Jump to content

Welcome Guest! Please read more information about our club!
IGNORED

Hesitation during acceleration

DC871F

By DC871F
in Open Discussions

 Share

Recommended Posts


DC871F ExperienZed

DC871F

Posted
  • Author
Posted
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.

Put the old module on the new distributor, fixed the hesitation problem (the original problem) damn!

So now a new problem, which I hope is the TVS valve since I have adjusted it without mercy . During low speed driving and you let off the gas, it seems the fuel just cuts off, same accelerating at low speed, then it will drive normal.

High end it accelerates nice and smooth. So the distributor with the OLD module fixed the issue. Which honestly I have issue with, unless there is an unseen issue (mechanically) with the old distributor. The car has 119,000 miles on it.

Any thoughts?

Link to comment
Share on other sites
Zed Head GrandMaster Z

Zed Head

Posted
Posted

The BCDD can affect throttle off/drop behavior.  And the dashpot.  The dashpot is easy to adjust and can have a big effect.  Loosen the big nut and screw the dashpot body inward to delay the throttle drop.  Too far and you'll get throttle-hang though.

Your original reason for the new/reman distributor was the hesitation wasn't it?  So you got a bad module (or a poorly grounded module) on a better distributor.  Once you got the right parts together, problem solved, apparently.  There are other electronics in the distributor than can have problems like the pickup coil magnet.  It tends to break. 

Can't emphasize grounding enough on the ignition system.  It's not about voltage, it's about current.  Current needs ground.  Don't throw that new/old module away.

Link to comment
Share on other sites
siteunseen GrandMaster Z

siteunseen

Posted
Posted
18 hours ago, DC871F said:

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.

I replaced everything with the efi, dropped the tank cleaned and coated, rebuilt the motor and took it for it's maiden voyage.  Spit and sputtered until 2,500 then pulled like a tractor.  I tried fooling with everything and the TVS was my best conclusion after reading about how it worked.  The contact hitting WOT at 2,500 had me convinced.  Ended up being the ECU drifting out of spec on the coolant temp circuit.  Fixed it for $5 and 30 minutes with a potentiometer but we know that's not your problem so I go back to the TVS. 

Good luck, I hope you get it figured out.  I want to see it when you wax it up nice and shiny. :)

Link to comment
Share on other sites
DC871F ExperienZed

DC871F

Posted
  • Author
Posted
17 hours ago, Zed Head said:

The BCDD can affect throttle off/drop behavior.  And the dashpot.  The dashpot is easy to adjust and can have a big effect.  Loosen the big nut and screw the dashpot body inward to delay the throttle drop.  Too far and you'll get throttle-hang though.

Your original reason for the new/reman distributor was the hesitation wasn't it?  So you got a bad module (or a poorly grounded module) on a better distributor.  Once you got the right parts together, problem solved, apparently.  There are other electronics in the distributor than can have problems like the pickup coil magnet.  It tends to break. 

Can't emphasize grounding enough on the ignition system.  It's not about voltage, it's about current.  Current needs ground.  Don't throw that new/old module away.

Mine doesnt have those components.

I adjusted the TVS (just with mounting screws), didnt take the cover off to manipulate the contacts, all fine now. Whats interesting, is that the TVS is no where near the original position before I even touched it a couple weeks ago.

So hopefully this chapter has come to a conclusion. A bad distributor, which was in itself an argues side story being that it came with a bad module, but at least it didnt take long to troubleshoot.

I really appreciate all you guys help, I really needed it, and I know more now than I ever thought about how a 280ZX operates, which honestly was just as valuable as fixing the car.

 

  • Like 1
Link to comment
Share on other sites
Zed Head GrandMaster Z

Zed Head

Posted
Posted
1 hour ago, DC871F said:

Mine doesnt have those components.

I keep forgetting that this is a ZX.  I think that they incorporated the dash pot's function in to the BCDD.  Which you do have, it's under the intake manifold.

Good luck.  Enjoy.  See if the parts supplier will just swap the module.

Link to comment
Share on other sites
DC871F ExperienZed

DC871F

Posted
  • Author
Posted
47 minutes ago, Zed Head said:

I keep forgetting that this is a ZX.  I think that they incorporated the dash pot's function in to the BCDD.  Which you do have, it's under the intake manifold.

Good luck.  Enjoy.  See if the parts supplier will just swap the module.

I saw the BCCD under the intake, doesnt look like I can do much with it. 79-81 have a dashpot, 82 they got wise, or fancy, one of the two. 

Thanks. 

Until next time.....

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing
×
×
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy and Guidelines. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.