some questions about cvt

[kaarel]

Hi

First question is about kickdown.I think it sometimes staies on.Accelerating hard revs go up 3500 and when I let go gas pedal rev stay on 3000 rpm.To get revs down, must accelerate again and then revs come down.sometimes need to do accelerating cycle few times.Weird is that it happens only once a day and only when getting revs up to 3500.

Do I have to regulate clutch gap?if car starts to move at 1400 rpm.

Cheers
Kaarel

[macplaxton]

I would have thought that the car should start engaging the clutch at 1050rpm - 1150rpm, with full engagement at 2350-2550rpm (from Green book data on forum).

If it is engaging at 1400rpm, then the clutch gap is too big and the clutch needs re-shimming to the correct clearance. Maximum gap is 0.5mm for checking. When adjusting, set to 0.1mm - 0.3mm.

The kickdown is operated by the cable earthing out and activating one side of the vacuum valve. This earth connector is near the bulkhead. It may be that the vacuum valve is sticking? Does the low ration hold switch work? The revs should rise slightly when it is on, as it should also do when the brake pedal is depressed. The brake master cylinder has a 20 bar switch which activates the vacuum valve, so that engine braking occurs when slowing down.

[kaarel]

Forgot to check if low ration works....will do that tomorrow.
Pressing brake pedal didn´t rise revs.eco gague rised insted.
When I move gear stick, and press that button down(which is on the gear stick) then revs little bit rise.

[macplaxton]

When I move gear stick, and press that button down(which is on the gear stick) then revs little bit rise.

It should do something like that, as when the button is pressed down, the clutch dis-engagement servo is operated. This delays the engagement of the clutch until the revs are near 2000rpm. It allows changes of selector position without crunching.

[volvodspec]

it shouldn't,

if you let the engine run idle and either press that button in D, use lowratio switch or apply the brakes, the engine isn't allowed to rev higher or lower. it indicates that the mixture settings are off because off the used vacuum, if you're mixture is set correct and you do any of the above, the engine might give a tiny shake if you look at it; but inside you don't feel a thing

that the revs rise indicate the mixture setting is too rich.

as for the weird kickdown-sticking problem, i'd inspect the tachometric relais first; look closely for cracks in the 3 larger solder puddles and re-solder them if so.

[macplaxton]

Must be around DAFs too long

I err on the rich side of things as I don't have to worry too much about emissions. I suppose you can lean off the mixture a bit, but if it stalls doing any of the above, then it's too lean.