Car died several times at idle

[Muskrat]

I have an L24 with an E88 head and early SUs, and a slightly larger cam. Distributor was changed before I got the car over to a 280zx style electronic distributor, and is now using a Fireball ignition coil. It has always had a noticable vacuum leak from the throttle shafts on the carbs, causing a slight bog off-idle while accelerating. I'm also using later model NGK plugs for an 83 ZX, my local O'rielleys doesn't stock the early Z plugs anymore.

 

On the way to class today, the car ran fine. After my classes, I started it up, no hiccups whatsoever. Then about 5 seconds later, the car abruptly died, no theatrics or backfiring, it just shut off. Turned the key, it started right up again, ran for a few seconds, then died, spun back up, and then died again. When I tried to start it after that, I could hear the engine firing with the starter engaged, but it wouldn't even maintain 300rpm and would die after I let go of the key.

 

After a little while I was able to get it started, and it idled fine with the choke engaged, and I didn't think anything of it at the time. Well, about two stoplights down, the car died again, and refused to start for a good 5 minutes. When I was finally able to get it to hold an idle, I got under the hood and set the idle to about 2000rpm, and was able to limp the car home. During the drive I noticed a considerable reduction in power.

 

I've been driving it for 11 months, and this is the first problem to date that I've had with it. Any thoughts would be appreciated, as this is my daily driver and I really need to find out why the car died like that.

 

EDIT: If I can figure out how to splice it into my current wiring, I have a 300zx coil sitting around that I could use if it turns out to just be the old fireball coil.

[A. G. Olphart]

Mike- If you haven't got it running right yet, here are a few random thoughts...

 

Is a vacuum hose broken/ is there a carb loose? It seems unlikely that raising the idle would affect the ignition system... the only place I can see that happening is in the distributor: the flexible wire going to the breaker plate/pickup could be the culprit. It gets flexed every time the vacuum advance moves, and I have had them break.

 

Is one of the SU pistons stuck/ prevented from fully dropping?

 

A big power loss sounds more like lack of gasoline, as does running better with the choke pulled. How are your fuel filters and fuel pump? I've had cars that started losing their ability to l climb hills due to dirty filters, but they would always idle. I'd check fuel delivery.

 

Is the ignition resistor taken out of the circuit when the starter is engaged? That can cause a vehicle to run on the starter and then immediately die if the resistor is bad or has a loose connection.

 

Sorry my answers are not more specific to your car--- I've never driven a Z, so can speak only generic terms.

 

Hope you've got it running- let us know.

[Muskrat]

Yup, actually got it working before class the next morning. Turns out that the coil was on its last leg, it got replaced with a spare Fireball coil that a friend had laying around. The car actually still has the ballast resistor wired in. If anyone knows exactly where it is, that thing will be gone before I leave the house.

 

All the vacuum hoses, including the ones on the distributor, have been replaced, the ones that were on there were actually already cracked. My SU pistons have plenty of free travel, especially after a shot of carb cleaner.

 

Thanks for the suggestions.

[A. G. Olphart]

Good to hear that you're on the road again.

 

You may have noticed that my mention of the resistor was phrased as a question. No clue as to where it might be (or if it exists) in Z's.

 

My experience with them has been on old American iron, where they were removed from the circuit when starting the car (allowing a really hot spark) but used to keep from burning out the coil in regular driving. (I leave them in place if the system is designed to have one... their failure is easy to diagnose).