pconno4

So i just replaced my head gasket, chain, sprocket, all my hoses, sparkplugs, distributor cap, and rotor, thermostat and battery. But i am still having the exact same problem as before i started on the head gasket project(i replaced the manifold gasket too, and had both the head and manifolds, cleaned at a shop). The problem is this, when i start the car it runs fine, i can drive okay but cannot accelerate past 2500rpm's as the car warms my accelration range decreases, until i cannot any longer when the car is hot and i have to turn it off. This has been a 4 month project and i am finally out of idea's so any would be greatly appreciated. Thanks

280zx 83 non turbo

NismoPick

Welcome to ZDriver! Hopefully you replaced the headgasket for a problem other than this 2500rmp prob. Thas a lot of work for nothing.

Anyway, it sounds like the common AFM (air flow meter) problem. J's "how to rebuild your afm" is a good start. Here's the Sticky link: https://www.zdriver.com/forums/240z-280zxt-s30-s130-tech-tips-275/js-how-rebuild-your-afm-15277/

Lemme break it down into several simple steps...
#1 Buy an air/fuel gauge (AutoZone sells them for a decent price), & hook it up so you can monitor the a/f ratio when adjusting the AFM.
#2 Adjust the AFM carbon track & also the spring tension to run better.
#3 Clean all the sensor connectors (get rid of the corrosion) and re-install them using a lil bit of di-electric grease.
#4 Check your timing w/ the vac advance disconnected.

EatmyDust

Nismo is right when I boght my z it would flood out at 300 rpm's and bog down. it was getting good fuel preasure, and it would only do it at surtan temps, so I manuly operated my maf and it worked better, it turned out to be a none repairable maf so I put a new one on, and havn't had a problem with it sence.

383ZJUICED

It Sound Like A Catalytic Converter Problem.
If You Have Access To A Lift, Or Jack One Side Up And Hit The Catalytic Converter With A Rubber Mallet And Listen If You Can Hear Anything Moving Around In There.

If You Hear Something Bouncing Around In There, Remove Your Exhaust And Drive It And See If The Problem Goes Away.

NismoPick

I really doubt it's the cat.... it would have to be packed full of rust, to block enough exhaust to make it run crappy... and it would prolly still run crappy at idle and min throttle. It could be, but it's about a 5% chance.
Just do the AFM adjustments w/ an a/f gauge.

jfairladyz

nobody suggested TPS yet?

pconno4

I took your advise about the AFM and i adjusted the track that the dial ran on. So thats fixed, i then took it out for a drive and it still didn't work. I think that can partly be attributed to the fact that my engine wasn't timed yet after i took it all apart. But i have to hold off on the results and taking the catalytic converter off(thats next on my list) because i made a really dumb move when my car was jacked. My emergency brake is not existant and i forgot to put the car in gear when i jacked it. So as i lowered it, it rolled foward and fell onto the floor jack. Which put a huge dent in my oil pan. Opps. So i when i went to time it today i had a loud and consistent banging noise coming from the lower engine. Not exactly sure what is banging yet but that will probally be discovered when i take the oil pan off. But i timed it threw the noise and the timing is fine now, but i will keep ya'll up to date on what happens. Thanks for all the tips, i know one of them is sure to work. O and i have already replaced the TPS sensor but there is that chance that i got a bad one. Thanks.

jfairladyz

the crank is probably hitting the oil pan. Not a huge deal as long as you fix it before you try to run the car again. Just pound out the oil pan and make sure the rails are striaght and level and you'll be alright.