Hey guys, long time no talk.

So, the mighty z is running, as most of you know. Finally put my new cat in, and took it down for its smog test. Well, two failed tests later, i am buffaloed.

The car is running way to rich. You can smell it, im getting like two hundred miles out of a tank of gas. I failed smog from my CO and Hydro Carbons. Basically, too much fuel, and too much not being burned.

I ran all the electrical tests on the AFM, and everything seems kosher. My question is when i ran the continuity tests on the TPS, it failed on the open throttle portion. I ran the tests like it says to in the haynes manual. I am wondering if my tps is fubared, and the computer is dumping gas like it thinks it has to be at full throttle all the time. Any thoughts?

Also, anyone know how to rig up an air fuel gauge on a N/A car with no O2 sensor.

Thanx

Bob

 

bob, you would have to weld in a bung on the exhaust as close as you can for it to work properly, also the tps is adjustable, and also your head temp sensor could be screwed, it controls fuel a bit.

 

not to sound like an idiot, but whats a bunge?

I actually dont have a head temp sensor, thats the one on the side of the block right? i was reading up on the tps adjustment, when i tried it, it didnt seem to make a diffrence.

think maybei should wind down my afm some more?

 

Yeah I would try that also. Pop open the black cover on the AFM, and lean it out first with 3 teeth clockwise. And see if that helps if not, try 2 more teeth. Just make sure you mark where you started from with a Sharpie. That is what I used on my AFM, I know where to put it for emissions and such, for next time. The marks also tell me, what points I can try. And when I started, I marked the place I began with in red marker. And the rest in silver. And also try adjusting your TPS also. It might help too. Hopefully this helps you out some. That is all I can think of for now.

 

You have a 79ZX which means yes you do have a cylinder head temperature sensor. If you don't that's your problem.

 

The sensor in question is in the thermostat housing, by the thermotime switch. When playing with my AFM, Ive found its just best to do it on the smog machine. Its too much of a headache having to make an adjustment and drive back, go home go back etc. I found a cool dude who put the car on the dyno and let me fool with the AFM while running. It seemed backwards on mine, NOx would spike with the flapper loose, and CO and HC would spike with the flapper tight.

 

not all the 280zx's came with a CHTS. Earlier models and candadian models came with a water temperature sensor located in the thermostat housing. It basically serves the same purpose however.

 

Thanks for all the ideas guys. I ordered a new tps today from autozone. i am pretty sure that is the culprit. i have leaned out the afm quite a bit, and it dosent seem to do any good. So, gonna give the tps the old college try. Let you guys know how it goes.

bob