Fuel issues

[tpangle85]

Need some advice on my 86 k10 305. I have been through 3 fuel pumps since starting to restore my 86. The first a return spring broke, the second the diaphragm ruptured, and the third is now losing prime if it sits a week and when my son drove it yesterday it quit on him when he was driving down the highway. When we got there to get him it looked like it was vapor locked, no fuel in the filter. So I removed the line from the carb reprimed the pump and it drove all the way home. Does anyone make a decent mechanical pump anymore, or should I go the electric route? Mine is a 3 line pump, should I try a two line without a bypass? I don't remember the brands of the pumps, but two are from Napa and I think the last I bought at Advance. Just looking for advice on what others have done that is reliable, because these China crap parts are not making me happy at the moment. And the whole fuel system is new, from tank to pump to Edelbrock carb before anyone asks.

 

[fast 99]

Delphi or AC delco. Went through 3 before I figured out what was going on. Cheap pumps did not have a return spring on top of the pump arm. Even though the GM pumps are made in China they are different.

 

[Grit dog]

Good news is it’s likely just poor quality fuel pumps. Bad news is, good luck getting a good one.
Anymore I feel lucky if I get a “good” (and my standards have been lowered) mechanical or electrical part anymore.
If it makes you feel better, couple years ago, I bought a reman alternator, parking lot swap since we was dead in the water 150 miles from home.
About 4 months later, that alt dies about 50 miles into the drive to the same destination (was in Canada both times so at least I could return the old part…). Stopped and quick bought a new battery so we could get our son to his hockey game in time.
Later that day, between games, went back to the same Napa I bought the other one from, pulled it out and exchanged it.
After 3 bad units in a row, 1 had smashed casting, bolt wouldn’t go through. Second just didn’t work. Third had a bent pulley and bearings sounded like they’d been replaced with almost round rocks, would have gotten a 4th one but all they had was 3 in stock.
So I got the first one and the nice lady opened up an electric drill and a pack of drill bits off the shelf and let me use them to ream out the hole on alternator #1, in hopes it actually worked. Thankfully it did and I made it home after the weekend and sleeved the bolt hole.
I don’t have many vehicles with mechanical fuel pumps anymore. But my buddy who’d just built a motor for one of his hot rod resto pickups went thru 2 Chevy fuel pumps in the span of maybe 10-20 engine hours. 3rd time was the charm for him.

 

[fast 99]

Good news is it’s likely just poor quality fuel pumps. Bad news is, good luck getting a good one.
Anymore I feel lucky if I get a “good” (and my standards have been lowered) mechanical or electrical part anymore.
If it makes you feel better, couple years ago, I bought a reman alternator, parking lot swap since we was dead in the water 150 miles from home.
About 4 months later, that alt dies about 50 miles into the drive to the same destination (was in Canada both times so at least I could return the old part…). Stopped and quick bought a new battery so we could get our son to his hockey game in time.
Later that day, between games, went back to the same Napa I bought the other one from, pulled it out and exchanged it.
After 3 bad units in a row, 1 had smashed casting, bolt wouldn’t go through. Second just didn’t work. Third had a bent pulley and bearings sounded like they’d been replaced with almost round rocks, would have gotten a 4th one but all they had was 3 in stock.
So I got the first one and the nice lady opened up an electric drill and a pack of drill bits off the shelf and let me use them to ream out the hole on alternator #1, in hopes it actually worked. Thankfully it did and I made it home after the weekend and sleeved the bolt hole.
I don’t have many vehicles with mechanical fuel pumps anymore. But my buddy who’d just built a motor for one of his hot rod resto pickups went thru 2 Chevy fuel pumps in the span of maybe 10-20 engine hours. 3rd time was the charm for him.

Yeah agree. Being a line tech see this every day although haven't seen that many bad reman parts in a row. Actually, reman has been much better than offshore new.

Back to fuel pumps. Learned a lesson on mechanical pumps with my 85. Can't remember the last time I replaced one for a customer so didn't have updated knowledge on what's good or bad. Just kept buying pumps till I figured it out.

 

[Grit dog]

^Idk, my buddy found an OE looking AC Delco pump. A big one, taller, for a big block or something. All I know is it came in an old school looking blue n white Delco box and it’s been working for several years now.

 

[fast 99]

^Idk, my buddy found an OE looking AC Delco pump. A big one, taller, for a big block or something. All I know is it came in an old school looking blue n white Delco box and it’s been working for several years now.

That's my original suggestion. Buy Delphi or AC Delco. Pumps without the spring, pump arm would stick 1/2 way or more down and didn't make any noise.

When accelerating on the freeway truck would shut down until throttle was reduced. Basically replaced the entire fuel system then took pump off and checked it. Replaced 2 more pumps that did the same thing. Until I found a pump with that spring, they were no good.

It's been a couple years now without any problems. So not to take chances it gets E free fuel and a about gallon of AV gas per tank as a stabilizer.

 

[Grit dog]

^AV gas is great bang for the buck around here. Just filled a canna couple days ago. (I always mix my small engine 2smoke fuel using straight 100LL. Makes it smell like I’m snowmobiling while doing chores and I never have to worry about draining the gas or stabilizing the small engines.
Same with the mowers and generators. Towards the end of season, run em low and dump in a couple gallons of AV. Gennys especially. They only get used when the power goes out. Could sit 6 months could sit over a year.
And it’s only a buck more than premium, 50c more than Ethanol free and the same price as premium if I was dumb enough to fill up near seattle!

Hey I’m not sure it’s still a problem, but being you’re from Spocompton I’m sure you’re familiar with filling up at the Maverik just over the state line by Cabelas. This summer I treated the boat to a tank full of no E 91 there before giving it 10 days of 87 cheap boat gas on Pendo.
The gas was NOT non ethanol. It wasn’t contaminated. It ran fine. But I didn’t “smell” it before pumping in a bunch.
I do that over here because some stations scam ya with E10, just like they overcharge for farm fuel….nother story.
But it burped gas on me when it was full. You have to listen very carefully while filling to cut it off before it burps and that gas station is loud AF…
It was definitely not no E. It stunk, even after going in and washing my hands.

 

[tpangle85]

Well I'm glad to see I'm not the only one who's been through several crap parts on my truck. I had a chance yesterday to take a look and the pump is pumping low capacity. I believe it must have an internal valve for the return that is sticking or something. You can see a lot of air mixed in the fuel filter until I pinch off the return line and it's crystal clear after that and runs like a champ. Never ran across this problem before. Guess I'll pick up an AC Delco pump and try that next because this one is marked Delphi, and if memory serves me correctly I believe the other two were Carter.

 

[fast 99]

Consider installing a filter before pump. Might be picking up crud somewhere getting in the check valves.

 

[tpangle85]

Consider installing a filter before pump. Might be picking up crud somewhere getting in the check valves.

That's probably not a bad idea actually, I cleaned the whole tank and replaced all fuel lines when I got the truck but there's always a chance of getting trash at the gas pump. I would hope the filter sock in the tank would catch it but who knows at this point.

 

[kzguns]

I went through a couple parts store pumps in less than 300 miles. I bought an edelbrock and so far so good.

 

[T-roy K10]

My 85 has a 96’ vortec 350 with no provision for mechanical pump. I don’t really trust external electric pumps and was thinking of replacing the short block to go back to a mechanical. thats Not looking like such a good idea now. Mechanicals used to be reliable, guess that changed too.

 

[squaredeal91]

I've got a holley mechical pump, it's a high volume. Been on there that 350 with no regulator since 2005. Been very pleased with it. And it's rebuildable like the old ac delco was

 

[ChuckN]

Engine Masters had an episode on fuel pumps, the one they picked out for most applications was a cheap Carter. I bought one for our old ‘54 3100 and it was great, probably less than 40 bucks at the time. But, it was a two-line.

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Edit: I also use an Edelbrock on my square, but that’s because I run an Edelbrock carb and they are sensitive to too much fuel pressure. I was impatient at the time didn’t want to spend time on a regulator. Bonus is that you can clock where you want the fittings to point.

 

[Ricko1966]

My 02 cents,do not switch a 3 line for a 2 line the 3 line bypasses back to the tank, a 2 line will hold pressure against the needle and seat and when the new formula gas expands due to heat it will blow the seat open causing flooding. A lot of the pump problems are old stock.pumps,not ethanol compatible, another fun fact the fuel pump lobe can wear off of the cam causing mystery pump problems. I don't want to write a book. All of the above happened to my truck I am now temporarily running an electric pump low and close to the tank, through a factory 3 line pump,with no pushrod and a restrictor in the return line to regulate pressure. Most ,not all,electric pumps are JUNK!!!! If somebody tries to scare you with the the diaphragm can rupture and fill your pan with gas,blah,blah no worries if it scares you I have a couple of work arounds.