squarelyfe
Full Access Member
- Joined
- Nov 8, 2021
- Posts
- 174
- Reaction score
- 104
- Location
- NORCAL USA
- First Name
- Larry
- Truck Year
- 1975
- Truck Model
- k25
- Engine Size
- 350
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!
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!
Last edited: