Got some ECU problemo's. Need help.

[protour_chevelle]

Ok, I got a new ECU from Jesse today... Plugged it in and I get nothing? I check all of my grounds....



Engine to body
Engine to frame
Harness to back of head
Harness to lower block
Harness to other side of block
battery to block

Check my wiring... Plugged my gas pedal module and the throttle body does its postioning thing when I turn the key but I get no spark, no fuel pump prime, nothing...

Thoughts?

-Matt

[Steve68]

Stumped me, Call Jesse or E-mail him, What exactly did he do for you??

[protour_chevelle]

Stumped me, Call Jesse or E-mail him, What exactly did he do for you??

Well see, I welded on the car... No battery in the car but ECU plugged in. After that everything went dead so I bought a new ECU from Jesse. I plugged it in and got nothing.

-Matt

[Steve68]

Maybe you got a bad one??

[andrewb70]

Maybe the welding blew a fuse somewhere???

Andrew

[protour_chevelle]

Maybe the welding blew a fuse somewhere???

Andrew

I checked that, all were good but I replaced them anyways.

Maybe you got a bad one??

I thought that too but a ECU will not take a tune if it is shot...

Man does this suck!

I talked to Jesse today and he said to check all of the ignition source wires(pink) and then to also check all of my grounds to make sure that one is not dead.


-Matt

[andrewb70]

Is the engine cranking over? If so you may pull a plug just to check if there is spark. At least it will give you an extra clue.

Could it be a VATS issue? Did Jesse disable that on the new ECU or is tehre a hardwired VATS bypass in your harness?

Just more ideas....

Andrew

[protour_chevelle]

Is the engine cranking over? If so you may pull a plug just to check if there is spark. At least it will give you an extra clue.

Could it be a VATS issue? Did Jesse disable that on the new ECU or is tehre a hardwired VATS bypass in your harness?

Just more ideas....

Andrew

I tried the ol pull a plug and ground it trick but got nothing.

The engine cranks over(the stock wiring for the old 350 was grafted in to turn the 6.0l over) so the starter wiring is with the car itself. The ECU is by itself under the hood.

VATS has been disabled aswell. I can't even get the car to sputter over due to no spark, fuel pump priming, injector pulse.

The thing thats just killin me is that it WAS wired right before the welding occured. Ever since we welded on the thing.

I check for wires near where the welding was done and all showed up clean with no burns, or wire showing.

I took a test light on the ignition source wires and got nothing(which means the computer is getting nothing)

The fuel pump will prime when I cut the signal wire and put it to a 12v source(relay source wire that is)

All time power is getting power all the time.

The 3 main wires off the harness that go to a relay are getting power(worked fine before welding aswell)

Just trying to give as much detail as possible. I'm going insane.

-Matt

[Steve68]

Are you still getting power to the relay in the start position

[protour_chevelle]

Are you still getting power to the relay in the start position

Which relay? fuel pump relay or the harness relay?

The harness relay switches but the fuel pump one doesn't because the signal wire off the ECU isn't getting any power.

-Matt

[andrewb70]

Any luck?

Andrew

[Steve68]

I don't know where to start without a diagram, sorry

[protour_chevelle]

Any luck?

Andrew

I just ripped the harness out of the car. Ripping all of the loom off and gonna go from there. So far it looks good. Perhaps just installing it again will fix it.

Good thing about pulling the harness... I found some potential wiring burn up issues so I'll solve those!

I'll keep you guys updated! The suspense to start this sucker is killin me.

-Matt

[toxicz28]

What type of battery terminals do you have? Top, or side. Is it possible that both were touching metal when you welded? Do you have fusible links, and if so, did you check them yet? It sounds like that could be your problem.

[protour_chevelle]

No fusible links. All were removed. I talked to a local performance place today and they sent me home with tuning software. Going to see if I can throw a stock tune in, remove vats and see what happens. I've heard of bad tunes causing the computer to do nothing.

Edit: Sidepost, and no clue if they touched metal :S All fuzes are a-ok.

-Matt