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So I'm ready to get my fuel pump wiring done, I need to hook up the wire that turns on the fuel pump. I took apart the relay center and got the grey wire but I see an orange and red wire going into the pump relay, I'm thinking that the red wire would be constant power and the orange is switched but I'm not 100% sure.
The person who answers first will receive a beer at Raceday if they attend
If it helps at all relay 87 is the orange wire 87a is the red wire
Just guessing. But the grey wire is probably going back to the fuel pump. So that's pin 30. Across from that pin is 87.
85 and 86 trigger the relay coil. So. Touch the green wire on 85 or 86 to power and u should hear the relay click.
Or. If that grey wire is goin to the pump, just apply 12volts to it and the pump will power up. Obviously for testing purposes only.
well the pump isn't getting power, I tried both the orange and red wire but still nothing. I'm sure it's not the green wire since the relay in the standalone harness already has a green wire coming out of it.
This makes me think that the standalone harness isn't getting any power. Another problem I had was that my starter isn't engaging with the flywheel
Did you put 12v to the grey wire going to the pump to verify its working?Quote:
Originally Posted by silverado_lover
I did not but the pump is about 2 months old
I finally busted out the volt meter but none of the wires are getting power. Shouldn't I be able to tap into any switched power line? The standalone is getting power.
I also checked the starter issue...it is indeed engaging with the flywheel
old thread, i know.... but I am having the same problem and was wondering if / how you resolved the problem. everything seems to work as it should but the damn thing won't fire because of the lack of power at the fuel pump.
I don't know what year truck you have but i didn't connect the wire from fuel pump to oil pressure sensor like the factory had it and my fuel pump wouldn't work 1992 chevy pickup.Once i connected that wire everything was good.
the oil pressure sensor is unplugged at the moment. i forgot to pull the one off of my old engine. will that matter?
It depends how you wired it but if you wired like i did connecting the fuel pump power from the new pcm to the power going to the fuel pump where the relay is under the hood without the oil pressure hooked up it won't work.
My fp relay wire is connected to the grey wire that comes from the c-100 firewall connector and it powers right up. Also my oil pressure sender is not installed yet and the engine runs. I also thought the tan wire from the oil sender needed to be hooked up to the fp wire so thats a puzzle to me too. Like gagliano7 said, maybe theres a different way to connect them. This is on a 1990 truck,5.3 4l60e swap with a NP harness. Try checking your grounds.
Ok. Heres what I have so far....
Terminal 86 on the relay should be a constant ground. But with the volt meter, it shows to be putting out around 12v. I am attaching a generic diagram I made. I was thinking that maybe i should ground the relay directly???
I forgot to tell you an important part of my initial start-up. My first attempt to power up the fuel system (to check for leaks) failed.I turned the key and nada. Went looking and found a blk/wht wire coming from c-100 and according to my wiring diagram it was a ground. Hooked it to the firewall and the f/p powered right up. I'm not good with wiring but I hope this helps or someone else can chime in.
Thanks. Ill look when I get home. However, I cut the wire and grounded the end going to the relay and it primed but quit cranking. So I reconnected the wires and it would crank again but no fuel pump.
Attachment 7824Going through the oil sender is probably a safety feature to shut the fuel pump off in case of a roll over. Pin 87A on the relay "should" be connected to the oil sender. This could be incorrect and maybe some will chime in to confirm that.
That Black white is a ground feed fed by the ECU to trigger the relay to turn the pump on.Quote:
Originally Posted by exboatracer
I Need to know what wire does what to better help you figure this out but maybe this pic can help you figure out what goes where.Quote:
Originally Posted by lost06
Please see my post here. http://www.ls1truck.com/forums/lsx-t...ease-help.html
it might be a little more descriptive.
Thanks for the help and advice
Thanks caprice for that oil sender rollover info. When I removed the old 350 I marked that tan wire that came from the oil sender since it was tied into the f/p wire. (I had no idea why oil sender and f/p relay could be related). Now I'll tie it back in.
Hey lost06, can't wait to hear that you your problem is solved. Let us know, it's usually something simple. Don't lose hope,it will work out.
yeah, it was really simple. I grounded that set of grounds to the coil bracket on the valve cover. Apparently, this is a bad idea. I moved the ground to the alternator bracket and my gauge started working and the pump kicks on.
Now, my truck would crank over BEFORE i would ground the fuel pump relay. Now it won't crank. I had an issue where the PRNDL switch wasn't allowing it to crank. I bought a new one and it fixed that problem. Now since I fixed the fuel pump.... it wont crank again...
GRRRRRRRRRRR!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!