Gas Tank Problem ????

[mholmes]

As almost all of you know Z's are notorious for having problems running if the gas tank hasn't been re-lined. I had mine done at a local radiator shop, lining is black material that they said would never come off. Car ran great after having this done up until about 2 weeks ago. Roughly 8 months. However, son has replaced the fuel filter twice so far and says it's still sputtering and dying. I haven't looked at it yet but does it sound like I have trash in the tank again?? Any help would be appreciated.....thx

[MikeW]

One option is to get a clear fuel filter which will help you determine if it truly is getting clogged up with debris from the tank. If you have SU carbs there's also a filter at each carb that could be a problem. Another possibility with SUs is that the needle valves in the float bowls can get stuck in the closed position. Finally, even though the tank itself may not be the problem - I'd hope that it would last 8 months - it's possible that there's debris coming from of the fuel lines themselves.

[JimmyZ]

I see you have a 1977 280Z. Have you verified the health of the ignition system? Check or replace the plugs. This would be the first place to start. Also check for vacuum leaks/unplugged lines.

I own a 240 and am not as knowlegable as your fellow 280 owners will be RE the stock fuel system. Perhaps after we have verified the above they can zero in on it.

Do you have FI or carbs??

Jim

[mholmes]

Sorry, here are some more specifics - fuel injection, plugs and wires have approx 6k miles on them,

[jmark]

I had a similar issue on our 78 280Z. Thought it had to do with a pin hole in the pickup line. Turned out the tank coating had not setup long enough and was flaking off clogging the filter etc....Once the tank was redone (at no cost to me) the problem went away.

[JimmyZ]

Sorry, here are some more specifics - fuel injection, plugs and wires have approx 6k miles on them,

It may very well be a fuel issue but...

I'd still pull at least two plugs and check. If you're burning any oil it is possible to foul them before 6K. I once had an engine that was passing so much oil the plugs had to be changed halfway through the week!

If you have a timing light with an inductive pickup you can use that to see if the plugs are firing/misfiring.

Try taking the cap off and seeing how much play there is in the shaft. (grasp rotor and wiggle side to side)

My line of resoning is that checking these things first is cheap and easy compared to the fuel system.

2c

Jim

[GeoffT]

JimmyZ - you mention distributor shaft play ...

I'm also troubleshooting a foul-running engine with sidedraft Mikunis

and what is probably the original fuel tank. The carbs probably need rebuilding or cleaning, and I found what looked like rust in both the

electric fuel pump filter and carb filters, so I suspect a dirty tank.

But also wonder about distributor - have several degrees (3/8" ?) of rotor play ... what is normal in a good distributor?

Thanks!!

Geoff

[JimmyZ]

I turned some new bushings for mine on a lathe with about .001" clearance from the shaft. There is virtually no play in the shaft now. You will have a smidge of play in the cam tower of the distributor. (Which equates to nothing measured at the cam) The "cam tower" is the partthat holds the rotor and has the cam. It slides over the shaft in question.

When I say "wiggle" I mean from side to side not twist. If you are getting 3/8" of total side to side motion when you grasp the rotor and push/pull then you are way out of tolerances.

I think you're twisting the rotor in which case you will get about 3/8" or 10 degrees of travel or so. (Normal) You're just turning the centrifugal advance when you do that.

Years ago, I had a distributor with so much slop the rotor was machining the cap! It ran a bit rough and didn't start well. (Go figure)

Here's a page I made for gas tank refurbishing. It is dangerous and best left to a shop. I wanted it "done right" though.

http://warbuddies.homestead.com/gastank.html

I'd square away your fuel problems first. They can act and sound like ignition problems.

2c

Jim