85 528e, no pwer, puffs black smoke at idle

[SEB]

Car runs rich at idle, .8 volts and drops to below .1 volt at WOT. Backfires on snapping the throttle wide open. I have replaced the coolant temp sensor, did all volt,ohm, and ground checks at the ECM and Idle module. Had to readjust the throttle switch at for continuity but everything else checked OK. Tried switching the ECM & AFM out of my 83 528e, no change at all. Replaced cap and rotor with a known good one, new O2 sensor, new plugs (Bosh gaped at .028). Swapped fuel regulator from 83 to 85 and new fuel filter also. New speed and referencer sensors too. Fuel pressure is about 30 psi w/vacuum and 38-40 w/vacuum unplugged. I can pinch off return line and car will rev up like it's suppose too but still runs rich at idle. Another strange thing is I can unplug the AFM and idle still sucks but engine will rev up like it's suppose to also. I'm running out of ideas!![/u]

[SeaWolf]

Check the temp switch, pull the 2 wires off and short them together (closed circuit), I had a similar problem on my 528e though not as pronounced.

If it runs okay you can drive around with that switch shorted until you can get a replacement.

- and did you test the idle air control valve ? It might be getting stuck, clean it with Carb cleaner and give it a squirt of very light lubricant to stop binding.

Good luck.

[a]

just for grins, swap in a known good coil.

[Xenocide]

Just a wild guess here, but have you checked to see if the cold start valve is stuck open?

[SEB]

I'll try jumping the coolant switch and let you know what happens. I took the cold start valve out before I checked fuel pressure to make sure it wasn't leaking and it wasn't. I have a coil on my 83 I can swap out, I was thinking about that also. When testing the ignition system running, coil wire has 10-12KV and wires at the plugs are 2-4KV which I think is to low. I'm amusing that the rich mixture is causing the low firing KV. I have a spark tool and that appears to be firing good. I was also wondering if the timing could be off and I going to pull the covers and check timing marks. Seems to me I have two problems going on. I put almost 300K on the 83 and never had any issues like the 85 is having.

Thanks for all of your suggestions!!