E30 just shuts down

[bchene]

This is my first post on the board. I have been reading it for years and this is the first time I have not been able to find an answer to my problem by searching. The number of times this board has helped me out is many. Anyway, I have an '87 325is that when running down the road will just turn itself off. No warning, dash lights do not flicker, no obd code generated, just stops. There does not seem to be any pattern, car temperature, time running, or flickering dash lights. Car runs a little rough at idle, but, really moves when you step on it. Until it decides to quit. In most cases after stopping the car will start right back up. Sometimes you may have to wait a while, but, it always goes.
new injectors
new fuel rail
new fuel regulator
new fuel filter
new plugs, harness, etc
new temp sensors (2)
cleaned and tested MAF
cleaned and tested ICV
tested for vacuum leaks
every wiring harness connection under hood pulled and cleaned
do not have a fuel pressure tester, but, there is fuel at the rail right after it shuts down
i am wondering about the TPS (rough idle) but i do not believe that if it were failing the engine would just shut down and then start up again.

hoping someone has experienced this before and can help.

Thanks

[8307c4]

Possibly a faulty fuel or main relay.

Then there exists a procedure with an ohm meter to pull codes out of the motronic unit but that takes a bit of doing,
you might be the kind inclined to do it but whether it will help is another story.

I would look into the relays, unfortunately they do cost around $20 each but it's a simple fix.

[danielson]

go check the connections at the ignition coil. i had this problem and it turned out one of the small screws was loose and the wire was jiggling around.

[E36 For Life]

+1 on relays. Most likley fuel pump relay.

[DLite]

Probably a crank position sensor flaking out.

[bchene]

Thanks for the responses so far. Ordered the relays and a TPS today. A friend stopped by and was able to read an obd code indicating a faulty TPS. Still question that one.
Will check the ignition connections and mountings this evening.
How/what does a failing/faulty crank position sensor manifest itself? Is there another symptom or symptoms that go along with the cps failing that i should be looking for?

Thanks

[DLite]

I'm pretty sure that the TPS is not causing your problems...rough idle, maybe. Also, the TPS is only a limit switch assembly, not a potentiometer, so you'll never see a fault code on your engine showing a faulty TPS...it had to be a code for something else that your friend was found...see here...http://www.pelicanparts.com/BMW/tech...de_Reading.htm

A bad or flaky CPS will cause the engine to stall just as you described at any condition.
There's a specification for the normal resistance of it, that you can check and verify (don't have a Bently to tell you what it is, but its been discussed here before, so you can search for it)--take it off the car to test it--beat it around in the palm of your hand to see if you can get a bad reading from it. However, you might test it and it look okay, but act up in service...they're relatively affordable...about $60.

A failing fuel pump relay will kind of cause the engine to sputter a little then die...as the fuel pressure gradually decreases.

A failing main relay--I think you would see a check engine light come on...but you said that isn't happening.

But all these are simple enough to look at...that I would check them all anyway.

[8307c4]

Get yourself an obd-ii scanner and a $10 obd-to-bmw adapter and that might tell you more,
otherwise the only thing I know is start replacing and keep replacing parts until you hit the nail on the head.

I learned that one the hard way.

[drumbeat23]

Did you ever figure out what the problem is? I have EXACTLY the same problem on my 1995 euro spec 520i. So far, I only swapped out the main relay, no help. I see you are from Maine, me too, I just live in Germany now for the Air Force. Please let me know what the result of your problem is, I will most likely try the same fix with mine.

[325bob]

I went through the same scenario for a few weeks, I thought it was 1 of the relays,as replacing them seemed to get it running, but that was just coincidental, the fuel pump was dying,and finally did.