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Another fuel pump wiring question- Ground upgrade on a 92?

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Another fuel pump wiring question- Ground upgrade on a 92?

Old 10-15-2018, 12:33 AM
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qwiketz
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Default Another fuel pump wiring question- Ground upgrade on a 92?

Hi all,

I have a 1992 with a racetronix harness, their bulkhead upgrade (heavier duty connector on the sending unit inside the tank and on the top/outside of the sending unit) along with a walbro 465.

I've been having some issues. I drove the car friday, and when I was about to my destination, it sputtered as if it was out of gas as I ran around a turn (not even fast) and then it ran fine for another mile. After sitting for 30 min, I went to leave, started the car and about 10 seconds after starting, it died. It wouldn't start after that, even for a second. I have a fuel pressure gauge on the rail and it wasn't getting fuel to the rail.

We added some gas in case my sender float was caught up and artificially showing fuel in the tank but that didn't change anything. i added at least 2 gallons.

Next thing we checked for power when cranking and at the harness to go into the tank, it was getting power according to my friend who was testing it. After messing with it a bit, we realized that it was't priming and it also wasn't doing anything during cranking.

So, we suspect it's a ground issue. I'm going to pull the sender and inspect the wiring on the ground side of things, but my question is, we do a bunch of stuff to the hot side of things, but what about the ground? Is there anything that should be done to improve the ground?

The racetronix kit does have a black ground type wire (or so it seems) when you install their bulkhead upgrade it. Should I be running that to ground such as the lug where the relay for the hotwire kit goes to above/in the spare tire area?

How can I test the quality of the existing ground? Sorry, I'm not much of an electrician!
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Old 10-15-2018, 10:08 AM
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BillDurant
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May not be related to your issue but on my 89 the ground back on the fuel pump was corroded. cleaned it up and all work fine
we took the top lid off and all was easily exposed to work on

Last edited by BillDurant; 11-03-2018 at 10:36 AM.
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Old 10-15-2018, 12:39 PM
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On my 96 the black ground wire they supplied goes for the battery to the frame to make sure the battery is 100% grounded to the frame.
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Old 10-16-2018, 08:33 PM
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Can you post a pic of the black ground wire? If I am correct, that ground wire has a butt connector and is on top of the tank, on the outside.

I had the same system for my 93. But was pissed cause I wasn't making fuel pressure at all. Everything was connected correctly. In my case, with the 255 pump, you have to punch out a small hole at the bottom of the pump. If you don't punch that hole out, no fuel pressure. Also, they kept sending me in tank wiring that was backwards for the fuel pump connector.

Last edited by 1993C4LT1; 10-16-2018 at 08:36 PM.
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Old 10-25-2018, 12:40 AM
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as an update, I took the sender out of the car and it primed ever time I did key on. I put it half way into the tank and it primed and spit out fuel. When I put it all the way into the tank and bolted it in, no dice. No prime/noise at key on at all. No fuel pressure. What would cause this?
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Old 10-25-2018, 12:44 AM
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Originally Posted by 1993C4LT1 View Post
Can you post a pic of the black ground wire? If I am correct, that ground wire has a butt connector and is on top of the tank, on the outside.

I had the same system for my 93. But was pissed cause I wasn't making fuel pressure at all. Everything was connected correctly. In my case, with the 255 pump, you have to punch out a small hole at the bottom of the pump. If you don't punch that hole out, no fuel pressure. Also, they kept sending me in tank wiring that was backwards for the fuel pump connector.
The black wire outside the tank, I had extended with an o ring connector and grounded it to one of the bolt on the sender before. The car ran for a few miles and short trips and then died and wouldn't refire.

Right now I didn't have it attached to anything when outside the tank and it primed fine. Once in tank, I'm getting nothing.

I'm using it with a walbro 465 pump so I'm not using the 255. The car ran for a while and then died, so it sounds a little different then your issue.... or so I think. I'm not certain of anything right now!

Last edited by qwiketz; 10-25-2018 at 12:46 AM.
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Old 10-25-2018, 12:52 AM
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Wtf that is weird. Hopefully someone here knows. But if I come up with some probable causes, I'll let you know.

Was the wire still grounded when you put the fuel pump back in the tank?

Crap I just noticed your response from above. Dumb question. On all turbine pumps, you have to punch/cut a hole at the bottom of the pump. Did you do that?

Last edited by 1993C4LT1; 10-25-2018 at 12:54 AM.
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Old 10-25-2018, 02:14 AM
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Originally Posted by 1993C4LT1 View Post
Wtf that is weird. Hopefully someone here knows. But if I come up with some probable causes, I'll let you know.

Was the wire still grounded when you put the fuel pump back in the tank?

Crap I just noticed your response from above. Dumb question. On all turbine pumps, you have to punch/cut a hole at the bottom of the pump. Did you do that?
so when I had the pump half way in the tank, I didn't disconnect anything to move it fully into the pump. The only variable was that it became more submerged and I bolted the 9 or so bolts in on the top/outside of the tank on the sending unit.

With the pump submerged but only halfway in the tank, it shot out fuel out of the top of the sending unit and I could hear it prime. The 465 is pretty noticable when on.
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Old 10-25-2018, 09:16 AM
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Ah ok, got you. The fact that it did shoot fuel means everything was good until it went inside fully. Have you tried contacting racetronix?
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Old 10-25-2018, 01:33 PM
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Had a similar issue on an '87 grand national I used to own. Put a walbro 265 in it with a hotwire kit and the pump would act like yours. I had to ground the tank itself to fix the issue. I did this by drilling into an outer corner seam of the tank to attach a ground connector. May not be the same issue you are having but might be worth attaching an alligator clip jumper wire to the frame and see if it improves.
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Old 10-25-2018, 01:39 PM
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There is a grounding connector that connects inside the tank on the sending unit tubes, is that extra ground there? When I replaced all the wiring on the outside and inside of the sending unit they sent me that.
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Old 10-26-2018, 01:21 AM
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Originally Posted by vader86 View Post
There is a grounding connector that connects inside the tank on the sending unit tubes, is that extra ground there? When I replaced all the wiring on the outside and inside of the sending unit they sent me that.
man that isnít ringing a bell. Hereís some photos of the sender


Last edited by qwiketz; 10-26-2018 at 01:24 AM.
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Old 10-26-2018, 08:27 PM
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sorry, a little difficulty uploading the photos off my phone. I worked on it for 5 minutes today and I think I have it narrowed down.

With the sender in the car, it won't work. When I unbolt it, and lift the sending unit up, it will start and acts normal. My culprit is the racetronix bulkhead adapter. I must have it clocked or installed wrong somehow. I will need to review. There are tiny letters on the unit to align it. I need to review because since its clocked wrong, my power wire is grounding out somehow. On their setup, there are two pins that are hot, the ground and the purple for the level sender.
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Old 10-26-2018, 08:30 PM
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I had so many pics of how to correctly clock the bulkhead on my old phone. But let me see if I posted them here.
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Old 10-26-2018, 08:35 PM
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Best pic I could find. Hope it helps!
http://www.corvetteforum.com/g/picture/9847522
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Old 10-26-2018, 09:24 PM
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Thanks! Iíll pull mine and take a look
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Old 10-27-2018, 01:55 PM
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Strange. Pulled mine and it looks the same as yours. Iíll double check again(not much trouble since I have the sender loose). Does the walbro 465 pump have anything funky on the wiring (such as reverse polarity)?

im thinking if there are two pins feeding the positive, that may be an issue if I have them switched.

Last edited by qwiketz; 10-27-2018 at 01:56 PM.
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Old 10-27-2018, 02:20 PM
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Measuring resistance and voltage is something you really should take the time to learn qw. It can be a little intimidating at first but you can easily master it with a small amount of practice. Most multi meters will have enough instructions to get you started. Just take your time and make sure your leads are connected correctly for what you're trying to measure and you have the correct scale selected for what you're trying to measure in the expected amount (amount of resistance or voltage).
To start just try measuring the resistance of/through bolts and wires. Once you have that sorted out you can measure the resistance along the entire circuit path like you can measure the resistance from the block to the frame and across each connection/termination. It can be very helpful to know what the resistance of the entire path from the block to the battery. And you can measure from the alternator to the battery. Or the other way from the battery to the starter. By then you should be able to determine the status of your fuel pump ground.
Similar using the voltage scale, is start measuring small batteries and your household power outlet to identify DC voltage from AC voltage. Then you can begin to measure the voltage to ground/frame/battery of different items on the car (DC voltage of course). Once you are confident with that you should be able to measure voltage drops along wires in a circuit across each connection/termination/device. By then you should be able to answer all your own questions - much better than using error likely explanations over the internet.

Good luck and hope this can help.
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Old 11-03-2018, 12:43 AM
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Any luck qwiketz?
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Old 11-03-2018, 01:05 AM
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Originally Posted by 1993C4LT1 View Post
Any luck qwiketz?
been a little busy with work and family. I did move the sender around after loosening it last weekend and the car started. It ran for about 30 seconds and then going down the slope in my driveway, I thought , ďoh no, here we go again!Ē But, to my surprise it refired and I drove it down the block and turned it around and parked it back in the garage.

im going to fully pull the sender and test the wiring if I have time this weekend.

i have all new parts coming in from racetronixs and I have an extra sender so Iíll get it figured out.
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