cpd004

iTrader: (13)

I have an Ls3 from a 2011 Corvette and a 4L60e from a 4th gen f body rebuilt by RPM Transmissions. I'm using PSi harness #HAR-1038. Per their recommendation, I am using an E38 and T42 from a 2008 Chevy Express van 2wd 5.3.

I had Speed Inc do a mail order tune to get the car up and running. The car runs and idles fine albeit not the best shift points. They told me that it will need to be dynotuned to adjust shift points, among other things. I never felt comfortable driving the car far the way it shifted, so I had it towed to them.

The motor came from wrecked Corvette that had just under 12,000 on it. After having some misfiring issues, I decided to put new plug wires and plugs in it. The old wires had some minor breaks in them probably from the accident. There was glass all over the motor when I got it. Using a handheld scanner, the changes of the plugs and wires got rid of the misfiring. I didn't know there was a misfire under load until it went to the Speed Inc for tuning.

They changed the plugs once again, cleaned the injectors, double checked everything and have determined that it must be the harness.

The drivers side injectors lose power under load and WOT. I have even replaced the injector harness with a new one from GM.

PSi suggested my gold blade throttle body may be the cause and suggested I swap to an Ls2 style silver blade. They also suggested Speed Inc try lowering the WOT setting to 99% in the tune from 100%. This was an expensive trial that made no difference whatsoever.

I believe the only codes I have are for a range selector switch and something about the anti-lock brakes. I can post the specific codes tomorrow. I believe the range selector code is set to not illuminate the SES light.

Speed Inc suggested I pull the harness and send it back for testing. That isn't something I'm looking forward to.

I don't know what change a range selector switch will make or if it will even make any difference. I'm also not sure how to go about putting one in as it seems to be a part of the shifter in OEM applications.

I did find this link:
http://www.hptuners.com/forum/showth...-codes-problem

I would appreciate any thoughts anyone has on where to look and what to do. I can post the tune it has if that helps.

Not sure if I'm better off posting here or in Tuning.

LSXConnection

are you sure that the motor was an LS3 and not an L99 out of an automatic vette?

cpd004

iTrader: (13)

The motor was from an automatic vette. As far as I know, the L99 was not available in the Corvette. Running the VIN shows the engine is an Ls3.

M6 Swap

iTrader: (1)

Driver inside the processor maybe? Is there 1 you can swap out available?

cpd004

iTrader: (13)

I tried the OEM ECM that came with the motor from the Corvette and it does the same thing.

cpd004

iTrader: (13)

After following up with PSi, they suggested we check a few things out before blaming the harness. They suspected the tune was at fault after I sent it to them and sent one to me to upload. I was skeptical since it had been to Speed Inc for tuning for over a week where they determined the harness was causing the drivers side coils not to fire under load, but after spending so much and never actually getting anything tuned, I figured it couldn't get any worse. A very short ten minute drive into the new tune and I was shocked. It seemed like the car had gained a huge amount of power. For the first time since the swap, I caught rubber at the 1-2 shift. It definitely needs some more tweaking, but it turns out it wasn't the harness. Jeremy from PSi...big thanks! Again, this was a very short 10 minute ride, but every time I got on the gas hard, it took off instead of just sputtering along.