cheezombie

I've had this '79 280zx for almost 3 years now. I'm driving from the bay area to fresno for school. Car runs great until i get into the city limits. The RPMs start going haywire, and the car eventually dies. I have to pull over to the side of the freeway and can't get it started up again. I eventually end up getting it towed the rest of the way. The thing turns over, but won't start. Any ideas for what the issue could be? Electrical? I'm no car genius, but i've been able to do several things using the factory service manual. But i can't really do anything about it unless i know the problem. Any input would be great, thanks!

*edit* and i love how you always notice typos right afterwards...

NismoPick

Moved to 280zx section.

Welcome back to ZDriver!

When a car won't start, it's usually because of:

#1: no spark
#2: improper amount of fuel.

So... when it won't start, check for spark. If you have spark, pull the spark plugs & look at the tips. Dry = no fuel, wet w/ fuel = flooded.

Most likely causes:

AFM, ignitor, fuel pump, etc... start w/ the basics.

cheezombie

when you say wet with fuel, do you mean dripping or what? I don't think it's flooded, cause i waited a day and it still didn't start.

FubarI33t

CHTS that thing will get ya. located next to #5 and #6 sparkplug. 2 wire sensor screwed right into the head. if thats bad. it causes that exact issue. try to start the car with the gas all the way to the floor. that will tell you alot. if it even burps that way. then spark and fuel is not an issue. the CHTS has a OLD plastic connector on it. if it corroded, or breaks, the car won't run.if you have to replace that conector. it's the same as the Fuel injector plug, can get at any parts store for 3.00$

cheezombie

The car started up today, i drove it around the block and the RPMs would randomly dip, which is the same thing that happened when it died on the freeway.

NismoPick

So... again check the basics:

Check: AFM, and CHTS / O2 (if your 79 has them). Check fuel pressure, and pull the spark plugs and check the tips (a very good indicator of what's going on in the engine).

lifegrddude

Any major vacuum leaks? Maybe your coil is getting weak or old too. Can you take a video or post pics of your engine bay?

duowing

For the most part this situation reminds me of the common ignition issue where it has problems as it warms up. Then eventually stops working or works really erratically until it cools back down then works again.

SHADY280

im gonna guess fuel pump or related system, if its sat, there may be rust or gunk in the tank/filter. it will float around and cause a blockage, thus starving it for fuel causing symptoms you have described.

cheezombie

I drove the car today, and it was perfect. It's hard to diagnose the issue when it has a mind of its own.. Doesn't the coil get really hot when it's bad? Cause it's only warm. The Spark Plugs and Cables are new, the fuel filter is 2 years old, Vacuum hoses are about 2 years old. The fuel pump is about 1 year old, and have recently checked the pressure on that. I don't think my car has a CHTS. I have yet to find a pattern on when it has issues.

SHADY280, if it is gunk floating around in the tank, what does one do about that?

SHADY280

you would pull the tank, takes about 1/2 hr if youve done it before, but can be a pain with the lines up top if they are really on there. change that filter. 2 years old is beggin to be clogged. dump the filter over and see what color the fuel is that comes out. if it has brown chunks, start looking for another tank. also check all the underhood wiring for water or corrosion in all of the connectors. its a pain but needs to be done on these cars. clean and get some dielectric grease for them.