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Discussion Starter · #1 ·
So I was having problems with my fuel pump intermittently cutting out so I ordered the walbro racetronix kit (Racetronix LT1 Fbody High-Performance Fuel Pump System). Now the old pump even though it was having problems was still running.

I took the old pump out and cleaned out the factory bucket which was coated with a layer of rust. The old sock was nasty. Cleaned everything and installed the new walbro pump into the factory bucket.

They include a replacement harness for the pump, so I replaced the original dirty old connector, replaced all the wiring exactly as it was wired before. Put everything back in the tank.

Now I have nothing. It doesnt prime or run at all. I pulled the pump back out and it isn't even filling the fuel bucket just filling to where the regular fuel level is inside the tank- which furthers my general idea that the pump itself isn't running.

Racetronix also includes an upgraded relay and harness for a 'hot wiring' mod to provide more current to the pump and thus higher fuel flow. I haven't installed it yet because I wanted to just get it running first before wiring an entirely new harness. From my understanding, while it's preferrable to use the new harness, without it, the pump should still operate fine.

Anyone have any suggestions as to why it's not kicking on?
 

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Discussion Starter · #2 ·
I was concerned it was an issue with a bad pump so I unplugged the new harness, stuck the old pump into some fluid to test it, plugged it back in with the old harness and tryed it again. Still no prime. So probably not the new pump.

I didn't unplug the battery, think it's a blown fuse?

Where is the fuse for the fuel system?
 

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Discussion Starter · #4 · (Edited)
Did that yesterday, checked the connection at the pump and had no power. Went looking for the fuse and NEVER found it. lol. According to my haynes- the fuel pump fuse on a 95 (and all 93-95 f-bodys) should be in the passenger compartment fuse block- which it isn't. Checked the power distribution block under the hood (supposed location on 96-97) and it's not there either. Since I couldn't track down the issue... or the fuse, I got the new harness that racetronix sent and wired that in. Since that runs from the alternator and essentially bypasses the stock power wiring I figured that would solve the issue. I got it running and it ran fine last night and this morning. Left the car in a parking lot for about an hour then tried to leave and the fuel pump isn't running. Took me all of 40 feet to kill all the fuel from the lines and stall out.

Has anyone had experience with the racetronix harness? It should still be getting an accessory power signal to prime the pump right? When you turn the ignition to 'on' I can hear the new racetronix relay click, but I don't get a power reading to the pump. Maybe Im getting a bad connection testing at the new connectors because they don't have channels to plug the probes into. The fuse on the new harness is good.

There was some rust in the tank but I didn't have the facilities or money to replace the tank right now. But the pump didn't just 'die' it was running fine on the 10 mile drive I made, and the 40 or so miles I drove last night. I went back out and tried to start the car and the pump just didn't come on. Think it's a possible pump contamination issue?
 

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Discussion Starter · #5 ·
Finally found a wiring diagram for the fuel system. Fuel pump fuse in the passenger compartment is labeled as "PCM IGN"

Still not working though.
 

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The lines only receive power when the system is priming and when the car is running. At least that's how it is stock on my car. I have a fuel pump power kill switch with an LED and the LED only lights up on prime and when the car runs. After the prime occurs it does not receive power until I go to start the car.

You said it's wired to the alternator, why isn't it wired from the fuse block?

I hope someone else chimes in here as I am far from an electrical expert. I just know a few things here and there.
 

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Discussion Starter · #7 · (Edited)
When I'm testing for power I have somebody turn the ignition to on to check for 'prime' power. No prime/no power coming from relay.

The racetronix harness takes main power off of the alternator to achieve higher voltage/amperage needs of the fuel pump. More power going to the pump - higher fuel flow.

But the relay still plugs into the stock bulkhead connector that the stock pump and sending unit harness would normally plug into. It looks like it's relaying the fuel sending signal to the factory wiring but bypassing stock main power. It is not bypassing the stock 'prime power' lead though.

What actually sends the power 'on' current to the fuel pump relay?
 

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Discussion Starter · #8 · (Edited)
Answering my own question - the PCM manages the fuel pump relay.

I tried using the 'fuel pump prime connector' to test pump functionality and I could hear the click of the relay (the racetronix relay), but the fuel pump still wouldn't work. To make sure the fuel pump was good, I jumped battery power directly to the pump and it worked without issue.

I guess the next thing to check is the factory Fuel Pump Relay. Although according to the wiring diagrams the fuel pump prime connector bypassed the stock relay. So if it wasn't working bypassing the factory relay, that shouldn't be the issue.

Maybe the new racetronix relay is faulty?
 

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Discussion Starter · #10 ·
I sent an email but havent heard back.

I'm waiting on a buddy to head over right now to give me a hand while I test the factory relay. If it's not the stock relay it's going to be that new racetronix relay.

The only hang up in that theory is that it doesn't explain the no power situation after I swapped the pump out but before I wired the new harness, which looks like it apparently depends on the factory relay to be working anyway.
 

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Discussion Starter · #11 ·
Ok so get this...

When my friend got over to help me test out the factory harness my battery was dead. We jumped the battery and.. everything works again?

For the moment thats cool but I still don't know why it's randomly not getting power.

Going back through the wiring, since the racetronix relay is dependent upon the factory relay it would make sense having the issue both times, I decided to just replace the stock relay. it was a $12 part at autozone and not nearly as difficult to replace as I keep reading online. 4 screws I think?

But it would seem that everytime the battery is disconnected it resets the system and it works again. Then something sets it off and again I dont have power going to the pump.

hopefully not a pcm issue. :/
 
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