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Discussion Starter #1
Group bought an 90 lx 5.0 for my Efi swap
And can only get car to crank?
No power to fuel pump
And also noticed no check engine light
When key turned to on??
Bad computer??
I can crank till I kill battery
Also no power to injectors with test light and key on
 

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Check the collision fuel shut off switch.
 

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This page on oldfuelinjection.com may help if you don't have a decent wiring guide. There is an injection harness power diagram down the page along with relevant pinouts. That may help you see the relationship of the injectors, FP, impact switch, and CEL, etc.

David
 

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Check to see if your getting power to the fuel pump. If so replace pump.
 

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You can shortcut that initial diagnostic. Air, fuel, spark. Spark is an easy test. Fuel - there is a Schraeder valve (tire valve) on the fuel rail to test fuel pressure. Take the dust cap off and press the center nib. If it squirts a little shot of fuel, the system had fuel pressure and you've now relieved it. Key the ignition on for 2 seconds and off without cranking. Try the valve again. If it squirts again, the rail was re-pressurized, so the impact switch and pump are good. Never test this way with the engine running to avoid a horrible death.

I suggest a rag above the valve to catch the little shot of fuel. If you don't use a rag, you may be blinded or start a fire, but the test results will still be valid. ;) You can also attach a fuel pressure gauge to verify proper pressure.

If no joy, I would begin troubleshooting at the fuses to verify battery voltage, then to the relays for same, then key ON to verify relay switching, and so on to verify power flow when and where it's expected. With multiple primary items not functioning, I'd suspect a basic power connection, relay, or switch issue.

David
 

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Discussion Starter #7
Dave thnx for all that
Arnold no power at pump or pump relay so there's more too it
And no cel on when key turned on
Weird
 

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Discussion Starter #8
David
Also just a dribble of gas and then nothing
Think it's old gas anyway
And no pump on
 

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Group bought an 90 lx 5.0 for my Efi swap
And can only get car to crank?
No power to fuel pump
And also noticed no check engine light
When key turned to on??
Bad computer??
I can crank till I kill battery
Also no power to injectors with test light and key on
poor gas into the throttle body, crank it. honestly, beyond that, i have no clue... the best advise i could give you is go on craigslist, there are allways a few mobile mechanics. get one of the good ones to come by and read the codes. is it cheap? not really... but still cheaper then sending it to a major shop, plus you dont have to load it up on a trailer and take it there. i've only done it once (actually in a very simalar situation) and they came by, and one of the wires havving to do with the oil presure guage got destroyed by the air box, so the truck just died and wouldn't start. they fixed it in 15 minutes, and it was done. it wouldn't be a problem, but on new cars its impossible to chase that stuff down. i would have never tracked down all of the oil pressure gauge wires to find out that's why the truck won't run. thats just my 2 cents though. good luck.
 

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Then start your troubleshooting from the fuses. All your non-functioning items are root to 4 fuses and 2 relays. I'll bet you'll find it pretty quick just probing for power at each fuse and relay. The power stops somewhere close.

David
 

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If you have transplanted a efi setup into a older car?
Hate to ask the obvious, but did you run key on power to the ecu and the fuel circuit?

Jet
 

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If you have transplanted a efi setup into a older car?
Hate to ask the obvious, but did you run key on power to the ecu and the fuel circuit?

Jet
+1. Exactly my angle to test for.
... no power at pump or pump relay so there's more too it
And no cel on when key turned on
Weird
There's your fuse and relay testing. Using the wiring diagram on the page I linked to early in the thread - note all the fuses get battery power direct from the battery and feed all the relays together, and all the relays get switched on (FP and ECU/CEL included) by one wire from the key switch RUN power. It's actually fairly simple when you stare at it long enough, but a bit snarled-looking with no wire colors to help separate the circuits.

So, no power at relays. Is that no power OUT or IN?

If no power IN to the relays, is there power at fuses? If not - work backwards to the battery for where power is lost.

If you have power at fuses and relays, but relays don't switch to give power OUT, then work backwards to the key switch RUN terminal, and if still no power there, continue back to the battery.

If you have both battery and key RUN power to the relays but they don't work, then you're just missing a ground to complete the circuit.

You have battery power, and just need to find where the link is broken from there to your relays in only two circuits. A volt meter or test light should have the answer if a few minutes. Good luck!

David

This diagram is from RJM Injection Tech sited at oldfuelinjection.com and I hope he doesn't mind me borrowing it for just this example. For props, he has a ton of great info on his site. I re-colored the wires in the relay circuits to make them clearer for this specific issue. The colors do not match the actual wire colors in the car. Be sure each circuit is complete, shown as RED wiring from the battery to fuses, YELLOW from the fuses to relays, BLUE from the key switch RUN terminal, and PINK from the relays to ground:

 

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David,

Thanks for the colored schematic! I'm going to need that soon, dropping a EFI 302 in the kids Merkur. And still kicking around running EFI in the Fairlane and Falcon.

Pretty simple after seeing it like that.

Jet
 

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Discussion Starter #14
Ok got it bad fusible link out in engine compartment!
Thanks all for the help!
 

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