Author Topic: e36 m42 rich condition after alternator install (Read 2606 times)

bearsbmw · « **on:** September 28, 2008, 03:36:56 PM »

Car is running rich at idle & at cruise... When starting the car when warm the rpms will go up and down untill I press the gas a little bit and it will correct and idle smoothly... Sometimes the check engine light will come on at cruise and if I push the gas a little it will go away*

*
Cleaned ICV
Vaccum Guage showing -30
91 octane gas

Any ideas?

Jimmy Lewis · « **Reply #1 on:** September 28, 2008, 06:21:37 PM »

What code is it throwing? I would make sure the AFM is good and clean if the light turns off with throttle input. There are tons of things that could make the car run rich, but since you obviously just did some work to it, I would check the stuff that you removed and such.

bearsbmw · « **Reply #2 on:** September 28, 2008, 06:38:49 PM »

When you say clean afm do you mean the inner workings under the black box on top? after I put the alternator in I ran out of gas(not realizing Duh!) and tryed starting the car and it would stall so I put my hand in the afm and played with the door flaper and worked the throtle at the same time... could that have screwed something up under the black box?

Jimmy Lewis · « **Reply #3 on:** September 28, 2008, 07:32:12 PM »

I don't know if it messed something up, but I would remove it and clean the inside, not anything under the cover, but make sure the door opens and closes without any catching. Make sure the actual probe thingy isn't damaged while you clean it though. I would see if you can find someone else with a M42 to test their AFM on your car, it's free and could save you a lot of time if that's the issue. Because the ECU tells the AFM when to open and close, manually opening it while it is running could have messed up something mechanically in the AFM.

bearsbmw · « **Reply #4 on:** September 28, 2008, 10:14:43 PM »

allright I will try that... thanks!

bearsbmw · « **Reply #5 on:** September 30, 2008, 05:47:20 PM »

AFM is ok ... I notice a pattern befor I get the check light and that is that Air/Fuel Guage is reading allways 11.4 befor it throws the check engine and Im prity sure narrow band O2s are never spose to hold unless they are at WOT or during engine brakeing... Befor I had this problem when starting the car cold in the morning the sensor would read 14 and slowly goto 18-19 untill I gave it some gas and now the exact oppostie is happening and its 16 to 12

bearsbmw · « **Reply #6 on:** October 02, 2008, 05:28:27 PM »

after 2 weeks of trying to figure out what was going on with the fuel I found that the heater element in the 02 sensor failed and with obd1 the dme will not see this and the sensor still keep's working but at idle get's too cold therefor tricking the dme into runing pig rich... thanks all who helped !