tuner upgraded OS to 2002 and did some small changes in PCM now misfire code?
12-25-2007, 09:54 AM
#1
tuner upgraded OS to 2002 and did some small changes in PCM now misfire code? Ok, recently I put a 10 bolt rearend from a M6 car in my 99 A4 Z28 car. I had a tuner do the changes for me in the PCM to calibrate it for the 3.42 gears as well as turn off the EGR/AIR codes and delete the rear 02 sensors. He also did some other small changes for the transmission to make the shifts more crisp, turned off the .2 shift delay between gears and removed the cat overheat protection. He also upgraded my OS to a 2002 OS.
Now when I get on the interstate and go any faster than 67 mph my SES light flashes at me and I throw a PO300 random misfire code, but the car does not run badly at all. It loses no performance and if you just barely accelrate from like 60 to 70 mph at the point the SES light starts flashing the way the car is running does not change one bit. No hesitation or even a slight miss or anything at that point. I have completely pulled the ignition system, checked the plugs which were just replaced 2k miles ago, changed wires, all that good stuff and the SES light still flashes at me at 67 mph and faster. Do you think this could be caused by one of the changes he made in the PCM or maybe did him upgrading my OS to a 2002 OS do this? Just looking for some opinions on this. thanks in advance.
Now when I get on the interstate and go any faster than 67 mph my SES light flashes at me and I throw a PO300 random misfire code, but the car does not run badly at all. It loses no performance and if you just barely accelrate from like 60 to 70 mph at the point the SES light starts flashing the way the car is running does not change one bit. No hesitation or even a slight miss or anything at that point. I have completely pulled the ignition system, checked the plugs which were just replaced 2k miles ago, changed wires, all that good stuff and the SES light still flashes at me at 67 mph and faster. Do you think this could be caused by one of the changes he made in the PCM or maybe did him upgrading my OS to a 2002 OS do this? Just looking for some opinions on this. thanks in advance.
Last edited by tording99Z28; 12-25-2007 at 10:52 AM.
12-25-2007, 02:33 PM
#2
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something in the tranny? tune? something got changed/ value got modified that shouldn't have maybe.
its somewhere hidden in that tune. your tuner should be able to compare stock VS new tune and see what all was changed
good luck
its somewhere hidden in that tune. your tuner should be able to compare stock VS new tune and see what all was changed
good luck
12-26-2007, 09:04 AM
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You might want to speak to the tuner and verify if he transfered the base '99 calibration to the '02 OS. There are significant differences between the '99 and '02 calibrations, not to mention the changes in the OS.
In the event the P0300 is real, I'd avoid pushing the car to the point it throws that code.
In the event the P0300 is real, I'd avoid pushing the car to the point it throws that code.
12-26-2007, 09:34 AM
#6
No, not cammed. Not YET anyway. Soon though.
He says he did copy the 99 calibration over to the 02 file and OS. The car runs good and pulls hard. The only thing I have to do to avoid the misfire code and SES light flashing is stay under 67 mph. If I go 67 or higher it flashes, even if I am just cruising at a constant speed of like 70 mph. Is there something that is suppose to happen at 67 mph in the PCM or something maybe?
I am going to go back to him and see if he can reload the stock 99 OS and tune and see if that takes care of it. If it does then I know that its something with the tune. He is a couple hour drive away though so I have to wait till I can get back up to him. He is a friend of a friend so I know he will help me fix it. Just thought maybe you tuning guys have heard of something like this before.
He says he did copy the 99 calibration over to the 02 file and OS. The car runs good and pulls hard. The only thing I have to do to avoid the misfire code and SES light flashing is stay under 67 mph. If I go 67 or higher it flashes, even if I am just cruising at a constant speed of like 70 mph. Is there something that is suppose to happen at 67 mph in the PCM or something maybe?
I am going to go back to him and see if he can reload the stock 99 OS and tune and see if that takes care of it. If it does then I know that its something with the tune. He is a couple hour drive away though so I have to wait till I can get back up to him. He is a friend of a friend so I know he will help me fix it. Just thought maybe you tuning guys have heard of something like this before.