Before you rail on me, yes, I used the search bar. I tried several iterations, found a few somewhat-related threads, but none that had my same issue, description of which follows. I decided to do some upgrades during quarantine, so car sat on jack stands for about 6 weeks. car was in storage from Nov-April on a battery tender prior to that. During that time, I installed coilovers, soft top helper straps, replaced clutch/PP/flywheel, and installed a Science of Speed supercharger (in that order). I was driving the car a bit before putting it up for those 6 weeks and the top worked absolutely fine - would go down/up in the normal 4-5 seconds. Following the 6 week layup, I started the car to check out the base tune and do a test ride before final tuning, went to drop the soft top and it was VERY slow. After the approx 15 min ride, went to put the top up (engine running - even tried holding revs at 3K to make sure alternator was spinning quickly) and it was painfully slow and needed some manual assistance to get all the way up. Passenger side motor is affected a bit more, ie: is the slower of the two, and stops about 1-2 inches short of where it did previously. I threw on a battery tender for a few days to juice up the battery a bit, tried again and the problem is still there. Seems like a voltage issue, right?
Car is a 2007 with 73K miles in excellent mechanical condition
Questions:
1) Bosch Cobra water pump for liquid HX/aftercooler draws 3-5 amps - is that enough additional draw to affect the soft top operation? My assumption is that the s2K's alternator produces adequate amperage to accommodate this small demand increase.
2) Could a weak battery be part of the problem - not enough juice to supplement the alternator's to generate the power needed by the soft top motors? Grasping at straws here.
Looking for some guidance on best way to locate the underlying problem. Thanks in advance!

 

All the expertise and pent up desire to share it, and no one has any ideas?

 

12vDC motor speed is directly proportional to voltage so a weak battery or alternator could easily be the cause. Anyway to determine the voltage? Any wiring grounds removed during all your work?

(Also graphing at straws.) Pull the fuel pump fuse and see how the roof motors run on pure battery power for maybe a clue.

-- Chuck

 

What does the fuel pump have to do with the soft top motors?? Anyway, I threw a new battery in just to see what would happen, went to raise top on battery power alone and it was only very slightly better. The passenger side still struggles to go up. Is there a voltage regulator between the battery and soft top motors that may be the culprit?

 

Meant to type aftercooler pump fuse since you're questioning its amperage pull.

-- Chuck

 

Good call. I have it on a battery tender now, going to let it sit for a few hours before trying again. In the meantime, going to grease all the frame joints, etc in hopes that'll help free it up a bit. Swapping in a known good s2k alternator Saturday afternoon. Fingers crossed.

 

I'd probably run the tests in the shop manual before replacing parts unnecessarily

 

How big a pain in the ass to get to the motors??

 

- Remove door sil
- Remove​Remove two hooks on airvent behind seat
- Remove airvent panel
- Remove screw from rear panel beside where the lower seatbelt bolt is by the seat.
- Pull that panel out
- Remove the gusset plates

If I am remember correctly, thats probably 5 minutes per side to get access to the motors?