Thanks for reading !

I just got this datsun 300 zx 1984 with 150 k miles. manual 3 L FI,

First is hard to start, you have to push the gas a little bit so it starts, once it starts it sputers and runs really ruff till it warms up a bit.
After warming up, it just idles badly going betwen 900 and 1200 rpms (note that should idle betwen 650 and 700).

It has power, and doesnt seem to miss as much in higher rpms.

The previous owner put bosh platinum 4 sparkplugs, wich i ve heard that they make the car miss, is this true ?
he also said had a tune up done (rotor, cap etc).

The computer only gets 1 code, 41 (fuel temp sensor) wich ill fix today. but i dont think this is the couse of the missfire.

I checked vacum leaks and i fixed one, but there were no more to fix.
Even if you unplug a vacum line, (to simulate a leak) doesnt seem to afect the engine runing a lot.

Im runing a set of diags to the sensors this afternoon, since the car came with the shop manual from nissan.

Thank you for your help.


Fire D. Husky

 

me again !

fifxed the ruff idle... someone had the timing way out of **** (whoever owned the car before) at least 15 degrees advanced.
One thing is advancing the timing but this guy cranked it all the way up.

anyway now it idles nice


BUT when it starts cold , doesnt idle faster (still wants to idel 500 or 600 rpms). meaning it will take a while for the car to want to run without hesitation (till the engine iswarmed up).

feels like if you started a carburated car without the choke. kinda.

thank you for your advice.


FDH

 

Very simple.... head temperature sensor !!!!

15 bucks later will be fixed


FDH