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1983 280ZX NA - No power and then sudden burst

2K views 9 replies 4 participants last post by  bificus 
#1 ·
All,


I'm having a tough time with my 83 280zx NA. Ive rebuilt from the ground up. (Cylinder Head RnR, New Gaskets all Around, New Hoses All Around, new electrical plugs, tested and cleaned fuel injectors, etc)


Symptoms:
At about 2k RPM the revs drop down about 200 RPM and then bounce between 2k and 1800. Something is compensating for something causing this but i dont know what.


Also, when you hit the gas, there is almost 0 power and then a few seconds in revs match torque and car has power for days.


My fuel pressure is awesome, all injectors squirting, spark on all 6. No vacuum leaks that I can find. Not sure where else to go. Any help would be appreciated.
 
#4 ·
True.

I'd suggest he check the plugs for the AFM and throttle position sensor for corrosion and break out the deox-it if there is.


EDIT (addition): I'm not sure if this is how it works, but what if he unplugged the throttle position sensor. That would isolate it as a test but I'm not sure if/how the car will run without it.
 
#7 ·
Faulty ignitor (or whatever they call it) could certainly cause a cutting out prob, but I've never heard of one cutting out just two cylinders only under certain conditions. So please let is know if that solves the problem. Also, i believe the N/As still used vacuum advance in the dizzy (didn't they?) It is common for the roller-ball assembly under the breaker plate to either lose balls or for the grease to just petrify after 30-some years and cause the advance to stop working. You can test this easily with a timing light on the marks and blip the engine - marks should move. (Can also test with cap off and sucking on vacuum line with your mouth - breaker plate should move easily.) If no movement, you need to disassemble the dizzy, clean up the mechanism, re-grease and put back together. This happened with a '76 I used to have and when rebuilt, the difference in increased power was really amazing.
 
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