2001 Runs only with FP jumped & No Tach
 

2001 sitting since 2003. Replaced fuel tank, pump, filter, and normal items (plugs, fluids, battery, etc). Stock computer and I assume has immobilizer (LS package and has the "offset" loop in the key).

The fuel pump does not automatically activate when cranking. The car will start with the fuel pump relay jumped (FP to GND at diagnostics box). The dash tach does not register. The speedo and other gauges do.

I haven't scoped anything yet, but was curious if anyone has run into a similar problem before, and if so, the outcome.

Stock ECU under there? Might wanna check. Also, if the car has been sitting since 03, any possibility of rodents in there?

Stock ECU, or at least stock ECU enclosure under there.

No evidence of rodents or rodent related damage.

Does it prime on key on?

No

Does the fuel pump relay click when you ground 2M? That would eliminate the wiring as a source of the problem.

Yeah I know; I have a schematic and a scope at the shop. ;)

I just don't think I have 2 problems: (1) no tach and (2) no fuel pump. I thought they would be related.

New confirmation: I suspected the MAF might (literally) be toasted due to a flame belching backfire event that occurred at the first start. It back fired while spraying starting fluid, shot a flame, and blew the intake pipes, maf, and top of airbox off the car. The lower box caught fire. It was impressive. Well, the car starts and idles, and runs with light throttle. It bogs with moderate or heavy throttle. No change with MAF plugged in or unplugged, so I get the feeling it's toast. When I pull the scope out I can test it, but it's even easier to just put a new MAF in.

Replace the relay.

With the maf unplugged, or dead it will run super rich.

Never spray anything across an airflow meter.

The car's wiring is as solid as it could be.

It needed a new MAF!!!! The tach came back to life and the fuel pump started running itself after replacing the MAF.

:bowrofl:

Smooth move Ex-Lax.

Glad you sorted it out. This gonna be a daily?

No, track car.

Also: Solid MIL but no code = dead ECU memory fuse.