Possible Fuel Starvation

[SteveJ]

Background:

I removed the rear bumper from my early 260Z. In order to do this, I had to drop the tank. The larger vent hoses had been replaced some time in the past with regular fuel hoses. Before putting the tank back into place, my friends and I replaced the 5/16 inch lines and fuel filter, the 3/8 inch vent hose and the 1/4 inch vent hose. Apparently I cut the 1/4 inch line a little short, but we got it to the expansion tank. I put the fuel back into the tank and filled it later in the evening.

Today I was driving the car around 60 MPH when I noticed a change in the exhaust note going uphill. This was accompanied by a lack of response when I pressed on the gas pedal and some decrease in speed. I stopped the car for a few minutes and tried to get back onto the road. I drove a couple of miles on a surface road. At first the car pulled fine uphill, but it did start losing power later. The engine recovered, and I tried to continue my trip.

The ramp was downhill, and the car accelerated nicely to about 74. That was followed by an uphill stretch. The car was losing power and would not respond to throttle inputs. I got off at the next exit, and when I pushed in the clutch, the car died. It restarted immediately, but hesitated a lot.

I drove the car around for the next hour to detect trends. It would do okay on the surface roads, even going uphill around 65 or so, but it would lose power going uphill on the freeway with a characteristic lean sputtering sound in the exhaust.

I'm going to put the car on the lift and look for kinked fuel and vent lines.

Are there any other suggestions from the peanut gallery?

Thanks!

[siteunseen]

Take the gas cap off and see how it does? Check the fuel pressure at the carbs. You may have knocked some sediment loose and it's made it's way to the carbs banjo bolt filters.

Good luck, hopefully it's nothing major. Blue was going to Florida and drive a truck back up. Said he may stop through Atlanta. Probably already done it though, been a couple of months.

[SteveJ]

He hasn't contacted me in a while, so I don't know if he made that trip.

I'll check at the carburetors, but it tends to pull nicely in the lower gears.

[Captain Obvious]

Duh. The Obvious suggestion would be to put the rear bumper back on. (Just thinking about what changed...) 

The symptoms sure support a fuel starvation issue. Works great under lighter load, but the system can't keep up under higher fuel demand conditions. Other than a kinked hose, maybe you stirred up enough crap to clog your new filter already? Is it a clear style that you can have a peek at?

[SteveJ]

Fortunately, it is. I'm looking around the house right now, trying to find any energy I can use to go out and work on the car.

After I get the car up in the air some, I can maybe get a clue. The good thing is that I stocked up on fuel filters a few years back, just for such an occasion.

[Captain Obvious]

Haha! I can't help you find the energy, but I can tell you that I understand completely. I've got my dash out right now to finally install my fancy new PWM dimmer and as much fun as that is, here I sit at the computer instead!

[siteunseen]

Two guys I look to for inspiration, suffering the same as me, vicariously getting our Z fix through a computer screen. 

When you find that "energy", let me know what to ask for.  I'm not cool anymore. 

 

[psdenno]

I think we all have those "I just want to get in the Z and drive without having to fix something, again" days...or weeks....or years.  Kind of explains those Barn Find  Zs that turn up from time to time.  Be strong!

Dennis

[Mark Maras]

I experienced the same symptoms once. Car wouldn't go over 45mph on flat ground. Less on a hill but would rev to 6000 rpm just fine. A partially clogged filter was the culprit. The engine uses a lot more fuel under load.

[SteveJ]

And....

After doing car repairs, the first rule of troubleshooting a new problem is to inspect the stuff you f***** with.

Pay attention to the bend radius.

[Patcon]

That might do it... Love an easy fix though!

Now that you found some energy laying around some where, can I borrow some?

Edited March 6, 2016 by Patcon

[SteveJ]

I used it up on that fix.

BTW, have you ever noticed how much gasoline attacks nerve endings on sunburned skin?