Hunting for idle when coasting, VSS related?

[mrcheezle19]

I too have this same issue. My uncle who is a lifelong mechanic said it's just the computer hunting for the best air to gas mixture, especially with a performance engine. I have noticed that it only does it for the first 10 minutes or so and then stops, but then on long drives will do it again like when I get off the freeway. Anyone have an update on this issue??

[blackhawkimpact]

I got the cel and code reads "vehicle speed signal not present". Still have some idle issue but it's not really bad so doesn't really bother me. The cel light does though. :(

[328ijunkie]

Wish i could shed some light but ive never had this problem :(?

[r4esh]

No one? 5 people have this issue and no one has tracked it down?

[r4esh]

No one figure this out?

[r4esh]

obd1 s52 swap = experiencing SAME issue.. ALL new sensors, etc...

To throw a spin on it all I finished my swap a while back and it was flawless. It had perfect idle. I went out of town for 3 months and my father drove the car about 1-2 a month. Came back and the idle just dances all over the place like your video...

[Beej '86 325es]

I found another thread, some of these guys are having the same problem. Some cases worse than others, some US motors, some Euro, some OBDII.
http://forums.bimmerforums.com/forum....php?t=1728019

[trackjunkie21]

Nope nothing, Still searching to no avail. It's getting worse with the warmer temperatures though.

[Beej '86 325es]

Did you figure out anything on this, trackjunkie?
Mine did this last night for the first time, just like your video...only not quite as bad.

BTW to follow up with my fuel injector "snaping' issue...I'm told that it does not affect the performance, and it's normal.
I had them cleaned and flow tested. One injector was not doing well, but now they're all within within less than 1% flow rate. I also changed my pump and filter.

[michal182]

First thing i tried was disconnecting the MAF and the car ran the same but a little rougher and a hard start.

[trackjunkie21]

disconnected my MAF and drove it to and from school. I felt NO difference in driving characteristics of the car and all symptoms were still present. This the likely culprit?

[michal182]

Possible solution

This is what i did...

Took off the air intake manifold with boot and all vacuum lines. Then cleaned all the oil dirt carbon out (lots of it). After that i took out the fuel rail and each individual injector, cleaned them, then cleaned the fuel rail with brake cleaner and compressed air. Then reinstall.

Now it runs fine. Take it out of gear while coasting and it instantly finds idle. No more bounce:)

Try it let me know if it works for you.

[trackjunkie21]

yes please!

[michal182]

I have this same problem with my m20 engine does exactly the same as in the video.

So far i cleaned the maf the bouncing continues but now once the car stops the finds idle instantly. Before it would bounce 2 or 3 times before it found it.

The next thing i noticed is that the intake boot/manifold has a oil like fluid and dirt so im going to clean that out an see what happens. Then moving on to injects/fuel rail/fuel pressure regulator.

Ill let you know how it goes.

[trackjunkie21]

New Fuel filter didn't do much, although it did help the startup issue I was having, Rev's don't creep up anymore.