O2 sensor heater...what can affect it?

[nando]

it's the green plug block that the cruise control plugs into. there's like 2-3 more plugs you can use to run to the ECU. it's usually a black/white wire.

VSS won't affect idle.. I don't know who said that, but they're wrong. when you're stopped, there's no signal input. Unless the ECU freaks out because the input is left floating, but I doubt it. Still, it's a good idea to hook that up.

[trackjunkie21]

If the IAT is faulty and telling the ecu the air is hot, would it cause a lean fuel condition?

Otherwise, my first guesses are vacuum leak, fuel filter, fuel pump, injectors, o2 sensor...but it sounds like you covered most of those.

Can this be a likely cause? Mine may be faulty and I'm still experiencing weird symptoms, albeit much better running after the exhaust leaks having been fixed.

[nando]

Yes IAT affects fueling.

[328ijunkie]

Esp if youre running the wrong sensor ;)


And no VSS doesnt affect idle at all (other than bumping the idle when youre in neutral or out of gear when your moving)

[lolcantturn]

So I think I've figured out the problem. I haven't tried to fix it yet, but hopefully I'll have time tonight.

I found some info on the VSS sensor, saying that if the road speed signal wire is not connected correctly, it can cause:
-the fuel to cut around 6800 RPM (yes)
-VANOS not kicking in (probably why I'm low on power and get a solonoid error code)
-idle won't hold when coming out of gear and slowing down (yes, mine dips when I blip the throttle)

So I think I've found the culprit.

The early Eta cars use both the C101 and the C104 in the glovebox. I've had a hell of a time trying to find out what the wires are for on the C104, but I know at least one of them is wrong.

Can someone verify these on the C104 for me?
BLK = tach signal
GRN/RED = OBC Fuel Cut (road speed signal)
YEL/WHT = Fuel Consumption (MPG gauge)

I've also got a separate BLU/YEL wire. I'm thinking that's a road speed signal that's supposed to go to the cruise control, not the ECU. I don't think this gets used though.

Let me know how it turns out. My c101 is out of an ETA car and the only thing I have hooked up is the tach signal in which case DaveSmed on this forum used a pin tool to hook it up through my C101 so the C104 tach signal wasn't necessary...still don't have the rest of it hooked up but let me know how it turns out for you as we have the same symptoms...


Are you getting worse-then-usual gas mileage?

[Beej '86 325es]

I guess I should clarify, when I say my idle is affected, I think that's purely because it runs lean. It stays pretty rock solid around 900 RPM except wanting to die sometimes due to lack of fuel.

Here's where I read that:

http://www.r3vlimited.com/board/showpost.php?p=569326&postcount=39

[lolcantturn]

which one of these pins are road speed/VSS?

http://www.akgmotorsport.com/usm50swappins.php

[328ijunkie]

As ive mentioned that chart is massively wrong

[lolcantturn]

As ive mentioned that chart is massively wrong

lol I did my C101 with it lulz.

[lolcantturn]

If it's wrong, whats road speed/VSS pin then?

[328ijunkie]

if it's wrong, whats road speed/vss pin then?

14. Typically speaking.

[Beej '86 325es]

Hmm, no change; you guys were right. The O2 still doesn't click on and it idles lean.

I routed pin 14 (BLK/WHT) on x20 to the BRN/RED wire on the middle C3 (yellow) plug of the cluster and verified continutity. From the Bentley, the BRN/RED wire should the "vehicle speed input" wire to the OBC.

Back to square one.

[328ijunkie]

Brn/Red is the INPUT to the cluster, not a VSS output. Try again.

[Beej '86 325es]

The middle yellow plug is C3 right?

[328ijunkie]

You should have the giant green snap in plug on the back of the speedo for the cruise control. Steal a signal from there. Works perfect for me everytime unless your cluster is jacked (which ive had happen)