Not sure if my issue is related to Bowden cable or Tranny itself.

I have an 82S with a 4 speed auto.

My behavior is such:

When accelerating -- it has a tendency not to want to upshift, unless I slightly back off gas.
In this case it will usually shift reasonably smoothly.

If I'm pure accelerating -- and it decides to shift on its own -- you get
a kick in the pants -- literally -- almost feels like whirrrrr/ bam!.

Not sure if that is a bowden cable adjustment -- or more "serious".

Tranny has good clean fluids and filter. Similar behavior before and after.

thanks,

Mike

 

'Bowden Cable' adjustment is for the timing of the shift.
Pressure Modulator adjustment is for the force of the shift.
You want to get the 'Bowden' adjusted first, and then (if needed) do the Modulator adjustment as minimal as possible to get you where you want to be.
Be sure you have a good, clean ATF level first.

 

Thank you,

So the need to back of throttle to upshift is related to Bowden cable?

for the Modulator cable -- have a link to adjustment info?

< SEARCH IS YOUR FRIEND >

https://rennlist.com/forums/928-foru...-pressure.html

thanks,

Mike

 

Did you mean 'need to back off throttle to upshift is related to Bowden cable ?' ?
The 'Bowden Cable' is the control pressure control valve cable. It actuates this valve relative to the rpm which will be relative to your speed in a given gear for shifting. If trans healthy, and this is adjusted correctly, shifts should be barely perceptible.
See my prior post for the S4 adjusting. It is probably the same for your MY. If it isn't (which I doubt), someone will chime in.
There is no Modulator cable. If adjustment is needed for this it is done directly at the Pressure Modulator. There is a small 'T' key under the black cap of the Pressure Modulator. Turning this key will subdue the force of the shift. Clockwise for softer shifts. Do this only if needed after you have adjusted the timing of your shifts.

 

Yes back off throttle.

Sometimes its hard to know how the car should behave if you have no reference.

I'll add these two to the list of things that need adjustment. I've also been
working on the vacuum system - so it is quite possible a contributor as well (at least to the modulation issue)

It also doesn't help I bounce from issue to issue and P-car to P-car. Not a truly bad problem to have -- but a problem nonetheless.
My list never seems to end :-)

thanks,

Mike

 

Mike,
Vacuum is, as expected, crucial for auto trans shifting. On the S4 the transmission vacuum line is rubber to hardline to rubber from the manifold to the pressure modulator. I replaced mine with a quality single line from Pegasus Racing. #3 line fits well. Also, check you have good vacuum from manifold and check to see if your modulator holds vacuum. If diaphragm shot and it doesn't hold vacuum, you'll need a new one.
Best Wishes
Craig

https://www.pegasusautoracing.com/pr...p?Product=3260

 

Just sayin'...

 

Settle down there Cowboy.
The vacuum issue may be pertinent to you to at some point, but you knew that.
We all help each other 'round here whether you're old or new.
Posting here has been on point.

 

Just sayin'...

BTW, thanks for the suggestions. To clarify: by '82s, I meant '82's (possessive,) not '82 928s. Oops. Still, close enough; I have a better handle on what to do now. The car is a lot of fun to mess with, after all, and always brings a smile when I walk out to the shop to see it and tinker. As far as I'm concerned, the 928 has always been the sexiest Porsche. I look forward to getting her mechanically stable so I can look into some of the cosmetics. I know a great saddle maker who I'd like to talk to about doing some leather tooling on the seats to give it that Wyoming flare. Tranny first, though. Thanks!

 

Sure Wyo.
Are you having trans issues ? If so, what you got ?

 

Quite settled, couldn't pass on an opportunity to post a pic of Jack. I assume most 928 owners have a sense of humor, but apologize if offensive.

Tranny, I assume, right or wrong, is the/a problem. Just bought the car a few weeks ago. First Porsche. Have only driven a little: 12 miles or so home, up and down the road. Put it in Drive and the response when throttled is disappointing, even embarrassing. Though I first assumed ATF, from the posts I've read and PMs received, I'm looking more at cables. Moved airbox, jacked up back end, messed with them a little, asked questions on the forum, learned a lot so that I can mess with them more, have to work on other things for a few days.

Thanks, Maine.

 

Absolutely no offense taken.
I thought you were going to call me a stuffy old New Englander.
Have a Good Night Wyoming.

 

My cousins in Maine wouldn't like it if I called another Mainer stuffy. Actually, for good or ill, the folks I've met in Maine seem to be a lot like the folks in Wyoming.


So, took care of responsibilities so I could play with the 928 this afternoon.

Got my hands up above the tranny to the cable, to my pleasant surprise. The Bowden cable appears to be fully adjusted already, though. Yikes! So, I left the cable to accelerator pedal fully adjusted (had less than 1/4" to go) and started to put it all back together to test drive and check ATF. Didn't make it.

I'd broken a vaccuum line when I removed the airbox so I replaced it and then the 32 year old plastic on one leg of the thermo switch broke as I was trying to route the lines to get a little less of a rat's nest look.

Reminded myself that the 928 is a toy. It can sit.

So, luckily, this forum had a picture of that weird looking part because the parts catalog did not. Ordered one, mildly surprised at the price, especially the $14 shipping. Decided that photo was enough to make it worthwhile to actually become a paid member.

Two questions:
If ATF is not the problem with my spongy tranny and the cables are fully adjusted, do these cables get so stretched out that they need to be replaced? Is it reasonably possible to shorten them by cutting the Bowden and putting an adjuster under the hood? This'd be a lot handier than lifting the car to adjust at the tranny.

I have to admit to being a bit disappointed in the much-touted Porsche engineering with respect to the rat's nest of vacuum lines in the '82. I know it got much better later on but, to me, it looks as though there was no real effort to arrange the lines neatly. It all looks like a rushed effort to satisfy emissions regulations.

 

Wyo,
After I installed a 'literally' brand new transmission, I had to do the 'Bowden Cable' dance to get the shifts right. Yes, on an S4 it is easier but it is very necessary. When I first set the 'Bowden' after setting the throttle cable, and test drove it to to find it's final setting, I found I finally had to leave the 'Bowden Cable' a lot looser than I thought I would've. My shifting is stellar with the 'Bowden Cable' not as tight as I am surmising you consider to have to be. Go through post #15 and set the cables as such. After you get the first adjustment on the throttle cable settled, you may find the Bowden does not need to be taught. Then again you may find that it does. This will only be after you set the throttle cable, and give it some test runs.