still having fuel delivery problems!!!

[XFlow_Fairlane]

ok about 2-3 weeks ago I started having fuel delivery problems (IE pump or filter crap)

I have been through a half dozen pumps and as many filters in the last 2 weeks. but seems like the pumps are not drawing/flowing enough fuel to run at highway speeds. looking for a checklist of things to try...

1. blow out fuel line from pump back with some compressed air

2. check cam lobe to make sure it is still there (how could I wipe out the pump lobe and none of the regular lobes?)

3. put gauge on output of pump to see what is going on.

4. try swapping on a v8 pump?

I put in a clear filter before the pump and there is nothing in it. car was running fine under boost and all of a sudden these problems started out of the blue.

 

[addo]

You need to "rod" the line to your tank. A decent gauge of baling wire with the end balled smooth and carefully fed from one end to the other - and the other way. Then blow it out.

Inspect your pickup and sock for fine cracks. Install new flex line and coat the metal tube with Blue Hylomar before sliding the rubber over it. This stuff is not really soluble in fuel.

DEFINITELY install a gauge between pump and carby. All of $25, tops. My final question - is the boost referencing in fact applying pressure (instead of vacuum) to the fuel pump diaphragm, restricting its pumping ability?

 

[JackFish]

2. check cam lobe to make sure it is still there (how could I wipe out the pump lobe and none of the regular lobes?)

Maybe if you had a seized fuel pump?

 

[XFlow_Fairlane]

1. well the frame line has several 90 degree bends so I am pretty sure feeding any wire in it is not gonna happen.

2. I have no sock in the tank (new tank I fabbe dup over the summer) like I said the pump seems ot have no draw on it when you put your finger over it (at idle)

3. all flex line is new on the car. only parts not new are the frame line itself

4. there are two diaphrams in a fuel pump (the working one and a "seal" one) I am applying pressure between these to which trucks the pump into seeing higher atmospheric pressure to compensat for boost. this last pump I put on I left the boost reference off of it (I have some serious lag withthe boost levels I am running so I can baby it and not get into boost) before I even finished the 15 mile drive home it was acting up (as soon as I got out of town and up to highway speeds)

 

[XFlow_Fairlane]

just pulled pump....cam lobe is fine. no damage to pump.

I think I will toss the pump back on tomorrow and rig up a jerry can and take a trip up the road and back maybe

 

[rbohm]

8) what i am planning if my tank pickup unti checks out is to add an electric pump nea the tank to feed the mechanical pump on the engine.

 

[addo]

If you can get a thin wire down the line then that can be a "draw" like running electric cabling. A bass guitar string has a nice chunky brass ferrule on the end and that could then be pulled through via the draw line, and then something larger. I've chucked them in my battery drill and used them like a drain cleaning tool on steel brake lines. But it really sounds as though there's restriction in that line. From memory, pump pressure is (max) 9PSI so you won't feel a lot with your finger on the pump anyhow.

I've rebuilt pumps myself (you can buy an OEM kit here with new diaphragm and check valves) so I know the lower seal you're also describing. My understanding was that you added vacuum to the lower side of the rubber. It drew back harder, and then expelled more fuel with each pumping motion.

You could get fancy and bend up a new line out of 3/8" stainless tubing.

 

[jswhite]

Two thoughts.

1) is the tank vent clear?

2) you can help isolate a fueling problem by doing fuel can test. Check out barry grant's web site: http://www.barrygrant.com/bgfuel/default.aspx?page=81

Good luck -- jay

 

[XFlow_Fairlane]

yeah the tank is vented ok.

busy getting stuff ready for the holidays here so can't play with it too much right now