S52 OBD2 minor bugs

[Varinn]

Got a couple bugs I need to iron out, hoping someone will have some suggestions before I start buying the specialty tools needed to check some things. Motor is completely stock, aside from intake manifold and swap related deletes.

-Cold start runs very rough for a few minutes, the colder the temp the worse it runs and longer it takes to recover. (Currently about +6*c at morning start)
-Sometimes when clutching in to shift the rpms will sit still or even rise by 100rpm before falling (even if throttle shut before clutch in)
-Clutching in when coming to stop the rpms will sometimes bounce at 500-750 for 2-3 seconds before stabilizing at around 700.



9/96 S52B32
1990 325i
No CEL but stored codes for SAP airflow (TRM is aware of the issue and working on a revision)
ISID tests show all sensors working correctly
M50 manifold conversion with Turner kit
TRM off the shelf tune (currently tuned for OBD2 manifold)
E39 rail, no running loss valve (tune deleted)
All new vacuum lines, intake boot, plugs, coil boots, etc (trying to find shop to do smoke test)
Beisan vanos rebuilt 2000km ago
Fuel pressure primes to ~50psi quickly but drops to 0psi overnight. Gauge does not fit on rail with CCV line attached to valve cover so no running measurements.
12lb flywheel (tuned to compensate)

[NickL]

With the rpm's hanging I had an e36 that when the icv was bad it would do that. I replaced the icv for a rough idle and the rpm hangs went away, rough idle got a little better. Sounds like the car is rich. When I was incorrectly tuned for injector size the car ran terrible cold and struggled to stay running when throwing in the clutch.

You said you're tuned for the obd2 manifold and you're running an obd1, are you running the correct size injectors for what you're tuned for?

[DesertBMW]

No CEL but stored codes for SAP airflow (TRM is aware of the issue and working on a revision)

That sucks. My flashes have that all taken care of.

[JCarp90]

lol^

[Varinn]

With the rpm's hanging I had an e36 that when the icv was bad it would do that. I replaced the icv for a rough idle and the rpm hangs went away, rough idle got a little better. Sounds like the car is rich. When I was incorrectly tuned for injector size the car ran terrible cold and struggled to stay running when throwing in the clutch.

You said you're tuned for the obd2 manifold and you're running an obd1, are you running the correct size injectors for what you're tuned for?

Thanks for the input, I'll try yanking and cleaning the ICV and MAF tomorrow to see how it reacts. I had a smoke test done today and found zero leaks in the intake system, so at least that's ruled out.

The shop who did the smoke test suggested yanking out the stock Bosch FGR8KQE plugs. They recommended trying a set of NGK BKR6EK for two reasons. Firstly they say the Bosch ones are pretty shit. Second was that they think in colder weather the plugs may be struggling to develope enough spark to ignite (on initial startup, during the enrichment period). They might be on crack but it's cheap and easy to try it out, Pelican specs them for all e36 M3's.

[NickL]

Those are the plugs I run in my car. It could be that, but I feel like it wouldn't be an issue. Start with the ICV and plugs are good maintenance anyways so its nice to rule that out.

[Varinn]

Those are the plugs I run in my car. It could be that, but I feel like it wouldn't be an issue. Start with the ICV and plugs are good maintenance anyways so its nice to rule that out.

Replaced the plugs with the NGK set a few days ago, also cleaned my MAF and ICV. Car ran worse initially but it seems to be getting better now, idle is not resolved with the added side effect of an occassional stall when clutching in and coming to a stop at the bottom of first/second gear.

The MAF was fine, but the ICV was filthy and fairly sticky. After cleaning it almost seems TOO loose with the center vane feeling like it has zero resistance to movement. Shake it once and it will clatter back and forth for a few seconds. Also checked with my buddies shitty meter and it showed readings of around 10/12/20ohms. Don't care enough to recheck with mine, just going to order a new ICV and coolant temp sensor, just in case.

[e30forlife]

Im having the exact same thing happen to me with the stalling out.. I have to feather the throttle to keep it from stalling sometimes.. If im cruising then coming up to a stop with it in neutral it will idle sometimes. Then the other times it will stall. Let me know if the ICV fixes it...I just checked for vacuum leaks on mine and I dont have any..