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Thread: 325i will not hold idle/Not Start

  1. #26
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    Small update, i replaced the new coil with the old one as well as the ISV. Just to make sure i ruled them out, despite both new and old parts showing correct resistances.

    The car still starts and dies, but now when i d/c the vacuum line for the FPR it holds idle AND throttle response is great (it does not surge or struggle for a moment).

    The warmer the car gets, the worse it runs (with the FPR disconnected). Once connected, the car can hold revs via the throttle, but once left to idle it dies.

    So this is surely a fuel pressure issue now, weather is still horrible and can not remove the injectors to test them. But does this sound like a bad FPR?

  2. #27
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    No e30s, again :(
    Dang, man. It sounds like its fpr related
    No e30s again.

  3. #28
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    Quote Originally Posted by superj View Post
    Dang, man. It sounds like its fpr related
    I ordered a new one just incase, but i just thought of something else.

    It could be that the fuel feed and return lines are switched, one of the previous owners changed the fuel lines to SS where one line is noticeably shorter than the other. It maybe that the fuel pump is pushing fuel into rail the via the FPR, hence why it is mechanically fine but acting up. I shall try switching those fuel lines around if i can, since one is shorter than the other.

    I do have some new 8x13 fuel lines (rubber) to swap out, but that is for a later time.

    I did mix up the heater core cooling system hoses, when i put the head back on, it caused intermediate heat as well as a strange "knocking" noise that periodically came and went and rpm/engine dependant.
    Last edited by H.J. 1981; 03-17-2019 at 02:38 PM.

  4. #29
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    No e30s, again :(
    I was wondering that but figured you covered it already
    Last edited by superj; 03-17-2019 at 09:21 PM.
    No e30s again.

  5. #30
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    Swapped the hoses, she cranks but does not even fire or start.

    As i removed the feed line (going to fuel rail) it was filled with fuel. The return line (from the FPR) was empty, so the hoses were indeed hooked up correctly.

    New 3 bar FPR has been ordered, fingers crossed hope that was the cause and it arrives quickly, car has been sitting for 3 weeks now.

  6. #31
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    No e30s, again :(
    are the cps and spark plug sensors swapped in the plugs by the diagnostic port? since they look the same, maybe those two got plugged in to the others wire?
    No e30s again.

  7. #32
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    Quote Originally Posted by superj View Post
    are the cps and spark plug sensors swapped in the plugs by the diagnostic port? since they look the same, maybe those two got plugged in to the others wire?
    They are in the correct order, the car ran just fine for a week, till it slowly started to idle lower and lower to its current state. I can swap them around as well and test that? But one of them is connected upside down to the other.
    Last edited by H.J. 1981; 03-18-2019 at 02:56 PM.

  8. #33
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    No e30s, again :(
    ok. I was just trying to think of things that I had done that caused no start issues in the past.
    No e30s again.

  9. #34
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    Quote Originally Posted by superj View Post
    ok. I was just trying to think of things that I had done that caused no start issues in the past.
    It always started in the past ever since i got it early January, slowly i started noticing how crap of a job the PO did, at least the workshop he took the car to. An Amature DIYer with access to online information and ratchet set can do a much better job than them. Over tightened bolts, nuts, super glue silicon on the oil pan and list goes on.

    All new wheel bearings, springs, dampers, front and rear mounts, engine mounts, transmission mounts, clutch kit etc basically i planned for a "minor" repair, it turned out to be a technical restoration.

    Only a week later, after installing a fresh head gasket (and thoroughly inspecting the head, block etc) did the start become more and more strange every morning. It would idle high, then low, sometimes erratic, sometimes it would die etc. I basically replaced every sensor in the engine bay at this point except the AFM.

    Only the fuel system is left, but i shall swap the CPS and the Impulse sensor connectors around and see what happens.

    After speaking with the PO last week, he assures me that the FPR and Pump were replaced in October 2018, again at that same workshop. I would not be surprised if they turned out to be faulty honestly.
    Last edited by H.J. 1981; 03-19-2019 at 09:07 AM.

  10. #35
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    No e30s, again :(
    I thought of something while reading another thread. check under the fuse box. a buddies 528e started doing a no start and it turned out to be corrosion under the fuse box. we took it to a shop because it was tearing us up and they found it right away because they had seen it previously
    No e30s again.

  11. #36
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    Quote Originally Posted by superj View Post
    I thought of something while reading another thread. check under the fuse box. a buddies 528e started doing a no start and it turned out to be corrosion under the fuse box. we took it to a shop because it was tearing us up and they found it right away because they had seen it previously
    I shall take a look at this tomorrow, i managed to swap the fuel feed and return lines back to how they were. As well as swapped the CPS and impulse sensor connectors, the car refused to start.

    Switched the connectors back, and she fired up. Cold start idle is maybe 550-600 rpms, give it gas and she response very well. Let go of gas, engines dies.

    Seems more and more likely to be FPR related than pump or injectors, i shall order a fuel pressure testing kit off amazon or ebay and test pressure at the pump, at the rail and on the return after FPR.

  12. #37
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    No e30s, again :(
    maybe the throttle plate stop is worn and its not sitting at the correct point anymore? I know its not like a carb where you set it however many mm open but I know it doesn't sit completely closed either.

    worth putting a feeler gage in there and comparing it to the book measurement?
    No e30s again.

  13. #38
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    Quote Originally Posted by superj View Post
    maybe the throttle plate stop is worn and its not sitting at the correct point anymore? I know its not like a carb where you set it however many mm open but I know it doesn't sit completely closed either.

    worth putting a feeler gage in there and comparing it to the book measurement?
    I recall messing about with that screw when installing and adjusting a new TPS, i can double check it but i do not think that is the real cause.

    Remember, slowly over a duration of a week, it was harder and harder to hold idle on cold starts, till now.

  14. #39
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    No e30s, again :(
    Ya, its tough trying to think what the trouble could be, especially since it slowly got worse over a week

  15. #40
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    Are you getting a check engine light?

    The TPS under the throttle needs to be working in order for the STOMP test to work. If you cant get the STOMP test to work - the TPS needs to be removed cleaned and adjusted. The Bentley explains how this is done.

    Once you get the fuel pressure gauge - post the results.

  16. #41
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    Quote Originally Posted by 95BMWIC View Post
    Are you getting a check engine light?

    The TPS under the throttle needs to be working in order for the STOMP test to work. If you cant get the STOMP test to work - the TPS needs to be removed cleaned and adjusted. The Bentley explains how this is done.

    Once you get the fuel pressure gauge - post the results.
    It is an EU spec car, we do not get the STOMP light like the US cars.

    TPS is new, and adjust correctly. It is definitely something with the fuel system. From the FPR, Pump or even injectors. As i said earlier, all sensors with the exception of the AFM are brand new now and have been tested multiple times.

    Disconnecting the FPR vacuum hose greatly improves the idle when cold, no warning lights and PO insists that the FPR and Pump have been replaced in october 2018.

    I did reseal the injectors and replace the small filters when replacing the head gasket, MAYBE an injector or two are clogged or just decided to slowly fail. Either way i shall be taking FP readings tomorrow when the tool arrives.

  17. #42
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    Fuel pressure tester kit as well as a new 3 bar FPR arrived yesterday, so i had a chance to test the fuel system.

    At the fuel feed line (going into the rail) a solid 3 bar fuel pressure when jumping the relay, so we can rule out the fuel pump in this case.

    Since the car would not start/idle correctly it would be difficult to test the FPR per manual, so i replaced it with a brand new one.

    The same issue persists, very low idle on cold start or no start (fires and dies), after revving it and letting go of the throttle it dies. The plate stop is adjusted to 0.400mm feeler gauge (a tad more than the manual 0.015").

    Looks like one or more injectors are clogged or not firing or weak. Unsure where to go from here, i can try to remove the injectors and remove the small filters on the top and see if that works, or i can order the new bosch updated ones (Bosch 0280 156 346).

    Disconnecting the FPR vacuum line increases the idle, which in my head means more air in the system, the engine stabilizes, which means there is probably not enough fuel going (one or more injectors are clogged/defective/not firing correctly as i said earlier).

    If i do replace the injectors, it means that the whole cooling system, ignition system and fuel system got overhauled...so much for a "mini" winter project
    Last edited by H.J. 1981; 03-23-2019 at 07:13 AM.

  18. #43
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    Managed to remove the injectors, gave each injector 12v and the solenoid clicks, meaning they they respond to voltage.

    2-3 injectors looked clogged from the top, meaning a bit of fuel was sitting on top of the filter, maybe just a coincidence unsure.

    Removed all 6 injector filters, reinstalled the rail, checked for leaked and started the car.

    Same as before, it fires but dies almost immediately or stutters/chokes for a couple of seconds (not all cylinders firing) and dies.

    Played with the throttle stop screw, made no difference.

    So, we have 3 bar fuel pressure, new FPR, ignition system is within spec (and renewed) and still fires and dies.

    Looks like it is time to get some new injectors, unless someone can think of something else to test?

    New DME and fuel pump relays as well installed.

  19. #44
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    No e30s, again :(
    I am out of ideas to test

  20. #45
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    My 325i is hard to start when cold. If I pump the accelerator when cranking, it will start right up. Have you tried pumping the accelerator while cranking? Several years ago it used be hard starting when warm. I have no idea what is going on.

  21. #46
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    Quote Originally Posted by aaverhulst View Post
    My 325i is hard to start when cold. If I pump the accelerator when cranking, it will start right up. Have you tried pumping the accelerator while cranking? Several years ago it used be hard starting when warm. I have no idea what is going on.
    It makes no difference, if i pump the pedal/throttle while cranking or not, it is definitely a fueling issue. Since we have flow and pressure from the tank to the engine (and back) the only thing left are the injectors.

    Locally they would charge me €200 to have 6 injectors tested and cleaned, though all i want is testing. If one is faulty, they can not repair it, so i went ahead and ordered the new Bosch injectors (€52.06 each).

    I am just a bit depressed, that the car has been sitting for 4 weeks not running due to this issue, but at least everything was tested properly and/or replaced (ignition and fuel system). Only thing left is the AFM and the DME after the injectors, which after numerous testing i doubt were the cause.

    I still have some work to do, such as rear transmission seal (that bitch o-ring is always leaking, despite Curil K2, i shall try another sealant), exhaust headers leak (broken stud) and replace the cooling hoses (lots of them are swollen). I am suspicious about the brakes, everytime i bleed them some small black particles come out (i suspect the O-ring/seals are being eaten). I have a list of "small" items here and there, just wish the car would fire up and run smoothly first, track season opened and id like to start thrashing it around tracks across Europe.

  22. #47
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    Injectors arrived yesterday and just finished installing them.

    Sadly my excitement was short lived, the car still cranks, fires and dies.

    if i hold the throttle, it idles but it struggles.

    I really do not know what to do next, the whole ignition system and fuel system is new including all the sensors (except AFM).

    Maybe i overlooked something, i shall remove the intake manifold and make sure that bitch tube is seated correctly (got extra seals) and adjust the TPS again to be certain.

    The valve sound loud, i guess that they need adjustment, but i do not think they are so badly out of adjustment that the car can not hold idle.

    So things to do:

    Intake removal and breather tube reseal/check
    Adjust TPS again
    Valve Adjustment

    Anything else?

  23. #48
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    No e30s, again :(
    No. Sadly.
    No e30s again.

  24. #49
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    Quote Originally Posted by superj View Post
    No. Sadly.
    I shall be also checking the fuel flow rate, not just the pressure (it reads 3 bar).

    Will also check the cap and rotor again, since i shall be spending most of my day on the car anyways, will be retracting my steps.

  25. #50
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    Managed to get her up and running finally.

    Since i wanted to check everything from scratch, i started with the basics. We have fuel pressure and spark so i went to check the TPS and Idle stop screw.

    Apparently i was doing it incorrectly this whole time, i was adjusting the stop screw to the back plate. When i re-read the bentley manual, it is designed to "prevent damage between the throttle PLATE and the housing", it is not meant to adjust the idle.

    So i took out the feeler gauge and set the TB plate to housing to around 0.15mm, reason for it the manual indicated 0.0015 inches (0.385mm), when i adjusted the plate anything above 0.15-0.20mm i could never get any continuity from the TPS sensor.

    Regardless after triple checking the TPS and Idle Stop, she fired up and held idle. After a drive around town and some 1/2 and WOT runs, its bang on near perfect, no hesitation or cut off at all. Warm idle is a bit high (i would say it is 900-950 rpms) but i can fine tune that out, since i will be removing the intake manifold to replace the cooling hoses underneath, i shall carefully fine tune the idle.

    Unfortunately when i went to the car wash, i smelled a strong fuel vapour odor. Opened the hood and the feed line (SS from PO) was leaking, luckily i had all my tools in the trunk, as well as the FP tester kit. So i cut the hose a bit and pulled it as far as i could and clamped it. Started and ran fine. I do have new fuel hoses, those will be replaced as well.

    I feel like an idiot, but then again i misunderstood and/or misread the manual. I was planning on replacing all the sensors, ignition system, injectors anyways since it is my DD, so i did not "waste" money, just time.

    I have loads of pics of all my work i have done so far, and i shall start my "build" thread when the time comes for that. For now, maybe a new radiator will be ordered (might as well) and new brake rebuild kits and we can start working on some minor paint/rust issues and go for some mods, oh and new summer wheels mounted on some nice rare RH Mesh wheels!

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