1980 10th anniversary, running poorly

[big mike]

I have a 1980 10th anniversary 280zx automatic. This is a CA car with 98,000 miles and up until now has been running great. Now when I accelerate I feel a hesitation in the engine like it is holding back, when I give it more gas it sometimes responds and other times hic cups a couple times and pops. A couple times it has stalled out when just making a slow turn. also (this is new) while running at 70mph the tach has dropped to zero and stalled out then picked up again. this now has happened 4 times and the last time it stayed off for 15 seconds or so and then started up again. anybody encountered this previously? No idea what it may be. Maybe dirt in the gas tank?

[zbane]

I'd start by checking the fuel system, from the interior of the tank forward... might be some crud getting in the mesh screen on the end of the fuel sending unit, and if there's some there you will most likely have some in the smaller cone shaped filter located in the fuel pump (assuming it's the original)... then forward to the engine compartment fuel filter.

[Z Factor]

Sounds like a fuel problem, such as bad gas, clogged filter, or maybe your pump is on the way out.

BTW - I was under the impression that 10AE's were manuals, not auto.

[black gold man]

I have a auto i think 500 were auto.

[dgcamp58]

Start with the easiest thing. Try a good fuel injector cleaner in tank before you fuel up

[big mike]

thanks all for your comments, I am planning on the fuel injector cleaner then tackling the fuel system. I have my son in law ( mechanic) taking the car today to see if it acts up for him as it does for me. will keep you filled in as I progress. thanks again for the input

[big mike]

mine has 96,000 miles, and in pretty nice shape. I got it from CA a few years ago. picture is on the top of the webpage in recent pictures.

[big mike]

checked the fuel lines and in the gas tank, all looks clean. Driving last night, engine quit numerous time and then started up again while still in drive position. seems like it may be electrical or maybe electrical to the fuel pump?

[Zed Head]

also (this is new) while running at 70mph the tach has dropped to zero and stalled out then picked up again. this now has happened 4 times and the last time it stayed off for 15 seconds or so and then started up again.

The tach dropping to zero seems like a sign of electrical trouble. When an engine with an automatic transmission dies, the engine stops turning almost immediately since it's connected through the fluid coupling of the torque converter. If the engine is really not spinning, I would be surprised that it restarted itself just through drag from the torque converter. Maybe it was actually still running but very poorly, with a messed-up tach signal.

The need to wait for 15 seconds also is a typical sign of a bad ignition module. The hiccuping and popping is also another symptom of a module going bad.

You have the E12-80 electronic ignition module on the side of the distributor. Might be worth studying, although they're hard to diagnose and seem to fail in different ways. Also expensive so not a simple swap-and-hope part.

[big mike]

The tach dropping to zero seems like a sign of electrical trouble. When an engine with an automatic transmission dies, the engine stops turning almost immediately since it's connected through the fluid coupling of the torque converter. If the engine is really not spinning, I would be surprised that it restarted itself just through drag from the torque converter. Maybe it was actually still running but very poorly, with a messed-up tach signal.

The need to wait for 15 seconds also is a typical sign of a bad ignition module. The hiccuping and popping is also another symptom of a module going bad.

You have the E12-80 electronic ignition module on the side of the distributor. Might be worth studying, although they're hard to diagnose and seem to fail in different ways. Also expensive so not a simple swap-and-hope part.

Zed head, We swapped the distributor shaft and distributor with one from another z and the problem disappeared. hence it was narrowed down to the distributor and ei module. I then purchased a module from Black Dragon, the most reasonable of anyone. just over $100. we put it in last night and the car seems to be running great again. My son in law felt that was the problem from the beginning, thanks for your insight

Mike

[big mike]

zed head, went thru the fuel system, my son in law thought it was the ignition module too. Borrowed a distributor from another club member and the car ran smoothly with no problems, hence the problem was narrowed down. got a new ei module from black dragon ( cheapest at 100 bucks) the new part is installed last night and the car runs perfectly. Thanks again for your help

Mike