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[RESOLVED] Electrical gurus step inside: fuel pump wiring

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1992awdlaser

15+ Year Contributor
3,051
26
Dec 5, 2004
Wallace, North_Carolina
First let me start by saying, if there is one thing I hate it's wiring.:beatentodeath:

Last night my car shut off for no reason. After a minute of diagnosing I found out the pump wasn't turning on.

This morning I tried to turn the pump on with the connector in the engine bay. When I hooked up the wire to the battery the wire started smoking almost immediately. The pump didn't turn on either.

Then I tested for power at the fuel pump connector in the hatch. Three of the wires make my test light light up. The only one that doesn't is the all black one.

Then I plugged the connector back in and commanded the fuel pump on via dsmlink. This should turn the pump whenever the ignition is on, it didn't. I was about to test the wiring at the pump housing by using the screws on it for a connection. Then I noticed the connector started smoking so I unplugged it and turned the pump settings back to stock in dsmlink.

So, something is keeping the pump from turning on. And whatever it is it's causing the wires at the connector in the hatch to start smoking when the pump is supposed to be turning on.

Any ideas will be greatly appreciated.
 
I have the stock wiring still. So doing a rewire might be a good idea now?
 
Before doing your rewire i would check the pump to make sure it works. If the pump is locked up it may be shorting out and causing it to feed back.

I will be pissed if the pump is bad. The first two wlabros I got wouldn't even turn on so I had to send them back. Then the third pump that they sent back to me only lasted a couple of weeks(couple hundred miles). And this is the pump that replaced that one. This pump doesn't have any mileage on it, just about 1-2 hours run time. I have had this one too log to warranty

snowborder714 said:
I would say so

I will get it done and see what happens.


If anybody else has any ideas share them.
 
This is an odd problem, but i'll try and help. Black/White is the fuel pump turn-on wire from the ECU, was this wire getting 12 volts when you tested it? Check for shorts with a multi-meter using the continuity setting on the meter and test from each wire to a chasis ground. Considering the the wires keep smoking when you apply power means there is a dead short somewhere in the car either @ the ECU, fuel pump itself, or the fuel pump wiring. Rule out the pump and remove it. Its a 2 wire pump so it will be easy, all you have to do is apply 12v and ground and if i rember right, 12v is red and ground is black on the walbro 2 pin harness.
 
This is an odd problem, but i'll try and help. Black/White is the fuel pump turn-on wire from the ECU, was this wire getting 12 volts when you tested it? Check for shorts with a multi-meter using the continuity setting on the meter and test from each wire to a chasis ground. Considering the the wires keep smoking when you apply power means there is a dead short somewhere in the car either @ the ECU, fuel pump itself, or the fuel pump wiring

I didn't test to see how many volts it was getting. I just hooked a test light up to each wire on the car side of the harness. That wire was getting power.
 
I will be pissed if the pump is bad. The first two wlabros I got wouldn't even turn on so I had to send them back. Then the third pump that they sent back to me only lasted a couple of weeks(couple hundred miles). And this is the pump that replaced that one. This pump doesn't have any mileage on it, just about 1-2 hours run time. I have had this one too log to warranty



I will get it done and see what happens.


If anybody else has any ideas share them.


Wow, Usaully these pumps are pretty reliable. After you diagnose the current issue do the re-wire
 
I took the pump out real quick. When I pulled the assembly out the yellow/blue stripe wire broke off at the housing. This wire leads into the assembly and goes down to this:
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The only other thing that is visible is the black wire that bolts to the top of the housing is getting coroded. I'm assuming that is the problem?
 
The pump turns on with power hooked up directly to it.
 
Look at the red and black wires where the attach on the underside of the top housing bulkhead. Sounds like the nuts were over tightened putting the wires on and broke the insulators shorting them to the assembly.

Measure the resistance to ground of all the pin in the connector. I'm thinking that the large black/white wire is shorted to the assembly at the bulkhead
 
The all black wire that was coroded was the problem. Luckily the wiring from the factory is a little long. I just cut off where it was coroded and put a new electrical connector on it. All fixed.


The wire that is broken, I'm assuming that is for the low fuel light?

Thanks for the help guys.
 
It's back to doing the same thing?WTF

I had to jump it before since the battery got low from testing things and trying to start it. It ran great for the minute I had it running. I just went out to jump it again and was going to leave it running so the battery could charge. But it's doing the same thing again. Just now the one wire isn't coroded.
 
Steve was thinking in the right direction.

I pulled the assembly back out to look at it again. The problem is the power wire coming of of the walbro. It was between the tank and assembly when I tightened it down.

It must have ran when I jumped it since I didn't have the housing tight. I just sat it in the tank to see if the black wire fixed it. Then when I tightened it down the wire made contact with the tank again. That's the only way I can explain it anyway.
 
It looks like the insulation is just missing in a small spot where it was pinched. Is heat shrink compatible with gas?
 
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