HELP!! TPI running excessively rich
puzzled john
05-15-2005, 08:01 AM
I was wonering if someone could help me. i just got my 85 tuned port running that has been sitting around a long time and it runs excessively rich to the point it makes your eyes water!! There are no codes and i already replaced the mass air flow and all of the injectors still no change?? I also have the correct fuel pressure at the rail and the return line is clear. What can cause this? i am thinking the ECM is bad. my car also has a piggy back ecm for the mass air flow (1985 only). THANKS IN ADVANCE FOR ANY HELP
1986Z28
05-15-2005, 09:48 AM
try replacing the O2 sensor i had the same problem with my caprice
puzzled john
05-15-2005, 11:52 AM
the o2 is new, also i had to time the motor, i was wondering if the fuel is timed with the spark, it may not be timed with the #1 cylinder on the cap, i wasn't sure where # 1 was on the cap. but it starts right up.
Morley
05-15-2005, 02:00 PM
the o2 is new, also i had to time the motor, i was wondering if the fuel is timed with the spark, it may not be timed with the #1 cylinder on the cap, i wasn't sure where # 1 was on the cap. but it starts right up.
No, the injectors are batch fired, so they will be firing when the valve is closed and when open.
Try removing the connector to the MAF and start the car and see if it is still running pig rich.
The box piggybacked to the ECM is the MAS module, it powers the MAF and provides the burnoff function.
Lastly, get a scanner (laptop, winaldl prog and simple cablebuilt from schematics on the winaldl site) and see what the BLM's are, check O2 voltages.
No, the injectors are batch fired, so they will be firing when the valve is closed and when open.
Try removing the connector to the MAF and start the car and see if it is still running pig rich.
The box piggybacked to the ECM is the MAS module, it powers the MAF and provides the burnoff function.
Lastly, get a scanner (laptop, winaldl prog and simple cablebuilt from schematics on the winaldl site) and see what the BLM's are, check O2 voltages.
puzzled john
05-15-2005, 07:59 PM
thank you everyone so far. I have a snap -on scanner. and the 02 is reading very rich 980+. when i unplug the mass air flow it is the same no change at all. do you think it could be the piggyback brain for the maf???
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