Automatic Downshift Cable Disconnect

[rh77]

After poking around under the hood looking at the emissions system, I came across the transmission kick-down cable (which I thought was electronically controlled intead of hooked to the throttle body).

The mod: remove the cable attachment to the throttle body.

If I'm willing to "whip it into shape" via the gear selector when things get urgent, are there any downsides?

Recently quoted by someone: "An engine is most efficient at 2/3 throttle at high load between 2000-3000 RPM." I've found that's is hard and sometimes impossible with that darn kickdown.

A concern: Wondering if the TC is involved in the cable position, or if it's based on load.

Is it worth giving a try?

RH77

Edited: Forgot to mention the mod, duh and grammar

[DaX]

Is this on the Integra or TSX? What is a TC?

I think you'll be fine removing the kick-down cable.

[MetroMPG]

I'd try it if it were mine.

One concern - are you the only one who drives this car? Is there a potential safety concern if someone else drives it and it doesn't kick down when expected/needed?

[SVOboy]

I had mine off for many months, it didnt change anything for me because it shifted at the lowest point already from my driving, so yeah. I'd take it off the throttle body and try it out for a bit, it only takes a few seconds.

[rh77]

I had mine off for many months, it didnt change anything for me because it shifted at the lowest point already from my driving, so yeah. I'd take it off the throttle body and try it out for a bit, it only takes a few seconds.

Hey he returns! Ben, I may try it today if it's easy to D/C.

Dax: It's on the 'Teg -- The TSX is throttle by wire, so it's all 'lectro

Metro: I'm the only driver 99% of the time - but a warning will be given or re-connect it quickly (if possible).

RH77
Heading out to the Garage

EDIT: Dax, the TC is the Torque Converter

[rh77]

Well, that certainly sucked. :thumbdown:

The cable evidently has more to do with the transmission than just a request to downshift.

Basically it acted like someone learning to drive a stick-shift: turn a corner and give it some throttle (or get on the highway), it downshifts but engine revs to redline and it's like someone is slowly letting the clutch out while going into gear -- accompanied by that burnt clutch smell. :mad:

Also, the TC didn't seem to engage fully at highway speeds. To prevent any further wear, I got off of the highway and hooked it back up. The TCU must intervene with with the "TPS reports".

So now, what would happen if it's extended the whole way? I hypothesize that the transmission would be quicker to kick-down and shift harder thinking that it's in open-loop -- or maybe not at all.

RH77

[LxMike]

the kickdown cable might also control the line pressure in the tranny. I know on the 5.0 mustang if you tried to disconnect it the tranny would think you was at w.o.t and wouldn't shift till 5,000 rpm's.

[rh77]

It's probably not like the "kickdown" cables of old.

On old GM TH350s and such the kickdown cable had one function and one function only: downshift at WOT.

Tempo a/ts have what is known as a throttle valve control linkage and I know for a fact the thing is darn sensitive to proper adjustment. It activates internal valving in the trans which regulates the transaxle's control pressure, which in turn affects the shifting characteristics.

Nice post Clench. You also updated the garage with the Lambo!

My '77 Olds had the Turbo-Hydromatic 400 that kicked-down at like 50-75% throttle via linkage. I was always fooling with than darn Quadra"junk" carb to get it to stay running on cold starts -- the Winter sucked -- sometimes it would take 5-10 minutes of careful idling and throttle input or else it would stall when put in gear. When the weather changed, so did the set screws. Some weekends, I'd fool with it for hours -- good learning experience. Otherwise, great first car. Rollin' couch.

RH77

[TurboMinivan]

The mod: remove the cable attachment to the throttle body.

As another choice, you could check to see if anybody makes a manual valve body for your transmission. While this would eliminate any automatic gear selection ability, it would certainly ensure the thing stays in whatever gear you want it to. Just a thought.

I've got a reverse-pattern MVB in my minivan and I love it.

[rh77]

As another choice, you could check to see if anybody makes a manual valve body for your transmission. While this would eliminate any automatic gear selection ability, it would certainly ensure the thing stays in whatever gear you want it to. Just a thought.

I've got a reverse-pattern MVB in my minivan and I love it.

I haven't heard of that, but it makes sense. The gear selector is pre-programmed to hold 1st and 2nd gears, regardless of speed or RPM -- but "D3" and D4" puts the whole works in the hands of the Tranmission Control Unit computer. I can generally hold the gear if I don't go above 42% throttle, otherwise it's kickdown-city. What's also frustrating is that is has "hill logic control" where it won't upshift while going up an incline unless the revs are 3K or higher.

So TurboMinivan -- you race your van? I used to have an '88 Voyager with the Mitsu 3.0L V-6, but always wanted the turbo.

Also, Welcome! If you like, post in the "Introduce Yourself" forum about your Minivan Racing Ambassadorship :)

RH77

[Spule 4]

Well, you saw not to do that, if you have ever had the kickdown break in the car you would have known this, had one come off and I feared transmission failure. Exactly the same as you described (Asin-Warner in a Volvo).

My favorite were the Mercedes with the electronic kick down button on the floor, no such problem.

I see your pic, Citroen C4 owner I assume? There are rumblings of PSA returning to the US, so maybe us here in the states will get a shot at one, or as a former Citroen owner, I can hope?

[rh77]

I see your pic, Citroen C4 owner I assume? There are rumblings of PSA returning to the US, so maybe us here in the states will get a shot at one, or as a former Citroen owner, I can hope?

Unfortunately, no -- not a C4 owner. If you click on the "Car I dream about" in the sig, you'll see the avatar: the C4 Hybride HDi (Diesel-Electric Hybrid). Only if...

There are so many European vehicles that could be modified to our emissions and safety levels, and perform as great economy or sub-compact cars.

RH77

[Spule 4]

Unfortunately, no -- not a C4 owner. If you click on the "Car I dream about" in the sig, you'll see the avatar: the C4 Hybride HDi (Diesel-Electric Hybrid). Only if...

There are so many European vehicles that could be modified to our emissions and safety levels, and perform as great economy or sub-compact cars.

RH77

Ah, I assumed for some reason you were from the UK.

Not sure if PSA will do much with Hybrids, time will tell tho. The newest Citroen I have had the honor to drive was one of the last CX cars (Automatique), it would be neat to see what other improvements have been made over time between this and my GS I had years ago.

[TurboMinivan]

I haven't heard of that, but it makes sense.

Again, it will depends if one is available for your application. If your trans is at least based on one which is supported in the race community, you may be in luck.

So TurboMinivan -- you race your van?

Yes, I do--it's been a hobby of mine for over six years now. I didn't really want to go into it and hijack this thread, so I was just sticking to the topic at hand. Perhaps I'll take your suggestion and post in the newbie forum.

[Toysrme]

You MUST NOT disconnect, or set a throttle valve (Kick-down) cable too loose. They govern the pressure supplied to the valve body that changes & holds gear ratios by engauging the clutch packs, and brakes inside the transmission.
Low fluid pressure will cause slipping and eventually distruction.
The faster, and harder an automatic transmission shifts, the longer it will last from less friction across the clutch & brake surfaces, and less temperature introducted into the fluid during the process when the transmission is allowed to slip (and/or) grab mroe than one gear at a time.
Most modern automatic tramissions with a soft take-off will engauge both first & second gears at the same time.






If you want to play, wire a switch based transmission gear controller, and a switch based torque convertor lock-up to control your transmissions solenoids.
Just be aware to introduce a by-pass for going back to stock ECU control. DO NOT leave the clutch engauged at lower gears, or when accellerating. And realize that you will get some amount of shift shock as all modern ECU's pull timing when they want to change gears to reduce shift shock. That means you not only won't get that advantage, you'll also get a minor power reduction any time the stock ECU feels that it is time for a gear change.