Stalling when slowing to a stop 95 obd1

[Rxs7evin]

So my obd1 M3 was automatic. I replaced the throttle cable and shortly after that it would stall when slowing to a stop. I tightened the throttle cable a little and it kind of went away. Possible coincidence.

Fast forward a few weeks and I did a manual swap. I swapped in the e46 M3 6spd. After resetting the computer, driving the car until it fully warms up, when clutching in coming to a stop sometimes the rpm’s won’t catch themselves and will fall too low and stall. If I’m idling in the driveway and press the clutch in, half the time the rpms will drop low and almost stall, then the rpms will bounce up and down for a few seconds before steadying out. Car is fine cold.

I just had the car coded to manual and the transmission light is now off as well. Symptoms remain the same.

Over the last year the car has new plugs, valve cover gasket, Bosch iacv, rebuilt vanos, new injectors, vacuum hoses, fuel pressure regulator, fuel pump, fuel filter, purge valve, etc etc. I scoped the cam and crank sensors and the waveforms are perfect. Only code is knock sensor 2. That randomly started after the rebuilt vanos. Check engine light will sometimes briefly flash in 2nd around 3k rpms.

[bmwstephen]

you had the car coded to a manual. was that via DME or through the cluster?

[Rxs7evin]

you had the car coded to a manual. was that via DME or through the cluster?

Through the cluster. Auto trans light went out immediately.

[Braymond141]

You need a new chip for the DME specific to a manual setup. You can’t keep the automatic one.

For the record, setting the throttle cable to adjust idle is NOT a properly setup car. You either have an intake leak or your throttle body idle set screw has been messed with.

the throttle cable should have zero tension on the throttle plate.

[bmwstephen]

What Brett said. I was just going to chime in. There are variations between the OBDI auto vs manual DME tuning from the factory (i.e. idle settings). Here is a list of differences I gathered below.

Type Appr EWS Basic CU Progr CU Notes Dinan Chip Version 506-EWS I 1404911 1994 M3 Manual Prod< 12/94 "Red Label" D900-2941 44A 506-EWS I 1403785 1994 M3 Manual Prod< 12/94 "Red Label" D900-2941 65A 1403787 413-EWS II 1744698 1404766 1994 M3 Manual Prod 11/94-12/94 "Silver Label" D900-2943 15A 1404231 413-EWS II 1744698 1404229 1995 M3 Automatic Prod 10/95 "Silver Label" D900-2943 15B 1403787 413-EWS II 1744698 1404732 1995 M3 Manual Prod >1/95 (supercedes "766") "Silver Label" D900-2943 15C

Now since you had an automatic which was likely produced after 1/95, you may have EWS II which is another painful barrier you have to deal with on an OBDI. You either have to get an EWS alignment or a bypass done depending on which route you go.

Also if you are stalling out, it sounds like you do have a leak in the intake tract somewhere just as Brett said. I would do a smoke test to see where it maybe coming from if the normal spots were already checked

[Rxs7evin]

You need a new chip for the DME specific to a manual setup. You can’t keep the automatic one.

For the record, setting the throttle cable to adjust idle is NOT a properly setup car. You either have an intake leak or your throttle body idle set screw has been messed with.

the throttle cable should have zero tension on the throttle plate.

I thought the chip was needed for obd2 vehicles because of a code that comes up? I emailed Kassel performance before the swap and they said obd1 vehicles are good to go and it wasn’t necessary. My Dme is 3.3.1

The throttle cable isn’t opening the plate at all. It was still automatic and immediately after I changed that cable it stalled on me a few times in a row. Had never happened before. On the side of the road I tightened the cable until it raised the idle and then I backed off again. After that I want to say it stopped stalling on me for the time being. Possible coincidence though. It’s a single owner car so I know for a fact the idle set screw has never been touched.

I can get my smoke machine to check for intake leaks. Everything is practically new though.

[bmwstephen]

You DME 3.3.1 is Bosche and uses a chip. The Obd 2 vehicles have Siemans DME which have an IC. So there is no chip for those (tuning OBD2 DME are done via software flashing).

Kassel performance isn't wrong that before the swap and they said obd1 vehicles are good to go as technically it does "Go" (but doesn't mean it is running properly).

[Rxs7evin]

Someone on Reddit did a 95 6spd swap. They said they had stalling issues and had Kassel do a custom chip that slightly raised the idle and it helped. Maybe that’s the route I need to go if I don’t have any leaks.

[Rxs7evin]

What Brett said. I was just going to chime in. There are variations between the OBDI auto vs manual DME tuning from the factory (i.e. idle settings). Here is a list of differences I gathered below.

Now since you have an automatic which was likely produced after 1/95, you may have EWS II which is another painful barrier you have to deal with on an OBDI. You either have to get an EWS alignment or a bypass done depending on which route you go.

Also if you are stalling out, it sounds like you do have a leak in the intake tract somewhere just as Brett said. I would do a smoke test to see where it maybe coming from if the normal spots were already checked

I did a bunch of reading before the swap and believe that for obd1 when you do the coding to Kombi it stops looking for a signal from egs and also updates the Dme. After coding, the idle speed was supposed supposed to go from 680ish to around 550 I’ve read. I’m still around 680rpm though so maybe the Dme settings didn’t stick? My transmission light did go away though.

My car is 8/95. Just had someone tell me that for their 95 6spd swap they had Kassel make them a custom chip that slightly raised the idle to get rid of stalling.

I can smoke the intake to check for leaks. Everything is new though from my saga trying to pass smog last year.

[Braymond141]

I don’t see how the tune is ready to go, but I haven’t looked at the data. I just know that a friend’s 840 I swapped required a new manual based chip as the automatic engine tune was looking for automatic specific behaviors that made the manual experience jerky and unreliable.

[Braymond141]

Guess I’m wrong. They are the same. You don’t want a 550rpm idle. 680 is ideal.

You have known intake / throttle body issues. Focus on that.

[Rxs7evin]

I scoped every sensor. Checked the throttle etc and it was all good to go. Weird thing was that if I’m fully warmed up idling in neutral and I push on the clutch pedal it will almost die and bounce back up.

I hit up Kassel performance for a custom chip to help with the stalling. They raised the idle to around 880rpms and said possibly raise the iacv duty cycle. Got the chip today and rpms stay solid when pushing in the clutch during idle. Maybe 1 out of every 10 times I’m decelerating and push in the clutch rpms will drop to 500 and come back. Before it was dropping to like 250rpms and dying occasionally.

Weird problems with their chip though. I immediately got code 66 for anti theft device signal dwa. Car is insanely hard to start. Have to give it throttle a bit. I pulled their chip and put my original back in and car fires right up. Have to hit them up on Monday I guess.

[bmwstephen]

PM’ed you

[Rxs7evin]

Forgot to mention I fixed the knock sensor 2 code by replacing my alternator. Been gone for a week now. Alternator wouldn’t charge at idle with the system loaded up. Would start dropping down to 12v.

[bmwstephen]

If your knock sensors are original, at your mileage they are toast by now. I changed them out when I did my cooling system and starter refresh. Car doesn’t pull back timing prematurely

[Rxs7evin]

Car only has 98k miles. I had to do the head gasket in 2010 around 70k miles and I’m almost certain I replaced them. Next time the manifolds off I’ll check. One of those strange problems though. It would flash the check engine light for knock 2 around 3k rpm’s every single day. Replaced the alternator and it went away lol.