Fuel consumption and Hesitation

[Glliw]

UPDATE:

I changed the fuel filter and it didn't seem to help much. I think overall the biggest culprit is ambient air temp. Time to start looking for an electric fuel pump I guess.

Another note, I took apart the old fuel filter to find it very browned. Whether this was a problem or not, it was on its way out.

-Will

[clayton 260z]

glliw,

I'm running an electric fuel pump, remember that su's only need around 3 lbs of pressure. You may have to add a fuel regulator on the return line.

Also are you running any type of performance cam in your car? If so you might need to have your idle turned up, mine idels at around 1300. I know that sounds high but thats where mine likes to be.

With the adding of the horns from the air cleaner and playing with the idle I have the car running very well.

Good luck,

Mike

[Arne]

Question - what distributor do you have in the car? Is it a dual-point as used on 240Z automatics? Did the 260Z use points at all?

[clayton 260z]

Arne,

I'm not sure if your asking me or GILLIW, but i am using the Mallory electronic and i believe the 260 came with electronic.

Mike

[Arne]

Well, then this may not apply to 260Zs. But automatic-equipped 240Zs had dual points and some relays and such to give a different advance curve while the engine was warming up. If there was something similar on 260Zs....

[Glliw]

glliw,

I'm running an electric fuel pump, remember that su's only need around 3 lbs of pressure. You may have to add a fuel regulator on the return line.

Also are you running any type of performance cam in your car? If so you might need to have your idle turned up, mine idels at around 1300. I know that sounds high but thats where mine likes to be.

With the adding of the horns from the air cleaner and playing with the idle I have the car running very well.

Good luck,

Mike

Which pump specifically are you running? The cam is stock.

Question - what distributor do you have in the car? Is it a dual-point as used on 240Z automatics? Did the 260Z use points at all?

Its the stock distributor and is electric.

-Will

[doradox]

I'm still betting on plug wires. Have you resistance checked them?

Steve

[Glliw]

Bah, skipped my mind amongst all the chaos this week with trying to pass calc/chem tests.

I will wednesday. I swear, Thanksgiving I'm grabbing a boatload of tools to bring down here to UCF...can't live without 'em.

[clayton 260z]

I'm running a Holly and have had good service, but I believe the carter pump is better.

Mike

[Glliw]

Okay, an update for you guys. I replaced the needles/nozzles in the carbs because one of the needles was worn. I also found that the fuel return line has a major blockage in it and whilst trying to blow clear the line with air, the line itself busted. For now, I have routed the fuel return line into the fuel tank vent line and reconnected at the rear of the car the vent line to the return nipple on the tank.

However, I STILL have a bucking under acceleration when warm. It is NOT overheating.

The timing checked out to be 10 degrees and all cylinders are firing.

[Glliw]

Another Update:

To whomever suggested a stock air cleaner helping, it did not.

Still the good ol' turd that it has become to know itself as.

I had planned to put a fuel pressure gauge in line after the pump today as well, but with the limited space between the pump outlet and the hardline(about 4 inches) I couldn't and will have to go back to the parts store and get some fuel hose to route the sucker. Hopefully that finds faulter in the pump.

Should it be 3 psi at all rpms? Just idle?

Any other suggestions you guys have, throw 'em at me. I'm all ears at this point.

-Will

[doradox]

Another Update:

To whomever suggested a stock air cleaner helping, it did not.

Still the good ol' turd that it has become to know itself as.

I had planned to put a fuel pressure gauge in line after the pump today as well, but with the limited space between the pump outlet and the hardline(about 4 inches) I couldn't and will have to go back to the parts store and get some fuel hose to route the sucker. Hopefully that finds faulter in the pump.

Should it be 3 psi at all rpms? Just idle?

Any other suggestions you guys have, throw 'em at me. I'm all ears at this point.

-Will

Wires.

Steve