Random misfire occurs @ 6000 rpms, need help.
Nov 3, 2007, 06:46 PM
#46
Subscribing as i have seen first hand on the dyno and at the track(s) cars w/ the same exact inconsistancies and break-up from the shop i bring my car to.
All of them run upgraded turbos from 30r to 35r and leaded race gas 114-118 oct.
All w/ stock coils no amplifiers of any sort and they run gaps about .021-.023
Some will do it only on the dyno.....some only at the track.......some just so random it gets frustarting to watch
The road race evo there is about to switch to cop's but it doesn't sound l ike that may 100% cure the problem.
So is there someone out there that has gone to the cop's similar to ifarted2's review on the ebay kit or buschur's w/ success in getting the misfire tamed?
I'm anxious to see if everyone's prob gets fixed and if so what it takes to keep the cars consistant.
Also most if not all the cars in ? run about 25-30psi boost press.
My car for some reason runs the same leaded gas, same stock coils, same gaps, but no misfire.............. unless i foul my plugs w/ the race gas puttering around.???
All of them run upgraded turbos from 30r to 35r and leaded race gas 114-118 oct.
All w/ stock coils no amplifiers of any sort and they run gaps about .021-.023
Some will do it only on the dyno.....some only at the track.......some just so random it gets frustarting to watch
The road race evo there is about to switch to cop's but it doesn't sound l ike that may 100% cure the problem.
So is there someone out there that has gone to the cop's similar to ifarted2's review on the ebay kit or buschur's w/ success in getting the misfire tamed?
I'm anxious to see if everyone's prob gets fixed and if so what it takes to keep the cars consistant.
Also most if not all the cars in ? run about 25-30psi boost press.
My car for some reason runs the same leaded gas, same stock coils, same gaps, but no misfire.............. unless i foul my plugs w/ the race gas puttering around.???
Last edited by PATRICK B.; Nov 3, 2007 at 06:49 PM.
Nov 3, 2007, 10:18 PM
#47
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One thing to check, this may seem strange, but my tuner told me about a customer who had a DSM with the same exact problem. He made the mistake of switching to a COP ignition before checking his "cam position sensor". The COP obviously didn't change anything, but as soon as they changed out the CPS the problem was gone. I tend to think that if it were the CPS that it would do it all the time, not just randomly, but what do I know, I'll try it and see this week.
I've been wondering if my 02 sensors could have gotten trashed from running 110 leaded fuel and maybe contributing to the problem?
I'm running 23 psi spiking to 24-25 psi, off the WGA on 93 oct making 400WHP.
I've been wondering if my 02 sensors could have gotten trashed from running 110 leaded fuel and maybe contributing to the problem?
I'm running 23 psi spiking to 24-25 psi, off the WGA on 93 oct making 400WHP.
Nov 4, 2007, 08:56 PM
#48
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Sgt Blamo - did you ever install the colder spark plugs? I'm curious because I just started having similar issues - but here's the thing - I have way less mods then you do - including stock igniton, turbo and no cams. I was looking into this prob and I was readin on the NGK site that your supposed to go colder for every 75-100 hp you have. I jusy ordered the BR8ES for my car which is in the 320 whp range. I actually was readin ur other post which said i think you were closer to the 400 whp - you might want to try the next step colder which im assumin would be the BR9ES.
Nov 5, 2007, 02:36 PM
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One thing to check, this may seem strange, but my tuner told me about a customer who had a DSM with the same exact problem. He made the mistake of switching to a COP ignition before checking his "cam position sensor". The COP obviously didn't change anything, but as soon as they changed out the CPS the problem was gone. I tend to think that if it were the CPS that it would do it all the time, not just randomly, but what do I know, I'll try it and see this week.
I've been wondering if my 02 sensors could have gotten trashed from running 110 leaded fuel and maybe contributing to the problem?
I'm running 23 psi spiking to 24-25 psi, off the WGA on 93 oct making 400WHP.
I've been wondering if my 02 sensors could have gotten trashed from running 110 leaded fuel and maybe contributing to the problem?
I'm running 23 psi spiking to 24-25 psi, off the WGA on 93 oct making 400WHP.
Nov 5, 2007, 03:08 PM
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I had the same exact problem you have and I changed the cam position sensor and it was gone!! I went through everything replaced complete ignition new AEM and fuel was perfect.I also went through 3 sets of different plugs.It was the CAM SENSOR.It only takes less than 3 minutes to change it.Yes I have buschur's COP.
Last edited by U2SLO; Nov 5, 2007 at 03:14 PM.
Nov 5, 2007, 03:13 PM
#51
I had the same exact problem you have and I changed the cam position sensor and it was gone!! I went through everything replaced complete ignition and fuel was perfect.I also went through 3 sets of different plugs.It was the CAM SENSOR.It only takes less than 3 minutes to change it.
Nov 5, 2007, 03:56 PM
#52
Well i'm here at the shop and the car i spoke of w/ the very intermitent prob even at idle is here on the dyno so i swapped out CPS from a 2G DSM we had laying around and let the car idle while we logged things and noticed that the batt volts jumped around quite a bit from 12.x-14.0 
We then tried hooking up another battery to the mini we have in the car and all of a sudden no irregular voltage just a nice steady 13.8-14.0
This made a huge diff in idle quality and so far so good as we did a dyno pull and car pulls smooth.
I'll update a little later if we conclude anything just sharing our trials and tribulations
We then tried hooking up another battery to the mini we have in the car and all of a sudden no irregular voltage just a nice steady 13.8-14.0
This made a huge diff in idle quality and so far so good as we did a dyno pull and car pulls smooth.
I'll update a little later if we conclude anything just sharing our trials and tribulations
Nov 7, 2007, 11:07 AM
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Hey guys - I was thinking about this some more and I really doubt the Cam sensor is the issue. Are all you guys with the misfire running Walbro 255s? Because I feel like there are so many guys running into this issue with various mods, there has to be a common link between them all. Could a fuel pump be the problem?
Nov 7, 2007, 12:20 PM
#54
Hey guys - I was thinking about this some more and I really doubt the Cam sensor is the issue. Are all you guys with the misfire running Walbro 255s? Because I feel like there are so many guys running into this issue with various mods, there has to be a common link between them all. Could a fuel pump be the problem?
The car owner has been pretty sick so I haven't been able to touch the car in days but I am logging some outputs tonight via AEM EMS. Should be able to tell if the CPS is the culprit... Also got another calibration (from my car that works flawless) that I am working on to try on this peticular car since his build is nearly identical to mine.
Nov 7, 2007, 01:31 PM
#55
I don't see a fuel pump being everyones problem. A lot of the misfire issues are at certain RPM's like in the case of the car I am working on, 7300rpms till about 8000rpms is the only place the problem really happens. At 8000 RPMs the car takes back off strong, and before the 7300 RPM's the car is VERY strong (PT6776 turbo @ 24lbs of boost). If it was a real pump related issue I would imagine at a certain amount of boost the problem would start and not go away later in the RPM's. Anything is possible however and I am slowly going through one thing at a time till I get my answer. In several cases people have cured the issue with a CPS.
The car owner has been pretty sick so I haven't been able to touch the car in days but I am logging some outputs tonight via AEM EMS. Should be able to tell if the CPS is the culprit... Also got another calibration (from my car that works flawless) that I am working on to try on this peticular car since his build is nearly identical to mine.
The car owner has been pretty sick so I haven't been able to touch the car in days but I am logging some outputs tonight via AEM EMS. Should be able to tell if the CPS is the culprit... Also got another calibration (from my car that works flawless) that I am working on to try on this peticular car since his build is nearly identical to mine.
I'm curious to see if it's fluctuating like our problem.
FWIW We ended up swapping out Odyssey small batts w/ another car in the shop and IT WORKED.
Volts were steady and car pulled as clean as ever.
Don't know if that is a common problem but hope it may help others.
Please inform me if anyone else out there has similar findings.
Nov 7, 2007, 01:42 PM
#56
Could you please do me a favor and log the batt volts.
I'm curious to see if it's fluctuating like our problem.
FWIW We ended up swapping out Odyssey small batts w/ another car in the shop and IT WORKED.
Volts were steady and car pulled as clean as ever.
Don't know if that is a common problem but hope it may help others.
Please inform me if anyone else out there has similar findings.
I'm curious to see if it's fluctuating like our problem.
FWIW We ended up swapping out Odyssey small batts w/ another car in the shop and IT WORKED.
Volts were steady and car pulled as clean as ever.
Don't know if that is a common problem but hope it may help others.
Please inform me if anyone else out there has similar findings.
I'll see what the battery volts does as well. Hope to have some information shortly here.
Nov 7, 2007, 01:50 PM
#57
The previous batt in the car in ? was replaced dut to the pos. terminal post rotating in the housing and causing an inconsistant voltage reading and misfire even at idle
Nov 7, 2007, 02:41 PM
#59
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I had the same exact problem you have and I changed the cam position sensor and it was gone!! I went through everything replaced complete ignition new AEM and fuel was perfect.I also went through 3 sets of different plugs.It was the CAM SENSOR.It only takes less than 3 minutes to change it.Yes I have buschur's COP.
Nov 7, 2007, 03:22 PM
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Great I was pissed to like I said went over the entire wiring harness replaced AEM cop ignition,fuel system plugs, plugs, checked grounds all over went crazy,then replaced the cam sensor the car was perfect good luck and please let us know!! Thanks.