Another 964 Convertible Top Problems
 

Dear Friends,*

I recently bought a 1991 convertible 964, with a non functional convertible top
So, I took the car to my local Porsche mechanic and he diagnostic that the problem was the convertible computer so we:
- Replace the old computer for brand new Specialized ECU repair
- Replace both brass worm gears on the windshield locking mechanism
- Replace both steel cables to the main mechanism*
Now , after almost everything replaced, the convertible top open and close but I still have a huge problem that I could pinpoint where is the solution
When I press the switch to open the convertible top, the latch mechanism on the windshield does not open! So I have to press the switch to close the top ( then the latch open ) after the that I press the switch to the open side again and the convertible top opens
To close it is the same problem, it close fine but when the latch hits the windshield it is on locked position, then I have to press the open side of the switch to open the windshield latches and then finally press the close side of the switch
Basically the latch mechanism sees to be inverted by some how*
Then in order to try to fix it:
-Send the ECU back to the company who made it, he check it at his bench and it was operating fine, then he check another brand new unit and it passed the test and he gave me the new unit*
-Rechecked the microswitch and the end points on the windshield latch motors
-Rechecked the microswitch on the windshield base*
-Rechecked the microswitch on the top mechanism*
Everything seems fine and I don't know why this latches are inverted
So, any help or idea is welcome at this time
Thank you all*

Ricardo*

This is a WAG, but is it possible when you rebuilt the latch motors and put in new brass gears the wires somehow got reversed? Seems like a long shot. Also, are the latch guides properly aligned? There is a small adjustment if the top is "bouncing" on the windshield top instead of latching.

Hello,

Thanks for the reply and for the help!
At this point nothing is discarded, Ill double check the orientation of the gear inside the lock mechanism and if that is correct I'll try to invert the wire on the locking motors
Right now they are correct since its a plug that have sides and you cannot plug it inverted
Also I'll check if the wire on the square plug that is attached to the computer its' not swapped
I heard that sometimes that plug get opened and all the wires jump out of the correct position
Let's see
Thank you all

Check out Heidi and Frannys Garage on YouTube, they have a piece on rebuilding the latch motors, along with other articles on the 993. You can see the proper orientation of all the components. I think the top on the 964 is very similar to the 993.

It all in the micro switches. Someone must installed the switches backward. Get photos and installed the micro switches right.

Hello,

But which ones? The ones on the locking mechanism near the windshield? Yesterday I unplug those and connected them inverted, but still the same problem
I also swap the ECU, for a Original Porsche one, and for 2 others Aftermarkets one and the same problem appeared
So, I think the the ECU problem is discard
I also got another locking mechanism and swap with mine and the problem persisted, so I can assume that the problem is not the locking motor or its internal microswitch
Now I'm thinking about some swap wire in the car or in the square plugs that connects in the ECU
I heard that is very easy to accidentally crack them open and get the wires swapped when reinstalling
But which one ? I'm thinking that may be the one for the close /open motor since both locking mechanism are turning to the same orientation and the left and the right LM are in two different square plug
http://forums.pelicanparts.com/uploa...1665499679.jpg
http://forums.pelicanparts.com/uploa...1665499715.jpg

You spent your money with the ECU rebuilder. ECU rebuilders usually help their customers solve problems. Next time consider other sources for your ECU repairs!

I have the Original ECU. I actually have 2 originals ECU that I saw working in a similar car, but when I install this same ECU in my car, it just don't work.
Anyway...

So they sold you an ECU you really didn't need, right? Hopefully, they refunded your money?

Did they help you by indicating that the timing between the locking motors is very critical?
One motor being off by one tooth to the other motor can cause your problem.

Hi Dave,

Of course they did! Not only that, they charge me for 2 new transmission cables, 2 new gear set for the locking mechanism not to mention the labor to "fix" and replace all that and they deliver me a car that the roof was not working

But that is OK, I'm over it already... I lost that money, it happens, its fine...

The worst part for me is that now I'm back at square zero

And NO, they did not help me indicating that the timing between motor ( and do you mean the timing between locking motors on the windshield?! Right ?) was that critical

So, in order for me to check the sync of the locking motor, do you have any suggestion?

Thanks

Yes.

You need to check the SR & SL signal timing when they both open. You can do this in the vertical position of the top.

Where are you located and who's the workshop?

I'll try to check that out
Im in Fort Lauderdale, its a small shop is called national porsches

thanks again

http://forums.pelicanparts.com/uploa...1665602873.jpg

You are aware that the ECU pictured is for a 993 and not a 964 like your car, right?
The 993 ECU requires an additional input, the Hd.

Try 9automotion in North Palm Beach. Gordon can fix it. I own two convertible 964s.