JD1964

I have a project car that we’re using as a donor for an engine swap. It a 94 Z 28 with LT1. I want to iron out the bugs before I pull the engine.

I can get the car running with good pressure to the rail but only when I unhook the fuel pump
harness and feed power from a battery directly to it.

With the harness hooked up, the pump won’t prime and it also won’t run by feeding power to the diagnostic connector under the hood.

So, pump is good but it won’t prime and it won’t run by powering the diagnostic connector

What are the steps I can take to figure this out?

I have a 96 vette by the way. I figured I could get good help here since the Camaro and Corvette have a similar setup in that generation.

thanks for anything you can suggest

C409

..... If I understand this correctly , the engine is still in the Camaro ? … Which electronics do you ultimately intend to use ? Camaro or Corvette ? … At this point , I assume you are just verifying the physical state of the engine ? … If so , continue on as you have by jumping the fuel pump circuit to get the engine running and perform your research ... Does the Camaro employ a VATS type anti theft system ? …..

JD1964

The 94 Camaro is the donor car. The receiving car is a 1979 Malibu wagon. Sorry for that confusion.

The Camaro does have vats. I can get it running but only when I hotwire the pump. When running there’s a miss in the engine. Not a bad one but I’d like to sort it out before pulling it from the Camaro.

The wagon will get the LT1 engine, 4l60e and any supporting wiring and electronics that the Camaro can provide. So, harness, ecu, sensors, etc...

The pump in the Camaro was actually seized. I had a spare Walbro on the shelf that I retrofitted to the Camaro sending unit. It bench tested good. It primed properly the first few times when installed on the Camaro. But now it won’t prime. But if I feed power directly to the pump harness, I get 45psi at the rail and can start the engine.

Other things that may or may not be related. The key won’t turn all the way back for removal from column and the fuel gauge is pegged to the max way past full.

Nomake Wan

On the Corvette the pump assembly and sending unit is one unit. Dunno about the Camaro, but if they are, then that points to some serious electrical issues in that circuit. Probably a good idea to yank the assembly and check all the wiring over again to make sure nothing has eroded or anything like that. And while it's out, trace the circuit to see if you even have continuity to the right places.

We may have had the same basic engine, but there are lots of subtle differences between the Corvette and the Camaro, not least of which is the actual chassis wiring layout. It may be better to ask on a forum like Gearhead-EFI or a Camaro-specific forum than it would be a Corvette forum if neither the donor nor recipient are a Corvette. Best of luck.

RUU

Did you check the fuse? A pump on it's way out can blow the fuse.

JD1964

Checking the ground for continuity and the fuses was my next step. Thanks.

JD1964

you’re right. I registered at Gearhead-EFI. I’ll see how it goes over there too.