If the diaprham is ruptured, you should taste gas I would think. At least you are in the park now.

Never even heard of that sub-system. I always assumed the ECU would adjust the injectors firing time based on the O2 sensor downstream data. I thought the fuel rail pressure was a constant no matter what. Anyone heard/know about this sub-system?

good persistance!!!

alan



Edited 1 time(s). Last edit at 01/10/2011 12:15PM by alanrw.
For reasons I can't go into on an iPhone while in a meeting, a clamp is an incomplete substitution for ampressure regulator. The clamp only increases resistance in the line, which has the effect of changing the pressure. But if the pressure from the pump, injectors, or manifold changes, the equation for pressure changes, and that set resistance with the clamp will no longer be accurate.

If you ever removed the hose to the regulator, you could also have a utter return line. This would also cause an increased pressure. However my bet is now on a failed regulator. Is that part hard to come by down there? Hopefully you don't have to trade an arm for it!

-----------------------------------------------------------------------------------
1989 - E30 - M20 - Manual. Approximately 270,000 miles
2000 - E46 - M52TUB28 - Manual. Approximately 110,000 miles

Alan, our cars over here, well at least the ones of that vintage don't have O2 sensors, mine has never had one, the socket where the O2 sensor relay lives, next to the fuel pump relay has been sitting empty from day one.

I did remove the vacum hose to see what diffirence there would be, it kept running, the only reason I knew it was off, was I heard the tell tale hiss of a vacum leak, pluged it back on, no change.

I did give a good suck on the vacum line, and there was no gas, I could also feel the vacum increasing as I sucked, like sucking on a blocked off pipe. I could suck and block the pipe with my tounge and maintain the vacum, I don't know for how long, maybe just a tiny tear in the diaphram, but no fuel, it is also a clear piece of line, so you would see it, I guess.

You can get all the spares here, they just not too cheap, I think that regulator goes for about R550 or about $80, but they waiting for stock.

----------------------------------------------------------------------------------------------------------------------------------
E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.



Edited 1 time(s). Last edit at 01/10/2011 12:45PM by Flyboy.
Quote
Flyboy
I did remove the vacum hose to see what difference there would be, it kept running, the only reason I knew it was off, was I heard the tell tale hiss of a vacum leak, pluged it back on, no change.

I did give a good suck on the vacum line, and there was no gas, I could also feel the vacum increasing as I sucked, like sucking on a blocked off pipe. I could suck and block the pipe with my tounge and maintain the vacum, I don't know for how long, maybe just a tiny tear in the diaphram, but no fuel, it is also a clear piece of line, so you would see it, I guess.
I'm not sure about this, just guessing, but I don't think a tear in the diaphragm should allow fuel to be sucked through. I'm thinking one side of the diaphragm would be the side with the tube leading to the intake manifold, whereas the other side should be open to atmospheric pressure. That way the diaphragm measures the difference between atmospheric pressure and intake manifold vacuum.

If the diaphragm was torn, sucking on the tube should just suck air through it.

The diaphragm itself should work against a spring-loaded, but otherwise sealed, plunger of some sort that varies the fuel flow rate from the fuel injector rail into the fuel return line which sends fuel back to the tank.

There would be a spring inside the regulator forcing the diaphragm against the plunger seal. The high-pressure fuel pump fills the fuel injector rail and builds pressure to the point where it overcomes the spring pressure and lifts the plunger off the seal, the spring thereby holding a fixed pressure in the fuel rail while allowing excess fuel to circulate back to the fuel tank. Changing the amount of vacuum on the other side of the diaphragm varies the amount of pressure required to overcome the spring force.

Sucking on the tube leading to the intake manifold should vary the fuel pressure in the fuel rail. At idle with the throttle closed is when the intake manifold sees the highest vacuum, and presumably that's when the least fuel pressure is required. Wide open throttle should see the least intake manifold vacuum, and therefor the highest fuel pressure.

I was starting to think the fuel pressure regulator diaphragm had torn, thereby allowing a vacuum leak through it. That would explain the hunting idle and other symptoms. But not explain why it's flooding? It should instead be running lean with a vacuum leak...

But you've already checked that the diaphragm seems to be holding a vacuum okay. It would be interesting to know though whether the fuel pressure actually varies when you suck on the vacuum tube. You could block the port on the intake manifold to prevent air from entering there, then suck on the tube while its connected to the pressure regulator while the engine is idling to see if you can detect any difference. You really should have a fuel pressure gauge inline between the fuel filter and fuel injector rail for this. But maybe you can tell if the pressure regulator is working like this.

If the regulator is somehow stuck, maybe it's stuck in the low manifold vacuum position (wide open throttle), ie highest fuel pressure, which is causing it to flood the engine under closed-throttle idle conditions???
Quote
Flyboy
our cars over here, well at least the ones of that vintage don't have O2 sensors, mine has never had one, the socket where the O2 sensor relay lives, next to the fuel pump relay has been sitting empty from day one.
The O2 sensor relay is for the O2 sensor pre-heater. Absence of the relay does not necessarily mean you have no O2 sensor. You may have the non-heated 2-wire version, rather than the 3-wire heated O2 sensor.

The O2 sensor, if you have one, would be mounted into the exhaust pipe not far downstream of the exhaust manifold, but ahead of the catalytic converter which you may or may not have.
Hi Ferdi
Nice to see you pop into to give your input to my problems, yes, I understand the fuel pressure regulator to work as you described.
No my car has no O2 sensor, I know that, niether does it have a catalytic converter, I know, I have had the exhaust off a few times before.
Of course now I am still at loss as to what is casing the rich condition, and at $80, I can not really afford to throw on a regulator in the chance that it may be that.
Although I think it may be.

----------------------------------------------------------------------------------------------------------------------------------
E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.
rkj
Quote
Flyboy
Hi Ferdi
Nice to see you pop into to give your input to my problems, yes, I understand the fuel pressure regulator to work as you described.
No my car has no O2 sensor, I know that, niether does it have a catalytic converter, I know, I have had the exhaust off a few times before.
Of course now I am still at loss as to what is casing the rich condition, and at $80, I can not really afford to throw on a regulator in the chance that it may be that.
Although I think it may be.

Like Ferdy sez, you really need a fuel pressure gauge to find anything out for real. I leave the gauge on over night too for a leak down test of the injectors; my daughters 1984 325 (with original injectors @ 200k) got the best grade in that test out of all the cars I've tested, go figure!

My 323 didn't have an 02 sensor or cats either; it was a euro car that never got usa speced (long story). Maybe cars set up this way are more sensitive to the FPR workings/nonworkings, and with the increase in vacuum, it may be a player.

At least the car runs now, now we can go from here. Do you have any old pressure gauge laying around for a fuel pressure tester?

I know you've gone over the valve timing but it does sound like it's off by the way it's running... Have you gone over the valve clearances??

Rick, is giving the first perseverance award of the new year! :cool2:



perseverance furthers
From your experiment with the clamp on the fuel line, it sounds to me like the ECU just needs to be reset.

For a long time, it lived with worn valves/cam, etc. and learned to adapt the injector firing to suit.
Then you put in a new cam and everything changed. Things may have been so far out of spec that the ECU couldn't adapt.
Resetting the ECU by disconnecting the battery for a while should reset it to factory values which should approximate the new parts conditions.

When you test drove it then turned it off and it did restart and run; suggests that the ECU is relearning. Without the O2 sensor, it has less feedback and it will likely take longer for it to re-acclimate.
Hi Rick/Peter
Yes, at least with it running, one has something to work with, I understand how you would suspect valve timing Rick, it does feel like that, the thought has crossed my mind as well, but I have checked more than once, and it looks good, on these belts the teeth are far enough apart, even one tooth out would be far enough to be blatantly obvious, if all else fails I will have to tear into it again.
The lifters in the M40 are hydraulic, so no clearances to take care of.
Peter, I was hoping it was something like that, been searching for info on that but have found none, I did disconnect the battery for about half an hour on Sunday when I was having all the drama, don't know if that is long enough, I must say, my test drive was not very long, was afraid of breaking down, so kept it close to home, any idea how long it should take?
unfortunately I don't have any way to test the pressure, but what I am going to do now is start her, then disconnect the vacuum line to the regulator, see if it makes a difference, then give it a good suck and see if it makes a difference, if so, I know the regulator is working and changing the flow with change in vacuum, that's about the best I can do now.
I just wish I could find literature on the Bosh Motronic M1.3 fuel injection system.

Edit; Thanks for the award Rick :dance:

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E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.



Edited 1 time(s). Last edit at 01/10/2011 09:47PM by Flyboy.
OK just tried to fire her up this morning after standing over night, back to the same flooding issues and no start :cloud:
After cranking for about a minute, the air is saturated with the strong smell of fuel, I turn the car off to go investigate.
Turns out the number four injector is soaking wet on the outside and the fuel has literally puddled up around it, on the intake manifold.
So it looks like the top half of the intake manifold is going to have to come off to investigate, as you can't see anything in there or do any work on the injector rail with it in place.

----------------------------------------------------------------------------------------------------------------------------------
E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.
rkj
Quote
Flyboy
OK just tried to fire her up this morning after standing over night, back to the same flooding issues and no start :cloud:
After cranking for about a minute, the air is saturated with the strong smell of fuel, I turn the car off to go investigate.
Turns out the number four injector is soaking wet on the outside and the fuel has literally puddled up around it, on the intake manifold.
So it looks like the top half of the intake manifold is going to have to come off to investigate, as you can't see anything in there or do any work on the injector rail with it in place.

Some times the good stuff just keeps coming :hitwithrock:
Quote
Rick
Some times the good stuff just keeps coming

Sheeeesh, don't you just know it, if I never had bad luck, I would have no luck at all.
Like I always say, "If you had to cut a woman in half, I would get the half that talks"

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E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.
Quote
alanrw
Well, you may very well be onto something here. What happens when you disconnect the vacuum line and suck? If the diaprham is ruptured, you should taste gas I would think.
Quote
Ferdinand
I'm not sure about this, just guessing, but I don't think a tear in the diaphragm should allow fuel to be sucked through. I'm thinking one side of the diaphragm would be the side with the tube leading to the intake manifold, whereas the other side should be open to atmospheric pressure. That way the diaphragm measures the difference between atmospheric pressure and intake manifold vacuum.

If the diaphragm was torn, sucking on the tube should just suck air through it.

After reading that very interesting Bosch Motronic article, I now have to admit that Alan was correct and I was wrong about this.

The Motronic article explains that the fuel pressure regulator diaphragm separates two chambers. The upper spring-loaded chamber connects via vacuum hose to the intake manifold, the lower chamber is pressurized with fuel. In this manner the pressure regulator reacts to variations in intake manifold vacuum, lowering the pressure in the fuel rail so that the fuel pressure always remains a constant 2.5 bar above the intake manifold pressure.

A torn diaphragm in the pressure regulator thus would lead to fuel being sucked through the vacuum hose into the intake manifold.

SInce you've already checked for that, I'm now leaning to thinking the fuel pressure regulator is not the problem.

It sounds more like an electrical issue, a leaking fuel injector, or something in the cold-start circuit causing the ECU to richen the mixture for cold-starts when it's not actually cold (i.e. failed coolant temp sensor).
Hi Ferdi, I must agree, Alan was indeed right, like you, after reading the article and having a better understanding of how the system operates I am not so sure it is the regulator either, in fact it would seem that even a failed regulator would not cause such flooding issues, as the amount of fuel introduced into the cylinder is purely a function of the injectors, controlled by the ECU.

Quote
Motronic 1.3 Article
The quantity of injected fuel thus depends solely on injector opening time, as determined by the ECU, and not on a variable fuel pressure.

I am also not too sure that it is a failed sensor, as if this were the case, the car would cold start as normal, but the difference would be that as the car warms up, the mixture would not be adjusted accordingly, but would remain at the rich start value, which is not the case.
Even from ice cold, it just floods and will not start as the plugs are soaked in fuel.
More and more I am beginning to think it is a mapping problem, where the ECU has gone screwwy for some reason, or it had adapted so far from the default settings to compensate for the worn valve gear, that now that all is as it should be, the mapping is no where close.

Anyway, I have not had time to work on it, as I have been working all day and then lecturing all night, so I hope to get to it this weekend, or next week sometime.
I am going to pull the top half of the intake manifold to get a good look in at the injector rail and injectors and piping, when I tried to start it on Monday, after cranking there was a strong smell of fuel, and peering through as best I could, I saw the number four injector wet with fuel and fuel pooled up on top of the intake manifold, so there is at best a pipe that is broken or maybe something more ominous, whether it is from all the tugging on the supply and return pipes or not I do not know, I will let you know what I find.

----------------------------------------------------------------------------------------------------------------------------------
E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.
Quote
Flyboy
Hi Ferdi, I must agree, Alan was indeed right, like you, after reading the article and having a better understanding of how the system operates I am not so sure it is the regulator either, in fact it would seem that even a failed regulator would not cause such flooding issues, as the amount of fuel introduced into the cylinder is purely a function of the injectors, controlled by the ECU.

I would actually disagree with you both. Perhaps someone can tell me where my thinking is wrong smiling smiley
The pressure regulator is a spring valve (using a diaphragm) that will open a path to the return line (back to the tank) when the pressure reaches a certain point. Sometimes that spring weakens, or the pressure provided by the manifold pressure isn't there, causing the valve to open prematurely and a state of low fuel pressure. This would cause a poor running engine, but would not cause flooding.
BUT, what if the valve were stuck closed? Or the return line back to the fuel tank were blocked? The valve would never be able to release the pressure, causing an unusually HIGH system fuel pressure as the pump continued to go. The ECU has the assumption that the fuel pressure is a constant, and times the injectors accordingly. If the Fuel pressure is increased, the fuel entering the engine is increased. The only exception I'm aware of is that to some degree the ECU can adjust for this using an Oxygen sensor (Which you don't have). But even cars that have them don't use them until the engine is warm, and the ECU is just adjusting for a rich condition, it does not know WHY the rich condition exists, and is only programmed to compensate to a degree.

I think it would be a good (and free!) test to remove the return fuel line in a safe environment and see if much fuel is coming out. I know when I did this with a properly working regulator that a LOT of fuel came out, so much that I was surprised there was anything left for the engine ;-)
But if it's a slow flow, a trickle or heaven help you nothing at all, there is certainly a problem with the regulator. I don't think the Bentley gives a flow rate for the return. I think this would have a lot to do with how easily your fuel pump can exceed the operating pressure.

Also of note, you said there was fuel coming out of the rail? If you had a large increase in pressure due to a seized regulator, you might be pushing fuel past weak seals, or good seals that were not designed for the increase in pressure.

Quote
Motronic 1.3 Article
The quantity of injected fuel thus depends solely on injector opening time, as determined by the ECU, and not on a variable fuel pressure.

Quote

I am also not too sure that it is a failed sensor, as if this were the case, the car would cold start as normal, but the difference would be that as the car warms up, the mixture would not be adjusted accordingly, but would remain at the rich start value, which is not the case.
Even from ice cold, it just floods and will not start as the plugs are soaked in fuel.

I don't believe this to be the case. The Temp sensor is what tells the ECU that the engine is cold. Right from start the temp sensor is used in the equation for the fuel/air ratio. Also, these sensors can fail at different temperature ranges. I just replaced a temp sensor in mt Dads ix that was causing large RPM hunting problems (500-1500rpm) when cold, and it ran like crap. Once warm it ran fine. Replaced the coolant temp sensor and all was fine again smiling smiley
I don't know if a failed temp sensor would keep the engine from starting. One of us could unplug ours and see what happens to the equation when there isn't a coolant temp sensor present smiling smiley

Quote

More and more I am beginning to think it is a mapping problem, where the ECU has gone screwwy for some reason, or it had adapted so far from the default settings to compensate for the worn valve gear, that now that all is as it should be, the mapping is no where close.
.

I think this is still the least likely. It is also one of the most expensive component you could replace! Though if you have a friend with a 318 you could swap in an ECU easily enough.

-----------------------------------------------------------------------------------
1989 - E30 - M20 - Manual. Approximately 270,000 miles
2000 - E46 - M52TUB28 - Manual. Approximately 110,000 miles




Edited 1 time(s). Last edit at 01/12/2011 01:25PM by Earendil.
Quote
Flyboy
Hi Ferdi, I must agree, Alan was indeed right, like you, after reading the article and having a better understanding of how the system operates I am not so sure it is the regulator either, in fact it would seem that even a failed regulator would not cause such flooding issues, as the amount of fuel introduced into the cylinder is purely a function of the injectors, controlled by the ECU.

Quote
Motronic 1.3 Article
The quantity of injected fuel thus depends solely on injector opening time, as determined by the ECU, and not on a variable fuel pressure.

I am also not too sure that it is a failed sensor, as if this were the case, the car would cold start as normal, but the difference would be that as the car warms up, the mixture would not be adjusted accordingly, but would remain at the rich start value, which is not the case.
Even from ice cold, it just floods and will not start as the plugs are soaked in fuel.
More and more I am beginning to think it is a mapping problem, where the ECU has gone screwwy for some reason, or it had adapted so far from the default settings to compensate for the worn valve gear, that now that all is as it should be, the mapping is no where close.

Anyway, I have not had time to work on it, as I have been working all day and then lecturing all night, so I hope to get to it this weekend, or next week sometime.
I am going to pull the top half of the intake manifold to get a good look in at the injector rail and injectors and piping, when I tried to start it on Monday, after cranking there was a strong smell of fuel, and peering through as best I could, I saw the number four injector wet with fuel and fuel pooled up on top of the intake manifold, so there is at best a pipe that is broken or maybe something more ominous, whether it is from all the tugging on the supply and return pipes or not I do not know, I will let you know what I find.

-----------------------------------------------------------------------------------
1989 - E30 - M20 - Manual. Approximately 270,000 miles
2000 - E46 - M52TUB28 - Manual. Approximately 110,000 miles

Agreed, if it was the ECU, it would be catastrophic. The only way I could see you frying the ECU is if the battery were still connected and you somehow shorted something. The thing is that the car was running ok before the repair so logic would dictate that something changed during the repair which is responsible for your no-start situation. At this point it is trouble shooting and verifying all conditions for a good start are present. YOu have already ruled out the fuel pump. Now you have to figure out what would cause a rich cold start condition. If the car has a cold start injector, is it functioning properly? Might as well disconnect the cold start injector and see where that gets you (unless the injector pintle is stuck open?)

For what it is worth, I once had a no start condition like yours (no repair) and it turned out that the connector to the ECU under the dash had worked loose.

alan



Edited 2 time(s). Last edit at 01/12/2011 02:30PM by alanrw.
rkj
Quote
alanrw
Agreed, if it was the ECU, it would be catastrophic. The only way I could see you frying the ECU is if the battery were still connected and you somehow shorted something. The thing is that the car was running ok before the repair so logic would dictate that something changed during the repair which is responsible for your no-start situation. At this point it is trouble shooting and verifying all conditions for a good start are present. YOu have already ruled out the fuel pump. Now you have to figure out what would cause a rich cold start condition. If the car has a cold start injector, is it functioning properly? Might as well disconnect the cold start injector and see where that gets you (unless the injector pintle is stuck open?)

For what it is worth, I once had a no start condition like yours (no repair) and it turned out that the connector to the ECU under the dash had worked loose.

alan

This man is the 318 twin cam expert, I don't know why I haven't offered this sooner.

[www.esatclear.ie]

I'm sure you could email or call Brenden and he would help you Flyboy.
Just read this thread on another car forum and it sounded kinda familiar? :mrgreen:

[www.camaros.net]


Read the entire thread.

alan
rkj
Quote
alanrw
Just read this thread on another car forum and it sounded kinda familiar? :mrgreen:

[www.camaros.net]


Read the entire thread.

alan

So, you're thinking it's the cold start system/injector? Doesn't the later 318 cars have a cold start via the Ecu?

For that matter, aren't all the later, 1.3 cars (4 and 6 cylinder) cold started with the Ecu?

Rick
Thanks for the relpys guys, (damn, a poet and he don't even know it) right now, I have no idea what it could be, could be anything I guess.
I will pull the return line and see how much is making it back to the tank, I know the return is not blocked, because I did pull it off and blow down it, and I could hear it bubbling in the tank, so if there is no return, it would have to be the regulator.

Rick, you are correct, the m1.3 system has no cold start valve, cold start is taken care of by the ECU.

Quote

During start-up from cold, injector pulse duration is increased to provide a richer air/fuel mixture and pulse frequency is also
increased.
In addition, the ignition timing is also retarded. Injector frequency & pulse duration and degree of timing retard depend
upon the engine temperature both during start-up and immediately afterwards. If the engine is restarted within one minute of the
first start occurance, less overall fuel is injected to reduce the risk of fuel flooding into the engine.

I must admit though, I fail to see how a dead temp sensor would prevent the car from starting, let us assume, it is dead and is giving a cold signal due to the fact that it can now no longer vary resistance with heat, the car would start as normal, but the problems would only start manifesting as the engine warms up, and the ECU fails to lean the mixture and advance the timing to compensate, thinking the motor is cold.
If it failed on the other side of the spectrum, then I agree a hard start may be on the cards, but that would be due to a lean run as opposed to a flooded condition.
But I guess I have seen stranger things.

Time to rip out all the whizz bang gizmos and slap on a nice set of Weber DCOE 40's :cool2:


----------------------------------------------------------------------------------------------------------------------------------
E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.
Well, I am not familiar with the four cylinders. My thought process was if it did have a cold start injector and said injector was raining gas into the induction system, perhaps that was the answer. If the ECU' handles cold start enrichment via the injectors themselves, then I doubt that is the problem as I have never seen an ECU lose it's program (partially anyways).

I would also assume the injectors will close if a bad connection situation should arise. It sure sounds like he is getting the inital shot of gas to start but after that, everything shuts down. hmmmm

Is the 4 cylinder an interference type engine? Are we absolutely sure the cam timing is correct? Any chance the new part timing marks are
incorrect?
alan



Edited 2 time(s). Last edit at 01/12/2011 11:05PM by alanrw.
Hi Al, the cam timing did haunt me, albeit only briefly, I have checked and double checked, I even tore back into it after I had put the whole shebang back together again, basically, it is not a complicated procedure, there is a little hole in the side of the engine block, in front of the flywheel, one is then required to rotate the engine until you are at TDC (No1 firing and insert an 8mm pin through the hole, which locates in a corresponding hole in the flywheel, thus assuring a good line up at TDC.
The mark on the cam is on the cam gear, which the new cam does not come with, you have to transfer your cam gear onto the new cam, so that mark is correct, as it is the cam gear that has always been in the car, the cam gear locates onto the cam with a key way, so it can only go on one way.
The distributor rotor bolts directly onto the cam gear, so is a very good reference, and with the pin inserted into the flywheel, and everything lined up to TDC, the rotor is directly over the terminal for Cylinder No1 in the distributor cap.
Also, the design of the belt is such, that even if you were a tooth out, it would be blatantly obvious, the teeth on the belt are that far apart.

Al, I think you mis understand, it is not a case of the car getting an initial shot of gas then shutting down, the spark is ever present and the fuel pump runs as it should, it is a case of far too much gas, I believe the only reason it attempts to start, is due to the injectors not having flooded the motor yet, but after firing once or twice, it is flooded and refuses to fire any further.
If you keep cranking away with the accelerator wide open, after about a minute it will fire sporadically and attempt to start. But by then I have chickened out and stopped cranking, to save the starter and let it cool down.

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E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.
I have never never seen a cam mismarked when it comes to timing and my experience is that cam drive components have locator dowels just to prevent mistiming/install issues. I was just trying to think way out of the box on this one..

Well, I guess we are back to the fuel pressure regulator in that case? Perhaps your initial theory that the fuel pressure regulator was in a specific place for a long time and switching out to the new cam changed it's position and it tanked is the answer here.

Guys, where are we on this one?

alan



Edited 1 time(s). Last edit at 01/13/2011 10:07AM by alanrw.
Hi Al, I do understand, and agree with you, I am already thinking so far out the box, I am already starting to suspect the left rear wheel bearing. :eyes:
Unfortunately, getting home at eight every night from lectures has not given me any time to work on it this week, and I have to give lectures this Saturday and Sunday as well, so the first chance I will get is on Monday afternoon after work.
Then I am going to take the intake plenum off and take a real good poke around under there at the injector rail, injectors, regulator, and Temp sender, and find out where that fuel is coming from, that I smelt and saw leaking onto the intake manifold.
What irks me is that I know it is something small, But with all the help of you good and knowledgeable folk, I know I am going to get it fixed soon.
Many, many thanks to all again for your valuable input, I do appreciate every post.

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E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.
Quote
Flyboy
Hi Al, I do understand, and agree with you, I am already thinking so far out the box, I am already starting to suspect the left rear wheel bearing. :eyes:
Unfortunately, getting home at eight every night from lectures has not given me any time to work on it this week, and I have to give lectures this Saturday and Sunday as well, so the first chance I will get is on Monday afternoon after work.
Then I am going to take the intake plenum off and take a real good poke around under there at the injector rail, injectors, regulator, and Temp sender, and find out where that fuel is coming from, that I smelt and saw leaking onto the intake manifold.
What irks me is that I know it is something small, But with all the help of you good and knowledgeable folk, I know I am going to get it fixed soon.
Many, many thanks to all again for your valuable input, I do appreciate every post.

Before you do that, I would seriously make sure that the excess fuel has a return path to the tank via the regulator and return fuel hose. I'm not sure how *best* to test this, but a good start would be to see if anything even comes out of the return hose. Or at the last, that something comes out of the regulator.
No Fuel coming out is guaranteed to cause an increase in fuel to the engine that the ECU can not predict or correct, AND it has the potential to cause the leak you are seeing in the rail. In fact it strikes me that the leak is likely a symptom of the extra fuel in the cylinder, not the cause of it. Fuel leaking out of the rail is not going to cause more fuel in the cylinder, but less. Finding the leak isn't likely to reveal the source of problem.

The severity of the problem I'm describing would have to do with the strength of the fuel pump. Also, don't the 318's use a lower fuel rail pressure but the same fuel pump? This would exaggerate this issue over a similar problem on a 325 if true.

I once managed to pinch my return fuel line while doing some other work (Either the head or a timing belt). and it didn't run so good.

Unless someone can tell me why this theory isn't correct? It's not exactly my first instinct with this problem, but I think we are all past our first, and in some cases our second and third instinct smiling smiley
It's certainly easier than removing the head...

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1989 - E30 - M20 - Manual. Approximately 270,000 miles
2000 - E46 - M52TUB28 - Manual. Approximately 110,000 miles

I agree with you, a blockage in the return would result in a rich condition, due to the fact that even though the fuel introduced into the motor is controlled by the ECU and has nothing to do with fuel pressure, you could compare it to opening a tap (faucet for you guys) half way while blocking the end of the hose pipe with your thumb, open the pipe for a second and close it again, X amount of water will come out of the hose, not open the tap all the way and do it again, far more water comes out due to the increased pressure behind your thumb.
Because fuel pressure regulation is totaly mechanical, the ECU has no way of knowing what the pressure is, and cannot adjust the open time on the injectors to compensate for variations in fuel pressure.
Now, an O2 sensor would pick up the rich condition and the ECU could then compensate, more reactive than a pro active solution, but better than nothing.
However in the case of my car that does not have an O2 sensor, the ECU is blind to the actual mixture condition, it will pick up a lean condition through the knock sensor, but it would have to be lean enough to cause the engine to detonate, but it has no way of seeing an extremly rich mixture, and you sit with a non runner, or a motor that runs like a mule, and a sick one at that, due to a faulty regulator.
So is possible due to a small achilles heel in the system, where the mechanical does not interface with the electrical in any way, unless there is an O2 sensor in the system.

Don't worry, I have no plans of pulling the head off, just the top half or the intake manifold, eight nuts, a throttle cable and an electrical plug.

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E30'S AREN'T BUILT, THEY'RE CAUGHT IN THE WILD!!!



When in doubt, use full throttle,
it may not improve the situation, but it will end the suspence.
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