Fuel Pump replacement questions.

Nice thread!!

Any suggestions for a 1988 Suburban, 2500, 350 TBI Fuel pump?

Have the fuel pump assembly out, It had no output. debating whether to just replace the pump or the whole assembly. Does anyone have any thoughts or ways to test the relay, etc? I didn't know about the extra wire.

I can't believe the pump assembly for the 40 gallon tank is 64.00 and the 31 gallon one is 94.00.

Any advice is appreciated.

Blacklion

TerryKing said:

Then there's my approach: Carefully figure clearance and use a sabre saw with a metal blade to cut a rectangular hole in the rear floor. File the sharp edges a little. Cut a piece of 1/2" pressure treated plywood 3 inches bigger both ways. Screw/glue the removed metal piece evenly on the plywood.

After replacing and testing the pump and maybe the tank adaptor (Rust Much??) place the metal/plywood patch back so the metal aligns. Hold in place and pilot/screw it into the floor in 6 or 8 places. Then remove it and use the caulk of your choice on the overlap section. Reposition and screw in place. Oh, put the carpet you removed back in place.

I have photos of this somewhere... Hmmm... I'll look

Some Japanese / European cars already have a removeable panel for the fuel pump. NICE guys!

Now YOU have one...

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Works fine in a pickup, where you're not cutting a hole from the passenger compartment into the fuel tank area.

If you're opening a hole from the passenger compartment, you'd better be sure your "patch" will survive any possible collision without leakage, or you risk filling the passenger compartment with gasoline and burning everyone inside alive.

You guys old enough to remember the Ford Pinto? ONE layer of steel between the gasoline and the people. When that ONE layer tore...people died very unpleasantly.

Mark Gilbert said:

The 98 PCM actually completely controls the fuel pump, it doesn't use the oil pressure switch anymore like the TBI motors did. Just for future reference

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Thanks for that.

BlackLion said:

Any suggestions for a 1988 Suburban, 2500, 350 TBI Fuel pump?

Have the fuel pump assembly out, It had no output. debating whether to just replace the pump or the whole assembly. Does anyone have any thoughts or ways to test the relay, etc? I didn't know about the extra wire.

I can't believe the pump assembly for the 40 gallon tank is 64.00 and the 31 gallon one is 94.00.

Any advice is appreciated.

Click to expand...

If the gas gauge worked properly, why replace the sender? If the gas gauge did not work properly, was it the sender that was faulty? More often, it's the wiring.

I would most likely replace the pump, the filter sock on the bottom, and the in-tank wire harness that connects the pump and sending unit to the top of the hanger assembly. Use clamps that don't damage the connector hose from pump outlet to hanger assembly.



Wire harness for a Lumina. For all I know, the same part number works for our trucks. The replacement harness tends to have wires of generous length.



This is why you replace the in-tank harness. New wire vs. original wire.

On my 88 C1500 5.7L I upgraded to the Vortec fuel pump AC Delco EP381. It provides more volume and can build more pressure but, will still run at 13PSI
https://www.summitracing.com/parts/ado-ep381/overview/

Make sure you

have power going in and out from the fuse.

Then check for power at the coil by turning the key switch. Check the ground at the coil also.

then check for power in and out of the relay contact.

if all those points show power going through check power at the fuel
Pump.

if you show power all the way to the fuel pump you probably have a bad pump. If no power at the fuel
Pump you have a broken wire. If no power anywhere between those points you have a bad wire. Start checking opens or grounds

I dropped the tank in my 99’ SUv in the driveway. It was about a 4 hour job on the ground. NOT FUN. Next time I’ll cut a hole under the backseat..

Just take the bed of the truck off, much easier as a pick-up.

Schurkey said:

Works fine in a pickup, where you're not cutting a hole from the passenger compartment into the fuel tank area.

If you're opening a hole from the passenger compartment, you'd better be sure your "patch" will survive any possible collision without leakage, or you risk filling the passenger compartment with gasoline and burning everyone inside alive.

Click to expand...

Coveman said:

my pump got louder over time and when I couldnt hear it prime anymore it was dead (no fuel pressure). I got one more run out of it by whacking the tank with a 2x4 and was able drive it and dropped it at the shop.

it was a full 44 gallon tank on my burb, didnt want to mess with it at home. Went with a delphi replacement

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Thats how the pump in the Express van went a few years ago. I stopped for gas nearly 300 miles from home. Filled the tank, went to start it, fired and died and then nothing. I had someone that was riding with me crank over the engine while I banged on the bottom of the tank. It fired right up and I drove it all the way home. When I pulled the tank it still had ~10 gallons in it. Was still a bulky, heavy job. Thankfully I had a transmission jack that made it much easier. I had the tank out and back in fairly quickly. Took about 2 hours including installing the Racetronix hotwire setup. I used a Delphi pump assembly with the newer oval connector.

FWIW the sending unit in the van was bad. The way GM built them they loosen up and then the contact does not touch the resistor on the sending unit. Then your gas gauge bounces all over the place. I think the float was slightly bent on the replacement. It shows empty when the tank still has 8 gallons in it. Now when it hits empty rather than worrying about being out of gas I just find the next town on the interstate and fillup.

After raising the long bed on my k2500 and installing the new pump and assembly, gas pours out on top on the tank when I fill it too full. Sounds like I didn’t reconnect some hose. Any ideas?


Sent from my iPhone using Tapatalk

Vent hose to filler spout?

PlayingWithTBI said:

Vent hose to filler spout?

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That or the "O" ring between the tank and sending unit got pushed out of position when the lock ring was installed.