Non starting 318i M40 (fuel issues, I think)
Posted by Flyboy
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I have to wonder if this isn't something as simple as the return line and the input lines being reversed on reassembly
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Ha! That'd be awesome, and something I've done before. If I recall, this results in a complete lack of pressure on the rail side, either because fuel can't flow in reverse in the regulator, or the return line back to the tank prevents any pressure from building. I don't think it would cause a flooding condition. Of course, we are still assuming it is flooding, correct? It's not like puddles of gas have been found in the cylinders? ----------------------------------------------------------------------------------- 1989 - E30 - M20 - Manual. Approximately 270,000 miles 2000 - E46 - M52TUB28 - Manual. Approximately 110,000 miles 
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No matter what it ends up being; I'm certain it will be something that did not go back in the reverse order of disassembly
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Here's hoping 
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Hi All, a few answers to some good questions;
Al, you are right in saying the return is clear, from where the flexible hose connects to the metal pipe from the regulator anyway. If the plugs were pulled and the motor spun, I doubt the fuel would come "gushing" out, but I do believe it will be able to be seen as physical liquid droplets being sprayed out, and just for giggles I will do the exersise and let us see what we get. Was running like a watch, except.........................there was a smell of fuel every now and again, normally at start up, that was not there before...hhhmmm???
Peter, I wish so too, unfortunately, it is not, firstly, the pipes were never disconnected during the work, there is no need, guys, the head was never removed, on the M40 motor, the cam is held in place by cam caps, that bolt over the journals, unlike some other BMW motors where the cam is housed in solid posts that have been milled out and head removal is required to slide the cam out the back. All that is required to be removed to get the cam out is the front timing covers and the tappet (valve) cover. The little M40 motor really is one of BMW's finest offerings, well thought out, and an awesome little motor. Also, I did pull the supply line to varify flow when I susspected the pump in the beginning, and flow was good and strong, also pulled the return, to blow down the line to confirm it was not blocked, so I know which line is which, feed goes to the rail, and return comes off the regulator.
Without question, it is flooding. Although puddles of gas have not been found in the cylinders, if I crank to start, then pull a plug, it is soaked in fuel, like you have dunked it into a container of raw, liquid fuel. Also, if, while cranking, you hold the throttle wide open, after a while she will sporadicaly start to fire, a classic symptom of a flooded motor. ---------------------------------------------------------------------------------------------------------------------------------- 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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Hi Rick, no I don't believe the cam is OEM, although who knows, the cam might be made by some outside company for and behalf of BMW, like a lot of the parts are, the motor manufactures have just become assembly plants. It may be the same crowd that make the cams for BMW, just not in the BMW box, or not?
The cam cost me R615 versus the agents price of ...........................wait for it........................................wait for it..............................wait for it..................R5 500.00, and that is not a typo. I aso replaced the rockers and the hydraulic lifters, so the whole valve train is new, it would have been foolish to put a new cam onto old, worn rockers, and of course a new belt. I see where this is going, but yes the cam is the same spec, I checked it properly against the old one before installing, as well as the rockers and lifters. I will post a few pics up later when I get to work. ---------------------------------------------------------------------------------------------------------------------------------- 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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Herewith a few pics as promised.
 ---------------------------------------------------------------------------------------------------------------------------------- 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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Hi Rick, in your dollars we would be talking; R615 = $90, R5 500 = $808, no idea how that would compare with what you would pay for a cam over there, but I guess we pay more.
There is a spray bar that runs above the cam with little holes that spray oil onto the lobes, from age, a couple of the holes clogged up with carbon, so, it would be a good Idea to pull the spray bar off every 100 000 or so and just check them and poke them open, I ran a drill through them and opened them up a little more, so no, no real issues, just a bit of preventative maintenance is all that is required. Now that you mention it, no, I did not pump up the lifters, they seemed pretty solid, could not compress them by hand, and they were full of oil in their packaging, so I assumed they were fine, and once the oil pressure came up, that would pump them up as they needed to be. although I must admit, anything above idle, the valve lash is noisier than I would have expected with all new parts. The motor ran great, like a watch, never missed a beat, steady idle spot on 750rpm, pulled smooth, although I guess the power would have been down, with the valves hardly opening, It was not obviously noticeable, she would pull strong in top gear from as low as 1500rpm. But then again, I don't race my car or it's engine, I drive right around the speed limit, but then again, it's not that sort of car (for racing). ---------------------------------------------------------------------------------------------------------------------------------- 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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Hi Rick/Alan
Indeed, I concur with what you say, and over the years it has always been standard practice to bleed the lifters before installing, normally by submersing them in a container of oil and pumping them in and out until they firmed up and became solid, then drop them into the motor. But these could not be pumped by hand, and they were the same length out of the box as the old lifters, so assumed they just went straight in, although the thought did niggle in the back of my mind. Upon tightening down the cam, there was resistance against the valve springs, and when I spun the motor, first by hand and then with the starter to check everything and build oil pressure, the valves do open and close, so it is not like the lifters are flat and not opening the valves. That said, the motor is dead quiet at idle, but noisier than I would imagine it should be, once it starts to rev up. No, during the short test drive, there was no real power, the car was flat and lacked power badly. OK, off to quickly rip off that intake plenum and then off to go lecture, will check in tonight when I get home again. ---------------------------------------------------------------------------------------------------------------------------------- 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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Hi Guys
Here is what I have, took the intake plenum off, all looks to be in order under there, no external fuel leaks at all while cranking.???????????? Weird Now here it gets even more weird, if I disconnect the return line and and bridge out the fuel pump relay so the fuel pump is running with the ignition on run, then there is good return flow, if I suck on the vacuum line from the regulator, then the rate of return flow increases and returns to normal when I release the vacuum. So, as I see it, the regulator is working as it should, and can be removed from the trouble shooting equation. Now the weird part, if I plug the fuel pump relay back in and crank the motor over with the starter motor, there is no return flow at all??????????????????????? The pump is working and delivering fuel to the rail, that, I have established. The only thing I can think, is that with the engine not cranking over and the relay bridged, the injectors are all closed, as the ECU has not yet received signal from the crank angle sensor to start firing the injectors yet, so all the fuel delivered to the rail is returned. When cranking the motor, the ECU gets a signal from the crank angle sensor, telling it the motor is turning over, and the ECU starts to fire the injectors, so, is it not possible that the injectors are staying open far longer that they should and thus the fuel is being delivered to the motor and thus no return, causing the extremely rich, flooded condition. So the question is, what is confusing the ECU??? Comments? does it make sense, or have I got it all cocked up here? ---------------------------------------------------------------------------------------------------------------------------------- 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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Okay, what about a different approach. What if the electrical system is royally F*cked?
I don't mean component level logic, I mean the getting power to different parts of the system. What if, perhaps due to something you did, perhaps due to dumb luck, the car can not produce a reliable and strong spark? This would make starting the car near impossible, and would of course make it run like crap even if you did get it started. Now, as for the fuel deliver, here is my only guess based on a few assumptions that I'll list: 1. With every injector wide open, the pump should still be able to exceed the required fuel pressure. 2. When attempting to start the car, a lack of fuel in the return line means that the fuel pressure is suboptimal. If #1 is correct, than there is nothing the ECU can do to drop the pressure that low. My guess then is that the Starter is drawing enough current that the fuel pump is actually effected. The efficiency of the fuel pump goes down, and is suddenly unable to supply the correct amount of fuel. If the voltage of the whole system dropped, then the spark plugs would not fire correctly. Like I mentioned earlier, I had a bad battery that dropped to 9-10 volts only when the Starter engaged. This was not enough to give a consistent and strong spark, even though pulling a plug revealed a visible spark. Have you measured the voltage of the system before starting, during the act of starting, and after the engine has started and the alternator is providing power? Anything that effected the spark would give the appearance of flooding, even if the quantity of fuel to the engine was low as well. It could be that you lost a bunch of your grounds. You are so caught up with the car not starting and not running well that you aren't noticing all the other weird stuff that usually happens when a ground wire is no longer grounded. Is that possible? A slightly different approach now: If, for the sake of argument, we assume the engine is not flooding, then I have an answer that solves the fuel rail mystery, the lack of a consistent start, and an engine with no power. A totally crappy thing about the fuel pump, at least in my own car, it doesn't have to have the negative lead attached in order to run. The Pump is actually grounded enough to the body that you can supply a positive voltage and it'll run. However it won't run great. The car will seriously lean out as soon as you start making demands on the engine (and thus the pump). On my own car, it was grounded enough that the car ran pretty okay, it was just missing about 80hp up high. What if your fuel pump is even less grounded to the car than mine, and really does require the ground lead on the plug to have a solid connection? In my car, the ground wire was actually loose at the plug, AND about 12 inches away from the plug out of site. You said you messed with the fuel pump, what if the ground wire became severed? What if your pump is grounded just enough to allow the current necessary to supply pressure to a fuel rail that has no holes. However if under starting conditions the injectors are doing their thing, the pump just doesn't have the oomph required to provide a consistent pressure, and thus a predictable quantity of fuel to the cylinders? This does not explain flooding, but it would explain everything else I believe. It's also a mystery that plagued my car for over a year. I assumed the pump was okay just because it ran :\ ----------------------------------------------------------------------------------- 1989 - E30 - M20 - Manual. Approximately 270,000 miles 2000 - E46 - M52TUB28 - Manual. Approximately 110,000 miles Edited 1 time(s). Last edit at 01/15/2011 03:36PM by Earendil. |
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It's all good Rick, your and everyone Else's input is highly appreciated.
You may not think it is much, but it is, trust me, it has helped to eliminate a lot of things. ---------------------------------------------------------------------------------------------------------------------------------- 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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Hi all
Thanks for the replys, I think we can rule the battery out for now, as you can imagine, all the tinkering did run the bettery down, and I have mostly been starting and cranking while jumped off the better half's Renault Scenic, I did also run a multimeter across the battery on day one, and got a good 12.5V with the car not running and the day I did get it to start, I was reading 14V across the battery. Remember, I did take it for a short test run, the one day, so the system would have been getting full juice with the alternator running. ---------------------------------------------------------------------------------------------------------------------------------- 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. |
Okay, that's good. Here are two more multi-meter tests that you should try so we can check them off the list. First Test: Check the voltage when you're attempting to start the car. I don't think it should drop below 12v. When I had my issue, the car read 12+ when sitting there, 14V when running, 9v when attempting to start. It couldn't handle the currant draw. Second test: Bridge the fuel pump like you have before, unplug the pump, and use the multi meter to see what the voltage is across the plug. Wiggle that plug around and see if it ever drops. ----------------------------------------------------------------------------------- 1989 - E30 - M20 - Manual. Approximately 270,000 miles 2000 - E46 - M52TUB28 - Manual. Approximately 110,000 miles
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Alright, broke down today or rather, managed to track down and bought a new Temp sensor, (yes, yes, don't worry, it is a genuine Bosch unit, not some Chinese knock off) and a fuel pressure gauge.
I know, I could have pulled the temp sender and tested it, but I thought, what the hell, while I am in there and it is relatively easy to get to, let me replace it, because once I put everything back on, it is impossible to get to. At least then I know it is out of the equation and I know it is good for the next 10 years. And I have to know what the fuel pressure is, and why, then I can eliminate it or find out why it is out of spec, which should solve the problem. I am never going to mount the gauge in my car, so at least I can add another piece of equipment to my workshop. Of course, as luck would have it, it is bloody raining tonight, so no work on the car.  ---------------------------------------------------------------------------------------------------------------------------------- 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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Just wondering how the problem child is making out
I caught a break today with one of my bikes, just fouled a plug from too much seafoam....  thank you Suzuki Gods
Rick |
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Hi Rick
Sorry, nothing much to update, just have not had the time to work on it. When I got home last night, I quickly dived in to replace the temp sender, which chewed up a bunch of precious daylight, I get home at 5:30 and it is dark by 7:00 now. Anyway, reason, the only way to get to the thing is with a 19mm tube socket, which I do not have, so I figured, since I won't be using the old one again, I would just break off the top plastic part with the contacts, I grabbed it in an adjustable pliers, the thing literally came apart as I grabbed it, it was rotten. So the new one is in (hope it seals.) Then I rigged up the fuel pressure gauge to check the great mystery fuel pressure, but I need to fabricate a new T piece, the one that came with the gauge is pathetic, the little ends that push into the fuel pipe are way too small, I had to put thinner pipe over them and then the fuel pipe over that, when I bridged out the relay and ran the duel pump, there was fuel spraying out everywhere, from where the pipe connects onto the T piece, so that ain't going to work, anyway, then it started raining, so I called it quits for the day, with another 45mins of daylight wasted. But it looks promising, when I ran the pump, the gauge was climbing through 2.5 bar, then the fuel started squirting out and I stopped the pump. Book says 3 bar. So, will try and get a proper T piece fabricated up today and test the fuel pressure tonight. ---------------------------------------------------------------------------------------------------------------------------------- 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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