Ideas on a random no-start condition?

[LateFan]

Well, knock on imitation wood grain vinyl, he has started and run really well for three weeks with no problems, cold & hot.

It looks like the last resort on most peoples lists, the DME, was causing some intermittent screw-ups. But I would recommend you start at the top of Jim Levie's troubleshooting list and work down it in order. Massive vacuum leaks were our first issue, then senders, a worn AFM, a worn out ICV, valves too tight, etc.

So I think this thread is done - thanks, all, for the good advice.

[Frankus12]

The part below seems to have been cut off from the top of your post - only came thru on the email notification...

"I also have an 86 eta thats died immediately after start. I also had a problem that cause no start that was from a relay underneath the driver dash cover, something the bentley missed because they cant assume 30 year old relays sticking."

That's interesting - was it ignition-related or fuel, do you know? Did it just not start, or was it sputtering rich?

I'll look at those soon. Thanks.

it doesnt sound like your problem, thats why i deleted it. but Whatever relay it was, it was causing the DME to not receive power, this was the day after i bought the car. It would just crank, absolutely no sputtering at all. I followed all the bentley procedures and ended up replacing the main and fuel pump relays (which didnt fix it) and eventually figured out how to test for power at the DME connector and found there was none. after a weeks worth of online reading, somewhere someone mentioned it could be the ignition switch, and that the circuit for dme does run under the dash, so i just pulled the lower dash cover and slapped all those relays around and it fired right up. Idk which critical relays are down there because i was so happy it was working i didnt care to replace them, if the problem ever reoccurs, which in almost two years time it has only twice, ive just kicked the cardboard bolster and slammed the door and it starts.

[LateFan]

Independent shop says no air leaks, it holds pressure, and the brake booster seems tight.

He says it started and ran fine for him.

The spare DME??? Fingers crossed.

[LateFan]

my idle creeps all over when cold...

The part below seems to have been cut off from the top of your post - only came thru on the email notification...

"I also have an 86 eta thats died immediately after start. I also had a problem that cause no start that was from a relay underneath the driver dash cover, something the bentley missed because they cant assume 30 year old relays sticking."

That's interesting - was it ignition-related or fuel, do you know? Did it just not start, or was it sputtering rich?

I'll look at those soon. Thanks.

[LateFan]

We did the torch test on the o2 sensor. Hot, it reads about .93V, then drops right off below .1V with the heat off. Black & sooty (not anymore).

So we know that's working.

With clean plugs and spare DME, it started right up, smooth as can be. Dropped to 700, perfect idle.

So we took it right to the shop tonight and left a note, in case it doesn't start tomorrow!

[LateFan]

Well, that's nice of you - thanks! (but my wife's parents were both from Lancaster County / Lititz / Kutztown)

We checked the temp sensors. Three have been replaced. The fourth I believe is the dash gauge sender, which works fine so far. It has only one contact in the plug connector.

Plugs cleaned, spare DME installed. Supposed to be warmer tomorrow - we'll lift it up and pull the o2 sensor and check the wires, try the torch test.

[Frankus12]

Yes, sorry I understand. Just wondering Pa because if you were close I wouldn't have minded swapping dmes as I barely drive while at school.

[LateFan]

Good ideas.

I believe we changed all 4 temp sensors - I'll check the receipts to make sure. Your sensor test makes sense.

My son is just now putting in a spare DME with 115k on it from a r3v member who did a swap.

He's also cleaning the plugs as I'm sure they're badly fouled, before we try another start. He just came in - first one is wet, sooty, and smells of gas. Have not touched the new ICV - idles really smoothly now when it's not doing the flooded thing.

PA 'cuz you want to come save us, or because your cars all rust and short out?! It's a dry N Calif car, now in dry Montana.

Sorry I'm so frustrated with this thing - I promised him we were buying a really reliable German car..... I have a '67 Alfa that always starts...what is up with this thing?!

[Frankus12]

my idle creeps all over when cold, im led to believe its my ICV, which cant be adjusted in to spec, to which bentley says that means its broken. I wish you had not said you got the AFM rebuilt, because that would have been my guess. a worn afm could send an abrupt high air volume signal to the dme, causing the very rich condition it seems youre experiencing..building off that though, it certainly seems to me like a rich condition, or just timing that completely shifts for some reason. You got the timing sensors changed, ICV (have you adjusted it per bentley procedures with ampmeter?), AFM, everything physically seems good. So heres my guess,

Sorry if this was mentioned already; You said you did all the temp sensors but the dash one, so you should have replaced a total of three. The ETA has two thermotime switches (they have different names cant remember tho) one controls timing and injection, the other controls the cold start injector. On mine, the one that does timing has two visible male/female connections, no bosch connector. if you have not replaced the one that does timing, I would immediately check on that, and the wiring all around that area as well. When the problem is occurring, (or not) take those connectors and put them together to simulate a closed switch, and see if that does anything and vice versa. This switch has made my car incredibly dificult to start when warm and sometimes cold. I know how unlikely it is, but I wouldnt rule out a bad DME or icm yet, seeing youve practically done everything else. Are you in PA? A red flag here should be the way it just shuts off sometimes, to me thats an electrical failure or a sensor grounding when it shouldnt or something, bad wiring or grounds somewhere perhaps. jiggle all your wires everywhere lol, you might be surprised, i know i was when I got mine running by slapping the relays under the dash cover.

[LateFan]

Put a new main fuel pump in last night. Fuel pressure now in the 36 range, which seems good. Started fine this morning, went for a short drive and it crapped out again. Wouldn't re-start. It almost kicked, but sputtered and blew clouds of black smoke.....?

I looked at realoem, and our brake booster vac line and fittings look totally different than those diagrams. We have a simple threaded fitting on the intake manifold forward of the throttle body, and a vac hose to a (new) 90 degree check valve at the booster.

Also - If the fuel vapor canister purge valve isn't functioning, isn't that sucking air right through the canister into the intake?

"Real" smoke test monday.

[LateFan]

Update -

We finished installing the suspension, and it's beginning to warm up outside so we can get some work done.

The car ran perfectly for a week. Like a new car. The smoothest idle, everything fine. Drove it 20 miles one day - perfect.

BUT, we never really fixed the problems, so we don't trust it yet.

Today we were taking it in for an alignment, and it wouldn't start. Same issue - black smoke, sputtering, barely idles. He took off the oil cap, and there was no idle change - doesn't that tell us something?

I'm thinking there's an intermittent big air leak somewhere -
Brake booster / vac check valve / o-ring at master cylinder?
Charcoal canister system?
Intake manifold gasket? (PO had a new head put on 5000 mi ago)

Bad o2 sensor?? (Brand new Bosch)

Would a cold start valve just decide to spray fuel when it's not supposed to? We replaced the temp-time switch.

We're taking it in for a "professional" smoke test Monday - maybe we're missing something. But if it's running well, how will they find the vac leak?!


To help others, the ICV was a big fix for idle problems, as well as a fuel pressure regulator and Air Flow Meter. We clearly had several things going on at once, and a lack of maintenance by POs.

[LateFan]

Not much to report - the car is up on jacks - we're rebuilding the suspension and replacing brake hoses.

I think the ICV AND the FPR were bad or failing, which was part of it. The fuel pressure still drops overnight, which makes me think the main fuel pump check valve isn't working. We have a new pump to go on when we have the back up to flush brake lines.

I still think we have some kind of intermittent vacuum leak somewhere - most symptoms point that way. Maybe the brake booster or o-ring, maybe the vapor canister hose system... My home-made smoke tester may have missed something.

[Milehigh30]

Latefan any updates. I've had almost the same issue and its time i need get to figuring it out. did the fpr fix it?

[///M42 sport]

no start no crank 325i '92

So this happened suddenly at a intersection. started with a irractic idle and loss of power. Limped it over to parking lot and died. Tried restarting car but then no crank. Disconnected battery and got engine to crank but then irractic idle and died again.

Tried stomp test 1444 = which equals no issues.

I'm think its a combination of problems right now. But weird that would not even crank

[LateFan]

Update..

Installed a new FPR. Started instantly - smooth idle, warms up fairly fast and drops to about 700 rpm. Re-started just fine.

Two days in a row, so maybe we've finally beat the odd day / even day thing.

Running fuel pressure is about 31-32 psi. Stayed in the 30s after shut-off, then started dropping after an hour. Next morning it was at 5 psi. Rebuilt injectors, no external leaks, new FPR........looks like I'm ordering a new pressure pump.