93 Suburban K2500 5.7L TBI Fuel Pump Fuse & Relay location

Just for kicks, take a rubber mallet, and give a rap on the bottom of your fuel tank. Then try to start the truck. I had the the same problem and I called a tow truck. He came out of his truck with a mallet and rapped my fuel tank of my 93 Blazer, and it started right up... the fuel pump was bad ,he told me not to shut it off, and go to the place where its going to be repaired, they replaced the pump, and all was ok.> Just an idea..

Can anyone tell me exactly where to find the electric fuel pump fuse and relay for the above truck? Also, which pins to bypass on the relay for a test? I parked it and it is no longer getting fuel (did a fuel pressure test and got zero). I want to rule out the electronics before I hire a truck to haul it out of the parking garage and 20 miles to home since I don't think they'd like me dropping the (1/2 full) fuel tank in the basement of my workplace.

I looked under the hood and saw no obvious fuses or relays for the fuel pump. I assume such a thing would not be in the interior fuse panel, though unfortunately I no longer have the owners manual which might tell me about it.

Thanks in advanced if anyone knows this information.

--Jeff

If you are one to run it low on fuel a lot, you can shorten the pumps life span a good bit. For max pump life, you realy want to keep it above 1/4 tank or so most of the time.

----------------- TheSnoMan.com

Aren't they on the passenger side firewall under a black plastic cover? That's where the relay is I think... also I believe there is a fuse in the fuse panel for pump too.

I don't know the test off hand but it would more or less entail hot-wiring the pump to see if it works, bypassing the relay. I think the relay is around $20 or so at NAPA and the fuse would be easy to check. I would just swap out the relay first.

----------- Elbert snipped-for-privacy@me.com

Go to your local library, and lookup auto manuals. I 'am sure your find one for a 93 Chevy.

My 93 had a test wire in the wire harness with a connector on it, i think it was gray, if you put a 10 amp fuse in line with it an 12v the pump should run if good. It is a direct connection tro the pump.

Ithink also, the relay is on the fire wall...Its been a long time,so please don't take this info a gospel..just trying to give you some ideas.

Thanks for the ideas. I could not find a fuse in the panel labeled "fuel pump" but checked them all and no blown fuses. I found a relay on the firewall in the engine compartment on the passenger side, and since it's the only one, I'm guessing it's the fuel pump relay. It has a schematic on it's plastic cover so I was able to figure out what to jump, but I still didn't get the pump running.

This afternoon I'll whack the fuel tank with a 2x4 and see if I can bump-start the pump. Failing that, I'll have to have it towed out of here so I can get it home and drop the tank.

Out of curiosity - how does having a fuel level under 1/4 tank cause additional wear on the pump? I never run out of gas, but have been in the habit of letting it get very low before filling up. I thought I was doing a good thing by burning up all the crud in the tank each time rather than leaving water/whatever build up in a layer on the top of the fuel. I'll ensure I don't go below 1/4 tank from here on out though.

Thanks again,

--Jeff

The pump is immersed in the gas and that is how it keeps cool. Exposed pump allows it to run warm / hot. GM

Thanks Bumpy - that did the trick. I gave it a whack with a 2x4 I had in the back and it started right up! Was able to drive it home and it even started again after I shut it off. Now I can take my time replacing the pump (and a few other parts).

Does anyone have any recommendations on manufacturers for fuel pumps, or just get whatever they have at the local discount auto parts store? They want $250 for the pump, if I remember correctly, so I can't imagine what they get for an OEM pump.

Thanks everyone for the help.

--Jeff

"Bite the bullet and get it at the Chevy dealer, it a big job, and you don't want to do it again! The top of the tank is probably rusted, and you will prpbably need to get the sender assembly also. Talk with the mechanics, it a bitch to get the assembly apart.

I couldn't do it myself, but my Chevy did it in 2.5 hrs!, They have done this job before!

Good luck! Bumpy

Get another GM pump....even auto zone carries them.

----------- Elbert snipped-for-privacy@me.com

Feeling lucky, I drove the truck to AutoZone and picked up parts - fuel pump, screen, and because I thought it was the cause of another big issue, a MAP sensor. Boy was my original information on the price of the parts wrong - I got them for far cheaper than I was quoted long ago. Replaced the MAP sensor 1st to see if that corrected the other big issue, and it didn't. Then did a fuel pressure check, now that my pump is actually pumping for the time being. I wanted to get an idea of what it was doing before I swapped it out. Fuel pressure between the tank and the filter (which is fairly new) read a steady/constant

4lbs of pressure. That seems extremely low to me, but can't find my manual at the moment to verify. Shouldn't a FI engine, even a TBFI, have a lot more pressure than that? If so, that would explain the other big issue with the truck. What is the acceptable pressure range?

Thanks,

--Jeff

TBI? IIRC 9-13 lbs Even if that ain't exactly right, 4 lbs is *way* too low.

-- Old Crow "Yol Bolson!" '82 FLTC-P "Miss Pearl" '95 YJ Rio Grande BS#133, SENS, TOMKAT, MAMBM