I shut off the engine after it was idling for about 20 min. Then, with the engine shut off, fuel began to bubble out from the accel pump shooters all by itself. It was as if it was boiling out just like a coffee percolator.

This was on a holley 650 dbl pump 350 engine with AFR heads without heat risers and a temp around 180f.

Is this normal?

 

Sounds like you have a fuel pump without a return line, such as a Carter, Edelbrock, etc.; and modern gasoline.

Put a stock fuel pump back on it.

 

"boiling out just like a coffee percolator."

Thats why they call it fuel purculation.
In addition to installing a fuel pressure relief system with return line.
You can install a heat insulation gasket-spacer between the fuel pump and block. And you can install a (wood) heat barrier carb spacer between the carb and manifold. to reduce heat soak. You can also install an under hood auxillary cooling fan to blow off some of the exess heat
around the fuel pump and carb, that skyrockets every time you car off. (heat soak) Especially on a blistering Texas summer day.
Third gens are famous for their exessive under hood temps because of the cramped engine compartment.

Do you have long tube headers?

Check the fuel line where it passes near the drivers side header collector, on the inside of the frame rail.
Bet its real close to the header and picking up all kinds of exess heat. Relocate the fuel line to the outside of the frame rail or along the inside of the rocker pinch weld flange, away from the exhaust heat.

 

...

 

Also, when you put the stock pump with return line back on there, make sure you use gaskets between the block-off plate and the block, and between the pump and the plate. In fact, you might even want to stack up 2 of them in each place; or, if you can find something suitable, make a block-off plate out of something non-metallic. Something like PC board material, enough layers to be the right thickness, might do pretty good.

Coated headers work miracles for under-hood temps.

 

F-Bird, is a fuel presure release the same as just a fuel presure regulator with a return line? My mechanical fuel pump is stock and has a return line on it.

But, I may have my fuel line too close to the passager header (shorties). It runs along inside the frame rail beneath the A/C box area. I piped it though a hole in the framerail all the way out the front. But I think it is still too hot in that area.I had long suspected that fuel line was heating up in that area.

I just can't figure where to run the fuel line without getting too close the header heat on either side.

 

Thanks RB83L69... I used to have a Carter, but I went back to a stock and utilized the return line. BTW, thanks for the idea of a insulating block plate. Would you know if summit or anyone else makes one already cut?

 

Yes thats a holley fuel pressure regulator used in reverse as a bypass.

A holley under carb heat shield will protect the fuel bowls from the heat radiating from the manifold runners.
Really makes a difference.

 

Hmm... thanks for the info

 

Buy some heat insulating sleeve from DEI or ThermoTech. Cover the fuel line with this. With heat insulation on the fuel line and the other tips given here, your perculation problems should be gone.

My fuel lines are covered in heat sleeving all down the passenger side. I use a heat insulating phenolic plate to mount the fuel pump ( Barry Grant ) and a 1\2" Phenolic plate ( Barry Grant )underneath the carb. Zero perculation problems.

Edit: Noticed you're from Texas. Wrap the headers in header wrap. ( DEI or Thermo-Tech ) Will make a huge difference.

Install a functioning cold air sysytem with a sealed box if you have the time and money. A Couple of functioning hood vents wll also help.

I use a 1984 factory glass hood modified with a scoop and hood vents off of a 1995 Grand Prix. Pictures to follow.

 

i'd love to see the pictures as well. sounds interesting.

 

Picture of hood scoop ( Early '80's Dodge Mini Ram. FWD version ) and vents from Grand Prix ( 1995?).

Edit: reduced image size.

 

looks good. i actually like that, not to mention they're cut out to be fully functional as well.

 

Thanks Deadbird...

 

opps. meant to thank chickenman...