Well this is starting to drive me nuts. My car never use to do it till a few days ago. When I am coming up to a stop the car just shuts off. The whenever it doesnt shut off the idle bounces up and down between 300 rpm and 1100rpm then after a few seconds it stops and stays steady. No issues while driving or start ups, vacuum is at avg 23-18.

Searched and found a lot of good info on this thread but I am running a electromotive TEC3
https://www.rx7club.com/showthread.p...+control+valve

 

I have the same issue now that the weather is warmer. If you figured it out, let me know.

 

On a car with the PFC or stock ECU with these symptoms, the first thing we check is the clutch switch at the pedal. With the tec3 I do not believe this even comes into play.

You may want to check the dash pot on the thottlebody, if the piston is crushed in, it will allow the TB plates to slam shut too quickly and cause similar issues.

 

Yep. Check the clutch switch first, then dashpot. If those are ok, check tps.

 

i have something very similar except i have a wideband to monitor. is it possible to run so rich that the car floods out while idle? i see as low as 10.2 when i idle (and i think sometimes even lower than 10 but my wideband floors at 10afr...) perhaps a tune is needed?

 

Ok should I unplug the clutch switch on the pedal. I cant stand pressing in the clutch to turn the car on everytime too.

 

Just bypass the switch and see if you still have the problem. If it still occurs, at least you got one thing that you wanted. Like everyone else said move on to the TB.

 

Wrong switch. The one at the top of the pedal is for the decel issue. The one at the bottom is for the starter cut.

To the other person asking about AFR's yes it sounds like you need to have your car tuned.

 

The one for the starter cut is it by the floor board on the wall or the one on the pedals arm like the brake light switch?

 

The starter cut switch is on the floor. The one up in the pedal assembly under the dash, is the one that is typically responsible for stalling issues.

However, like I said previously, I do not think it comes into play with the Tec3. I know it does nothing with the Microtech and Haltech. With your car I would be looking at the dash pot on the throttle body

 

Banzai thanks for the help man

awsome i will try this today
https://www.rx7club.com/showthread.p...light=dash+pot

So i went to look at the dash pot and the gap between the pots white tip and the bracket arm is about as wide as two credit cards width. Thats with the car turned off. And by the looks of of the white tip its really dirty and gunky so I will get some cleaner and blast it out of there . I will keep you guys updated.

Another question do you think I will have to recalibrate mines?

 

another thread that i found good info on the clutch switch too
https://www.rx7club.com/showthread.p...+switch&page=2

 

 

I have a fsm but it doesn't show what measurments it should be. Do you have a link to closed and open measurements .

 

The spec in the FSM does not give actual measurements, it just says the rpm at which the dashpot should make contact with the throttle. It is pretty useless for your situation. You will have to adjust the dashpot by trial and error.

 

fully extended it's 1/4 of an inch and should make contact with the throttle "plate" at 2800 rpms. This might need to be adjusted for your application.

Open:



Closed:

 

YMMV but everytime I have a bouncy or surging idle it turns out to be my TPS (Throttle Postiion Sensor). Mine slips out of spec pretty easily, but once I adjust it back to the factory range my idle is fine again.

 

Just want to make sure I did this right so I had my wife hold the rpms at 2800 Rpms then I adjusted the dashpot till it touched the bracket then I secured it.before all that I removed it from the car and cleaned the white part with carb cleaner now it goes in hard and springs out fast.

 

sounds like you have it. Keep in mind that that is the factory stock rpm that it should engage. you might need to adjust your to suit your application. that being said, it could turn out that its not the dashpot at all.... don't we just love FD tuning?!



For future searchers since RenoCYM brought it up, the TPS range on the PFC is:
VTA1: closed 0.10 to 0.70. open 4.2 to 4.6.
VTA2: closed 0.75 to 1.25. open 4.8 to 5.0.

 

Update well the car hasn't shut off but is still doing the bouncy idle.

 

Check your TPS

 

Ok after searching on how to check the tps with a voltmeter I got my numbers. I still dont know if they are good or not all I have is what the fsm says it should be at and how to do it. I used the diagnosis ground because it was easier to stick the ground stick.

- First one I did was the 2nd from the top (green wire with red strip), this goes to the 3F ECU
1.25 closed and wide open throttle 4.93

-Second one I did was Bottom (black wire with green strip), this goes to the 3G ECU
.54 closed and wide open throttle 4.20

What do you think?

 

I'm having this same problems since it got hot as hell here, car shuts off and idle goes up and down like I have a huge vacuum leak

 

If all else fails, unplug your ISC (back middle of the UIM, white plug) and set the idle manually, see if that helps

 

Ok I will try that what about my voltage numbers are they good they seem to be within the specs I got from the fsm.