Reply to Thread

Post a reply to the thread: Fuel pump diagnosis and full test routine.

Your Message

Click here to log in

Please correctly re-type the phrase f o o t d o c t o r in the form box. Re-type it without the extra spaces and put the one space where it should be. We apologize for having to do this but this silliness helps slow the spammers.


Additional Options


Topic Review (Newest First)

  • 05-25-2010, 01:19 PM

    Any resolve??? Did the car blow up? Still looking

    for answers? Let us know, we are hanging here...
  • 05-18-2010, 09:27 PM

    So... what happened with this?

  • 05-15-2010, 07:31 PM
    Mr. Mental

    Re: CPS sensor 115 K Ohm

    ok, you do know that the other CPS plug is lower right... yes?

    Very easy to confuse those connections.
  • 05-15-2010, 03:56 PM

    Re: CPS sensor 115 K Ohm

    You have the scale on your meter on the wrong setting. Go to the link posted above and look for page 1210.6 B-6 in the diagnostic manual mentioned. This will help you keep all the various signal paths straight and greatly aid in your diagnostics. A methodical approach is MUCH easier than trying to kill all the rats at once.
  • 05-14-2010, 04:49 PM

    Just replace them both - It isn't worth the effort

    just to "try" them out...
  • 05-14-2010, 12:53 PM

    Can I swap these over to check if the fault follow

    Going to investigate with my torch (flashlight ... not oxy acetylene)

  • 05-14-2010, 12:51 PM

    CPS sensor 115 K Ohm

    Have I found it? Top left plug (CPS) is showing 115K ohm

    The other is about 580 K Ohms which I believe is the specified.

    Strange thing is that it does indeed seem to be giving 2 Volts AC when cranking.

    Have I got it guys?

    (Before anyone goes mental local dealer is ordering my CEL light!!!)
  • 05-13-2010, 09:56 PM

    Re: Fuel pump diagnosis and full test routine.

    Have you done a plug check to assure none are partly fouled,and what plugs did you use when replaced.You replaced fuel lines,go thru and retighten hose clamps.Mine leaked such small amounts there were no drips,no gas smell,but it made a differance.Don't forget the hoses in the tank on the pumps,mine was split and hard to see.Did you put gauges on to check fuel pressure ?Check the "gap" of the CPS's(may as well replace when you are there).Remove "crank vent" lines from intake and plug to make sure it not sucking unmetered air thru valves and check the rubber bends between MAF's and DK's for hairline cracks(leaks),also check the end caps on the intakes for leaks.Good luck
  • 05-13-2010, 01:37 PM

    Re: DK motors?

    did you check the engine temp sensors yet?
    they are three sensors on the back of the engine.
    they all need to finction right for the DME to send the right fuel mixture.
    than if that is checked
    look into new fuel pumps.
    maybe you like to eliminate the intank fuel pumps completely and get walbro external fuel pumps.
  • 05-13-2010, 09:45 AM

    Re: Unless your car was built in 1989, the STOMP test

    OK thanks I'll pop it in PRONTO!

    appreciate the kick up jacksie I needed motivating again. TA Nathan
  • 05-12-2010, 12:36 PM

    also, just take off the rubber intake boot...

    while you are looking into the dk motors, watching the butterfly valves. have a second person turn ignition on to position 2. do both the butterfly valves move the same ?
    have them step on the gas pedal / then release the pedal, while you are watching the butterfly valves. Do both the valves open to the same distance and do they go back to where they started.(watch for opening and closing speed) shut off ignition do the butterfly valves close? if the dk's are opening and closing- i'd rule them out.
    if they are slow.. clean them (ynot posted a dk rebuild with pictures)

    The dme issue of pulling 1 fuse and the car still runs - i've seen twice in the last year. puzzled the hell out of us the first time we saw it. the guys issue was a faulty fuel pump (it would pump fuel, but couldn't keep up with the fuel demands above idle) and IT had nothing to with the dme'S. I have yet to try this on my car.
  • 05-12-2010, 12:19 PM

    It WILL work in your car.

  • 05-12-2010, 09:56 AM

    Unless your car was built in 1989, the STOMP test

    will work - put the friggin bulb in!
    (If you read further down the post you linked to, you will see when this was first available).
  • 05-12-2010, 05:00 AM


    Hi Harold I'm not certain its just the bulb that needs replacing. Do you have experience of just installing a bulb and having it work? I'm hesitant to take apart something that is working, to install a bulb when it might turn out the Motronic and loom parts are also missing.

    From another bmw board

    "It is not only the missing light bulb.
    Depends on built year/month and MOTRONIC version. On the EURO version the bulb place is empty. And the wires between cluster and MOTRONIC are not there.
    Lots of discussions on the German E32 forum about this.
    For example on the MOTRONIC 3.3 it is possible to do the wiring, on the older 1.2 of the M70 EURO version it is said not to be working.
    Stomp test function was only required for U.S. specification models.
    EURO versions do not have them, also Japan spec cars do not have it."

  • 05-12-2010, 04:46 AM


    without using the diagnostics built into the system, you are just throwing darts into the air hoping you hit the target.

    Replacing the CEL bulb is really easy and that stomp test will tell you what you need to figure out your issue.
  • 05-12-2010, 04:35 AM

    Re: Cluster removal involves 4 screws - takes about

    Hi TX

    I have a pair of throttle bodies on order (ebay 170). Plan from here is

    1/ Check resistance on impulse senders and CPS sensors is in range
    2/ Compare side to side on Impulse and CP sensors
    3/ Check if pulling one side or the other makes a difference to running.

    4/ Install new throttle bodies (when I rebuilt mine the paths that I presume report how open the body is were very worn).

    5/ Consider either new CPS outright or installing the lamp in the cluster so I can do a stomp test.

    6/ Impulse senders are new as I replaced the cables approx 2 years ago. I will see if there is a way to test these while running.

    I'm a man with a plan. Running out of things that can be wrong here!


    (PS Have checked for vacum leaks thoroughly with break cleaner)
  • 05-12-2010, 04:30 AM

    Re: Wild guess is bad DME. Did you swap sides?

    Hi Yes we swaped the DME over and it does not swap which bank runs badly.

    Could be the EML that is not controling the two DME's correctly?
  • 05-12-2010, 02:05 AM

    Wild guess is bad DME. Did you swap sides?

    Also sounds like that one fuel pump is leaking gas, if you say it's squirting out of the motor housing.
  • 05-11-2010, 02:23 PM

    Cluster removal involves 4 screws - takes about

    5 minutes to do a light bulb install. CPS sensors are more involved - you need to "move: the power steering pump out of the way to access them. Try reading the resistance across the contacts first - should be around 540 ohms. Both need to be close to one another in values. If not, best to replace them both - remember, your car is almost 20 years old! and they are most likely the originals...
  • 05-11-2010, 01:18 PM

    Re: Your Mobile Electrician should just keep driving

    You are right.
    Back on my own again! Throttle bodies and CPS next. How hard is it to swap over CPS?

    Putting a bulb in my dash is going to be hard and I'm not sure justifiable to do a stomp test. Might not be all that is missing after all?

This thread has more than 20 replies. Click here to review the whole thread.

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
1e2 Forum