HELP- Fuel Pump

[jcain226]

I have an 88 GMC 1500 RCLB. Put new Delphi pump in 2 mos ago, along with a bunch more restoration items.
Just put new alternator in; Truck was running great; I had about 1/4 tank of gas, and just filled it up. It sat for a few days without being driven, and I am in N Texas with temps over 100.
Put new alternator in and drove to the shop to return the core. Got back in truck to leave and it wouldn’t crank. Would turn over, but wouldn’t crank unless I sprayed carb cleaner in carb.
Checked fuel pump fuse and relay and both are good;
I think my fuel pump went out;
Could it just be coincidence that the pump went out after only 2 mos?
A guy at the shop looked at it and asked about the gas. He actually called it and said he was betting that I just filled it up, and even asked if I got gas at racetrac, which I did. He said something about the high ethanol gas combined with filling it up and sitting in hot temps prob caused vapor lock and fried the fuel pump.

I am admittedly a newbie to all of that; but does any of that sound accurate? He said those old motors weren’t designed to run off of high ethanol, so he would suggest putting an additive in every few tanks.

I am just wondering if I just got a bad fuel pump, or if it is related to something else. It was running great until it wasn’t, and then wouldn’t even start. No warning!

I plan on tilting the bed up tomorrow or Tuesday and get a closer look at the pump, but just wanted to get feedback.
Thanks!!

 

[MIHELA]

Was it a quality name brand pump? Running them with low fuel level is hard on them because the fuel acts to cool the pump. That's why they often fail right after a fill up.

 

[jcain226]

Was it a quality name brand pump? Running them with low fuel level is hard on them because the fuel acts to cool the pump. That's why they often fail right after a fill up.

It was a Delphi. I thought it was higher quality when I bought it, but I don’t know if Delphi is considered quality or not.
Is it normal to go out without warning signs?

 

[MIHELA]

They often do. You can't hear it prime when you turn the key to run?

 

[jcain226]

No, it’s dead.

 

[Frank Enstein]

Bang on the bottom of the tank. Sometimes that will "un stick" it. That can serve to confirm it's pump failure so you don't buy one you don't need.

Frank has an external pump as does my wife's Astro. Tons easier to change on the van!

 

[jcain226]

Bang on the bottom of the tank. Sometimes that will "un stick" it. That can serve to confirm it's pump failure so you don't buy one you don't need.

Frank has an external pump as does my wife's Astro. Tons easier to change on the van!

If you run an external, do you bypass the in tank pump altogether?

 

[Schurkey]

Got back in truck to leave and it wouldn’t crank. Would turn over, but wouldn’t crank unless I sprayed carb cleaner in carb.

"Cranking" and "turning over" are the SAME THING.

Apparently your truck cranks, but won't start and run.

Checked fuel pump fuse and relay and both are good;
I think my fuel pump went out;
Could it just be coincidence that the pump went out after only 2 mos?

HOW do you know the fuel pump failed? Could just as easily be a wiring problem.

For that matter, how do you know it's fuel-pressure related at all? You could have a failed ignition system. Have you checked for spark?

A guy at the shop looked at it and asked about the gas. He actually called it and said he was betting that I just filled it up, and even asked if I got gas at racetrac, which I did. He said something about the high ethanol gas combined with filling it up and sitting in hot temps prob caused vapor lock and fried the fuel pump.

I am admittedly a newbie to all of that; but does any of that sound accurate?

No, not accurate at all.

He said those old motors weren’t designed to run off of high ethanol, so he would suggest putting an additive in every few tanks.

My '88 gets nothing but E10; and has for at least as long as I've owned it. I bought it in '97.

I am just wondering if I just got a bad fuel pump, or if it is related to something else. It was running great until it wasn’t, and then wouldn’t even start. No warning!

I plan on tilting the bed up tomorrow or Tuesday and get a closer look at the pump, but just wanted to get feedback.
Thanks!!

Start with finding out if the pump has proper power supply. I wouldn't even tilt the bed before probing some wires.

 

[Erik the Awful]

No, not accurate at all.

Agreed. The mechanic doesn't know, so he's bull$#!+ting a hypothesis.

When brand new the TBI pump is barely "adequate". The best option for TBI owners is to upgrade to the Vortec fuel pump. The TBI runs just fine on it, and you have room for engine upgrades. Here's the $100 Delco pump, but I used the $20 TYC and my truck's been running fine for two years on it.

More Information for GM GENUINE EP381

 

[PlayingWithTBI]

He said something about the high ethanol gas combined with filling it up and sitting in hot temps prob caused vapor lock and fried the fuel pump.

I don't understand how an in-tank fuel pump with a bypass return line at the TB can get "vapor lock". I'm declaring bull$hit.

I live in the Tonopah desert which probably sees higher temps than your area, I don't have any issues with my 88 and an EP381.