cpu for convertible top 1988 cab

[rekstein1]

both gears in both motors were replace as in just in case method. I was not aware that there was a timing thing. as when replacing the gears there is an outer gear that trips the micro switch to stop the motor so damage doesn't occur.

I am going to call those guys just to check as to what they have to say. Its nice to know there is an alternative to ECS. I have never heard of them and they did not come up as someone who repairs cpu's. They need to modify their SEO. did you use them before?


I don't think the answer is obvious here. other than perplexing. I feel if nothing they can add to whats already whats been done will result in me sending them both units i guess for a second opinion. They look intense and professional, nice webcite could be my only hope .

stay tuned

Rich

[mysocal911]

Originally Posted by mysocal911

This test provides key information. Possibilities:

1. The locking motors' timing may be incorrect, i.e. the phase of brass gears relative to locking motor switches.
2. The cab top ECU has a problem related to the unlocking mode when the locking motors are locked.

If you would like to discuss your technical problem, you can call the website mentioned in post #7.

You can check the state of the locking motor switches by using an ohmmeter between each of the switches, SL & SR, and ground.
They should both indicate an open when they are in either the locked or unlocked position.

[mysocal911]

Originally Posted by rekstein1

I am going to call those guys just to check as to what they have to say. Its nice to know there is an alternative to ECS. I have never heard of them and they did not come up as someone who repairs cpu's. They need to modify their SEO.

It's just like any type of advertising, it's basically how much you are willing to pay (Google).

Originally Posted by rekstein1

did you use them before?

Yes, a number of times with good results.

Originally Posted by rekstein1

I don't think the answer is obvious here. other than perplexing.

Nothing is ever obvious when you're troubleshooting an electrical problem!

[mysocal911]

This should be helpful in troubleshooting the 911 Cab Top system:



The power relay must always close for any function to occur, e.g. the lock/unlock relays having an effect.
By watching how the relays behave when various modes are requested, one can get a idea of how the system is functioning.

[mysocal911]

You've found your problem, right?

[rekstein1]

As they say and this is how the story goes: Here is the update:
Took the car to another shop recommended by Systems Consulting here in N.J., Powertech.
First things first. Let me just say what an unbelievable person Loren is at Systems Consulting. Anytime, and I mean even Saturday's after buisness hours, I would get a follow up email, either that hour or the next day. System Consulting and Loren are a unknown Gem to the Porsche Community.
Why are they not well know when it comes to DME and CPU repairs and mentioned more often in this forum is, as explained to me by Loren, they do not put alot of money into their SEO for the web. A low profile good guy who cares about people who just happens to be his customer.

In regards to ECU Doctors, the other people. No one ever returned a call, or an email. Their chat people to try to get an answer to a problem, were well trained ,but only relayed messages that were never returned. Finally if you ever had a CPU repaired by them there is a tag on the back that if removed voids the warrenty
Reason being in my case I got a substitute CPU. This unit was check elsewhere and its has an anomaly. Hence my purchase of a second CPU unit , that was subsequently sent to Germany for final testing.

Stepping back from this whole thing, there is a very last step to my knowledge that is not documented anywhere and would have prevented this whole fiasco.

To recap, the convertible top stopped working after 4 years of no problems and with a perfectly rebuilt CPU from ECU doctors. Under warrenty, ECU replaced the CPU and I went through the Convertible top checklist provided here in the forum. The problem from the beginning was the convertible top motors would not open.

Applying 12v to the wiring bypassing the cpu, the motors would unlock and lock, the top would also retract fully. Bringing he top halfway forward and then taping the switches in the top by the locking motors to simulate the locked position, the motors
this time going through the CPU the locking motors would only work in one direction.

Hence the thought that the CPU is still bad.

The problem: if the locking motors work when bypassing the cpu why don't they work
when going through the cpu?

This stumped the first mechanic I took the car to. Apparently according to Loren, if the motors are not timed right they confuse the CPU and it will not open the motors.

This begs the question how does one determine the motors are timed correctly?
Nowhere is this fine point explained anywhere. Or, that how does one determine if the locking motor is bad? It opened and closed when 12 v was applied. So is it a timing thing or a motor thing?

This is the problem, as the top worked great for 4 years. How to determine this. So obviously the motor is bad in this scenario and its not a timing thing as things worked fine for 4 years.

As all these parts for the convertible top are ridiculously expensive I ask the forums helps for people's thoughts on motor testing and timing.

I am sure other people threw in the towel and said screw it, and I am converting the top to manual operation due to the cost ,as I can't figure out what the hell is going on. I just couldn't go down that road. In essence its 5 parts in the operation of a convertible top, how hard could this be?

Back to the story. So at the second shop, Powertech, the initial assessment was to replace the locking motors and the top motors. As these are the original top motors which are dual motors, the upgrade is go to a single motor. Unfortunately your need to upgrade the cables as well. this runs into total parts cost of 1K. This in addition to the locking motors cost of $2600. If the CPU is bad thats another $600 part. This does not include labor, this is pure parts cost .I can see why people threw in the towel.

To Powertech's credit and honesty, they they determined that only the locking motors were the issue, and I dodged a $2600 cost. Thankyou Mike.

I would like to in closing that Loren at Sytems Consulting for being a great person. I encourage the community to use his services. In NJ, Powertech for your Porsche needs

Finally, does anyone know how to test these locking motors and to time them for the next person, so no one has to go through this?

On the road with a working convertible top

Rich

[A horse with no name]

Hi...To never-ever have trouble again, go manual...Why they went to electric on a G series beats me... As an owner of a '86 Cab, they are a 'one arm' up or down, and any age will find no difficulty whatsoever in doing so -> "Happiness' Is" you'll find, is no electric top