MAF dirt, rich or lean results and dead CATS?
08-20-2008, 09:36 PM
#1
MAF dirt, rich or lean results and dead CATS? Basically I think I fucked up.
Tuning the MAF this morning, nothing seemed wrong, just logging getting in values but noting the correction for the MAF with STFT was weird vs LTFT.
Put car away at lunch and went along my day.
Come to evening now and I went for a drive. Car was SLUGGISH. Lite throttle and the car did not cleanly accelerate, like hitting mini hurricane level gusts as a headwind kind of feel. Not good. On 50% throttle and WOT, strange "popping" and thumping noises coming out the exhaust. Thumps didn't sound like in front, but rather from underneath, ie exhaust. Large pops out the back pipe just cruising or decelerating but not the sound of backfire, more like "pressure buildup" and a deep bass rich pop. I've restored various previous tunes from over the past few days and even before I messed with HP tuners. No dice.
I focus on the MAF since I was tuning that solely today. I take it apart and find lots of dirt on it caked on. Not good. I clean it up, take the car for a drive and find the original tune had 5-14 percentage off on LTFT from the initial 21-24 I logged when I first started tuning.
I'm wondering if the dirt gave me a false reading which when I added to the MAF, told the PCM I had more air and thus more fuel was added. An hour or two of running this way tuning the MAF and ended up running too much fuel through my cats which ended up killing them?!??
Yesterday evening and tonight had similar air conditions, yet obviously something's fucked now. Throttle response isn't as crisp and the lack of power shows as even in cool temps and the dark, I'm not roasting my tires on command in first from a roll.
Some input in the matter would be appreciated...
Tuning the MAF this morning, nothing seemed wrong, just logging getting in values but noting the correction for the MAF with STFT was weird vs LTFT.
Put car away at lunch and went along my day.
Come to evening now and I went for a drive. Car was SLUGGISH. Lite throttle and the car did not cleanly accelerate, like hitting mini hurricane level gusts as a headwind kind of feel. Not good. On 50% throttle and WOT, strange "popping" and thumping noises coming out the exhaust. Thumps didn't sound like in front, but rather from underneath, ie exhaust. Large pops out the back pipe just cruising or decelerating but not the sound of backfire, more like "pressure buildup" and a deep bass rich pop. I've restored various previous tunes from over the past few days and even before I messed with HP tuners. No dice.
I focus on the MAF since I was tuning that solely today. I take it apart and find lots of dirt on it caked on. Not good. I clean it up, take the car for a drive and find the original tune had 5-14 percentage off on LTFT from the initial 21-24 I logged when I first started tuning.
I'm wondering if the dirt gave me a false reading which when I added to the MAF, told the PCM I had more air and thus more fuel was added. An hour or two of running this way tuning the MAF and ended up running too much fuel through my cats which ended up killing them?!??
Yesterday evening and tonight had similar air conditions, yet obviously something's fucked now. Throttle response isn't as crisp and the lack of power shows as even in cool temps and the dark, I'm not roasting my tires on command in first from a roll.
Some input in the matter would be appreciated...
