It's weird. It needs to be babied off the line, or it feels like it will stall (but never does, just stutters a bit) unless it's warm. . .then it takes a quick jump on the peddle to bypass any surge and it drives fine until. . .

At cruising speed, be it 25/35/45 and maybe at 55 (dunno) it will just start to die, kinda like I'm slowly letting off the peddle. I'll then let off the gas for a second and then depress the peddle to resume cruising for a few minutes then it does it again and the cycle continues. Could I be using gas faster than the pumps can supply? Doesn't seem to do it on the highway though. . .but I think I can feel it surge, not real hard, kinda quick like. Also, it seems to accelerate fine, no having to let off the gas to resume accelerating.

Any idea where to start?

Its a 1987 F250 with a carb 460. Dual tanks, in tank electric pumps. Both pumps work, but I can hear them run? Am I suppossed too?

 

what do you have the fuel pressure regulator set to? carbs need 5-7psi, no more no less. what carb are you running?

 

No fuel pressure regulator that I can see. . .carb is the stock Holley/Motorcraft 4180.

 

Fuel filter? Even the pick up filter in the tank. Do you have duel tanks and does it do it on bothtanks,www since each tank has it's own pump? Sounds like a loss of fuel, either pressure or volume.

 

Yes actually, I tried that earlier today and it does it on both tanks. It seems to do it less on the rear tank, but that could just be in my head.

I looked for a fuel filter on the drivers frame rail, I didn't see one but I could have missed. . .

 

Each fuel pick up has a filter screen over the pickup. But the chance of both going bad at the same time is low. There is a fuel filter somewhere besides the pickups. It is after the fuel valve towards the engine.

 

The filter is located inside the carb inlet fitting. I would also do other simple stuff like looking for vacuum leaks.

 

id start with a fuel pressure check... simple check and cheap tool. factory tank pumps put out 40ish psi pressure so they need a pressure regulator... if yours doesnt have one maybe it got retrofitted with low pressure pumps, otherwise it would just be a regular mechanical pump (which imo is the way to go... the less electronics there are, the less there is to troubleshoot )

 

Filter in carb? That brass cup filter thing? It just sits in there lose, rattles around. . .

Tank pumps are factory low pressure, I beleive the same low pressure ones that would have fed the high pressure pump in a stock '87 EFI setup.

How do I check the fuel pressure? There is no schrader valve anywhere

 

The inlet filter for the carb should have a spring in there to hold it against the inlet. Carb engines all had low pressure pumps and my '84 has a filter along the lefthand frame rail. EFI's got the high pressure pumps.

Two ways to check pressure; 1) Pull the line out of the carb and use a hose to hook a up a pressure gauge. Since there is a return line you just dead head the guage and read the pressure. You can also cut the metal line, insert two short sections of hose and install an inline schrader valve.

 

Word

I guess I got something to do in the morning! I'll post back any findings

 

Ate to much today at the cookout. . .

Anyways, there is no inline fuel filter on the frame rail anywhere. The two lines come off the tank selector switch and go straight to the carb. Haven't got around to the pressure test yet, will do that tomorrow.

On top of all that I got another problem. . .won't start from the key anymore Ran fine all week and until I parked it yesterday, nothing today. . .starts fine with the ole screw driver across the terminals trick though

 

just a bad solenoid... 15 dollar part last time i got one

 

It can't be the solenoid if he can jumper across the "S" terminal on the solenoid and activate the starter. It has to be something in the ignition switch wiring.

 

i thought he just jumpered between the 2 big posts... didnt know he jumped from one of the little ones