Mechanical fuel pump beef/info rant

[AuroraGirl]

Good feedback. I am at 5,000 ft. elevation in a temperate climate, so, hopefully that will mitigate some of those problems.

have you adjusted your carb for that eelvation? edelbrock has a guide for elevation and you will qualify for adjusting the springs inside the carb or something like that to account for the elevation.

 

[cstew47]

have you adjusted your carb for that eelvation? edelbrock has a guide for elevation and you will qualify for adjusting the springs inside the carb or something like that to account for the elevation.

I'll look into that, thanks

 

[fast 99]

A couple years ago I put a new engine in an 85 K20350. The fuel pump appeared old so it was replaced. Afterwards, when trying to merge onto the freeway it started to run very lean, no power. Ran decent otherwise. After spending a bunch of time diagnosing a fuel flow problem, it ended up being the pump. The pump arm was partially stuck down and not getting full travel. Tried a replacement pump of the same brand. Same thing happened. No spring on top of either arm. Started looking at different brand pumps. Only brand that had the return spring then was GM. Now I have a spare, problem solved. Did another engine last month. That pump has different outlet angles. Searched and found a Delphi pump. It has the spring and I have another spare one. Just an FYI.

 

[squarelyfe]

Well, if you google "symptoms of too much fuel pressure", one of the things that is cited is poor fuel economy. I will keep the group posted as I run this tank down.

Yes that is true to a point, if you are dumping too much you are releasing more causing it to go through more fuel prematurely, other than that it's likely a tuning issue. Did it get any better for you?

 

[AuroraGirl]

Yes that is true to a point, if you are dumping too much you are releasing more causing it to go through more fuel prematurely, other than that it's likely a tuning issue. Did it get any better for you?

If your fueling is off your vacuum is going to be off, yes? if so, your timing will indirectly be off then

 

[cstew47]

Yes that is true to a point, if you are dumping too much you are releasing more causing it to go through more fuel prematurely, other than that it's likely a tuning issue. Did it get any better for you?

I'm still monitoring the first tankful. I'm also playing with octane. I designed the engine to have a 10:1 CR, but, I have aluminum heads and I'm at 6,000 ft. I have been trying half and half regular to premium and now I'm down to 3:1. So far no pinging. Premium here is double regular.

 

[Rusty Nail]

Ive always run AIRTEX pumps in GMT400 trucks - but not the carbed version ever - but mostly cuz they aint no good past one year and one day. Losadface

 

[68post]

Hey so the other way of doing it in another sort of company in the bid process is to bid low like that BUT you make up for it by padding the bill with more hours and or parts that weren't needed to justify the higher rate. So you replace parts that are good. Now to be careful though because they can send a vehicle or item to a shop that has nothing wrong to see if you are cheating them. But depending on the service you provide in the business there are always a way to get it back in the long run.

I was asked while on a commercial job what our rate would be to bid on a service contract and told the man our current hourly rate which he thought was too high to gain the other companies business. I then had to explain that the large Co that was doing their work was likely padding the bill to cover their ridiculously low hourly rate. I then had to explain exactly how much work can actually be accomplished in less than an hour (if being honest), but also that the minimum half hour drive to the job and fuel in a heavy service truck wasn't necessarily free for any company.
I don't know if he actually got it, but a lot don't.

 

[ChuckN]

So my info rant goes like this..

At some point you will have to replace your mechanical fuel pump if not using an electric fuel pump. Some of you know this story, but others will learn something here. In general carburetors typically don't like more than 5 to 6 PSI. They aren't fuel injected needing 40-50+ psi. Most rebuilders and carburetor companies will tell you this as well. It's not to say that you can't run more PSI but in general the number is lower for a reason. Anyone thinking about buying a cheap pump will want to pay attention. If you have ever had fuel come out of the top of your carburetor or dump too much without being a leaking well plugs problem, past the upper gasket it's likely either your float was set too high, you had a sticking float OR you had TOO much fuel psi blowing the needle/seat open allowing fuel to continue into the bowl and then over.

A while back after buying a cheap pump at O'Rileys I found this out the hard way. I didn't know it but in the past years the company AIRTEX got a really bad reputation and eventually sold they company to someone else. They are put together in China with zero fuks given. Why? Probably because they didn't give a crap what batch of springs they threw in their pumps and weren't quality controlled their pumps in turn would put out 9 to 12 PSI do some searching around the internet and you'll read the same story many times told in different versions. So you realize that the spring is what's internally regulating the PSI. Back in the day AC Delco was a genuine quality parts line. That's when you would get a pump that was embossed AC on the side of the body and they made parts that would last for years.

I know what you're thinking already..how is it that GM sold engines without fuel pressure regulators just using mechanical pumps and you never heard anything until now. Well.. apparently the bean counters were willing to overlook something long enough until they had enough complaints to fix the issue..untill the later pumps came along..

Fast forward to the world of SBC cheaper fuel pumps.. There is no more AC Delco making pumps. Also found this out the hard way. Getting to the heart of this post.. my BEEF is with companies branding there names onto Airtex pumps!

I tried to buy a shiny eBay chrome pump. Seller says 6 psi but later states 8 psi-no thank you! You would still need a part for your part meaning at 8+ psi you likely need a fuel pressure regulator!


Next I moved onto "screw this I'm getting an AC DELCO" ultra fail... Apparently AC Delco stopped making or having quality parts built. That's right I went to AutoZone bought an AC Delco fuel pump and in the box with the paperwork says Airtex and on the bottom of the pump has the "A". Nope again not running effing Airtex. I know some will say they worked for them and they will but they don't last or just fail.


After multiple pumps I called a local parts supplier who told me that they had a Delphi pump maker of new GM parts at 5 PSI great I said. Then when I got home I pulled it out of the box and noticed the A on the bottom of it! My curiosity got the best of me and decided to look around the internet about this company. I found another website and guys were talking about how they got Delphi pumps with Airtex paperwork in the box! At this point I'm really pissed off, my grandfather worked for general motors for 40 plus years and he was one of the head mechanics on the assembly line at the tarrytown plant in New York. I've had GM running
my veins and always been told that AC Delco made great parts as I've known them to. Anyhow I decided to pull the paperwork out of the Delphi box and to my surprise it didn't have the Airtex paperwork it just read Delphi from one of the states so I just decided to install it even though it has the A on the bottom of it which makes me very suspicious. I'd like to believe that they knew it was going on and talked to airtex about this to make a slightly better quality actually putting out what they say it does at 5 PSI so far so good we'll see. It's pretty common for people to run fuel pressure regulators. I have a clean engine bay and I bought a nice new hard line from the mechanical pump to the quadrajet, I didn't want to have to cut a brand new Hardline to run one of those cheap ass fuel pressure regulators that sits on top of the engine that have a bad rap. I've run them before and had one fail with true psi. If you read around the internet they're not accurate and the numbers don't even represent the actual PSI. I just think it's sad that all these companies are buying cheap pumps and branding their name on to the boxes and you end up paying more like in the case of the AC Delco and AutoZone was $45 the guy had said oh that's one of the last ones I think they're discontinued no crap they're discontinued for a reason I come to find out so do your homework otherwise you're looking at $140 Holley or Edelbrock mechanical pump which seems crazy or on early models you may need another return line to your gas tank to try to relieve some pressure if that helps. I believe this is how GM corrected the overpressure on mechanical pumps in later years but don't quote me on that.

Here are a few photos showing the pump I just bought that was branded AC Delco with Airtex pump in the box and no it wasn't a return I actually called the Delco website number because they had a part on there about counterfeit parts. She said it looks like Delco may have contracted with Airtex, I was shocked and pissed!

I hear ya. The overarching theme is that all the “name brands “ are farming out their names for the purpose of marketing the almighty dollar.

I recently purchased a whole brake setup from Rock Auto, and spent extra for the AC Delco items. Guess what? I paid 15 bucks an item (or so) extra for the box. When I pulled the part from the box, it had the exact same off brand name that I could’ve bought for less money. I could go take a pictures of the tag that’s on the brake hose, but you get my drift. Same cheaper part, AC Delco box.

I’m not going all “‘MURICA” here, but good lord, the bumper brackets I bought this week from Classic Parts stamped Taiwan, was a helluva time getting matched up with the Summit bumper that I bought. It’s the world we’re living in, and it’s no better to buy from LMC, since they charge a premium, and their parts are also from overseas. Perhaps they are better there.

If the parts work, that’s fine- but perhaps I still live in the shadow of Flint, MI. And when I buy parts that are rebranded and not from them, I guess it’s kinda heartbreaking.

 

[SirRobyn0]

I hear ya. The overarching theme is that all the “name brands “ are farming out their names for the purpose of marketing the almighty dollar.

I recently purchased a whole brake setup from Rock Auto, and spent extra for the AC Delco items. Guess what? I paid 15 bucks an item (or so) extra for the box. When I pulled the part from the box, it had the exact same off brand name that I could’ve bought for less money. I could go take a pictures of the tag that’s on the brake hose, but you get my drift. Same cheaper part, AC Delco box.

I’m not going all “‘MURICA” here, but good lord, the bumper brackets I bought this week from Classic Parts stamped Taiwan, was a helluva time getting matched up with the Summit bumper that I bought. It’s the world we’re living in, and it’s no better to buy from LMC, since they charge a premium, and their parts are also from overseas. Perhaps they are better there.

If the parts work, that’s fine- but perhaps I still live in the shadow of Flint, MI. And when I buy parts that are rebranded and not from them, I guess it’s kinda heartbreaking.

I just posted this in another thread this morning but the folks in this thread might find it interesting even though it's about fan clutches.
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"I ended up installing two or three Hayden manufactured fan clutches. Two would never engage, the other was stuck engaged. After that I ordered an ACDelco unit. Realize at the time the Hayden units were around $50, and the ACDelco unit around $150, and I had to wait a couple days to get the ACDelco fan clutch. Well I installed that one and it has worked flawlessly ever since.

I also learned Hayden manufactures most of the on the shelf store branded fan clutches like duralast and masterpro.

There are not a lot of fan clutch manufactures left. Hayden, and GMB are about it. I do not know if ACDelco is actually making the fan clutches they sell, but mine was marked made in Mexico.

If your at all interested I have a GMB fan clutch on my Jeep as mopar no longer produces them and the GMB has been fine. If I were to complain about it at all I'd say that I'd like it to come on just a touch sooner than it does, but it does do it's thing just fine."

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I don't think "name brands" farming out the actual making of a product is all that new but I do think the quality has changed. Check this one out. On my Dodge truck, it's an fuel injected 1992, I put three Delphi pumps in it. Delphi makes a lot of OE electrical parts and is generally highly regarded, but all three of these pump were marked made in china. Like you I don't have to have an american made part per-say but I'm never thrilled to open a box and find china, on an electrical part. Anyhow 1 bad sending unit, and 2 no starts later I bought a Masterpro pump from O'Reilly's 1/2 the cost of the Delphi unit, made in America and still working fine.

It's getting hard to keep up on which manufacture is making good parts. And then ACDelco has to brand themselves to some not so great parts, and some of the best, so again it can be hard to tell what's what.

 

[Grit dog]

To get even a little more philosophical about this, I can sort of understand, actually I can totally understand why a company (ACDelco or whomever) would discontinue making OE quality parts for old, low demand applications. I can even understand aftermarket’s doing it.
Now, fuel pumps for small/big block GM engines should be and are still relatively high demand compared to say bumper brackets or sliding window gaskets or dash pads, but in the grand scheme of things the number of old carbureted Chebbys on the road is a small fraction of what they used to be.
Not an excuse for what’s left to be steaming piles of ****, but whatever….
Add a spare fuel pump to your repair kit and tools…
The bad part is “newer” car parts are equally JUNK.
I’ve told the story about going thru 3 alternators in the Napa parking lot to replace the Napa alternator that was aboot 3 months old on a LS powered Tahoe.
And 3 hydro boost pumps for a Dodge Cummins that was less than 10 years old….of which they lasted chronologically about 30,000 mi, 3,000 mi and 3 days!

 

[SirRobyn0]

@Grit dog And I live in the world of dealing with that on a daily bases at the shop.....

 

[Grit dog]

@Grit dog And I live in the world of dealing with that on a daily bases at the shop.....

Yeah how do you even warranty your work when you know there’s a good chance it will fail prematurely? Parts only?

 

[SirRobyn0]

Yeah how do you even warranty your work when you know there’s a good chance it will fail prematurely? Parts only?

Nope, full warranty sometimes loose our butts. Take my Dodge fuel pump for example. 3 Delphi units from one supplier, 1 Masterpro from another supplier. If that had been a customer rig we'd be eating the labor. In the old days parts manufactures stood behind their parts and we'd submit a labor claim. They'd typically pay a lower rate than the shop rate and it would take a month or so to get it but at least it was something. No one does that anymore....

If that had been say a power steering pump, or anything with a core, we'd loose the core to the first parts supplier and have to pay the core charge to the second one, thus further loosing our butts.

And one of the reasons shops around here are charging $175 an hour and still not turning a decent profit. Couple that with 10K monthly rent, I could go on and on.......

 

[Grit dog]

^Yup, it’s always been advantageous to fix your own car, financially. And inflation etc aside, just this parts issue I’m sure is inflating rates even more.

For parts that are rebuildable, like starters and alternators specifically, have you guys considered or do you have them rebuilt locally or buy local parts?

After the alternator debacle on the Tahoe, the kids low mile Mustang had a bad diode or 3 in the alternator. Caused some weird almost inexplicable issues since it still “worked”. Tip for the mechanic, the Ford Triton engines, if alt looses a diode, it randomly emits some electrical interference that presents like a bad cam sensor. Would have never figured that out on my own within the internet….
Regardless, I had him go get it rebuilt down at Sound Starter and Alt in Tacoma. Cost was comparable to a reman and way cheaper than a supposedly brand new high output aftermarket unit.
2 years later it’s still good and I KNOW it got a new rectifier (the problem) since remans don’t get new rectifiers if they test out good.