Filthy rich 98 with no codes. Any ideas?
#1
Filthy rich 98 with no codes. Any ideas?
I have a 98 SE 5 spd. Here's a little recent maintenance background. I replaced the fuel filter, cleaned the MAF, and cleaned the K&N about 5k miles ago. I replaced spark plugs with OE NGKs about 12k miles ago when I changed the valve cover gaskets.
Recently, the car has begun running very rich. It smells like cold-start idle well after it has reached operating temperature. Also, my fuel mileage has dropped a little (only premium since ownership). I've never had an OBDII vehicle run this rich with no codes. The only code I have ever had on this Max was when I forgot to reconnect the intake temp sensor after replacing the radiator about 3 months ago. I reconnected the sensor and the light went away. In the last couple thousand miles, the car runs very rich. Has anyone run into this situation? Any ideas?
Recently, the car has begun running very rich. It smells like cold-start idle well after it has reached operating temperature. Also, my fuel mileage has dropped a little (only premium since ownership). I've never had an OBDII vehicle run this rich with no codes. The only code I have ever had on this Max was when I forgot to reconnect the intake temp sensor after replacing the radiator about 3 months ago. I reconnected the sensor and the light went away. In the last couple thousand miles, the car runs very rich. Has anyone run into this situation? Any ideas?
#3
Thanks for the input. It was running perfect for a couple thousand after I cleaned it, but I suppose it's possible. Short of getting my hands on another MAF, is there a way to definitively test it?
Edit: Will the voltage readings be out of the FSM specs without tripping a light?
Edit: Will the voltage readings be out of the FSM specs without tripping a light?
Last edited by nelledge; 12-30-2010 at 08:27 PM.
#5
#6
yea if u have a multimeter, or a friend that will let u guinea pig his MAF.
#8
#10
as far as i know if the voltage is out of range it will trip the CEL, but the voltage could also be slightly off causing the car to think its sucking in more air then it really is causing it to run rich.
#11
Should I follow the FSM test points directly at the ECM or is their a proven 'easier' test point for the MAF and O2s?
#12
#13
im thinking maybe you have a manifold leak exhaust or intake thats making your engine suck in too much air. the thing is if its an intake leak it will usually cause all kinds of drivability problems. grab a scantool and check your long term fuel trim and short term fuel trim thats a good place to start
do you have any major drivability problems? missfiring, hard start, long start, hessitation?
do you have any major drivability problems? missfiring, hard start, long start, hessitation?
#14
Thanks for all the replies! I was going to start at the signal values for the MAF and O2 sensors and move onto checking for intake/vacuum leaks today. However, someone offered cash to take the ol' gal this morning. I'm gonna miss her. She was a great car.
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