High RPM Misfire - Cut out problem... HELP??
10-06-10, 03:53 PM
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High RPM Misfire - Cut out problem... HELP??
OK, here is the dealio
Fairly recently, I started noticing a problem on hard acceleration with my IS as most of you know I am .net/CL OG member and have a custom supercharged/supra TT block-GE head/GS400 TB motor.. has been runnng awesome for 4+ years the motor has been perfect, only problems I have had recently is some down time with my SC after popping a belt finally last year after 2+ years of abuse....
I drive alot in traffic and still drive the car almost daily, when I am hard on it i kept feeling like the Rev limiter was kicking in early.... when i finally paid close attn to the gauges etc i noticed that:
1 - it happend regularly at just over 4500 rpm.....
2 - it happens ONLY if i am pushing the gas pedal past 50% throttle
(IE : if i am at half throttle, accelerating steadily but not aggressively
the car will run steady thru 4500rpm to redline and NOT misfire/cut out.)
3 - it feels like the typical rev limiter/cut out, or like Ignition is misfiring badly
pretty much like i lost a Cyl....?
4 - misfire/cutout happens in any gear if I rev. hard thru 4500 rpm...
5 - when I felt it originally, I always lifted immediately & shifted assuming I
hit the rev limiter.(not paying attn) ..but i began to think..."damn that seemed to hit early" .... but I had NO CE LIGHTS in this time. other than the hi-rpm misfire (?) issue the car starts & runs normally nothing strange.
here is where it gets interesting...
6 - I decided i had to actually PAY ATTN, & TEST this problem..so recently I kept my foot down for a second or two after i felt the misfire and BAM!!! ...CE light,.. can't remember all the codes....but when I looked them up it was basically:
- Evap. Emissions Sys. problem, - PCV valve, Charcoal canister issue etc.
- O2 sensor problems B1-S2 failure + B2 S2 failure...
about 6+_ different codes came up kind of random tho & nothing reflecting a problem with ignition or fuel...??
7 - all CE ligts clear when i reset the ECU by killing power from the battery and they do not come back again unless i hold my foot down again for a second after the misfire/cutout hits at 4500PM, then they all come back again. If driving normally & not hard, I do not get any CE lights at all.
I have checked for Vacuum/ boost leaks after the MAF sensor thru my entire intake system etc and i found nothing, the AF ratios when this hits are in the 12. range...nothing abnormal based on how it was running before this problem arose.
I have replaced the MAF sensor with a brand new one, no improvement
FYI... i am still running the I manage electronic fuel pressure management to add fuel under boost & from what i can tell it is working perefectly as usual. I am also running an HKS DLI ignition systemr And a Turbo XS ignition amplifier. i ran them both as a test after i got the HKS to see what happened and i noticed no problem so I left them both in they connect to the ECU totally differently so i was curious if they would complement each other or cause a problem... the Turbo XS connects to the ECU harness under the ECU cover while the HKS connects to the Ignitor leads right in the engine bay... i have run the car like thsi for almost 3 years....with no problem. (and no discernable improvement either...) I am planning on pulling out the Turbo XS unit and selling it as i think the HKS is fine for my needs on its own.
Because it is a hi rpm/over 50% throttle only issue i have a concern that it could be VVTI related... / or some kind of fuel problem...? Ignition problem?
Obviously,...I am at a loss.....
Finances are tight as a **** still and i really need to try and troubleshoot this as far as i can go on my own before i have to bite the bullet & pay some one to help me figure it out... So as many things as I can check off the list as possible causes for this pain in the *** problem will be a big help to keeping the cost of this repair affordable for me.
I appreciate Any help or advice, i defer to your collective genius
Help!
Ed G.
Fairly recently, I started noticing a problem on hard acceleration with my IS as most of you know I am .net/CL OG member and have a custom supercharged/supra TT block-GE head/GS400 TB motor.. has been runnng awesome for 4+ years the motor has been perfect, only problems I have had recently is some down time with my SC after popping a belt finally last year after 2+ years of abuse....
I drive alot in traffic and still drive the car almost daily, when I am hard on it i kept feeling like the Rev limiter was kicking in early.... when i finally paid close attn to the gauges etc i noticed that:
1 - it happend regularly at just over 4500 rpm.....
2 - it happens ONLY if i am pushing the gas pedal past 50% throttle
(IE : if i am at half throttle, accelerating steadily but not aggressively
the car will run steady thru 4500rpm to redline and NOT misfire/cut out.)
3 - it feels like the typical rev limiter/cut out, or like Ignition is misfiring badly
pretty much like i lost a Cyl....?
4 - misfire/cutout happens in any gear if I rev. hard thru 4500 rpm...
5 - when I felt it originally, I always lifted immediately & shifted assuming I
hit the rev limiter.(not paying attn) ..but i began to think..."damn that seemed to hit early" .... but I had NO CE LIGHTS in this time. other than the hi-rpm misfire (?) issue the car starts & runs normally nothing strange.
here is where it gets interesting...
6 - I decided i had to actually PAY ATTN, & TEST this problem..so recently I kept my foot down for a second or two after i felt the misfire and BAM!!! ...CE light,.. can't remember all the codes....but when I looked them up it was basically:
- Evap. Emissions Sys. problem, - PCV valve, Charcoal canister issue etc.
- O2 sensor problems B1-S2 failure + B2 S2 failure...
about 6+_ different codes came up kind of random tho & nothing reflecting a problem with ignition or fuel...??
7 - all CE ligts clear when i reset the ECU by killing power from the battery and they do not come back again unless i hold my foot down again for a second after the misfire/cutout hits at 4500PM, then they all come back again. If driving normally & not hard, I do not get any CE lights at all.
I have checked for Vacuum/ boost leaks after the MAF sensor thru my entire intake system etc and i found nothing, the AF ratios when this hits are in the 12. range...nothing abnormal based on how it was running before this problem arose.
I have replaced the MAF sensor with a brand new one, no improvement
FYI... i am still running the I manage electronic fuel pressure management to add fuel under boost & from what i can tell it is working perefectly as usual. I am also running an HKS DLI ignition systemr And a Turbo XS ignition amplifier. i ran them both as a test after i got the HKS to see what happened and i noticed no problem so I left them both in they connect to the ECU totally differently so i was curious if they would complement each other or cause a problem... the Turbo XS connects to the ECU harness under the ECU cover while the HKS connects to the Ignitor leads right in the engine bay... i have run the car like thsi for almost 3 years....with no problem. (and no discernable improvement either...) I am planning on pulling out the Turbo XS unit and selling it as i think the HKS is fine for my needs on its own.
Because it is a hi rpm/over 50% throttle only issue i have a concern that it could be VVTI related... / or some kind of fuel problem...? Ignition problem?
Obviously,...I am at a loss.....
Finances are tight as a **** still and i really need to try and troubleshoot this as far as i can go on my own before i have to bite the bullet & pay some one to help me figure it out... So as many things as I can check off the list as possible causes for this pain in the *** problem will be a big help to keeping the cost of this repair affordable for me.
I appreciate Any help or advice, i defer to your collective genius
Help!
Ed G.
10-06-10, 06:38 PM
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If you have o2 sensor problems, pcv valve issues, and etc that can all be related to how well the car runs and can cause them to run rough and have hesitations, is it almost like it is "bogging" out ag 4500 rpm?
10-20-10, 11:38 AM
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so I just bought an AT is300, and have the same issues. The seller made me fully aware of it and is helping me deal with it. Point of the story is, he first thought it was timing related, how ever, after some basic trouble shooting, a friend of his who is a Toyota mechanic said its an ECU issue that was somewhat common. I am waiting to get mine reflashed, hasn't happened yet, so I don't know if this will fix the issue, but he swares it will, and I have had the EXACT same issues you have, i just haven't gotten my codes read so I can't tell you how that matches up.
Hope my first post on CL helps a little bit. Sorry if it doesn't
Hope my first post on CL helps a little bit. Sorry if it doesn't
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