Hunting for idle when coasting, VSS related?

[trackjunkie21]

not sure anymore, will do more testing after work.

[lolcantturn]

Jason89i is viewing this thread...............hopefully his old wisdom will enlighten us.

[328ijunkie]

VSS is pin 42 at ECU on both E34 and E36 harnesses. (VANOS)
VSS is pin 73 at ECU on both E34 and E36 NONVANOS harnesses

[lolcantturn]

VSS is pin 42 at ECU on both E34 and E36 harnesses. (VANOS)
VSS is pin 73 at ECU on both E34 and E36 NONVANOS harnesses

Of course it is <3

[328ijunkie]

See ninja edit ;)

[trackjunkie21]

See ninja edit ;)

would make sense. will be pulling the cluster today to determine where the break is.

[lolcantturn]

See ninja edit ;)

see my ninja edit ;)

[Beej '86 325es]

so is pin 14 on x20 still VSS on both harnesses? No right?

Beej has an E34 harness then I presume since didnt he check Pin 42 on his ecu for continuity and it was good ?

I'm pretty sure I have an E36 harness.

I just checked continuity from the VSS BRN/RED wire on the cluster all the way back to the DME pin 42 and it's good.

I checked voltage at pin 14 of the X20:
2V with key OFF
4.5V with key at ACC
9V with key ON
12V when running
If this is truly a signal wire, shouldn't I be getting some low voltage signal that would fluctuate when driving?

I think I'll pull off my throttle body tomorrow and try and do a proper test on the IAT sensor.

[Beej '86 325es]

I think I'll pull off my throttle body tomorrow and try and do a proper test on the IAT sensor.

Removed and checked IAT sensor and appears to be working properly.

[trackjunkie21]

I hate to say it, but somehow I fixed the issue At first I wasn't getting continuity at pin 14 and when I pulled the cluster, there was nothing coming from the cluster either. I disconnected everything and checked if all the pins were in good shape on the cluster and I sprayed them with electric component cleaner. I left the car idling while connecting the cluster back and all I noticed was the car smoothed out and revved up right when I connected it, sent chills down my spine. I'm a bit mad though because not only did I not find out why and how I fixed the problem, just by simply disconnecting and connecting wires but also that I broke one of the ears off my euro cluster. I shall have a video later with how the car performs.

[Beej '86 325es]

I don't want to jinx it, but are you sure it wasn't just the O2 clicking on?
Once mine clicks on, A/F ratio returns to normal and the car runs fine, but it takes a while.

[Highway1]

specs on engine? It would be best for you to list them that way we can conclude as to what is NOT causing it so we don't end up throwing random parts at it.

Well... mine doesn't always do it. only sometimes. but then again I never really coast in neutral anyway so it's not a big deal.

m50 and harness from 94 325ic auto.
cone filter
obd2 headers


Kinda related. Is the m50 supposed to instantly rev to 2,200 when cold starting?

[trackjunkie21]

I don't want to jinx it, but are you sure it wasn't just the O2 clicking on?
Once mine clicks on, A/F ratio returns to normal and the car runs fine, but it takes a while.

Well you jinxed it :D, just kidding but the problem has come back. It actually works opposite to yours. The fluctuation happens once the car warms up. Anyway i know it is still vss related because now the car doesn't rev up to 1,000 when coastong or driving down my driveway. About to run a wire from
The cluster to the dme.

[trackjunkie21]

Another thing I've noticed is that when the car is full warmed up and I try to start it, it kinda slowly reluctantly revs to idle instead of revving up to about 2,000 as it should.

[Beej '86 325es]

I'll have to check and see if mine does that too.

I noticed the fuel consumption wire that feeds the economy gauge also goes through the DME. I found that mine was not connected at all.
Any chance that would affect engine running?