Fuel Fluke

Is your tank or gas cap is vented properly?

I have been running the car with the gas cap open and still getting a massive drop in fuel pressure.

Pulling thru an electrc is not a good idea. If you need a pusher pump (the elctric is out back by the tank, correct?) then run it all the time. Although if you have an electric, I would not have bothered running a mechanical at all. The block off's cheaper than a pump :D.

The elec pump was already on there when I bought the car... it's a small cheap pump. I just got done bypassing the mech pump and just using the electric pump..... it only pushes 4 psi and when the motor is held at a sustained RPM it drops to 3 psi... that's not going to cut it... so I just shut the motor off.

The routing of the line is odd. IMO, it should not ever go up over the inner fender bulge and then down to the pump.

I just copied what was on the car when I bought it. Where does the line usually run when it enters the engine bay area? I wouldn't think it should go between the shock tower and the headers.

It should not be idling as high as it is. I dont know the package or your tuneup. But if the thing hangs up at 1100, your ignition curve needs some work. If you can't get it to idle at 800 or less, especially with a stick, your carb needs work after you fix the distributor.

It only idles at 1100 when I'm having the vapor lock problem or whatever it is that's causing it. The curb idle is around 900 RPM is what I got it set at.

70Duster440 said
I've got a Carter mechanical pump. If I remember it was the strip version but without a regulator the needle bounced like crazy and it tended to overpower the seats in the carb. A regulator got both of those problems under control but I did notice that after time, while running, the gauge read lower and lower yet the bowls remained full.

I would try adding a regulator ( http://store.summitracing.com/partdetail.asp?part=QFT-30-803&FROM=MG and did include a mounting bracket) and reset the float levels. This regulator is preset at 6.5 psi. 7 and over you risk overpowering the needle and seat. Don't waste time with the parts store regulators with the dial on them.

I have the bouncy needle going on. I have no problem buying a regulator. My problem is I can't get the fuel pressure to stay the same..... it drops when the motro gets hot. Adding a regulator would not cure the problem I'm having will it? I mean the pressure drops to around 4 psi!

rumblefish360 said
Theres a pair of good thoughts.
I'm with Moper on the fuel line. Odd routing. It did leave a question mark in my head as to why that way. OE runs the frame rail preety far up to the pump.
Heat in the carb was a wonderment in my head.

So running the fuel line that close to the header is OK?? Are you really, really sure about that?? LOL! I'll go out here and look at it and see where it should be located down the rail. I didn't realize the OEM location was routing it that way.

I'm going take the carb off and look for trash in the bowls or anything that might be causing a drop in pressure.... actually I really don't know what I'm looking for. I've read that higher pressure will keep fuel from vopar locking. I don't know why but my pressure drops to 4 psi so then this allows the gas to vaporize and then I'm coasting down the road with the motor stalled. This has happen to me I know at least 4 times and each time I was lucky and coasted out of traffic.

Thanks for everyones help... keep those ideas flowing!