new to the forum sorry if this is a repeat question. my car starts it will run 6-7 min then dies. before it dies it smells rich, see black smoke then dies. i restart it, runs 30 sec dies and will not restart until cold. i have replaced- fuel pump, fuel pressure regulator, crank trigger, cam sensor, module, computer, ignition switch, electric temp sensor, fuel filter. i have unplugged map sensor does not change anything. i put a scanner on it the codes were 303, and i don't remember the code but it said mass volumn air a-circuit performance...i just put the scanner back on and there are no codes. any help or input would be much appreciated....thank u

 

Just a guess (and that is all I'm doing now), I'm guessing your O2 sensor is failing, causing the car to dump too much fuel (hence smelling rich). The CEL codes will probably point to the nature of the real problem. Can your scan tool read historical codes?

 

Hi Bob, welcome to MCF.
Jason will remember I had the same problem 2 w/e ago. (Look on this site for "Braking News" post by me) Although I was getting a O2 sensor code and had Rich smelling exhaust, it turned out that my MAS was not sending all the correct signals to the PCM. This caused the engine to run Rich, then gave me the exact symptoms you described. The engine running Rich caused the O2 sensor code. But I never got a MAS sensor code. You could be having the same problem if your MAS is old or aftermarket.

 

The '303' code would indicate that cylinder #3 is misfiring.


Your symptoms are indicative of a bad ICM.

 

hook your scanner back up and check the MAF data...the readings at idle should be around 4-6...any higher the engine will run incredibly rich...also, watch your 02 data...the readings should be constantly changing from 80mv-900mv...if your scanner can do a graph, it should be reading an up and down graph...also, check your short term fuel trim...it should read plus to minus 7%, no more or less...as long as your oxygen sensor (b1s1) is constantly switching, it is reading correctly...

 

the scanner i was using is a centech tomorrow i will put it on a laptop scanner....thank u so much for your comments ...i will let u know what happens

 

cool...let us know what the scanner shows