A study of slow power windows

[spidernut]

I decided to tackle the slow power window issue on my Spider. I do not recommend this procedure by the way, but figured out what is going on with the motor and mechanisms that cause the windows to be slow.

After removing the power window regulator, cable and pulleys, I realized that the original lubricant used had turned into a sticky wax like substance which impeded the ability of each part to function properly. I suspected this since they always seem to work faster when it is hot outside than when it was cold. I cleaned the parts then lubricated them again. If you ever decide to do this procedure, make special note of how the cabling is wrapped around the spindle for the power window regulator. The cable must be put back together exactly the same, wrapped the right directions and the correct number of times for the regulator to work correctly.

Once everything was together and re-aligned and the cable tension adjusted, I found that the windows were very fast at rolling down but still moderately slow at rolling up....slower than I preferred but greatly improved.

As the window rolls down, the pulleys roll easily and remain parallel to the door. Tension on the cables is minimal. When rolling up, the cables tighten more (due to the weight of the glass and friction against the window felt and track felts) and the pulleys angle slightly (no longer parallel with the door) due to the load. Even with strong voltage to the power window regulator, the motor runs fast when not under a load but slows significantly when placed under any load.

Basically, the power window motors are slightly under-powered for the job.

At least my driver's window (the one that I worked on) is significantly improved and no longer an embarrassment. Once I mentally recover from working on the driver's side, I'll tackle the passenger side since the window almost stops as it rolls up.

[fiat218]

Mine does the same,faster on the down side, slower coming up,as if it running low on power
Great explanation

[BEEK]

the slowness is inherent of cable operated power windows, a mitsubishi 3000gt also has cable operated power windows and they are also slow. i do agree proper lubrication and proper glass alignment will make them go faster. but like fiat wiper motors slow is fast!

[majicwrench]

I have no idea if fiat window regulators have them but......every other power window I have ever worked on has some sort of spring that load when the window goes down, and the spring assists the motor in then raising the window. It's how they compensate for the weight of the window. No such spring on a fiat??
And yes, I lube window mechanisms all the time, both power and manual.
Keith

[spidernut]

There's no counterweight spring on Fiats - probably because the window wouldn't roll down.

[ORFORD2004]

I add another ground to the switch. It solved my slow window on my 83.

[porkchopious]

My '74 Spider doesn't have power windows but I had the same issue with my '67 Ghibli recently. We totally dismantled the motors and repacked the motor transmission with new grease. We also replaced the pitted, burned motor bushings then tightened all cables and aligned and lubricated everything. What a difference! The windows don't go as fast as a modern car, but are acceptable.

As another poster said, make sure your ground is good and there is not unnecessary resistance in the power supply.

Good luck!

David