Hesitation during acceleration

[JSM]

1 hour ago, rcb280z said:

He needs the later one. 12-92.

I have that graph also, just forgot I did. 

I'll look when I get home.

[siteunseen]

2 minutes ago, JSM said:

I'll look when I get home.

I've got one too, if you need that one.  It's off a JY ZX so it may be crap but you can have it for shipping charges, IF I can figure out how to get it separated from the distributor. 

[DC871F]

Thanks all. I need the whole thing, my vacuum advance is bad, and to find just the advance is impossible.

What do you guys think of the module curing this problem? There is a thread here that they guy says a new module cured his problem of a cylinder that was dropping.

The 31-1002 is what all the searches on the autoparts houses say mine is.

I dont quite understand that, but.....

 

Edited January 17, 2018 by DC871F

[siteunseen]

I'm not one to whizz on your parade but ive read many threads where folks don't even run vacuum advance. take that for a grain of salt but it's out there if you feel like reading until yours eyes bleed.  I hope thats your problem but I have a funny feeling there's more to it than something simple like we're thinking. There's a reason such a nice car was put out to pasture like the one you have.  I hope I'm wrong but...

[JSM]

Mine in my drawer are just e12-80.  I check the shed tomorrow for distributors. 

Also, don’t forget http://car-part.com/cgi-bin/search.cgi

All used but some have warranty. Just check to ensure the warranty is refund, not credit. 

Edited January 17, 2018 by JSM

[rcb280z]

I don't understand the "Made no difference" after he installed the potentiometer. Should have made a noticeable difference right? Read my Potentiometer  thread. I definitely noticed a big difference. 

[DC871F]

33 minutes ago, siteunseen said:

I'm not one to whizz on your parade but ive read many threads where folks don't even run vacuum advance. take that for a grain of salt but it's out there if you feel like reading until yours eyes bleed.  I hope thats your problem but I have a funny feeling there's more to it than something simple like we're thinking. There's a reason such a nice car was put out to pasture like the one you have.  I hope I'm wrong but...

I don't think the vacuum advance is the reason for my issue, but a bad ignition module. 

When I first got the car back on the road, it ran strong for the next few drives. Then this hesitation set in. It's so stark, it really seems it's dropping cylinder. But the kicker is, finding that sweet spot where it accelerates nicely. 

Intriguing, yes, to me anyway.

 

[Zed Head]

Weak spark or module breakdown are possibilities.  Usually the modules overheat and start acting weird until you let them cool down.  But, maybe yours is on the edge.  Module problems are hard to diagnose.  One thing often overlooked on the the ignition system is the need for a really solid ground.  The coil "charge" is totally dependent on current.  High energy coils are really more high current coils.

The ZX module grounds through the distributor body.  Poor grounding could limit current and make for a weak spark at higher RPM.  Maybe add a dedicated ground wire (another one actually, there's supposed to be one there already) to the distributor mount.

[DC871F]

On 1/17/2018 at 12:33 AM, Zed Head said:

Weak spark or module breakdown are possibilities.  Usually the modules overheat and start acting weird until you let them cool down.  But, maybe yours is on the edge.  Module problems are hard to diagnose.  One thing often overlooked on the the ignition system is the need for a really solid ground.  The coil "charge" is totally dependent on current.  High energy coils are really more high current coils.

The ZX module grounds through the distributor body.  Poor grounding could limit current and make for a weak spark at higher RPM.  Maybe add a dedicated ground wire (another one actually, there's supposed to be one there already) to the distributor mount.

So If I made a living from fixing 280ZX's, I would be really hungry, divorced, and sleeping under a bridge.

New distributor is on. Now it wont accelerate past 2100 RPM (no load), then just quits. If I slowly push on the accelerator, say about 2000 RPM, the RPM will pulse between quitting and 2100. Timing is close to 8' as I can get it. 

I adjusted TVS, and if I adjust it anymore other than where it is now, it  wont even accelerate, it will just die.

All the meanwhile it idles perfect.

All this is static in the shop, cant even get it out to drive because it will just sit there and backfire.

I'm almost out of ideas, other than a bad TVS.

Theres a saying, enough horsepower you can make a brick fly, maybe if I spend enough money I can make this car run, or more education.

Edited January 25, 2018 by DC871F

[Zed Head]

I would put the old distributor back in and see if the problem goes back.  To the original problem.  You've already had two bad parts.  A third wouldn't be a surprise.

[siteunseen]

Don't you love that 240!

Are you watching the tvs while twisting the throttle rod? Does it come off the rear contact when you give it fuel then click on the front when you get around 2,500?  I bent the vanes on mine to get it to do that right, closer together if I remember right.

Save all your part boxes for storage space under the bridge.

[DC871F]

What kind of problem were you having?

I did not have the cover off, but I trouble shot the TVS earlier, it seemed to check out.