Mgodsy

Hi everyone,

I'm new to this forum and hope to get help to resolve my issue.

I have a 1968 C10 that I have done an LS6 conversion out of a 2004 Z06 corvette and an 4L60E trans out of a truck.

The problem I'm experiencing is that when the engine is in park it runs good and has good throttle response. It sounds like a beast. But, when I put it in drive and give it gas it cuts out so bad that the truck will hardly move. I get no trouble codes on the scanning tool.

I'll list what has been done to try to make this simpler,

I purchased the LS6 with the computer and wiring harness. I sent the harness and computer out to be configured for my truck. The company that did the wiring and programming also changed the throttle from DBW to Drive by Cable and I changed out the throttle body to a drive by cable.

-I have replaced the plugs and wires
-Verified firing order
-Verified fuel pressure at start and at idle. Consistent 58psi
-Changed fuel
-The new wiring harness only has 4 wires for it to run- fuel, key on power, constant power and fuel pump. Also has a ground. I verified the wiring was hooked up correctly
-I get no trouble codes on scanner


Again, when the truck is in park sounds like a beast, as soon as I put it in drive and give it gas it just falls on it's face and barely has enough power to move the truck. It runs very rough when in drive and giving it gas.


Any help will be greatly appreciated!!!

DW SD

My first bet would be placed on fuel pressure. Could you describe the fuel system? Are you using the returnless setup from a corvette? Is your filter possibly a restriction or the lines themselves?

What is your fuel pressure under load?
Whole different ballgame fuel pressure under revving in neutral and load.

Doug

Mgodsy

Thank you very much for the help DW SD!!!!!

I put in a new Boyd tank with the Stealth 340 in-tank pump with an external adjustable regulator/filter. I started with the corvette style reg/filter but the pump was too strong and the regulator could not handle the load.

I have a fuel pressure gauge at the end of the fuel injection rail and it measured 58psi with the engine under full throttle. It did drop to 50psi when I first applied gas but that only lasted maybe a second and it recovered back to 58psi.

DW SD

I don't know at what pressure drop would cause a stumble. I had that issue that I tracked to one broken fuel pump. Initially, my two pumps were in series. Once I removed the failed one, it ran like a champ. I never had a fuel pressure gauge to correlate.

Do you have a proper tune?
Any chance your injectors don't match the tune?
Doug

Mgodsy

I sent both the wiring harness and computer to a guy that has been in business for over 15 years doing this type of work. With that said mistakes can happen.

I have a local company that does programming. I'm going to take the computer to him and have them ensure I have the right programming.

I'll let you know what he finds.

Thanks for the support!

truckdoug

iTrader: (25)

yeah something is up with the throttle body swap i bet.

showdog75

iTrader: (8)

Your tuner should be able hook up a laptop and get a idea of what's going on. Bad injectors or possible issues with changing from dbw to cable.

Sebtarta

iTrader: (1)

Was the trans working before?