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Old 04-07-2017, 09:03 PM   #1
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Car: 1985 Pontiac Firebird Trans Am
Engine: 305 LG4
Transmission: 700R4 Automagic
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TV Cable woes

I'm at my wit's end trying to figure out my car's TV cable issues. Basically, since I've had it, I have to have the adjustment tab pushed all the way towards the firewall in order to get hard, strong shifts. This usually isn't a problem, but if I depress the pedal a little too hard it will auto adjust (like it's supposed to do, apparently) and the adjuster clicks out just very slightly but then my shifts are completely wrong...very soft and early and it doesn't downshift.

So in order to try to finally get this fixed, I purchased a new TV cable from Orielly's (Pioneer CA1970, the same one listed in rockauto for my car). Getting the new one in was an entire ordeal because the fit with the rubber grommet into the transmission housing was ridiculously tight. I finally got it in, however, but it seems like the cable is entirely too short! With the adjuster tab pushed all the way in, it can just barely fit onto my carb's linkage, and when I depress my pedal it adjusts nearly all the way out! I decided to drop the pan and take a look at the plunger and lever.

With the TV cable adjuster ratcheted out after flooring the pedal, when rotated back to idle the metal lever isn't even touching the plunger! I know this is incorrect according to TVmadeEZ.com, since when properly adjusted at idle the lever should be slightly pressing the plunger into its bushing. When I push the adjuster tab all the way back in and look at the lever, it's depressed the plunger way into the bushing further than it should be! I assume my old cable was doing this same thing albeit to a much lesser degree, but still incorrect.

I assume this all means that somehow the cable that is supposed to work with my car is too short?? I'm honestly at a loss as to what to do now or what cable I actually need for my car. As far as I'm aware the transmission and everything else is stock for a 1985 LG4, at least it looks like it anyway.

Any input would be greatly appreciated!
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Old 04-08-2017, 12:19 PM   #2
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Re: TV Cable woes

1. Can you compare the length of the old cable and compare it to the new one? You might be wasting your time trying to get the new cable to work (might a bit late for that...)

2. Do you have the new cable routed the same way as the old cable?

3. If you have to run the cable out of adjustment (all the way to the firewall) to get the transmission to shift properly, there's something else seriously wrong.

4. You "think" all is stock. This probably doesn't matter, but are you still running the Quadrajet or is there a Holley or Carter (Edelbrock) carburetor in place?

I seem to recall that someone did a cable length comparison between a bunch of TV cables from different applications; TPI, TBI, Carb, V8, V6, etc. If you can find this post, it may be helpful.

Edit: Here's the post:

https://www.thirdgen.org/forums/tran...wn-detent.html (TV Cable Kickdown Detent --> Just the facts please)
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Old 04-08-2017, 03:24 PM   #3
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Re: TV Cable woes

You don't adjust the cable tighter to get hard strong shifts. You install a shift kit. The TV cable is self adjusting and there really isn't anything that can go wrong outside of it breaking or binding. My factory cable from 1986 is still in fine condition.

If it won't downshift with the cable adjusted properly then there's an issue possibly with the throttle valve plunger either sticking of leaking... Sonnax makes a kit for this:

http://www.sonnax.com/parts/2512-thr...nger-valve-kit

If the trans is shifting slow and mushy then it's probably starting to slip inside and needs a rebuild. Was this trans built for hard, fast shifts? The stock transmission is not really designed to handle that. It's designed, like any stock transmission, to shift positive but not jerk your head off. If you want that you need a shift kit at minimum.

Rick

Last edited by GeneralDisorder; 04-08-2017 at 03:34 PM.
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Old 04-10-2017, 07:44 AM   #4
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Car: 1985 Pontiac Firebird Trans Am
Engine: 305 LG4
Transmission: 700R4 Automagic
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Re: TV Cable woes

So I just decided to ditch the new cable and use my old one. I made sure to clean it up good and make sure it wasn't binding or kinked. And yes, I have the original quadrajet and bracket that attaches to a stock GM manifold.

After having someone operate the throttle while I was watching the valve in action, it almost seemed like the aftermarket TV cable was ratcheting out too easily. When the pedal was depressed, it did make the lever go flush with the valve bushing, but after releasing the pedal back to idle and depressing again, it would never make the lever go flush with the bushing again, thus not pushing the valve in far enough. Almost like the spring was too stiff for the cable housing to pull without ratcheting.

I did compare the lengths best I could and they seemed almost identical, but the locking mechanism on my stock cable was definitely stronger. This leads me back to my initial problem...in order to fully open my throttle plates my stock cable does have to ratchet out ever so slightly, but in the past it caused my shifts to be soft and stacked (way too little line pressure apparently), so I had to have the adjuster all the way into the cable housing to get good shifts and just make sure never to press the pedal to the floorboard really hard.

Now, I did notice before I dropped my transmission pan that the fluid seemed to be over-filled. What kind of effects could that have on shifting? I haven't been able to drive it again yet, but I'll find out if anything has changed as soon as I do.
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Old 04-10-2017, 09:41 AM   #5
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Re: TV Cable woes

Did you even read the link I posted for you? The throttle valve is probably sticking. It's spring operated so having your cable artificially tight by not letting it adjust properly is putting more spring pressure at an earlier throttle opening than it is supposed to need. You need to inspect it at the least and probably just have the $50 throttle valve kit on hand.

Rick
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Old 04-10-2017, 08:03 PM   #6
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Car: 1985 Pontiac Firebird Trans Am
Engine: 305 LG4
Transmission: 700R4 Automagic
Axle/Gears: No clue

Re: TV Cable woes

Quote:
Originally Posted by GeneralDisorder View Post
Did you even read the link I posted for you? The throttle valve is probably sticking. It's spring operated so having your cable artificially tight by not letting it adjust properly is putting more spring pressure at an earlier throttle opening than it is supposed to need. You need to inspect it at the least and probably just have the $50 throttle valve kit on hand.

Rick
Yes I saw the link...but the valve isn't sticking at all. It moves in and out freely and the spring has good tension. I did want to take the sleeve and plunger out to inspect it but the little pin holding it in was stuck in there pretty good and I didn't want to risk breaking it off.
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Old 04-10-2017, 09:23 PM   #7
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Re: TV Cable woes

You can't pass judgment based on the plunger and sleeve alone. That is not the actual valve. The plunger actuates the valve via spring pressure and it is not a linear relationship. If the actual throttle valve (which you can neither see nor inspect without removal of the plunger/sleeve/spring) is sticking you will not know it by watching the plunger and sleeve.

The plunger spring may be too short as well. Go to part three of the following article and read about short spring syndrome (SSS). A TV kit would likely correct this as it would include the spring, etc. Sonnax makes nicest parts I've used. Get one of theirs.

Read this:

http://www.tvmadeez.com/article/

Rick

Last edited by GeneralDisorder; 04-10-2017 at 10:04 PM.
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Old 04-20-2017, 08:39 PM   #8
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Car: 1985 Pontiac Firebird Trans Am
Engine: 305 LG4
Transmission: 700R4 Automagic
Axle/Gears: No clue

Re: TV Cable woes

Just thought I'd give an update:

So after finally getting my car ready to run, I put in the original TV cable, and set it by letting it ratchet out by pressing the pedal to WOT. The AT fluid I used was Castrol Transmax High Mileage, and I also added a pint of Seafoam Trans Tune for good measure. After properly warming the transmission up and shifting through the gears, I actually ended up having to use 2 gallons of fluid to get it into the proper area on the hot dipstick! So now it actually shifts like its supposed to! The shifts aren't as jerky as they were before at wot, but they are firm and shift properly at around 5k-ish rpm, and they are actually smooth at low throttle! It also downshifts properly as well. So I don't know if the fluid and filter change had anything to do with it, or if the trans tune loosened something, but at least it works now!
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