GT500Ron Posted May 16, 2009 Report Share Posted May 16, 2009 About 2 months ago I purchased a K&N CAI without a tune and my 08 GT500 ran strong but a lot of you guys said I was running a way to leaan and I needed a tune. Well, last week I ordered a tuner with tune for K&N from VMP. I loaded it yesterday at lunch and drove it back to my office and to the local cruise last night. I was a very happy camper because the performance is great. This was about 60 miles on the new tune. This morning I decided to play with my toy and the check engine light came on. I took it to a local shop to scan and it turns out that at around 3,800 RPM with the engine warm number 5 misfired. We decided that it was because the tune was new and the ECU was still learning. The car was still running great so we reset the code. SO,,,, I decided to play some more and after about 20 miles of stop and go driving and running through the gears at around 5500 RPM between changes the Check Engine Light is back on. I just ran the scan with my new tuner and guess what, number 5 has misfired again. My SCT 3000 does not give me any additional details but I reset the code again. My question, do I have a problem or is the ECU still learning? Link to comment Share on other sites More sharing options...
Vette Killer Posted May 16, 2009 Report Share Posted May 16, 2009 About 2 months ago I purchased a K&N CAI without a tune and my 08 GT500 ran strong but a lot of you guys said I was running a way to leaan and I needed a tune. Well, last week I ordered a tuner with tune for K&N from VMP. I loaded it yesterday at lunch and drove it back to my office and to the local cruise last night. I was a very happy camper because the performance is great. This was about 60 miles on the new tune. This morning I decided to play with my toy and the check engine light came on. I took it to a local shop to scan and it turns out that at around 3,800 RPM with the engine warm number 5 misfired. We decided that it was because the tune was new and the ECU was still learning. The car was still running great so we reset the code. SO,,,, I decided to play some more and after about 20 miles of stop and go driving and running through the gears at around 5500 RPM between changes the Check Engine Light is back on. I just ran the scan with my new tuner and guess what, number 5 has misfired again. My SCT 3000 does not give me any additional details but I reset the code again. My question, do I have a problem or is the ECU still learning? I doubt the ECU learning mode would have any impact on a single cylinder missfire...the fact that the same one returned would lead me to think you have a bad coil on that cylinder. Link to comment Share on other sites More sharing options...
Leroy Posted May 16, 2009 Report Share Posted May 16, 2009 About 2 months ago I purchased a K&N CAI without a tune and my 08 GT500 ran strong but a lot of you guys said I was running a way to leaan and I needed a tune. Well, last week I ordered a tuner with tune for K&N from VMP. I loaded it yesterday at lunch and drove it back to my office and to the local cruise last night. I was a very happy camper because the performance is great. This was about 60 miles on the new tune. This morning I decided to play with my toy and the check engine light came on. I took it to a local shop to scan and it turns out that at around 3,800 RPM with the engine warm number 5 misfired. We decided that it was because the tune was new and the ECU was still learning. The car was still running great so we reset the code. SO,,,, I decided to play some more and after about 20 miles of stop and go driving and running through the gears at around 5500 RPM between changes the Check Engine Light is back on. I just ran the scan with my new tuner and guess what, number 5 has misfired again. My SCT 3000 does not give me any additional details but I reset the code again. My question, do I have a problem or is the ECU still learning? Suggest to swap the no 2 & 3 coils if the light comes on with the same code for no 3 regap your spark plugs to 030. If it moves to no 2 you have a bad coil. You might just regap all the plugs on that bank while you are there. There have been some reports of plugs fouling due to higher supercharger boost with custom tunes Ted Link to comment Share on other sites More sharing options...
GT500Ron Posted May 17, 2009 Author Report Share Posted May 17, 2009 Suggest to swap the no 2 & 3 coils if the light comes on with the same code for no 3 regap your spark plugs to 030. If it moves to no 2 you have a bad coil. You might just regap all the plugs on that bank while you are there. There have been some reports of plugs fouling due to higher supercharger boost with custom tunes Ted Thanks for the suggestions guys. Tonight there was a new twist to this thing. The Check Engine Light did not come back on but at one point just cruising along at slow speeds the Check Engine Light started flashing and flashed for at least 10 seconds, maybe more and then turned off. When I got home I checked to see if any codes were returned but it said no codes on the display. The car is running great during all this. Link to comment Share on other sites More sharing options...
GT500Ron Posted May 17, 2009 Author Report Share Posted May 17, 2009 Thanks for the suggestions guys. Tonight there was a new twist to this thing. The Check Engine Light did not come back on but at one point just cruising along at slow speeds the Check Engine Light started flashing and flashed for at least 10 seconds, maybe more and then turned off. When I got home I checked to see if any codes were returned but it said no codes on the display. The car is running great during all this. Another update to this issue: Today I flashed it back to stock tune. I put it through stop and go, hard starts and high RPM shifts for about 15 miles with no issues, except for a lot less performance than with the tune. I did notice that the boost with the tune would jump up to about 10lb and stock is only about 5lb. Maybe I was fouling my plugs???? I will leave it stock for a few days to see what happens. Link to comment Share on other sites More sharing options...
littlejohn Posted May 17, 2009 Report Share Posted May 17, 2009 I would guess that it is your plugs; gap 'em to .035, or while you're at it buy some NGK TR6IX iridium plugs gapped to .035 to ensure no spark plug blowout. It's what I have in at 600+ rwhp, and have no issues, car pulls like a freight train. Link to comment Share on other sites More sharing options...
GT500Ron Posted May 17, 2009 Author Report Share Posted May 17, 2009 I would guess that it is your plugs; gap 'em to .035, or while you're at it buy some NGK TR6IX iridium plugs gapped to .035 to ensure no spark plug blowout. It's what I have in at 600+ rwhp, and have no issues, car pulls like a freight train. I am now waiting to hear from VMP to see what they think is going on. Earlier about 19 miles after I returned to stock tune my Check Engine Light came on while backing out of my garage at about 1,000 RPM. This time the returned codes were P0171 (System too Lean (b1) and P0174 (System Too Lean (b2). This must have something to do with the ECU Learning, Right? The K&N leans out at high RPMs or WOT, Right? Link to comment Share on other sites More sharing options...
gtt500 Posted May 17, 2009 Report Share Posted May 17, 2009 I am now waiting to hear from VMP to see what they think is going on. Earlier about 19 miles after I returned to stock tune my Check Engine Light came on while backing out of my garage at about 1,000 RPM. This time the returned codes were P0171 (System too Lean (b1) and P0174 (System Too Lean (b2). This must have something to do with the ECU Learning, Right? The K&N leans out at high RPMs or WOT, Right? Have you tried using the stock air box again to rule out a lean condition ? It may also be air turbelence causing the MAF sensor to scew-up. Link to comment Share on other sites More sharing options...
Slabo Posted May 18, 2009 Report Share Posted May 18, 2009 I am now waiting to hear from VMP to see what they think is going on. Earlier about 19 miles after I returned to stock tune my Check Engine Light came on while backing out of my garage at about 1,000 RPM. This time the returned codes were P0171 (System too Lean (b1) and P0174 (System Too Lean (b2). This must have something to do with the ECU Learning, Right? The K&N leans out at high RPMs or WOT, Right? I wouldn't drive my car with the K&N CAI without a tune. If you are running the stock tune put the stock air cleaner back on until Justin can help you out. Link to comment Share on other sites More sharing options...
GT500Ron Posted May 19, 2009 Author Report Share Posted May 19, 2009 I wouldn't drive my car with the K&N CAI without a tune. If you are running the stock tune put the stock air cleaner back on until Justin can help you out. VMP emailed me new tunes with adjustments for my issues. I loaded it today and have only driven a few miles but with no codes returned. The performance is very good and I am a happy camper. Thanks to everyone that replied Ron Link to comment Share on other sites More sharing options...
ingram4868 Posted May 19, 2009 Report Share Posted May 19, 2009 VMP emailed me new tunes with adjustments for my issues. I loaded it today and have only driven a few miles but with no codes returned. The performance is very good and I am a happy camper. Thanks to everyone that replied Ron Good news. Let us know either way after you've put some miles on it. Link to comment Share on other sites More sharing options...
GT500Ron Posted June 1, 2009 Author Report Share Posted June 1, 2009 VMP emailed me new tunes with adjustments for my issues. I loaded it today and have only driven a few miles but with no codes returned. The performance is very good and I am a happy camper. Thanks to everyone that replied Ron I just returned from the North West meet at (Grabber's House). This put this tune to a great test with lots of hot weather 70 to 85MPH cruising on the trip down and back with the AC turned way up. On the cruise we did a lot of 0 to 80 and one or two 0 to 100mph runs through the gears. When I got home the trip was 375 miles and my average MPG was 19.9. Last year the same trip was ended at 17.1 mpg. The performance was great. I was able to hold my own from the stops with even the SS's but then again we were not racing so who knows. My boost was hitting around 10lb and I did not install a pulley. No returned codes and very smooth awsome performance. Thanks to Justin for a quick successfull response to my issues. Link to comment Share on other sites More sharing options...
GOTSVT? Posted June 1, 2009 Report Share Posted June 1, 2009 Justin is good! Link to comment Share on other sites More sharing options...
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