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

Posted by Flyboy 
Ok, I mentioned in my canbelt thread that the new cam, rockers and lifters went in today :biggrin:
But when it came time to start...nada.
I thought I would move this part of the topic to its own thread, for the benifit of those who are having similar issues and won't really look at a cam change thread.

Alright, so on start up, the motor fires once or twice, then nada, nothing, bugger all, just cranks over with no attempt to fire.
I check spark, good, so it must be fuel.
So this is what I have so far;
If I let the car stand a while, and then try start, it will fire once or twice then just crank, no attempt to fire.
If I throw a bit of fuel into the intake pipe between the throttle body and airflow meter, she fires right up, and then dies as the fuel exhausted.
Changed the fuel pump relay with the horn relay which I know is good, I put it in 2 weeks ago.
If I pull the supply line to the injector rail off and turn the key to run, no fuel delivery until the motor starts cranking, (Dave says this is normal, so not too worried)
If I pull the relay out and bridge pins 30 and 87b (in effect bypassing the relay and supplying direct current) the pump ran the first time, and straight afterwards the car started and ran for about 10 sec then died.(bridge removed and relay in place)
I have since not been able to get the pump to run again by bridging out the relay pin 30 to pin 87b.
The filter is not blocked (checked) if I crank the engine with delivery line removed, it pumps plenty fuel out (after the filter)

I replaced the in tank fuel pump about 4 years ago with a good second hand one when it gave up the ghost.
Any thoughts, I am fearing that the pump is on the way out again, last time it died, the symptoms were the same, but Dave thinks I may have another issue, and that scares me.
And I need to get this car running asap, as I have plenty commitments from tomorrow, and am not going to have time to work on it, from tomorrow I am teaching weekends Saturday and Sunday and weeknights until 9pm, and still my regular day job, and without the car I will not be able to meet the commitments.
Please guys, any thoughts, I am desperate.

----------------------------------------------------------------------------------------------------------------------------------
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 01/08/2011 01:20PM by Dave_G.
Is the electrical connector to your airflow meter plugged in?

I once spent most of an hour trying to diagnose a similar non-starting issue only to discover I had forgotten to plug my airflow meter back in.



Edited 1 time(s). Last edit at 01/08/2011 01:21PM by Dave_G.
Hi Ferdi, it is, I even clipped it loose and re seated it, just because, didn't know what else to do, I pulled the hood, radiator, fan timing cover, dizzy and tappet cover to do the cam change.
The only two things electrical I touched were the temp sensor in the side of the radiator, and cleaned the pickup face of the position sensor while the pulley was off. Jus wiped the oil and grime off with a rag, did not remove or unplug it.

----------------------------------------------------------------------------------------------------------------------------------
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 01/08/2011 01:21PM by Dave_G.
You say when you jumped the fuel relay the car still wouldn't run? Jumping the relay is the same as hard wiring the fuel pump to the battery. The next thing I would do is to get a test light on the fuel pump connector and make sure you are getting voltage to it. If you are and still no fuel, I would be verry suspicious of the fuel pump. But it seems to run when in the key start position not key run position?

alan



Edited 2 time(s). Last edit at 01/08/2011 01:22PM by Dave_G.
That is right Al, I jumped the pins and heard it whizzing away, so I thought, ok, seems to work fine, I let it run (the pump) for a good 10 secs or so, then removed the wire and put the relay back in. went to start the car and it fired right up, ran for about 5 secs then died, then it didn't want to know.
So I pulled the relay again and jumped the two pins, but this time the pump would not run at all, tried it 4 or 5 times, but no joy, could not get the pump to run again.

I will check the connectors at the pump tomorrow morning when it gets light, bit dark out there now, and the garage is full of the motorbike resoration, so no space in there.

Yes, before I had a dig into the Bently and found the "jump the relay" trick, I pulled the flexible rubber hose off the injector rail and "thought" that if I turn the key to run, I should get fuel coming out, as I thought the pump was hot on run, to pressurise the system for starting.
But on urning the key to run, I go no fuel flow, but as I cranked the motor, fuel came out, like a mechanical pump would, But Dave says this is normal, there is no flow until the starter in energised. I must admit I only did it twice, so if it is intermitant, I may have got lucky twice, but that still leaves me wondering why the car did not start. That is how I know the filter is not blocked.

----------------------------------------------------------------------------------------------------------------------------------
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 01/08/2011 01:22PM by Dave_G.
So with further investigation it seems as if there is no power getting to the pump, pulled the back seat and the access panel, checked the connections, all good.
I then put the multi meter across the connections, while cranking, and no voltage reading, so I then went one step further and removed the relay and bridged bus 87 and 30, in effect hot wiring the pump straight to the battery, still no voltage reading across the connections.
Now according to the wiring diagram, it seems simple enough, the power goes from the battery to the relay, to fuse 11 and to the pump, so not something I could have disturbed doing the cam replacement.

----------------------------------------------------------------------------------------------------------------------------------
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 01/08/2011 01:22PM by Dave_G.
Well, then logic would suggest you need to check the connection between the battery and the relay socket? Something was disturbed, but interestingly, it runs for a few seconds at crank so juice is getting to the relay, no, at least momentarily?

alan
rkj
Quote
Flyboy
So with further investigation it seems as if there is no power getting to the pump, pulled the back seat and the access panel, checked the connections, all good.
I then put the multi meter across the connections, while cranking, and no voltage reading, so I then went one step further and removed the relay and bridged bus 87 and 30, in effect hot wiring the pump straight to the battery, still no voltage reading across the connections.
Now according to the wiring diagram, it seems simple enough, the power goes from the battery to the relay, to fuse 11 and to the pump, so not something I could have disturbed doing the cam replacement.

You need to start at the pump and work backwards, checking every connection/junction along the way. It's electrical, take nothing for granted.
Here is the update guys.
Fitted brand new fuel pump relay, all working fine now, when cranking over, pump runs and supplies fuel.
That is the problem, it is supplying too much fuel, the reason the car won't start is that it is flooding.
I went all the way back to basics and pulled each plug to check for spark, all have good strong spark.
But I noticed that if I cranked the engine over and then pull a plug, it is soaked in fuel, so there is fuel delivery, just too much of it.
Question is, what would control that.
Checked airflow meter flap, it is free and smooth.
Pulled the plug off the cold start valve, no difference, still floods.
If I disconnect the pump then it will start, use the fuel and die.
Disconnected the battery for about half an hour to see if the ECU would reset to default or something (don't know how clever that was?) no change.
Stripped the whole front down to the belt again and double checked my cam timing, it is spot on.
Checked and reseated all plugs around the injection system.
Any Ideas guys, I am desperate, and totally at loss.

----------------------------------------------------------------------------------------------------------------------------------
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 sounds to me like you are losing spark shortly after it firs up. Check to see if the plugs are wet after it runs a bit then dies; that will confirm if the spark is quitting.
If that is the case, I would double check the main relay...jumpering it would eliminate it or confirm it as the cause.
Hi Peter, thanks for the input, I am at my wits end, I can't take it anymore, if it ain't one thing, it's another, spark is good and does not quit, I put a plug into each plug wire in turn and cranked the motor over and the spark was strong and consistent, also, if I look at the wiring diagram for the fuel pump, the fuel pump relay is connected and activated through the main relay, so if the main relay was no good, then surely the fuel pump relay would not close and power the pump?
It is definitely getting way too much fuel, if I crank it for 15 seconds or so, then pull a plug, it is soaked in fuel, like you dipped it into a cup of raw fuel, and you can smell the strong smell of fuel in the air.
Going through the threads, and from what I have been able to find in the manuals, it looks like the coolant sensor is a big culprit of fuel air mixture problems, rich running and high CO levels.
The manuals show two temp sensors on the side of the head of the M40 below the intake manifold, mine does not have that, but does have one in the side of the radiator with 3 wires on it, could that be it?
My car does not have and never came out with a Catalytic converter or an O2 sensor.
While I was working on the car, doing the cam swap I did leave the car on run for about 8 hours to listen to the radio while I worked, do you think that could have damaged anything?
What about resetting the ECU, I have read somewhere that it develops a map to your car, maybe something has sent it screwy, and it is just chucking too much fuel now, can it be reset to a default profile?

Sorry for all the questions guys, but I have poured through the manuals, Haynes, Bentley and the big BMW one that was available here for download a year or so ago, and I just am not finding any answers and I am just at my wits end, I had to cancel a class today that was worth a thousand bucks to me, because I had to try and get this piece of sh*t running, and from tomorrow I have to give class every night after work until 9pm, so it leaves me no time to work on this thing.
And you guys are the only people I can turn to who know what they are talking about, I am beyond desperate now.

----------------------------------------------------------------------------------------------------------------------------------
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 Peter, thanks for the input, I am at my wits end, I can't take it anymore, if it ain't one thing, it's another, spark is good and does not quit, I put a plug into each plug wire in turn and cranked the motor over and the spark was strong and consistent, also, if I look at the wiring diagram for the fuel pump, the fuel pump relay is connected and activated through the main relay, so if the main relay was no good, then surely the fuel pump relay would not close and power the pump?
It is definitely getting way too much fuel, if I crank it for 15 seconds or so, then pull a plug, it is soaked in fuel, like you dipped it into a cup of raw fuel, and you can smell the strong smell of fuel in the air.
Going through the threads, and from what I have been able to find in the manuals, it looks like the coolant sensor is a big culprit of fuel air mixture problems, rich running and high CO levels.
The manuals show two temp sensors on the side of the head of the M40 below the intake manifold, mine does not have that, but does have one in the side of the radiator with 3 wires on it, could that be it?
My car does not have and never came out with a Catalytic converter or an O2 sensor.
While I was working on the car, doing the cam swap I did leave the car on run for about 8 hours to listen to the radio while I worked, do you think that could have damaged anything?
What about resetting the ECU, I have read somewhere that it develops a map to your car, maybe something has sent it screwy, and it is just chucking too much fuel now, can it be reset to a default profile?

Sorry for all the questions guys, but I have poured through the manuals, Haynes, Bentley and the big BMW one that was available here for download a year or so ago, and I just am not finding any answers and I am just at my wits end, I had to cancel a class today that was worth a thousand bucks to me, because I had to try and get this piece of sh*t running, and from tomorrow I have to give class every night after work until 9pm, so it leaves me no time to work on this thing.
And you guys are the only people I can turn to who know what they are talking about, I am beyond desperate now.

Flyboy, sorry you're not having much luck. I know little of the four bangers but if the fuel is coming in to the motor too heavy shouldn't there be a regulator in the system?

Rick
I always thought fuel injector pulse (the amount of time the injector sprayed fuel) was an ECU function. I am not all that surprised a cold engine would have wet plugs after a no start condition. My understanding is that the fuel pump shuts down in a no start situation. At this point, I would hard wire the fuel pump and try to start. But test lights are your friends here.

Does the ecu get a run condition from the crank position sensor? If the ecu is not getting that signal, it thinks the engine hasn't caught and will shut down the fuel pump, no?

alan
Hi Rick/Alan, yes there is a regulator, well a fuel pressure regulator, the little canister looking thing with the vacum hose attached to the intake manifold, checked the connections, they are good and secure.

Al, that is the problem, the pump does not switch off, as long as you keep cranking, the pump keeps running, I know because I got the other half to crank the motor while I was in the back of the car with the back seat and inspection plate out, and I could hear the pump whizzing away merrily inside the tank, and as long as she was cranking, the pump was running.
Does this sound like a fried ECU maybe? :giveup:

----------------------------------------------------------------------------------------------------------------------------------
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, before I ruled out the ecu, I would want to know how the main relay is triggered. It could very well be a sensor from the motor to the ecu is at fault here. Need to see a schematic.

alan
Okay, I'm trying to follow the current conditions. The car has both spark and an abundance of gas? And both are present in the cylinder? Also, sometimes it starts but does right away?

If the answer to the second question is "no, it never starts", check the voltage on the battery. I had a slow starting condition(crank 5-8 times) that was cured by replacing the faulty battery. Everything looked like it was "okay" but the battery just couldn't provide the juice needed for a strong consistent spark. Obviously if the car starts fully and then dies, it isn't the battery. I figured mine out by putting a volt meter on the battery and having someone try and start it. It was reading an okay voltage when just sitting there, but under start conditions the voltage dropped to around 9v!

If it does sometimes start and stop, Can you test the fuel pressure? It sounds like it could be a plugged fuel filter. Those suckers will sometimes let the car start, but don't allow the enough gas through to keep her running.

I some how don't think it's the ECU. Most electronics fail catastrophically. They don't usually decide to just start doing their math wrong smiling smiley
Also, most electronics of this nature dona sort of error checking(or should) wherein if they sense an internal fault, they shut down for fear of causing damage. The ECU for the antilock brakes for sure functions this way. Hopefully the main ECU does too.

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

Quote
alanrw
Does the ecu get a run condition from the crank position sensor? If the ecu is not getting that signal, it thinks the engine hasn't caught and will shut down the fuel pump, no?

alan

The crank position sensor is used on start up only. The ECU will not provide a spark until it gets a reading. However, once it has, and the engine fires off once, the CPS is no longer used. If the car has spark at all, it probably isn't the CPS. If the car dies after starting it Really isn't the CPS.

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

Quote
Earendil
The crank position sensor is used on start up only. The ECU will not provide a spark until it gets a reading. However, once it has, and the engine fires off once, the CPS is no longer used. If the car has spark at all, it probably isn't the CPS. If the car dies after starting it Really isn't the CPS.
Are you sure about this? I'm no expert on the whole Motronic wizardry, but I do know that when my M20 was experiencing odd missing and stumbling at high speeds after more than an hour of driving, it ended up being caused by a faulty CPS. It seems to me that the ECU would need to know the location of the pistons at all times, not just when starting.

__________
Dave
'91 325iX
Yes, the CPS is continuously read by the ECU. Without that signal, the ECU wouldn't have a hope in hell of controlling the ignition timing or the injector firing.
rkj
Quote
Dave_G
Quote
Earendil
The crank position sensor is used on start up only. The ECU will not provide a spark until it gets a reading. However, once it has, and the engine fires off once, the CPS is no longer used. If the car has spark at all, it probably isn't the CPS. If the car dies after starting it Really isn't the CPS.
Are you sure about this? I'm no expert on the whole Motronic wizardry, but I do know that when my M20 was experiencing odd missing and stumbling at high speeds after more than an hour of driving, it ended up being caused by a faulty CPS. It seems to me that the ECU would need to know the location of the pistons at all times, not just when starting.

I was going to suggest the same thing, I'm no expert on the Motronic either but I have followed the E30 forum for some time. Thanks Dave

Rick
Hi Guys, its 3am here, and I am in front of PC, can't sleep, this is driving me insane, I even have a killer headache, Lord knows how I am going to make it through this day.

Ok, update, I have rechecked everyhting, nothing seems out of place.
I tried a little experiment, I got the better half to crank, while I was in the back with the seat and access cover out, so I could get to the tank, or more importantly the pump terminals.
I disconnected the wire supplying power to the pump and got her to crank the car, it would start, run for 2-3 secs, until the fuel in the rail was exhuasted then die.
You could hear and smell it was running very rich, if I hooked up the power terminal so that the pump runs, it would not start.
If I diconnected the power from the pump and got her to start it, and then reconnected the power while it was running, it would die.
So I am convinced it is flooding out and getting too much fuel........................but why?

----------------------------------------------------------------------------------------------------------------------------------
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, perhaps I'm wrong. 3 of the most experienced e30 guys just went against me. And I won't claim to have studied any sort of schematic, that lite tid bit came from experience. I once had a failing/dirty CPS that disabled the car from starting, but it never had trouble driving for hours on end. But you could literally turn the car off and try and restart it and it would fail. This went on formonths with no change in symptoms until I Danes off the CPS and readjusted it to the proper distance. No more starting issues.

It also seems to me that the car can control timing just fine without it, since it only gives the position of a single cylinder, correct? Somehow it knows when to fire the other 5 without getting a signal from the CPS.

Now y'all have me confused. I'm gonna go start my car to tomorrow and yank the CPS out and see what happens tongue sticking out smiley
For now, forget everything I've said about the CPS.

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

Quote
Flyboy
Hi Guys, its 3am here, and I am in front of PC, can't sleep, this is driving me insane, I even have a killer headache, Lord knows how I am going to make it through this day.

Ok, update, I have rechecked everyhting, nothing seems out of place.
I tried a little experiment, I got the better half to crank, while I was in the back with the seat and access cover out, so I could get to the tank, or more importantly the pump terminals.
I disconnected the wire supplying power to the pump and got her to crank the car, it would start, run for 2-3 secs, until the fuel in the rail was exhuasted then die.
You could hear and smell it was running very rich, if I hooked up the power terminal so that the pump runs, it would not start.
If I diconnected the power from the pump and got her to start it, and then reconnected the power while it was running, it would die.
So I am convinced it is flooding out and getting too much fuel........................but why?

Pressure regulator shot, or coolant temp is whacked out. Both would cause the engine to flood in a way that the ECU could not compensate for or even realize was happening.
You can take a multi meter to the sensor. Youll need a fuel pressure gauge and somebits of hose to test the regulator.

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

But get some sleep first!!!

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

And sorry about the typos. Computer is down and all communication is via my iPhone. Typing AND proof reading is difficult at best for multi paragraph posts sad smiley

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

I hear you, and the only things I can think of are the temp sender, as I have heard about how they are a cause of great grief when it comes to fuel delivery, or the pressure regulator, strange thing is that it was running sweetly when I drove it home on Friday afternoon, it always starts first kick. I parked it, and then after working on it on Saturday..........nada.
The little vacum pipe on the pressure regulator is secure and leak free.

The manuals all show two temp sensors on the side of the head, below the intake manifold, one for the gauge and one for the ECU, mine does not have that, mine has got one at the thermostat with a single wire, for the gauge I assume, and one in the side of the radiator with three wires, I assume that is for the ECU, or for the aux fan, I dont know, there is a sensor on the head with two wires, it has a blue connector, could that be for the ECU.

----------------------------------------------------------------------------------------------------------------------------------
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
there is a sensor on the head with two wires, it has a blue connector, could that be for the ECU.
I've never actually seen an M40 in the wild, but based on the M20, I'm going to guess that that's the one. Blue connector, two wires sounds just like the ECU coolant temp sensor on the M20.

__________
Dave
'91 325iX
OK, he has ruled out fuel pump as he said he directly wired it to battery voltage with the same result. Can there be a condition where the injectors will fire continuously which would explain the flooding out? But I am hard pressed to believe you can flood out an engine in a couple of seconds with the injectors firing continously. We really need a schematic and troubleshooting guide. If the cps is required for timing, then it needs to be checked.

alan
rkj
Quote
Flyboy
I hear you, and the only things I can think of are the temp sender, as I have heard about how they are a cause of great grief when it comes to fuel delivery, or the pressure regulator, strange thing is that it was running sweetly when I drove it home on Friday afternoon, it always starts first kick. I parked it, and then after working on it on Saturday..........nada.
The little vacum pipe on the pressure regulator is secure and leak free.

The manuals all show two temp sensors on the side of the head, below the intake manifold, one for the gauge and one for the ECU, mine does not have that, mine has got one at the thermostat with a single wire, for the gauge I assume, and one in the side of the radiator with three wires, I assume that is for the ECU, or for the aux fan, I dont know, there is a sensor on the head with two wires, it has a blue connector, could that be for the ECU.

I'm pretty sure, even though your car is laid out differently than USA cars, that sensor in the radiator is for the aux fan in front of the ac condenser/radiator. Do the books indicate what that blue connector sensor is for (the ecu sounds right to me), but again, I don't know your car very well if at all.

I can't stop trying to help though.... Sometimes a break helps to figure things out- may the force be with you~
rkj
Quote
alanrw
OK, he has ruled out fuel pump as he said he directly wired it to battery voltage with the same result. Can there be a condition where the injectors will fire continuously which would explain the flooding out? But I am hard pressed to believe you can flood out an engine in a couple of seconds with the injectors firing continously. We really need a schematic and troubleshooting guide. If the cps is required for timing, then it needs to be checked.

alan

The whole thing seems so odd to begin with; Flyboy didn't have any of these problems to start with. I keep on thinking he knocked something loose while he was working on things... hate it when that happens.
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