1995 5.7 TBI Hesitation

[sbdblyss]

Hello,

I have searched and have not found anyone who has experienced this issue after installing heads, cam and intake manifold.

Specs:
5.7 TBI
Edelbrock performance package (heads, mild cam, high rise intake manifold, chip to richen fuel system)
Everything else is stock except for new cat and dumped exhaust At rear end.

Truck ran great before installation of above listed items. Now, truck stumbles a but at idle, but not too bad. Dyno shows only 104hp at max RPM and lean AFR. Truck hesitates when accelerating at about 2000rpm (falls on its face).
Rattles once in overdrive due to lean condition.

Troubleshooting steps taken:
Taken to multiple mechanics Out of desparation and all have claimed nothing is wrong...
Second chip from edelbrock.
Compression great.
New injectors (twice)
Fuel pressure at 12.5psi
Valves in perfect adjustment
New fuel pressure regulator
New fuel filter
New distributor, cap and coil
New vaccum lines
All grounds perfect
No CEL

Any advice is greatly appreciated. I can post a video if that would help.

Kindly,
Jake

 

[sbdblyss]

After a year of battling with this Edelbrock setup, we had decided to remove it and return the truck to stock. We were hesitant to do so because the truck has been restored and built for a Marine and Edelbrock helped sponsor the process. This post was literally a last ditch effort as Edelbrock was baffeled and so were many mechanics.

Today, while returning the chip to stock, we realized that it had not been installed properly. Edelbrock sent us a piggyback board with their chip installed and it required the stock chip to be installed on top of it. This was not originally clear, but after inspecting the piggyback board during removal, it was apparent that we had made a huge mistake in overlooking this. The truck is now running a lot better but still needs some work before we dyno it again. I hope that oversight will help someone in the future.