Ok

Got the idle speen under control now w/air adjustment screw then throttle linkage adjustment screw. However, as soon as the car gets to 170-190 on my
Autometer water temp guage the engine starts to hunt like a overloaded generator. I have to think it has something to do with when thermostat opens?

Should I take out the thermostat?
Test water thermosensor?

Car sounds mean a hell I'll tell you what.

 

Could be not enough fuel (lean AFR) or not enough air (air adjust screw closed too much). At around 180 degrees the fast idle system disengages and the throttle plates close some.

 

I do have the air adj. screw turned in pretty far but used that and throttle adj. screw to get idle right before running temp. My Autometer AFR meter is just shy of in the middle.

However, I dont remember seeing my factory water temp guage move. I was wondering if maybe I got some water sensors wired wrong? I doubt it and I dont even know if that would cause that problem.

The hunting problem has definetely got to have something in common w/water temp. There is always something to learn w/ a RX7, thats one of the things I love about it most.

 

You did it backwards. It doesn't matter how well it idles when cold--not at first, not if you want to avoid the situation you are now in. Keep your foot on the gas for 20 minutes until it warms up if you have to (I've done it before). Cold idle should be adjusted last. Cold idle is always relative to the warm idle settings. The cold idle fuel is a % correction of your warm idle fuel. Your mechanical fast idle system holds the throttle plates open to add more air relative to your warm idle position. Your ignition timing is going to be different relative to your warm idle ignition timing.

You have to work backwards. Always set the warm idle first. Get a basic stable idle when warm by adjusting the throttle plate, air adjust screw, and target idle speeds in the PFC if applicable. Lean out the mixture some so your AFR is at least as lean as 12:1-12.5:1. Adjust the dashpot and fuel cut recovery speeds so that your engine will not stall on decel or when free revving. Then cut the car off and let it cool down overnight.

Cold idle tuning can now be performed. Start the car up, using the accelerator pedal to keep it alive if necessary. Adjust low load cold idle fuel through the water temp correction table in the PFC to at least keep the idle somewhat stable. Adjust your fast idle cam screw (assuming it's still one the car) if necessary in order to open the throttle plates. Adjust the IGL, IGT, and cold ignition retard maps to minimize popping/backfiring. The higher load column of the water temp correction table can be adjusted the next time you cold start the engine, in order to set AFR when you are driving around and not just idling. You can also adjust the cranking fuel and timing to improve cold starts by using the cranking fuel map as well as the P9-P10, N1-N2 matrix of the IGL and IGT maps.

After cold start is tuned, hot start idle can be tuned assuming that you are not in the middle of winter. Warm the car up completely and drive it around. Stop somewhere and let the car heatsoak for 10 minutes. Start the car up and observe the hot start AFR. Verify that your idle is not surging (if ISC is equipped). Adjust your IAT correction table in the Datalogit so that your AFR is no more than .3-.5:1 leaner during hot start compared to your regular idle AFR.

After you've done all this your car should idle pretty consistently. It's a lot of work. There's a reason why good tuners are paid so much.

 

Do you have a stock ECU or PowerFC?

Some other things to check -

- A bad clutch switch will cause all sorts of idle weirdness, especially with a stock ECU.

- A dirty or stuck ISC can cause hunting, you can clean it with carb or brake clean off the car.

- Is the motor ported? A ported engine will have a lope to it that you probably won't be able to iron out, that's normal.

+1 on the suggestion to tune the idle when hot, that is the right way to do it.

Oh, a misadjusted TPS can sometimes cause idle hunting, but it's pretty uncommon.

Dale

 

I have Power FC computer.

I did port the motor.

Also I did notice a crack in my TPS but I know it was like that before the rebuild.
If the hunting was from the porting wouldnt it do that all the time and not just when its warm?

 

bump

 

bump, cause im having tha same sort of problem

 

Try unplugging your IAC/ISC to see if it stops hunting.

 

12-12.5 at idle?