hi guys so i got this 79zx and the car has idle problems starts and turns off on me at points, so i tried fixing it by self diagnosing and assumed it had to do with the air flow meter boot which was torn up when i got the car so i replaced it with an original one, then i followed up that replacement with a new fuel pressure regulator, yet the car still has these problems. Ive noticed that the car once i start driving it the car is slow at responding when i begin to accelerate. from 0mph to 20mph it seems as the car begins to choke and has a hiccuping action to it. once its above the 20mph range it seems to be a bit more responsive but still has those symptoms of hiccuping and it sounds as if the car is releasing pressure because you can hear a pshheww (sound if that helps) and is it does so it jolts. Any help as to what may be causing this would help so much guys

so recap problems,

1. car has idle problems, hard to start, and once on idle the idle is accelerated and above 1x rpm
2. car turns off while driving at points
3. car has a hiccuping motion to it when bellow 20 mph
4. sounds like air is being released and jolts
3. non responsive as you press the accelerator

 

Welcome to Zdriver man. First off, I would start by cleaning all your connectors. TPS, AFM, ICM, etc... You just need a toothbrush, and some WD-40 works great. And just spray a little on the contacts, and run the brush across them. You will know they are dirty if they are a greenish color. Let them air dry. And then after all that, see if the Z runs better. If not look into seeing if it is getting the correct air, fuel, and spark combination. And good luck.

 

Sounds like you got your hands full with this one.

Not sure of your expertise ... but I have attached an engine component diagram and a trouble shooting guide (pgs 15-22) of Tune-up PDF.

And just as WildmaN says ... the electrical connections are very important and making sure they are clean and functioning is paramount to the operation of the whole system. These usually go first ... get dirty ... and as simple as it may seem ... the grounding is important.

Wishing you luck ... and hopefully many enjoyable miles later.

 

thirded on the connector cleaning. do a tune up, plugs, cap, rotor, wires. also important, fuel filter, and timing. if either of those are off, it will do odd things as you have described. if it still has a cat, measure the temp on either side to see if its clogged as well.

 

u might check ur dropping resistor two. i had mine go out and it took me forever to figure out what it was good luck man

 

thanks for your help guys, currently i have not been able to do much to see if most of these things you guys tell me to try will work seeing im currently going to college and working most of the time as well, drag would love to fix my car and have it running but its going to take some time at this rate. what i have done is that ive checked spark plugs and made sure they were calibrated right, and i was able to fix the idle problem i also changed the gas filter and well it seems to run cleaner, yet the car still Sputters and chokes and as a result i think im losing engine power as a result of the sputtering and choking wanna clean the connectors but im not sure how to but i will try to research on this a bit more all and any insight is much appreciated. Im having this electrical mechanic examine the car with a computer that he claims will try and figure what may be causing the problem, ill keep you guys posted, just got this car and this car seems very hungry for some major freeway tearing cars very new and has been stored most of its life and im very eager to drive the car at its optimum level i know this fairlady is capable of treading.
-Xavier (workingprogress)

 

hey new to the forum but got it figured out=) okay I know for a fact my Air flow meter is out is there any way of not paying 300 bucks for a new one? its a 79 l28 4 bolt 5 pin connector afm if anyone has one