M10 Awful Idle and Exhaust

[stanhayward]

Hey guys, I recently bought a 1985 318i for $650 to swap an M20 into but I want to fix up the M10 at the moment. I know very little about M10s so I'd appreciate someone's opinion.

When I bought the car, the PO said that he thought there was an issue with the cold start injector/valve. When you try to start the car - and this is Edmonton so about -25C in the winter) - you need to pump the throttle pedal for at least 10 seconds before it will come to an actual idle. Before that, it is REALLY hesitant and idles at 200rpm before stalling. After you get it to idle, you have to hold the throttle to get it to idle at ~1000 but it's still very rough and shudders the car. It will idle though at around 300rpm and not stall after you can get it to start. This seemed consistent with the cold start injector not working. The exhaust is also very blue and it smells like pure gasoline.

We hit a warm spell up here today so I tried starting it (~5C) and it still was having similar issues. This led me to think it could be either the idle control valve ($$$$$toofuckingexpensive$$$$$) or maybe the fuel pressure regulator that was just flooding the engine upon starting.

If anyone has an idea, please share. Thanks so much! One quick summary of the issues:

-Need to pump the throttle to start
-idles at 200-300rpm upon starting
-thick, blueish exhaust
-exhaust smells like pure liquid gasoline

[Smelser]

throw away the idle control valve and block all ports that lead to and from it.
set an idle using the screw and the stop on the throttle valve.
if its still really rich, remove the cold start.
if its still really rich, get the injectors removed and cleaned and give it a tune up.

P.S. TAKE YOUR F*CKING WINTER BACK. ONTARIO IS SICK OF THIS WESTERN DEEP FREEZE!!! WE WANT OUR +5 AND SUN!!!

[stanhayward]

throw away the idle control valve and block all ports that lead to and from it.
set an idle using the screw and the stop on the throttle valve.
if its still really rich, remove the cold start.
if its still really rich, get the injectors removed and cleaned and give it a tune up.

P.S. TAKE YOUR F*CKING WINTER BACK. ONTARIO IS SICK OF THIS WESTERN DEEP FREEZE!!! WE WANT OUR +5 AND SUN!!!

Okay thanks I'll try that. And no thanks I'm enjoying the weather for once ;)! I had to pick up my brothers MK1 VW from Calgary in -39C. And it didn't run so we had to trailer it that was the coldest I've ever been so 5 is good :D

[thebutterson]

To test for a leaky cold start injector remove the injector while keeping it connected to the fuel system and turn the key to the second position a few times to build up good fuel pressure. If the cold start injector is leaking, it should be replaced or cleaned. You can also check that the thermo time switch is working by placing a test light on the plug for the cold start injector and attempting to start the car. The light should come on for no more than 8 seconds I believe. Once the car is warmed up you can try to lean out the idle by turning the adjustment screw on the AFM out to increase the air bypassing the flap.

What's the idle rpm when it's warm? You may need to increase the idle, 300 rpm is way to low. I forget what the rpm actually should be, but my car seems happy to be at 1000. I have the idle system removed.