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Fuel Pump wiring - '98 Suburban

04-17-2007, 05:27 PM
As soon as I reconnected the new fuel pump, I checked to see if the pump would humm when I turned the key on - it did. So I bolted the tank back up and the filler neck. Tried to start it and nothonig happened. So I got back under the truck and had my son turn the key on -and I moved the harness forward and back near the crossmember above the rearend and it started to humm. So I got out and it started right up. So how hard our bad is it to put a new harness in our should I just get a new picktail that clips into the pump? Thanks....Ted

04-17-2007, 06:18 PM
Ted: Your problem could be as simple as a bad ground which is located on that crossmember. That would be the 1st thing I'd check. Unfortunately you'll probably have to drop the tank again for good access.

I know when I changed the pump in my '98 I could only drop the tank so far before the wires started stretching. So if you think maybe that's what happened and a wire partially pulled out of the plug you'll have to go from there. If you do end up splicing in a new pigtail make sure you use a good butt splice with heat shrink ends to seal the splice from the elements...Steve

04-17-2007, 08:20 PM
Thanks Steve.....I'll check that out first. When I dropped the tanK I had it blocked really good and used the floor jack to lower it a little at a time. I had the passenger side lower than the drivers side. I got it low enough to get my arm between the top of the tank and the bottom of the frame only. I'm glad that the tank wasn't full. Thanks again....Ted

Old Dave
04-18-2007, 01:03 PM
I had to replace the pump last June in my 97 Suburban and could not get the 4 pin connector loose from the top of the sending unit. I ended up cutting the four wires and putting a 4 pin flat trailer plug on(male & female) so if I ever had to replace it again it would be much easier. I soldered the wires together and used 2 layers of heat shrink on each wire to make it watertight and coated both parts of the connector with grease to keep water out. I left the wires long enough so if I have to drop it again, it will come clear down with the floor jack. It's been almost a year and I haven't had any problems.

04-18-2007, 05:09 PM
Some of the fuel pumps have problems where the wires plug onto the fuel pump.
If that is the problem spot they have a new plug in kit.
Or as said check that ground good.
And also some replacement pump modules come with the new wiring kit.
What brand of pump or fuel pump module did you replace with?

04-19-2007, 09:03 PM
Update on my fuel pump problems - it's running again! Turned out to be the ground connection wasn't as tight as it was suppossed to be - and I added 5 gallons of gas. I test drove it and put half a tank in - just in case I had to drop the tank again. The new fuel pump that I replaced was an AC Delco MU-152. Thanks again for all of the advice...Ted

04-20-2007, 08:43 AM
You are welcome and thanks for posting back how it went and the fix.
Glad you found the problem and all is well.

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