Fuel starving issues

[mkaenel]

Hello,

My EB tends to feel like it is running out of fuel while driving. It sputters and stalls out sometimes even driving on flat surfaces.

What I have done to fix the problem.

1. I had the carb rebuilt and tuned on the truck. Also made sure there is no vacuum leaks.
2. I went through both of the fuel filters (one by the tank and one by the carb) and cleaned and/or replaced the filters.
3. Plenty of gas in the tank.

When the electric pump is on it shows about 3.0 to 3.5 psi at the fuel pressure regulator (right next to the carb). Seems low and should be at 5-6 psi.

Can a mechanical fuel go bad and quit working properly?

My next step will be to r and r both the mechanical and electric fuel pump.

Any thoughts on what else to look at? It has a mildly built 302 and an Edelbrock 4 barrel carb.

Thanks for the help.

Matt

 

[blubuckaroo]

I won't even try to debate the advantage of either an electric or mechanical pump.

But...
You really only need one pump and one filter. Any more just makes troubleshooting more difficult.

Two pumps won't provide more flow or pressure. In fact it is hazardous to pump an electric into a mechanical.

Two filters won't make the fuel any cleaner. An additional filter in the wrong location though, can pick up head and contribute to vapor lock.

Speaking of vapor lock, it's that time of year again. Have you got any part of your mechanical pump suction line running anywhere near an exhaust pipe?

 

[mkaenel]

I won't even try to debate the advantage of either an electric or mechanical pump.

But...
You really only need one pump and one filter. Any more just makes troubleshooting more difficult.

Two pumps won't provide more flow or pressure. In fact it is hazardous to pump an electric into a mechanical.

Two filters won't make the fuel any cleaner. An additional filter in the wrong location though, can pick up head and contribute to vapor lock.

So simple remove the mechanical or the electric pump plus one of the filters to simplify the system. I am assuming the mechanical can just be bypassed.

thanks

 

[No Hay]

I also have a bigger cam with Edelbrock 650. When on a slow trail in the heat, it can get rough like vapor lock or boiling gas, but is fine as soon as speeds increase. It doesn't take much to cool it enough to run smooth again. I hear an insulating plate is enough to remedy, but rerouting the gas line helps too.

I just went through this on the C2 when the fan clutch went out, in stopped traffic. The gas boiled, stalling the car before the motor temp even got hot. Buy the time I pushed it to the side and pulled the air cleaner, it was cool enough to start and run (TWICE). I just had to keep moving!!

Must be tough in the hotter climates.

 

[bronconut73]

I carefully routed my lines away from heat and installed a phenolic spacer beneath my carb.
No problem since doing that.
And I have taken temps with my laser pointer temp gun out on the asphalt in central Florida highway traffic and found air temps exceeding 111° F.
Afternoon traffic heat can over heat almost any classic vehicle.

Can't imagine how bad it is in places like Arizona, New Mexico.....

 

[jckkys]

You never want a fuel filter between the tank and whatever pump you use. AFBs aren't easy to adapt in inline filer to. I used the Edelbrock #8129 chromed fuel line and filter. Then I used an adapter to reduce the size to 5/16" double flare to and from the filter and then to the mechanical fuel pump. One of these fittings make it easier;
http://www.ebay.com/itm/AFB-CARTER-...-16-/281387706629?hash=item418403a905&vxp=mtr
This screws into the carb fuel inlet.

 

[rwill]

The tank it's self has a screen that (if Original) rust/catches a lot of trash.This can cause a fuel starving problem.

 

[half cab]

The tank it's self has a screen that (if Original) rust/catches a lot of trash.This can cause a fuel starving problem.

I've had this ^^^ problem before ...sediment from the main tank blocked the fuel line. Clean tank and blew out lines n good to go.

 

[Whoaa]

Another common problem is fuel tank venting, or lack of. If the fuel tank(s) aren't venting and the cap(s) are tight, it will have the same effect of starving for fuel.

You can blow air back through the vent tubes to make sure you hear it gurgle in the tank, and/or just loosen/remove the cap and see if the issue is resolved

 

[mkaenel]

all good things to check and advise.

Thanks

 

[jckkys]

I've dealt with the fuel tank crud issue. It would starve for fuel, die, and after sitting it would run for a while and die again. The rust or whatever plugged up the pick up filter, or sock seemed to fall off then accumulate again. A few tank fulls of dirty gas was the cause. The tank is plastic so just hosing it out, fixed my problem.