Alright, i bought my car a year ago from an impound yard, it ran fine and all, they say it was switched from fuel injection to carb.i fixed the overheating problem which was making it stall out on me before, now it does the same thing, only it invoves fuel now.

I have a fuel pressure gauge that reads about 5-7 psi when my car runs good and when it dies out its about 1-3 psi. To get my car to run again i have to get out of the car, pop the hood, and unscrew the hose clamp leading from the gauge to my carbureator and wait till a steady flow of gas shoots out and put it back together.

A few mechanics said i was getting air into my lines somehow, just idk where.

In auto mechanics class at school i lifted it up and dropped my gas tank (pain in the a**) and took the old fuel injection pump off and connected the line that went to the bottom of the tank to use as the new fuel line (shop teachers orders).

i just cant figure it out! my car runs awesome in the mornings and starts dying alot after i drive it for a while. its just annoying having to pull over to fix the problem and then have it happen again not even a mile down the road.

Any suggestions????

 

how are your injectors doin? they in place good? i would throw in some cleaner to get it all cleaned up and make it easier to work with. now as for the air. is the gas refill cap closing good? when you open the cover for the cap is it wet around it?

 

i do have pics: like how it looks..

 

Pressure when it runs

 

How its set up

 

Carb is a bit dirty? cleaned it not long ago (month?)

 

Sorry about pic sizes, need any more tell me what to get and ill post a pic up

 

You have an in-tank fuel pump? You said you removed the old fuel injector fuel pump so did you replace it with a carb appropriate pump? If so is that working okay? If you have insufficient or inadequate fuel pressure at the carb, you should have about 5.5 psi to satisfy a q-jet, then I would suspect fuel pump issues. AIr in the lines may cause that as would a bad pick up problem. Or a bad fuel pump.

Or is all what I said above bad if you have a mechanical fuel pump? I would still suspect fuel pump problems.

 

That fuel pressure regulator looks like the one I have on my Camaro. I have a Holley fpr. There is a diaphragm in there that can get hard and brittle that can cause fuel flow problems. Are we copasetic there?

 

hmm. ok this is what i would try, just to make sure the fuel is going where it it supposed to go not leaking or anything like that, will also show weak spots in the fuel process. buy urself the ultraviolet leak kit, the one for the gas system and put the car into a garage or wait till night and see where your car is letting off faults. it worked marveouls for me,

 

yea its a holley

 

Another thing, i can take the pressure gauge off and have a hose running straight to the carb from the pump, and the problem still exists.

 

Fuel pump.

 

Pumps push better than they suck. The factory mechanical pumps were mounted fairly low to let gravity help a little. But, electric pumps were always mounted near or in the tank.

You would have been better off if a new in-tank electric was installed while you have the tank down, and a good return-style regulator installed. Water under the bridge.

But if the pump will provide pressure at first, most likely the pump is weak and loses it when warm.

 

I also didn't see a return line from the regulator, are you running a return style regulator? Other than that, I agree with the above posts about a weak pump.

 

what exactlly do you mean by return line from regulator?

 

Our cars have a feed line and a return line. The feed line is the 3/8" tube from the tank and the return line is the 5/16" line.
five7kid mentioned it, having a good return regulator, but your picture doesn't show a return regulator.

A mallory 4309 is an example of a return style regulator. One line goes in, one goes to the carb and one goes back to the return hose. This helps with the flow of fuel, equalizes the pressure and most importantly, keeps the fuel pump cool.

 

I didn't see where you said what kind of pump you have - I may be blind because I read it twice.

make sure all of your connections are not leaking before the pump or you will suck air. Also make sure none of your lines are near the exhaust as this will cause vapor which doesn't pump.

Do you need a regulator? What pressures does the pump put up without it?

If the regulator is good and the lines do not leak then it must be the pump getting weak when it gets hot.

If it is an electric pump your wires may not be good causing too little current to get to the pump. Also check your ground.

Good lines and good wires and good regulator = bad pump

If it is a mechanical pump just change it as they are cheap. If you want to go to mechanical make sure you have the place for one on your block with the rod for the cam lobe.

 

IMO, if you don't have a return line regulator you will need a pump that shuts off at a certain pressure like one of those cheap A/C pumps (I forget what else they are called). They ran a low enough pressure for a carb but were not meant for perf applications.

Deadheading is bad for pumps not built for it. A positive displacement pump should not be deadheaded such as a vane or diaphram. A centrifugal pump can be deadhead for short periods. I know that's more than you cared for but always good to know.

 

i have a holley blue pump with a mallory 4309 regulator like ozz said. I ran a 1/2 inch feed line and used the stock feed line line as my return line. Works but pump surges telling me i need a bigger return line. I think the pump is your problem but the regulator isnt helping anything either. If you have a mechanical pump provision on your block you could try one and see if it fixes it. Cheap experiment. Hope i made some sense.