P0300 Code after Cam Swap
03-16-2018, 04:44 PM
#1
Teching In
Thread Starter
P0300 Code after Cam Swap
Just installed a BTR stage 4 Truck cam on my 2012 5.3 GMC Sierra. Took it to get dyno tuned and after leaving shop it started turning off StabiliTrak and traction control when stopped( at Idle), then I would speed up and StabiliTrak and Traction Control would turn back on. Then check engine light came on with code P0300 (random misfire). Drove it back home and going up a hill truck reduced engine power. Checked all cylinders on idle and they are all firing no misfires. Could it just be because the new cam is confusing the computer?
03-16-2018, 05:01 PM
#2
A cam such as that one requires the calibration to be altered on the misfire detection. If you were to watch a live data scan with something like HP Tuners they would be showing sporadic misfires and tripping the code on you.
I would talk to the tuner and ask if they did that or have them do that so it doesn't keep happening.
I would talk to the tuner and ask if they did that or have them do that so it doesn't keep happening.
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GmcSierra53 (03-16-2018)
03-16-2018, 10:12 PM
#3
If it is turning off stabilitrak and Traction control at idle my guess is you don't have enough vacuum at idle. There was a guy posting on here a couple of days ago having the same issues due to the overlap of the cam he installed in a suburban.
03-19-2018, 11:08 PM
#7
Are suggesting an exhaust leak? This is definitely possible, I’m assuming, based on the OP, that the only change done was the cam...since it is a BTR stage 4, and that he already had the supporting valvetrain mods done with the previous cam install (most people wouldn’t go from stock to that cam on a whim, it’s a pretty big cam for a 5.3). I would also wonder what converter he is running, but that’s another issue.
I’m not saying the tuner did anything wrong, just didn’t do enough to account for the change in idle and low rpm characteristics. Any tuner can make the fault code go away, but there is an art to balancing the running characteristics in the tune with the sensitivity of the fault detection.
Don’t blame the tuner, just give him a chance to modify the tune for the issue you are having or make recommendations for you to address some underlying cause...like spark plugs/gap settings to help with the engines needs after the new cam.
(Of course we are assuming it was installed and reassembled correctly)
I’m not saying the tuner did anything wrong, just didn’t do enough to account for the change in idle and low rpm characteristics. Any tuner can make the fault code go away, but there is an art to balancing the running characteristics in the tune with the sensitivity of the fault detection.
Don’t blame the tuner, just give him a chance to modify the tune for the issue you are having or make recommendations for you to address some underlying cause...like spark plugs/gap settings to help with the engines needs after the new cam.
(Of course we are assuming it was installed and reassembled correctly)
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03-20-2018, 08:39 AM
#9
I think it turns out he just went with way too much cam...I think I read in another thread that BTR swapped him out to a stage 1 cam.
Not enough vacuum, not enough tune, and not enough stall for the cam. Like I said, this is a big cam for a 5.3 if you aren’t ready to run at high rpms!
Not enough vacuum, not enough tune, and not enough stall for the cam. Like I said, this is a big cam for a 5.3 if you aren’t ready to run at high rpms!
03-22-2018, 02:49 PM
#10
Teching In
Thread Starter
Truck has a 5.3 with a 6l80. Running longtube headers, yank 3600 stall, built diff with 4.10 gears, ls7 lifters, blue beehive springs, Chromoly pushrods, CAI, dyno tuned. I took it to the tuner yesterday and he said it was the misfire sensitivity he adjusted it and no more check engine light. Update drove it back home 50+ miles then parked it for 30 min and turned it back on and on idle check engine light came back but just blinking then went away no more check engine light for now.