P Side Cruise Module access; gotta' yank the dash? [Snappic]

[Schrade]

[Franke]

Wow. They built the car around the cruise module.

[Schrade]

Wow. They built the car around the cruise module.

I think they did there Franke...

So test time. Everything hooked back up dry, and test per FSM flow chart.

First test I presume is to test the Cruise Servo Activation / request.

[Schrade]

Then the jumper wires in the sockets...

(noticed a fresh bloom in the garden)









The jumpers did NOT peg the Cruise servo, for Cruise request.

Should have done so, because the Cruise DOES work, although with the surge / 2MPH swing.

ANYONE SO FAR? Before I go to the 'NO' response in the flow chart???

[Schrade]

Alright; let's go to the 'No' servo response...

"Test for continuity / short to ground on Circuit 403"

This means test Socket 'A' for 12V input? (or 5V input??? )
And test Socket 'C' for a good ground???

[Franke]

Schrade, I would repeat the test to make sure the proper sequence is followed. The servo should have pulled in. You might be gettin' tired by now. Nice flower by the way.

[Schrade]

Recycled the 'Cruise Servo Request' test.

It failed.

Analysis:

As best as I can tell, 'Run the engine for one minute', before this first test, is to build vacuum in the Cruise servo reservoir (it sure won't go Closed Loop in < 1 minute), and see that it holds vacuum, while the 2nd jumper is put in place - terminals G and K.


Servo Failure subsequent test, on flow chart, is continuity on Circuit 403, from Cruise Module Connector, to Cruise Servo.

Dis-connect the Servo Connector, alligator clip on 'C' terminal of Cruise Module harness, another on the Servo harness connector:



and get a reading:



It passed for continuity. And it would not ground out a 12V source (short to ground).

PASS, for continuity test ---> now test Circuit 402.

(if you pace your life with your thumbs, on your digital device / phone / etc., and you can follow this, you're sharp. My pics, and explanation DO make it easier, HUH? )

Circuit 402 passed for continuity as well, and ALSO would not ground out 12V (short to ground).

Next flow chart step is vac leaks; Servo Reservoir first...

[Schrade]

Does the reservoir ball for the Cruise Servo have a diaphragm in it?

[Franke]

Hmmm... never took one apart but I would think it would have to have some kind of check valve to prevent loss of vacuum when the manifold vacuum drops due to engine acceleration. Not sure on that though.
I had a slight vac leak at the double rubber connector right under the plenum near the power steering pump. The rubber was spongy due to the years of use. PO used black RTV and just goobered it all over the connector in an attempt to fix the leak. It worked for a while until I bought the car. I fixed it permanetly with new fuel line hose for both ports when I pulled the plenum. No more leaks. Do you have a mitey vac pump to test the reservoir?

[Schrade]

I went to buy one @ Advance. Manager said the [rental] was better. Plugged it in @ #1, with the Check Valve capped off @ A:



It held vacuum (after quite a few squeezes).

Then flipped it around, measured @1, with vent #2 capped, and Brake Pedal kill port #3 capped.

IT held.

Then @ #2, with #1 and #3 capped; ditto.

And @ #3, #2 and #1 capped. Also held.

Then flipped the pump @ #3. The Brake Pedal vac line did NOT hold vacuum.

Apparently, the shop that did the A4 swap did not get the Brake Pedal kill port properly seated.

Haven't finished on that line yet, to confirm...

Could this vac leak also cause the 'off idle sag'???