Mayday!!! Mayday!!!Mayday!!!

[obxtrainman]

After a year of driving, all at once my 240Z dies after I get her up to around 50 miles per hour:dead: It idles fine. It runs up through the gears a little low on power, but still runs. Then after I try to cruise in fourth gear,,,it dies:dead: It will start right back up, immediately. It will get me home at a lower speed. It will not run at a higher speed. I had just replaced the voltage regulator the night before this all started to happen. I wouldn't think this should be the problem. I can dump he clutch when it dies, and it starts back up. When I bought the car it had the problem of dying out. The owner had gone through many things/ He finally changed out the tank for a refurbished tank from out west. His mechanic had already gotten rid of the original electric pump near the tank. There is a new mechanical pump on the engine with no hoses hooked to it. There is an in line electric pump, and an in line glass filter. Is it electrical? Or filthy carbs???:stupid:

Thanx for any help in advance:rambo:

OBX

[MikeW]

I'd first check the fuel filter.

[obxtrainman]

I've been keeping the inline fuel filter element changed. I changed the one year old,,,,around three thousand miles on it, inline, electric , fuel pump earlier today.

[EScanlon]

The key phrase "It runs up through the gears a little low on power, but still runs" is perplexing.

When you say a little "low" on power, are you saying that if you push the accelerator down to the floor it will die or bogs completely down to where it stumbles?

If so, and this is a long shot but it DOES happen, check the vacuum advance mechanism INSIDE the distributor. Simply disconnect the vacuum hose from the carbs, and with the dizzy cap off, suck the air out of the vacuum advance and then let it loose. The lower plate of the dizzy should rotate AND return easily. If it stumbles, or does not move at all, or return, you may have a problem with the advance plate. That's a little plastic piece with ball bearings in it that allows the vacuum advance to rotate. Over time and age they crumble and fall apart leaving you with a stuck or malfunctioning vac adv mech. You need to replace it, but they're available from the dealers.

Other than that, I haven't got any thing else to offer.

E

[KDMatt]

Hrm... maybe this is a shot in the dark... but I had something similar to this happen once...

I was getting on an off-ramp on the freeway, and when I pushed in the clutch, everything died... and then promptly came back... Turns out my battery cables were really, REALLY corroded and were occasionally not making good contact and thus, killing everything.

'Might be worth looking at.

[Nigel1943]

Possibly fuel starvation, pump, fuel line, carb float levels and tank.

It could also be electrical, coil faulty.

[clindayag1]

"It runs up through the gears a little low on power, but still runs". i have the same exact problem. my friend says the timing might need adjusting or something. i dont have the instruments to do that so i dont know if thats the solution. maybe you can try it out

[hd240z]

I would also guess a fuel delivery problem. A couple of more things to check would be for rust and/or dirt inside the gas tank plugging the fuel pick-up screen and the SU carb fuel inlet screens. If your gas tank has not been cleaned previously, you can pull the plug on the bottom and see what comes out. If its dirty you may have to remove the tank and have it cleaned and sealed inside. The SU carb inlet screens are located inside the fitting where the fuel lines attach.

Good Luck

[obxtrainman]

Thanx for all the comments fellas. I believe EScanlon hit the bulls eye. I sucked on the vacuum hose on the vacuum advance assembly, and absolutely no movement occurs. It's stuck. I'll try to order one from courtesy Nissan today.

OBX

[Z train]

Get rid of that glass filter before your car resembles a SD-40 losing it's turbo.

[JimmyZ]

Thanx for all the comments fellas. I believe EScanlon hit the bulls eye. I sucked on the vacuum hose on the vacuum advance assembly, and absolutely no movement occurs. It's stuck. I'll try to order one from courtesy Nissan today.

OBX

If you don't have one already it is a good idea to have a timing light. A meter which tests for dwell is nice but not absolutley necessary either. Both said tools could help you greatly in this case. There are some great posts for tuning to be found with the search function.

You can compensate for the lack of vacuum advance by adjusting the timing to compensate for the lack of advance provided by the dashpot. Not an ideal solution but it would let you see if advance is to blame. Specs on early Z dizzys show that centrifugal advance and vacuum advance are roughly equal with cent advance doing a little more of the work. Total advance provided is 11-20 degrees depending on which dizzy you have. A friend of mine used to run mad amounts of advance while experimenting with performance gains. (Up to 40 degrees Norm 12secdualSU)

I'm betting it might be your point gap being off due to misadjustment from vibration, improper installation or bushings in your distributor being worn and giving erratic action. A dwell meter can accurately check the function of the points while the motor is turning. Simply setting point gap with a feeler guage is OK but may not be good enough in certain cases. Also check that your points contact faces are clean and free of pitting. Some meters have a points test feature which is just a fancy name for continuity test. It might just be a good idea to swap 'em anyway.

Poor fuel delivery can also cause the problem you are having. Check the ignition first though. Verify that the plugs are unfouled etc before poring over the fuel system.

2c

Jim

[jezze]

Time for a valve job perhaps. Check your points first if you're still running them.