Need Help
It seems that it is a gremlin somewhere in the fuel delivery. I am experiencing the same thing.
I left my car in open loop with the pig rich idle and light cruise. It seems that the problem is at very low throttle "super rich condition" with a sudden jump in AFRs after 25% and up of TPS. The car will go from 11.0-10.9 to 14.9-15.2 in less than a mm move at the gas pedal while cruising. Therefore, in closed loop... the car will try to match the 14.7 target at the super rich condition and when it sudden jump the AFR.... the car will go super lean causing a lot of hesitation and stalls. After a few hours or maybe a day.... it will throw the P0172.
Very frustrating!
I left my car in open loop with the pig rich idle and light cruise. It seems that the problem is at very low throttle "super rich condition" with a sudden jump in AFRs after 25% and up of TPS. The car will go from 11.0-10.9 to 14.9-15.2 in less than a mm move at the gas pedal while cruising. Therefore, in closed loop... the car will try to match the 14.7 target at the super rich condition and when it sudden jump the AFR.... the car will go super lean causing a lot of hesitation and stalls. After a few hours or maybe a day.... it will throw the P0172.
Very frustrating!
Honestly, anything I could think of you already had listed. It never hurts to double check things.
On a side note, I was just down there yesterday finally getting my new Evo tuned. I didn't know that was your Evo sitting there in the shop. I was standing there looking at it and had no idea
EDIT: I'm sure a boost leak test was already done on the comp. inlet, but did you connect the tester to the throttle body? I've never heard of this happening and most logical things have been checked, so I'm just throwing this out there... it could be a retarded idea. Could boost possibley leak through the valve guides and past the valve seals? I'd assume if boost could leak through then the car would burn oil. New IM gasket maybe?
Edit 2: Nevermind, you're having this problem in vaccum, right? So a boost leak shouldn't be the cause. If there was a vaccum leak big enough the cause an issue then sure enough a boost leak would be obvious.
On a side note, I was just down there yesterday finally getting my new Evo tuned. I didn't know that was your Evo sitting there in the shop. I was standing there looking at it and had no idea
EDIT: I'm sure a boost leak test was already done on the comp. inlet, but did you connect the tester to the throttle body? I've never heard of this happening and most logical things have been checked, so I'm just throwing this out there... it could be a retarded idea. Could boost possibley leak through the valve guides and past the valve seals? I'd assume if boost could leak through then the car would burn oil. New IM gasket maybe?
Edit 2: Nevermind, you're having this problem in vaccum, right? So a boost leak shouldn't be the cause. If there was a vaccum leak big enough the cause an issue then sure enough a boost leak would be obvious.
Last edited by MitsuJDM; Oct 1, 2009 at 11:49 AM.
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Honestly, anything I could think of you already had listed. It never hurts to double check things.
On a side note, I was just down there yesterday finally getting my new Evo tuned. I didn't know that was your Evo sitting there in the shop. I was standing there looking at it and had no idea
EDIT: I'm sure a boost leak test was already done on the comp. inlet, but did you connect the tester to the throttle body? I've never heard of this happening and most logical things have been checked, so I'm just throwing this out there... it could be a retarded idea. Could boost possibley leak through the valve guides and past the valve seals? I'd assume if boost could leak through then the car would burn oil. New IM gasket maybe?
Edit 2: Nevermind, you're having this problem in vaccum, right? So a boost leak shouldn't be the cause. If there was a vaccum leak big enough the cause an issue then sure enough a boost leak would be obvious.
On a side note, I was just down there yesterday finally getting my new Evo tuned. I didn't know that was your Evo sitting there in the shop. I was standing there looking at it and had no idea
EDIT: I'm sure a boost leak test was already done on the comp. inlet, but did you connect the tester to the throttle body? I've never heard of this happening and most logical things have been checked, so I'm just throwing this out there... it could be a retarded idea. Could boost possibley leak through the valve guides and past the valve seals? I'd assume if boost could leak through then the car would burn oil. New IM gasket maybe?
Edit 2: Nevermind, you're having this problem in vaccum, right? So a boost leak shouldn't be the cause. If there was a vaccum leak big enough the cause an issue then sure enough a boost leak would be obvious.
I am having the same issue right now. Eating up gas like it's free, getting to the point I can't afford to drive to work. Problem is my Evo is my daily driver, getting to cold to ride the bike now. Mine started after having tranny replaced. HELP!!!
I haven't had any luck tracking this down either ... i re-enabled my ECUs ability to throw the p0172 error code and it basically comes back after 1-5 minutes of driving. The driving conditions don't seem to be a factor, I've driven it for 1-5 minutes at <= 20mph and 1-5 min at ~60mph
Although I think my issue might be slightly difference since the data that I collect while logging (with EvoScan) does not match the data that is stored by the ECU when the error code is encountered.
The standard Evo VIII fuel maps go well into the 9.x:1 AFR at higher RPM which is pretty rich (at least in general I think so) and even my modified map which dips into the mid 10.x:1 at peak RPM would still cause a P0172 System Too Rich Bank1 condition.
alicea8541 ... what kind of MPG are you getting? ... For a comparison, with aggressive driving my Evo will get about 15-16 street, with more relaxed driving i can get ~18 mpg street. (highway I'll get ~24 mpg or so)
Although I think my issue might be slightly difference since the data that I collect while logging (with EvoScan) does not match the data that is stored by the ECU when the error code is encountered.
The standard Evo VIII fuel maps go well into the 9.x:1 AFR at higher RPM which is pretty rich (at least in general I think so) and even my modified map which dips into the mid 10.x:1 at peak RPM would still cause a P0172 System Too Rich Bank1 condition.
alicea8541 ... what kind of MPG are you getting? ... For a comparison, with aggressive driving my Evo will get about 15-16 street, with more relaxed driving i can get ~18 mpg street. (highway I'll get ~24 mpg or so)
I haven't had any luck tracking this down either ... i re-enabled my ECUs ability to throw the p0172 error code and it basically comes back after 1-5 minutes of driving. The driving conditions don't seem to be a factor, I've driven it for 1-5 minutes at <= 20mph and 1-5 min at ~60mph
Although I think my issue might be slightly difference since the data that I collect while logging (with EvoScan) does not match the data that is stored by the ECU when the error code is encountered.
The standard Evo VIII fuel maps go well into the 9.x:1 AFR at higher RPM which is pretty rich (at least in general I think so) and even my modified map which dips into the mid 10.x:1 at peak RPM would still cause a P0172 System Too Rich Bank1 condition.
alicea8541 ... what kind of MPG are you getting? ... For a comparison, with aggressive driving my Evo will get about 15-16 street, with more relaxed driving i can get ~18 mpg street. (highway I'll get ~24 mpg or so)
Although I think my issue might be slightly difference since the data that I collect while logging (with EvoScan) does not match the data that is stored by the ECU when the error code is encountered.
The standard Evo VIII fuel maps go well into the 9.x:1 AFR at higher RPM which is pretty rich (at least in general I think so) and even my modified map which dips into the mid 10.x:1 at peak RPM would still cause a P0172 System Too Rich Bank1 condition.
alicea8541 ... what kind of MPG are you getting? ... For a comparison, with aggressive driving my Evo will get about 15-16 street, with more relaxed driving i can get ~18 mpg street. (highway I'll get ~24 mpg or so)
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Just filled it up this evening on my way to work. About a 40 mile round trip. Then put another 28 miles doing some logging to see if I could find the problem. Zero boost, 68 miles and I have almost ate up half a tank. Ouch. May have figured out my problem. Stock O2 sensor when it worked logged .04-.8 volts while logging idle in order to set latencies/scaling. The replacement O2 sensor stays at .8-.9, pretty much never moves. Just sent an email to oxygensensors.com to tell them they either sent me the wrong one,(plug matched though) or it was defective.
Cali's car put us over our nerves on this one ;(
we tried everything we could.... and did our best to be fair about the labor and work we did...
the cars behavior is the most ODD thing ive ever seen on one of these cars...
it will just cycle itself in the negative trims.. 0 to -25 then zip back to 0 then -25 etc...
cb
we tried everything we could.... and did our best to be fair about the labor and work we did...
the cars behavior is the most ODD thing ive ever seen on one of these cars...
it will just cycle itself in the negative trims.. 0 to -25 then zip back to 0 then -25 etc...
cb