S52 start & stall

[Tisoc]

Howdy.

I’m having a stalling issue with my OBD2 S52 e30 with an M50 manifold. This originated when I removed the manifold to replace the heater hoses.
The car starts beautifully, but stops within seconds & won’t idle. Quick application of the throttle causes the car to stall immediately. I removed the intake manifold again to double check everything & installed new gaskets for good measure as well as replacing the CCV with an OEM Unit. I smoke tested the car & have verified the absence of any vacuum leaks. Everything is air tight with the Kassel M50 manifold kit. The weird thing is that the car will at least hold somewhat of an idle with the oil cap removed.
I have checked fuel pressure at the pump & at the rail & it is around 50ish psi which is within spec.
The car is throwing 3 codes: P0101, P1509 & P1550 which are MAF & ICV codes. I swapped out the ICV & MAF with know good units with no result. I ensured that there was continuity between the pigtails of these two sensors from the plug to the DME plug with the help of wiring diagrams.
I followed the entire e36 Bentley troubleshooting guide on stalling & everything checked out, except that it’s suggesting that the DME might be bad.
Is it possible the DME is bad even though the car can still start & show trouble codes? The biggest thing I should mention is that pigtail on the Vanos solenoid had cracked insulation & it sparked when I accidentally touched it with a ratchet. Maybe I partially bricked the DME when I did this?

Grace me with thy knowledge please.

[twright]

It sounds like a vacuum leak. I know you smoke checked it, but I would look again. Is the big rubber elbow under the middle of the intake manifold correctly positioned into the intake manifold?

[Tisoc]

It sounds like a vacuum leak. I know you smoke checked it, but I would look again. Is the big rubber elbow under the middle of the intake manifold correctly positioned into the intake manifold?

If you’re referring to the turkey neck from the ICV to the intake boot, then yeah, it is air tight with no cracks since it’s a new part along with the rest of the rubber on the intake side. All the current symptoms suggest a vacuum leak, but I Smoke tested under pressure & used a rubber glove on the intake boot to visually make sure I wasn’t losing air somewhere. The glove stayed inflated like a balloon.

[bradmer]

I had multiple codes (not all the same as yours) and the engine would cut out. Turned out to be a loose electrical wire on the terminal block in the engine bay from all of my go fast urethane bushings vibrating the crap out of the chassis. When I was researching those codes I found threads that had similar multi code issues with wires that had melted together within the harness. Maybe trace the wires back and recheck the splices into the e36 wiring harness.
Everything grounded?
CCV ok?

[Tisoc]

I had multiple codes (not all the same as yours) and the engine would cut out. Turned out to be a loose electrical wire on the terminal block in the engine bay from all of my go fast urethane bushings vibrating the crap out of the chassis. When I was researching those codes I found threads that had similar multi code issues with wires that had melted together within the harness. Maybe trace the wires back and recheck the splices into the e36 wiring harness.
Everything grounded?
CCV ok?

All the grounds checked out good as did the power cables on the distro block. The CCV is a brand new BMW part. I guess the next step will be ripping out the harness & inspecting all the wires since you mention that they melted together on other cars. I’m using a harness adapter so it should be fairly simple to just pull the whole thing off.

[bradmer]

Maybe try a known working DME first? I don't know if I would pull it off, rather pull the wires apart from each other in place to see if any of them have fused to others where they shouldn't have. Time consuming but inexpensive to do.
I would replace the piece with the cracked insulation, is this it?

Solenoid switch

1

11361738494

$184.43

[Tisoc]

Maybe try a known working DME first? I don't know if I would pull it off, rather pull the wires apart from each other in place to see if any of them have fused to others where they shouldn't have. Time consuming but inexpensive to do.
I would replace the piece with the cracked insulation, is this it?

Solenoid switch

1

11361738494

$184.43

So I already got another solenoid on there with no change in behavior. I tried asking around on Facebook on e36 pages to see if could get a loaner DME & offered some monies for their trouble but no biters. No luck finding an EWS delete ecu locally either. Spending a few hundo on a maybe is a tough pill to swallow.

[bradmer]

So I already got another solenoid on there with no change in behavior. I tried asking around on Facebook on e36 pages to see if could get a loaner DME & offered some monies for their trouble but no biters. No luck finding an EWS delete ecu locally either. Spending a few hundo on a maybe is a tough pill to swallow.

Have you had a chance to dig into the harness? There's a fair amount of direct current power running through those small wires and they can heat up, issues can be caused. I would trace that thing down prior to shelling out for a new brain. I did something similar recently where I had some funky connections, went back in and used heat shrink over the new soldered connections.
I found this below from the master Jlevie in a thread on bimmerforums about P0101 and MAF is good.

"Since the code will set before the engine is started and since you have tried two other MAF's, I'd say the problem is either in the engine wiring harness or in the MAF input section of the DME. You should run continuity and ground tests on the MAF wires as a first diagnostic step. If that doesn't reveal a problem I'd be tempted to swap in a different DME before I swapped out the harness."

And I figured out how to post a link.

https://www.bimmerforums.com/forum/s...sn-t-a-bad-MAF

[Tisoc]

Have you had a chance to dig into the harness? There's a fair amount of direct current power running through those small wires and they can heat up, issues can be caused. I would trace that thing down prior to shelling out for a new brain. I did something similar recently where I had some funky connections, went back in and used heat shrink over the new soldered connections.
I found this below from the master Jlevie in a thread on bimmerforums about P0101 and MAF is good.

"Since the code will set before the engine is started and since you have tried two other MAF's, I'd say the problem is either in the engine wiring harness or in the MAF input section of the DME. You should run continuity and ground tests on the MAF wires as a first diagnostic step. If that doesn't reveal a problem I'd be tempted to swap in a different DME before I swapped out the harness."

And I figured out how to post a link.

https://www.bimmerforums.com/forum/s...sn-t-a-bad-MAF

I’ll probably tear into it this week, tied up with mother’s Day right now. I’ll update the thread by the end of the week. The continuity to the MAF & ICV checked out good from the plugs to the DME connector.

[Tisoc]

Well that was a long ass mother's day.... So the car is up & running perfectly again. The issue? The ground wire from the main relay to the DME (pin 73) was only hanging on by a few strands & ripped while I was combing through the harness. Same thing with the MAF plug, bad ground wire. Super stoked to have this ish figured out & hopefully this helps somebody in the future.