M42 Vehicle Speed Sensor/ Timing off/ Bad Idle?

[lolcantturn]

Replaced the TPS to a new OEM TPS and also tried various ECU's and it does not work. I've had working stomp tests on my previous E30's so I know how to get it to work, but it seems like its not working, and I'm probably going to contribute my bad idle to whateve the problem may be. Any ideas?

EDIT: I got my codes read by a diagnostic tool and it came up VSS (Vechicle speed sensor). Can this really affect idle? My idle sounds like its cammed

[Dj Buttchug]

wait so the car wont flash codes at you?

[roguetoaster]

Have you tried actuating the TB by hand in the engine bay, seems like the cable may not be adjusted correctly?

Otherwise, does your CEL light up when you key up the engine? If not bulb/board failure.

[Dj Buttchug]

Otherwise, does your CEL light up when you key up the engine? If not bulb/board failure.

^this

[lolcantturn]

Have you tried actuating the TB by hand in the engine bay, seems like the cable may not be adjusted correctly?

Otherwise, does your CEL light up when you key up the engine? If not bulb/board failure.

I have indeed done that. It does not flash codes at me. The CEL lights up on accessory.

[roguetoaster]

Guess you must have an electrical fault somewhere, likely at the TPS or in its loom. Is the wire kinked at the end of the plug boot/skirt?

I would start diagnosis by jumping/powering the correct two terminals on the TPS plug (not sure which two) and try to tell the ECU you are at WOT 5x.

[lolcantturn]

Guess you must have an electrical fault somewhere, likely at the TPS or in its loom. Is the wire kinked at the end of the plug boot/skirt?

I would start diagnosis by jumping/powering the correct two terminals on the TPS plug (not sure which two) and try to tell the ECU you are at WOT 5x.

Wire is not kinked. I did not jumper the TPS, but I did get a snap-on diagnostic tool to read the stored codes of my car. What came up was
Vechicle speed sensor (VSS).

Can this actually affect idle on a M42?

[Balleristic31]

Shouldn't it's on the diff

[Dj Buttchug]

dude did you set the speed sensor ohms before you installed it...??? You cant just slap on a new tps.

Banking on TPS is not reading properly causing shitty idle?? this will not throw any codes

I dont have a bentley but theres specific ohm setting on full range tps sensors.

[lolcantturn]

dude did you set the speed sensor ohms before you installed it...??? You cant just slap on a new tps.

Banking on TPS is not reading properly causing shitty idle?? this will not throw any codes

I dont have a bentley but theres specific ohm setting on full range tps sensors.

I...never..knew...this....


Welp.


I'll take a look at the E36 Bentley if there is one

EDIT: I'm not sure how right this is:

http://www.r3vlimited.com/board/showpost.php?p=3372979&postcount=2

[lolcantturn]

I'm not sure how you would adjust the TPS- It's not like the M20 where it can "slide," the M42 TPS just has two holes for screws and thats it.

[roguetoaster]

I'm not sure how you would adjust the TPS- It's not like the M20 where it can "slide," the M42 TPS just has two holes for screws and thats it.

I am fairly sure the "adjusting speed sensor ohms" thing should have had a /sarcasm appended. AFAIK a TPS is fit and forget.

[Dj Buttchug]

forgive me of my sarcasm op. I was heavily intoxicated. updates?

[lolcantturn]

I am fairly sure the "adjusting speed sensor ohms" thing should have had a /sarcasm appended. AFAIK a TPS is fit and forget.

forgive me of my sarcasm op. I was heavily intoxicated. updates?

LOL.

Well, I ohm'd out my CPS.
According to a fellow on M42 club, the CPS should be 640ohms +/- 10%
Mine checked out at 618ohms. So that seems fine. I though that the CPS might have skewed the ignition timing a bit.


I checked my O2 sensor and it was greatly out of spec, the volt reading was really high.
But that's strange if my O2 sensor has been out of spec this whole time as I've been getting consistant 32MPG highway.


Here are some of my symptoms, just to recap:
Long cranking times (5 seconds give or take)
Or weak starts (1 cylinder...2 cylinder.....2....then all 4 cyls fire)
Or sometimes I'll have to give it gas to start
Sounds cammed.
At any RPM it doesn't really hold it, if I rev it to 3k and try to hold it there it'll go up or down 100rpms- sounds like there is a very very tiny misfire
Can't hold the A/C on.
High idle- 950rpm
Cold starts are extremely shitty. Idles at 100-200rpm then gets better as warms up.
No codes except the vehicle speed sensor.
Yes, that firewall wire is disconnected

What I've changed, and these are all new OEM parts:
Cam position sensor
Fuel filter
ICV (changed this a lot)
AFM (from a known well idling E30)
Fuel injectors, flow tested
Coil packs
Spark plugs and wires
TPS

There is no vac leak as per smoke test.

[Dj Buttchug]

what about fuel pump? checked pressure?