I wanted to share my experience with a fuel delivery issue that began November 2019 as I was driving home from the Turkey Rod Run in Daytona. My 40 Ford Pickup with a 290hp GM crate SBC, block hugger headers connected to full exhaust, Turbo 350, Edelbrock Performer intake, 600 cfm Edelbrock carb, Tanks Inc poly tank and mechanical fuel pump were installed by the previous owner. I added an electric Holley red pump mounted in front of the fuel tank below the pickup. This combo ran well for years. I have a few other OT vehicles that I turn wrenches on so I know my way around an engine somewhat. On the ride back about a 2 hr trip the engine stumbled as I was doing about 75 mph. I rarely use the electric pump but have run this set up on all my vehicles as a way to deal with fuel quality and vapor lock issues should they occur. I'd never had to run the electric on the '40. When the stumble occurred it felt like a fuel delivery issue. I activated the electric pump and continued on home. In the months after the problem got worse so I decided to replace the mechanical fuel pump which was an Airtex stock-type pump. Due to the sectioned crossmember performed by the PO to allow room for the pump a high performance pump would not fit so I went with another Airtex. The issue continued in different situations and times including at idle in traffic. This led me down the vapor lock rabbit hole. I rebuilt the carb, insulated the fuel lines added a shroud to the electric fan, etc. The issue continued. I blew the fuel lines and swapped in a new tank fuel filter, return line. I finally added a fuel gauge, regulator and transparent filter. I decided to replace the Airtex with another new unit. I also purchased an AC Delco hi volume pump that had dimensions that might've fit . The AC Delco pump was 1/4" too large in diameter and interfered with the sectioned crossmember. So I installed the new Airtex unit and could see the pump barely pushing fuel into the filter. It provided 6psi but the problem persisted. I walked away from this issue a few times. I finally decided to re-section the crossmember to allow the AC Delco pump to fit. I had a/c, heater hoses and a pretty paint job in the way. I got it all back together with new pump to filter lines and the problem has been solved. One of the first things I wanted to upgrade when I purchased the truck was to add a hi volume fuel pump . I submit this experience for anyone who is dealing with this type o f issue. I should add I never had an issue until my recent move from NY to FL, which supported my incorrect vapor lock theory. The re-section cut. Yes, there was bondo to deal with. Don't judge my welds, please. The fix. Thanks for your time.
Mechanicals do work better than electric. The trick with them is to get them fed. I once had starvation issues with a Pontiac 462 that had a Quadrajet. I installed a fuel cell with a sump and dual 1/2" take offs. I ran two 3/8" steel tubing lines to a tee at the mechanical fuel pump. WOW!! What a difference. That car just charged all the way to the top with no issues. It was like I put a new engine in it.. The old timer who gave me the dual fuel line tip said to run two 3/8" lines not 1/2". 1/2" makes for the column of gasoline to be too large and heavy to pull when the 3/8" column is just right..
The 2 new Airtex pumps could not provide the volume. The stumble usually occurred above 2200 rpm. Also, at idle on a warm day in traffic. I still have the electric Holley pump connected. The AC Delco is rated at 110gph and 7psi
A fuel starvation issue will take away your confidence in driving any long distances. I found it hard to believe two "new" Airtex pumps couldn't deliver enough fuel when the original one did. The AC Delco pump is not cheap but neither is getting stuck away from home.
I heard lots of bad about Airtex pumps, mechanical and electric. I put one of their replacement in tank pumps in a ot Vette, it lasted a month. Went back with an AC, was still in the car when I got rid of it two years later.
I was uable to find a stock profile pump that could flow the necessary volume. I didn't mention it earlier but I also tried a Carter pump and suffered the same issue.
The Jalopy Journal
