Bouncy Idle...???
 

So I've been searching and searching now for about a week as time permits, but the more I search the deeper & deeper I get off track. I figured I could start my own thread and bounce back and forth from searching to here since there just seems to be so much stuff related to bouncing idles.

I'm at the point of temporarily getting rid of the TMIC by use of some PVC tubing and I was wondering what to do with the other two smaller hoses...??? (Fatter one goes to top of upper intake & skinnier one goes to black elbow right after the MAF)

My car is a 87 Turbo II but the previous owner changed motors. It now has a 90 motor (supposedly w a street port), 3" Racing Beat Exhaust and HKS piggy back computer.

The car starts up pretty good... It sometimes takes a second try to catch. Meaning, it'll start and idle will drop almost to 100 and stall... or drop to 100 or so and something kicks it up to 2000 or so (cold start...?) Then it gently comes down and actually idles pretty good. I take it for a gentle spin, (a mile or two or so w out boost) and once its warm the idle is going from 800 - 300 over and over again.

Also when I stop at the light it'll do the same drop sometimes as I first explained... almost to 100 and stall or almost to 100 and catch before something raises it to normal....??

Any input would be greatly appreciated...!!! I feel like the more I search the more lost I become.

Vacuum leaks?

You'll also want to check the ECU pin for the clutch switch as the ECU will alter the way the engine runs a bit when the clutch is depressed versus not depressed. You also might want to check the pulsation damper to see if it is set properly. Its purpose is to prevent the throttle plates from closing too quickly and choking the engine when coming to a stop. And you might want to check the voltage output of the alternator to see if too little is being created, which might affect the operation of the car.

Alternator is at 13.75 during idle.

Idk wtf happened but I took it for a spin to warm her up so I can check the TPS and she's sputtering and running like shit. Pulled her in and removed the intercooler... the TPS is reading NOTHING. Not even when I sweep it WOT, still NOTHING.

I don't get it...?? Last time I messed with the TPS it was reading fine...???

I used this link: FC3S Pro v2.0:&nbsp TPS adjustment for 1986-1988 RX-7 Turbo II models to check it.

Also my turbo was GLOWING and stock temp gauge was past the middle which SCARES me.

Uggggh.

Did you measure the voltage or the ohms?

I'm over here trying to maintain patience, searching, checking clutch switch, reading FSM, etc, etc when I was thinking maybeeeee the Harbor Freight Multimeter is junk...??? Checked back here and sure enough I was on volts not ohms...!!

Anyways, I set it to exactly 1.00 ohms and she idles pretty good at about 800 rpms. I give her some throttle (around 4K) and it comes back down to 300ish / shakey then back up to 900ish & does that 4-5 times before smoothing back out at 800.

I took a video but am having trouble uploading it.

Another quick ride (about a mile long tops) and I pull back into the garage, turbo is GLOWING red and somewhat into downpipe. Stock temp gauge is a little above middle again.

I think I'm good. Timing was off. Car feels like a beast again and idle isn't bouncing anymore.

Turbo was only glowing slightly after a mile drive and went away in seconds after pulling in.

Sometimes it's sooooo simple. Thanks again SATCH.

Ehhhh so I jumped the gun... It takes a good warming up for idle to start bouncing again.

Tomorrow's another day.