Disconnected CSS to solve transmission problems, what are your thoughts?

[Artkez]

I have described the issues with the transmission on this car since the day we got it in previous posts (https://www.sl113.org/forums/index.php?topic=38463.msg281062#msg281062).

The basic issue is that while driving it would randomly engage into a transmission freakout mode where the shifting would occur very harshly and with a aggressive jolt to the car. The car was basically undriveable in this mode. We discovered that this mode was able to be reset by pulling over, turning off the engine, and turning it back on again. This would reset everything and the car would perform as usual. We figured out that this mode would get engaged any time the accelerator was depressed quickly to accelerate while in a high gear. It was essentially a kickdown mode that would allow the car to down-shift to gain acceleration, but then would get stuck in this downshifted mode and the shifting behavior would be altered at lower gears. When accelerating from stop, the car would shift late at a way higher rpm, shift hard, and jerk forward in an uncomfortable way from 1st to 2nd and from 2nd to 3rd.   

After much troubleshooting, we eventually figured out with the mechanic that the solution was to disengage this Constant Speed Solenoid. See photos attached. This completely disables the accelerator-based kickdown mode and allows the car to be driven normally without fear of accidentally engaging the freakout mode. Now a kickdown is still able to be achieved by engaging the button on the floor underneath the accelerator pedal, or by manually shifting the car from 4-3. This proves useful in situations where greater acceleration is needed such as merging onto the freeway or passing someone while in high gear. 

Just disconnecting one wire has made such a remarkable improvement in the driving ability of this car, we are beyond happy with its current performance. Before this it was basically undrivable due to fear that this crazy shifting mode would be engaged. On the freeway for example where you cant pull over this would be disastrous.  Driving very carefully it could be avoided but you couldn't get the acceleration when needed and felt unsafe on the freeway.

Obviously we feel weird about disconnecting something that is clearly meant to be connected but are very happy with the current results. This car has no air conditioning, and the temperature in southern California is generally constant. We dont drive on overly hot or cold days.

The question is, does this solution we've found have any adverse effects  on the engine we are unaware of? is this a proper solution? could it point us to a perhaps more official or accepted solution to keep this car driving how it is now.

[Artkez]

See photo from below

[Artkez]

view from the top

[rwmastel]

It sounds to me like something may be wired improperly.  Maybe someone with wiring diagram skills can help out?

And, are you able to edit your topic title to change CCS to CSS?

[Peter van Es]

And, are you able to edit your topic title to change CCS to CSS?

He can't but you, as a moderator, can. Move the entire topic to a new board temporarily, click the box: change the topic's subject and make the fix. Do not post a redirection post. Then move the topic back to the correct board and again, do not post a redirection topic.

[Pawel66]

It sounds to me like something may be wired improperly.  Maybe someone with wiring diagram skills can help out?

And, are you able to edit your topic title to change CCS to CSS?

Exactly. I think something in wiring is off. There is a very clear schematic in Technical Manual now of gear box wiring, I would go through that.

It sounds like power was delivered to the small screw on the gear box connector as gas pedal was pressed. CSS normally has nothing to do with it...

[rwmastel]

He can't but you, as a moderator, can.

Well, I was going to try, but somebody beat me to it. 

I thought if the OP modified post #1, it allowed them to modify the subject as well.

[ja17]

Most likely it is the improper adjustment of the engine linkages or idle speed solenoid. The solenoid is opening the venturi solenoid switch. When this happens the transmission modulator pressure is not lowered enough to permit smooth down shifts and correct upshifts. Doing the linkage tour is good place to start. You are incorrectly solving your hard shifting problems by lowering the rpms far enough to close the intake venturi switch.

[Artkez]

Thanks so much for your responses , we really appreciate it ,  I am  very hesitant do do anything in that the car and especially  the transmission is running so well  and smooth

I visited a Local MBZ transmission  shop in los angeles and he looked at it and thought that the double acting solenoid on top of the transmission was stuck  or frozen thus he disconnected it .  it created the same result as disconnecting the CSS .  Once   these items are disconnected  the transmission sifts very SMOOTH  upshifting as well as downshifting.  The kick down switch also works great, but i rarely used it.

 The only problem in disconnecting these items is that it does not down shift form 4th gear to 3rd gear when i need to pass another car on the freeway when my speed is 50miles per hour,  the car does  not respond to my depressing the accelerator pedal abruptly  to drop it from 4th to  3rd gear, it makes me try to pass this car in 4th gear.

 If i connect these wires the transmission goes into a crazy mode when i try to pass a car at 50 miles per hour requiring me to stop the car and turn off the power to reset it .  the transmission mechanic thought that i should leave it this way  disconnected as trying to adjust it would cause a lot of hard shifting issues  If i disconnect  these items the cars shifts very smoothly

Joe -
Question is it harmful to the transmission if  i leave it disconnected and drive this way ?  If i need to  downshift can i manually shift from 4 th gear to 3rd gear at 50 miles/hr ?

Thanks so much
 Arthur

[rwmastel]

Arthur,

I think you'll find that near everyone on these forums will recommend you get the car components and systems working as designed.

I know you are hesitant to work on things yourself, but the linkage tour guides you through making physical adjustments to the lengths of all the linkage rods.  Very little risk regarding breaking anything.  Sometimes these linkages get adjusted to compensate for some other component being worn out or poorly adjusted, so going back to factory linkage specs can expose these problems and make the car run worse.  If that starts happening, just undo the last adjustment to get the car running better.

You're in Los Angeles and you're a full member with access to the membership roster.  Find other members in LA and plan a weekend get together.  Lift the hoods and teach each other about your Pagodas.  If nobody can host at their house, maybe meet in a parking lot of a restaurant where you can eat and feel your cars are safe. 

[ja17]

The electrical switch on the intake venturi regulates the transmission modulator pressure. If it is not set correctly, you can have the kind of issues you describe. It cannot operate correctly unless the engine linkages and the electrical idle solenoid is set correctly. When these are correct the two screws on the switch can be loosened so the switch can be rotated to adjusted correctly. All this information is covered in the "linkage tour".  The switch is part of the electrical system which operates the solenoid on the transmission. The solenoid on the transmission is one of the systems which regulate the transmission modulator pressure. Occasionally the switch can go bad also. I would start off by testing the switch. Disconnect the two wires going to it. The switch should be "on" (no resistance) engine on, at idle in gear. Next with engine off and ignition on and accelerator partially down,  the switch should be "open" (not able to pass current). If the switch test "bad" it can be removed and opened. Clean the two contacts inside, test and re-install. The slotted mounting holes can be used to set the switch to the correct engine rpms (linkage tour). If your transmission solenoid or linkage is stuck, it can usually be freed without removing the transmission. Check the switch and linkages first. As long as your transmission is not slipping when you start off, you should not do any harm having that electrical circuit disconnected.

[Lorsar]

After much troubleshooting, we eventually figured out with the mechanic that the solution was to disengage this Constant Speed Solenoid. See photos attached. This completely disables the accelerator-based kickdown mode and allows the car to be driven normally without fear of accidentally engaging the freakout mode.

What other things did you and the mechanic do aside from disconnecting the constant speed solenoid? My guess is one of those other things resolved (even if temporarily) the problem.  The constant speed solenoid has nothing to do with the kickdown mode or any transmission shifting.  The constant speed solenoid only pushes on the linkage a small amount when moving the shifter into reverse or drive.  What is the rpm on your car when idle and warmed up?  It should be around 750.  Now that the CSS is disconnected, what happens to the rpms when you move from park to reverse or from neutral to 4?

[ja17]

The Constant Speed Solenoid can affect the shifting if it moves the linkage far enough to open the venturi switch. Hence the problem goes away when it is disabled!

[Artkez]

Joe
Thanks so much for the very informative response.  My CSS switch was not even working , it does not press or punch anything, i think the rod that goes in and out is stuck and not effective  it touches nothing.  The wire that is disconnected has power and when disconnected  inactivates this circuit . See picture #4  No power is going to this circuit . 

When this circuit is disconnected  the transmission is very smooth, no thumping, no hard shifting, you can not even hear or feel it shifting  it is very smooth and like my Lexus ha ha.
The only problem is that is does not shift from 4th gear to 3rd gear when i am going 50 mph and i want  to pass a car , if i press the accelerator pedal 1/2 way down it will not automatically downshift to 3rd gear.  The kickdown switch works very well but it is too aggressive and i rarely will use it

How does a well tuned Pagoda work   will it shift to 3rd gear  from 4th gear if the pedal is depressed abruptly ?

Thanks so much
Arthur

 

[rwmastel]

How does a well tuned Pagoda work   will it shift to 3rd gear  from 4th gear if the pedal is depressed abruptly ?

If the car doesn't downshift as you expect, and you don't like to activate the kick down switch, then just shift manually from 4 to 3.

[ja17]

Arthur, looks like you may have several problems. Your engine linkage may not be adjusted correctly, so the switch on the intake venturi (near air cleaner) is not working or not adjusted correctly. Your CSS is inoperable. The transmission linkage/solenoid might be stuck. Disconnecting parts of the electrical are just compensating from the problem. Do you know how to adjust the engine linkages?

[Artkez]

If the car doesn't downshift as you expect, and you don't like to activate the kick down switch, then just shift manually from 4 to 3.

hi Rodd    that is a great idea, i did this a few times yesterday and it worked great !!!   Thanks

Arthur

[Artkez]

Arthur, looks like you may have several problems. Your engine linkage may not be adjusted correctly, so the switch on the intake venturi (near air cleaner) is not working or not adjusted correctly. Your CSS is inoperable. The transmission linkage/solenoid might be stuck. Disconnecting parts of the electrical are just compensating from the problem. Do you know how to adjust the engine linkages?

Hi Joe  you are absolutely correct, i was with a group of Pagoda enthusiast  in San Diego yesterday and realized that there were many discrepancies between my car and the ideal , specification adjusted pagoda engines.  Someone during the history of my car has adjusted my car  to be in running order rather than following the specifications and manuals.  I am very happy  finally being able to drive the car and have the engine and the trans work beautifully.  The exterior and looks of the car are also top notch  so we are smiling and happy.

 I think my goal in the next couple of months is to find a mechanic or enthusiast in los angeles  to help with the Linkage tour and  gear box analysis.  that should be fun  !

Thanks for all the feedback, we'll keep you posted

Arthur and Steven

[rwmastel]

Hi Joe  you are absolutely correct, i was with a group of Pagoda enthusiast  in San Diego yesterday and realized that there were many discrepancies between my car and the ideal , specification adjusted pagoda engines.

This is the best!!