RaTT92

But even when im not changing gears and keeping the gas staedy I get this jurking from the car. Its very random and is only after its been running for about 30 min

RaTT92

Also when I start it in the morning it doesn't want to stay on by its self. I have to hold the gas down to keep it up until the car warms up then it idles by its self but doesn't seem to have a set speed. It could be idleing at 800 at one light then 1000 at the next. Is this my air flow meter?

SHADY280

the bucking and inconsistant idle may be timing. check it, set it higher than stock, bout 10-12 deg. youll be happy with that little increase. or if you like to time by the total timing method, start at about 36 deg. also sometimes that afm is out from years of use, it may need an adjustment. also change your fuel filter and spark plugs, basically do a tune up if you havent yet.

RaTT92

Ive changed the spark plugs. No change.
How do I adjust the Air flow meter?

WildmaN

Here check this thread out, it should help. Good luck
https://www.zdriver.com/forums/240z-280zxt-s30-s130-tech-tips-275/js-how-rebuild-your-afm-15277/

RaTT92

Il get on that and let you know what happens.
Thanks a lot

WildmaN

^ No problem man, glad I could help. Hopefully it gets your Z going better. Keep us posted.

RaTT92

So I did the tune up thing on the flow sensor and it was all good.
It had no change on the cars performance or idle. I think the guy before me replaced the whole thing.

Now today a coolant hose had a pin hole in it so i drove it to work and before i got there it started to not let me get up to 2100 rpm
I got it to work and changed the hose put in new coolant and cleaned off the engine.
Now I still cant go above 2000 rpm or the car acts like I let off the gas completely until it gets to 1500 rpm and then i can climb back up to 2000 and it does it again. Doesn't matter if its in gear or not it just wont go over 2000.

Any Ideas???

NismoPick

Try unplugging the TPS.

RaTT92

whats the TPS??

NismoPick

TPS = Throttle Position Sensor
AFM = Air Flow Meter
CHTS = Cylinder Head Temp Sensor

ZXGrinch

TLA = Three Letter Acronym

RaTT92

Thanks a lot!!
I pulled the conector off the tps and it was full of coolant so I spray evaporating electrical cleaner in there to blow it out and now it runs fine.
Its still got a rouph idle but im taking it to be timed within the next few days.

Thanks again!

RaTT92

Could the cold start valve be the reason why the engine wont hold it self up when the engine is still cold?

What exactly does a cold start valve do?

WildmaN

Yes it could, also the air regulator can cause problems when cold.

The cold start valve when the engine is cold. Dumps more fuel on startup, until it gets enough to idle smoothly. Usually will kick a higher rpm. Sometimes mine works, and sometimes not. lol