Fuel pump quits exactly 15 mins into running, requires cooldown period

GS70350

Round Headlights.Like em?
May 25, 2001
423
0
16
33
Huntsville, AL
Hello everyone. It’s been a long time since I’ve posted. I’ve had children and business has taken me away from my Buick hobby for a long time. The Buick’s have suffered from neglecf. The gs is running well and I put it in storage last month after an undercarriage detail. Still needs paint again but that will be another day. The Tyype was set outside after the paint job got ruined by an automatic gate crushing quarter panel 5 days after job was done, 7 years ago. I never put the weatherstripping back on I was so disgusted. Anyhow I want to drive it again, and get it back to where it once was. So I bought a tt e85 chip, 80 lbs injectors, new acufab regulator, and a dw?320 pump, new tank, sending unit, etc and got it running again this time on e85. Moved it around the lot and that’s it about a year ago. It ran and ran well, although i didn’t road test it. Started it recently and added fuel again, so now maybe 10 gals. It cranks and runs (have console switch for fuel pump), but will idle/run for exactly 15 mins and then stalls. Fuel pump shuts off. Hotwire relay in trunk licks on when I flip switch, but no pump. Let it sit for a little while and flip switch, bingo head pump and it will start and run again for 15 mins, dies same story. I feel there is high resistance building in the electrical circuit but haven’t tried tracing it yet. Any ideas? I also have a problem with too much fuel pressure at idle, regulator can’t be dialed down enough to drop below 55 psi line on or off. Think return line is too small (factory tubing). Wanted to get it running well enough to go round the block and get trim reinstalled, screw the bodywork for now. Thanks for your insight.
 

ScottHeidinger

Active Member
May 2, 2015
698
121
43
50
northeast Florida
If you let it sit for a year with E85 sitting in the injectors, pump and lines bad things can happen. e85 attracts water and water in the fuel system will cause rust and can clog fuel injector baskets. If you’re going to let it sit you want to get the E85 out of it. If you run E85 it’s best to drive it daily. I would start by removing the fuel injectors and looking in the top baskets for signs of rust and/or clogging. Take a look at them and see what you can. I’m no injector expert but I’ve read that the baskets are removable and the flow is normally better matched without them.


This may or may not be your issue but what I’ve read has motivated me to make sure mine is driven daily and if it’s going to have to sit I would get the E85 out and put some 93 octane in it.


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