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Replaced engine now running like crap

1K views 6 replies 4 participants last post by  Sixt3 
#1 ·
This is somewhat of a long story but I'll try and keep it as short as possible with as much detail as I can think of. I have an 06 AWD SS that I bought about a year ago with some mods already done to it. I was told when I bought the truck, the engine was just rebuilt buy a very reputable shop outside Toronto that specializes in corvette's with a block out of an 06-07 z06, it had a K&N cold air intake, cam, ported heads, oil pickup relocation, kooks long tube headers, 3200 stall, trans rebuilt with a shift kit and trans cooler, and some unrelated suspension and exhaust work. the truck has been driving great since I bought it. A few weeks ago I left work for lunch, picked up my food and when I started the truck it sounded like it was misfiring and wasn't driving right. I was only 2 blocks away so I limped back to the office. After work, I started the truck, same thing happened, I was driving it about a half mile to the auto parts shop to have the codes ran when it started making a metal on metal noise, the engine light started flashing and the truck stalled as I was pulling over. The truck wouldn't turn over, engine was seized. I had the truck towed to a local engine shop where they quoted me $6500 to rebuild or $2500 to pull and install another engine( I have a spare complete motor I pulled out of my 07 when I totaled it) I decided to do the R&R myself and save some cash. It took me a full day to pull the engine out myself. I found a broken valve spring, shattered piston #7, the exhaust valve shot out the headers and is rattling around inside the Y pipe, and the intake valve fell down and was lodged between the crank and engine wall which seized the motor. Fun. when I put the new engine in and started to connect the harness I noticed the crank position sensor did not match. After doing some research on here I found that between 06 and 07 they changed from a 24x to 58x and they are not interchangeable. So I pulled the complete harness out and installed the harness and ECM that went with the 07 engine. Once I got everything back together, (including the stock stall) and relearned the passlock the engine fired right up, ran for a couple seconds and shut off. Found a loose ground on the front pass side of the block, tightened the ground and it started and ran again. I did have a reduced engine power light on, this was caused by the geniuses at GM, for whatever reason from 06 to 07 they changed two wires on the gas pedal at the TPS, they left them in the same position and the same colors but switched what each wire did. I re-pinned the TPS and the truck seemed to run great. It was idling at about 600, but every 20-30 seconds it would kick up to around 1000 and the engine light would come on and flash 19 times. My friend who is a tech at the local Chevy dealer hooked up his scanner and was showing the front right 02 sensor was not working. I replaced the sensor, still runs like shit. Starts fine, but when I try to drive I get little to no response, almost as if it's going to stall, then kicks in and takes off. Also noticed on the drive back up to his work my truck did not want to shift past 3rd, I was at 4500 rpm on the freeway at about 60mph. The codes I was getting with the cheap scanner are
P0171 bank 1 system too lean
P0175 bank 2 system too rich
U1017 lost communications with engine module
P0973 shift solenoid A control circuit low

I'm thinking there has to be something in the wiring, maybe another couple pins were changed between the two years, any input is helpful, I'm hoping to get this resolved sooner than later as my patience is running thin.

Thanks in advance
 
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#4 ·
One thing to keep in mind, once you update that VIN it may take care of at least some of the issues, but you will not be able to tune it with HPTuners due to a VIN/OS Year mismatch. EFI Live will work though.

There may be some subtle differences in the OS going from 06 to 07 also causing conflicts but I'm not sure what they are exactly. I ran into that when considering putting a 09 PCM in my 07. Changing the VIN would still be a good start though.
 
#5 ·
Theres also differences between the 2006 and 2007 TCM and transmissions that you'd have to take into mind when swapping. I don't know the specifics but I doubt they will mix/match well.
 
#6 ·
Did you retune your old ECM for the new bolt ons?
 
#7 ·
I did not retune, but I did find out when i installed the new harness I switched bank 1 and bank 2 02 sensors, so when I had it scanned and found bank 1 wasnt working and replaced it I actually replaced bank 2 which didn't need to be replaced. Boneheaded move I know. It is running much better now that the bad sensor has been replaced, still not shifting right, thinking maybe the trans solenoid, hopefully find out tomorrow
 
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