Cruise control won't hold speed.. What to check?

[RSBob]

Originally Posted by deputydog95

I believe this is the same guy in referenced in my post. Kris from cruise control repair dot com?

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Yup, the same guy is me. My bad.

[deputydog95]

Originally Posted by DRACO A5OG

Deputy, please keep us posted on the repair, very curious if it was the servo or module.

You mean there's two things? Thought it was just the module. Am I supposed to send this guy both?

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[DRACO A5OG]

I would contact him and ask. I think our 86-88.5 3.2 brothers have different CC set ups.

The Servo is in the engine compartment and the module is in the frunk behind the cardboard shield.

[deputydog95]

Originally Posted by DRACO A5OG

I would contact him and ask. I think our 86-88.5 3.2 brothers have different CC set ups.

The Servo is in the engine compartment and the module is in the frunk behind the cardboard shield.

Already on it, email sent

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[uwanna]

Originally Posted by deputydog95

You mean there's two things? Thought it was just the module. Am I supposed to send this guy both?

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NO!! Your problem is an aging CC module that won't hold speed not a defective servo!
In all the threads on CC in this forum, I have never encountered one where the problem was a bad servo. Perhaps a servo that wasn't hooked up correctly to electric wiring or vacuum may have been a problem, but never a bad servo.

[uwanna]

Originally Posted by DRACO A5OG

I would contact him and ask. I think our 86-88.5 3.2 brothers have different CC set ups.

The Servo is in the engine compartment and the module is in the frunk behind the cardboard shield.

86-89Carreras use exactly the same system with vacuum servo and module, with two exceptions. They use a 14pin module vs 10 pin, and the module is relocated inside the car under the dash. It operates identically.

Correction: '88-'89 Carreras started using an electrical servo in lieu of the vacuum servo. Basic operation remained the same.

[DRACO A5OG]

^^^ there you have it :-)

[Jesse16]

I will relate my experience with repair this year. I had Kris or Cris (the new guy on the block) repair mine and it did not work when returned. He did warn that he cannot test his repair. I had already bought a non-working back-up module which I sent to Beckman here in NC who do repair and test of modules primarily for Mercedes. They confirmed the Porsche part number is one they can repair. They have a big place and charge real but not stupid money and guarantee for a year. That unit did work when returned and is still working so my vote is do it right and spend a bit more. Repair time was one day plus shipping, easy. You pay when job is complete with a CC.

[uwanna]

I have posted this before to help save folks from frustration and unneeded extra work while troubleshooting cruise control problems, and since we again visit CC problems, it bears repeating here. The Bentley manual has a glaring error in the CC troubleshooting chart as pertains to checking the clutch switch. The Bentley chart will lead you astray and cause you untold frustration by letting you think you have a bad clutch switch. By the way, it's really not Bentley's fault, they simply reproduced the chart that appears in the FACTORY manual, which is also wrong. Anyway here the info:
cruise control

[uwanna]

Originally Posted by Jesse16

I will relate my experience with repair this year. I had Kris or Cris (the new guy on the block) repair mine and it did not work when returned. He did warn that he cannot test his repair. I had already bought a non-working back-up module which I sent to Beckman here in NC who do repair and test of modules primarily for Mercedes. They confirmed the Porsche part number is one they can repair. They have a big place and charge real but not stupid money and guarantee for a year. That unit did work when returned and is still working so my vote is do it right and spend a bit more. Repair time was one day plus shipping, easy. You pay when job is complete with a CC.

And the burning question is, how much is: "real but not stupid money"

[Jesse16]

I think it was like $200 plus return ship plus tax in my case. Vs $70 plus shipping as I remember to Kris. Think the initial comment is that its more now. They will tell you the cost when you contact them, very straightforward. They answer the phone, its a real business.
Beckmann Technologies, Inc.

[DRACO A5OG]

Originally Posted by uwanna

I have posted this before to help save folks from frustration and unneeded extra work while troubleshooting cruise control problems, and since we again visit CC problems, it bears repeating here. The Bentley manual has a glaring error in the CC troubleshooting chart as pertains to checking the clutch switch. The Bentley chart will lead you astray and cause you untold frustration by letting you think you have a bad clutch switch. By the way, it's really not Bentley's fault, they simply reproduced the chart that appears in the FACTORY manual, which is also wrong. Anyway here the info:
cruise control

Oustanding! Thank You Brother Uwanna

[deputydog95]

Originally Posted by uwanna

I have posted this before to help save folks from frustration and unneeded extra work while troubleshooting cruise control problems, and since we again visit CC problems, it bears repeating here. The Bentley manual has a glaring error in the CC troubleshooting chart as pertains to checking the clutch switch. The Bentley chart will lead you astray and cause you untold frustration by letting you think you have a bad clutch switch. By the way, it's really not Bentley's fault, they simply reproduced the chart that appears in the FACTORY manual, which is also wrong. Anyway here the info:
cruise control

This wouldn't have anything to do with speed bleeding off though, right?

[uwanna]

Originally Posted by deputydog95

This wouldn't have anything to do with speed bleeding off though, right?

Correct, has nothing to do with speed bleeding off.

[uwanna]

Originally Posted by Jesse16

I think it was like $200 plus return ship plus tax in my case. Vs $70 plus shipping as I remember to Kris. Think the initial comment is that its more now. They will tell you the cost when you contact them, very straightforward. They answer the phone, its a real business.
Beckmann Technologies, Inc.

I used the Ebay guy before when his price was $80. He does do excellent work, tests the unit, gives a lifetime warranty and pays for return shipping. The two he did for me are still working perfectly after a couple of years. My only concern was the price increase to $190.
911 928 Porsche Cruise Control Computer Repair Service to Your Unit 92861712700 | eBay

I have personally repaired four units myself with a removal of the lacquer type coating on the back of the PC board with acetone, reflow of ALL the solder joints and replacement of some bad capacitors. One caution, you must use a very pointed soldering iron and make sure none of the tiny connections "bridge" to another connection with stray solder! It's quite tedious work, but very rewarding!

[kyngfish]

Originally Posted by deputydog95

I drove for 3 hours on the interstate Sunday night. That's why :-)

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Yep, that would do it for me too.

[deputydog95]

Originally Posted by uwanna

I used the Ebay guy before when his price was $80. He does do excellent work, tests the unit, gives a lifetime warranty and pays for return shipping. The two he did for me are still working perfectly after a couple of years. My only concern was the price increase to $190.
911 928 Porsche Cruise Control Computer Repair Service to Your Unit 92861712700 | eBay

I have personally repaired four units myself with a removal of the lacquer type coating on the back of the PC board with acetone, reflow of ALL the solder joints and replacement of some bad capacitors. One caution, you must use a very pointed soldering iron and make sure none of the tiny connections "bridge" to another connection with stray solder! It's quite tedious work, but very rewarding!

Yeah, I'll just pay the $80 LOL.

[megerian]

Originally Posted by uwanna

86-89Carreras use exactly the same system with vacuum servo and module, with two exceptions. They use a 12pin module vs 10 pin, and the module is relocated inside the car under the dash. It operates identically.

Minor quibble, they aren't exactly the same in this date range. My 88 has an electric servo, not a vacuum servo.

[uwanna]

Originally Posted by megerian

Minor quibble, they aren't exactly the same in this date range. My 88 has an electric servo, not a vacuum servo.

I stand corrected, forgot about the switch over to electric servo for '88-89. With the exception of the servo, the operation is still very similar.

[unclebilly]

I parted out an 87 years ago. I think I have the electric servo still if you need it.