2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

No start after fuel pump re-wire

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Old Oct 20, 2015 | 08:09 PM
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No start after fuel pump re-wire

Hey everyone hopefully this is a simple one.
Did the fuel pump re-wire according to the diagram in this thread:

https://www.rx7club.com/2nd-generati...rewire-732904/

Now the car will just crank and not start.

Troubleshooting:
No issues before re-wire
Fuel pump works when jumpered
Fuel pressure went up pretty high to about 43psi, adjusted back to ~38
(Aeromotive FPR)
Pulled plugs and they are dry, no flooding symptoms. (I believe)
Still have compression (poor mans test method)
Double checked connection at afm

Thoughts:
With all of the research I did, I am confident I got the wiring correct. I am a little confused however on what to do with the stock injector resistor relay thing. Leave it connected after splicing other wires? Or just remove it all together?

I will test out the afm next and look for any potential simple things I overlooked but please share any ideas you have.
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Old Oct 20, 2015 | 08:09 PM
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Forgot to add that I did make sure to remove the jumper wire from the check connector.
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Old Oct 20, 2015 | 08:20 PM
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From: tulsa,ok.
You need to be more clear on the injector relay you speak of. There is a fuel pump relay and resistor that is part of the fuel pump circuit and there is a resistor box for S4's which have low impedance injectors thus they are two separate components so which specifically are you talking about?
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Old Oct 20, 2015 | 08:41 PM
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With that response I feel like that may be the issue. The writeups available on this topic make it a confusing job. Which would be the correct of the two to splice?

Name:  fueldiag_zpsi0cnqpuo.png
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The two bear a similar name and both are relays? The one I spliced was F-09 in the image. (The one behind the pass. headlight)
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Old Oct 20, 2015 | 08:51 PM
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From: tulsa,ok.
Both of the relays in the FSM diagram are part of the fuel circuit. On a side note, the injector box is something completely different than the two relays provided in the FSM diagram and is part of the injection system.

Now getting back to the fuel relays, I'm guessing when you tested the fuel system w/the jumper in place it was w/key to on. Correct?

The injector resistor box is for 86 to 87.5 S4's. If by chance you have one it would be bolted to the passenger fender near the AFM. If you unplugged it for some reason it would kill voltage to the injectors and the engine would not receive fuel.

Last edited by satch; Oct 20, 2015 at 09:11 PM.
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Old Oct 20, 2015 | 10:21 PM
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Ok I am a moron. I made the modifications to the resistor box instead of the relay. Wired everything back up as it should be and she fired right up. The injectors were not working because of the resistor box as you said. Thanks for the help.
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Old Oct 20, 2015 | 11:11 PM
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From: tulsa,ok.
You live you learn as it's all part of the process.
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