KOKO Test: CCA moves, TCA doesn't.
07-12-04, 08:46 PM
#1
KOKO Test: CCA moves, TCA doesn't. Now What?
I'm troubleshooting a low transition and slow primary onset, and started with the 6x KOKO test. 3rd gear WOT pattern is about 10-6-10.
With me under the car, and my gf doing the ignition, I can get 6+ movements of the CCA. Then I restarted, revved the engine to recharge, and we repeated the test with me underneath looking at the TCA. No movement, ever (just the CCA up top clicking and doing it's thing again).
I remember testing the TCA during the hose job a few months ago using a vaccuum / pressure gauge, and it seemed a little slow to respond.
1) Does the CCA movement indicate the vacuum chamber is good for sure? (Or at least a safe assumption for now)
2) Should I focus my attention on the TCS next?
3) Wouldn't a faulty TCA or TCS cause a worse boost pattern?
With me under the car, and my gf doing the ignition, I can get 6+ movements of the CCA. Then I restarted, revved the engine to recharge, and we repeated the test with me underneath looking at the TCA. No movement, ever (just the CCA up top clicking and doing it's thing again).
I remember testing the TCA during the hose job a few months ago using a vaccuum / pressure gauge, and it seemed a little slow to respond.
1) Does the CCA movement indicate the vacuum chamber is good for sure? (Or at least a safe assumption for now)
2) Should I focus my attention on the TCS next?
3) Wouldn't a faulty TCA or TCS cause a worse boost pattern?
Last edited by dgeesaman; 07-12-04 at 09:05 PM.
07-12-04, 09:33 PM
#2
Rebreaking things
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1. Yes, the CCA operates off vacuum only.
2. TCS? I take it you meant TCA. Since the TCA requires vacuum and pressure to function properly the first thing I would do is confirm that your pressure chamber is holding pressure.
The easiest way to do this is by removing a line from the pressure chamber. If you hear air rushing out you know the pressure feed line, pressure chamber, and check valve are working correctly. From there you can trace the line to the TCA pressure solenoid (located on the LIM) and down to the TCA.
I suggest looking at this before the TCA vacuum system because I think it's easier to examine and you already know that your basic vacuum system is working.
If you don't uncover anything you're left with the vacuum turbo control solenoid on the rat's nest and the input/output vacuum lines.
3. The TCA should still work with just pressure or vacuum, but it will operate slower than normal, causing a funky transition.
2. TCS? I take it you meant TCA. Since the TCA requires vacuum and pressure to function properly the first thing I would do is confirm that your pressure chamber is holding pressure.
The easiest way to do this is by removing a line from the pressure chamber. If you hear air rushing out you know the pressure feed line, pressure chamber, and check valve are working correctly. From there you can trace the line to the TCA pressure solenoid (located on the LIM) and down to the TCA.
I suggest looking at this before the TCA vacuum system because I think it's easier to examine and you already know that your basic vacuum system is working.
If you don't uncover anything you're left with the vacuum turbo control solenoid on the rat's nest and the input/output vacuum lines.
3. The TCA should still work with just pressure or vacuum, but it will operate slower than normal, causing a funky transition.
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