turbo control KOKO test question
 

The desctiption of the KOKO test usualy says
"Watch Charge Control Actuator work each time"
"Watch Turbo Control Actuator work each time",
from http://www.autosportracetech.com/RX-...alBoostPattern


My charge control actuator stays in or out as I turn the key on and off. The turbo controll actuator just moves for an instant and then just goes back to where it was. My question is, should the turbo controll actuator stay like the charge control actuator does, or does turning the key on just make it twitch?

Thanks,
Dale

Turning the key should make it move in and stay in, or move out and stay out.

If it's twitching that suggests either a leak in the actuator, lines, or solenoid.

Dave

SKOR!

if thats true, then it seems I found the problem sector. now to just hunt down the specifics.

Thakns

Here's one thing you can do:

Do you have a mityvac? If so, unplug one of the lines to the TCA up where they reach the top rats nest, in front of the UIM. Use your mityvac to apply pressure or vacuum. Look to see that the TCA opens/closes when apply it, and there is no leakage. If no leakage, and it moves smoothly (I think it needs around 7 psi to extend completely), then look to the solenoids and lines in between.

IMO, if you demonstrate the TCA itself moves properly without leaking, it's best to buy both new turbo control solenoids and install them. That solves most TC problems.

Dave

Ok... I tested actuator with mityvac, and it works find. so i pulled UIM to check solenoids. If I unplug solenoids, and koko, The voltage on the pins does the same as the actuator did. meaning spikes to 9V or so and then quickly drops. BUT!, if i check to ground, one pin is 12V, and the other is nothing. Resistance across the solenoids is about 34 ohms, like i think they should be, and if I hotwire the vaccum side solenoid, it opens fine. Also, if I check the connectors to both solenoids, their is continuity between them (they are parallel), meaning its not loose pins on the connectors or something.

Anyone have any more troubleshooting ideas I might try?

Thanks,
Dale

this is the exact scenario im finding on my car!

did you ever find out what was going on?

Well it seems the ECU only powers the solenoids for a moment during KOKO - like I said I wasn't sure. I can't check my car b/c the wife's not home and it's not a one-person test.

I suggest you tee that line and take the car for a test drive. It should produce 10psi from 4500 on up as long as you're boosting, and it should vent that 10psi immediately when you let off the throttle.

On the vacuum side, it should do the same thing on the road - about 20" Hg under boost at 4500+, and go do 0 immediately when you let off.

From: http://www.fd3s.net/boost_problems.html (about halfway down the page)

"Date: Sat, 5 Sep 1998 11:41:28 -0500
From: "Steve Wynveen"

Yeehaa, my car is finally 100%, pr...."

This post describes in detail how he went about it.

I figured out to test it myself, and indeed, it's supposed to move for only a brief moment.

https://www.rx7club.com/showthread.p...59#post7935659

Dave