Variomatic - low gear hold switch

Post by **Vario Si** » 04 Aug 2005 04:13 pm

Didn't seem to be much suction if any... with or without switch on...

I'll try and sort the hose at the weekend and see what the situation is like after that.

Post by **Duvel78** » 05 Aug 2005 08:59 pm

Ohhh that's the topic I needed, perfect

And I see that Wouter and Will are there

Ok here is my case.

I've tried to help people with a 340 variomatic in Belgium (nice car!), only 90.000 km. The engine didn't run great in N and it was impossible to go from D to R or from R to D without cutting of the engine (horrible noise if we tried..) I've checked and adjusted the carb, that problem is solved, the engine runs very well in N now and it's easy to go from D to R.

BUT, there's another problem: driving the car is like driving with the low gear switch always on!!! The revs are continuously very high, the engine is of course very noisy all the time, uncomfortable to drive, I feel that brake on the engine and it's bad for the engine... But the owner didn't know it because the car has just been bought and he didn't know the "normal" behavior of a 340 variomatic (and I understand it!) But I know there is something wrong on the car... (I didn't mention the fantastic fuel consumption

)

More precision about the problem:

- no revs difference (N or driving) when the low gear switch is on or not. The bulb inside the switch is good but it never illuminates the switch!

- When I put the car in D and press at the same time on the button of the gear selector, when I try to accelerate, the car doesn't shake at all and it accelerates totally normally!! >> not normal! (if it was working good, it would be the same effect as selecting a wrong gear on a 340 with manual gearbox)

Does that mean that the depression system doesn't work (my point of view!) or am I wrong?

Wouter, I've read your explanation, do I have to check the EMVK on the same way that you have explained for our member VarioSi? (hoses to the variomatic and so on)

I've a picture (PIC1) of the EMVK and I must say that I was surprised to see a hose going nowhere!

I was also thinking that it could be the "depression" valve (right word?) on the second picture (PIC2), on the other side of the enginebay; I have removed on of the 2 wires (neutral position) and putted it back, I heared the "CLICK" that I was expecting if it was working...

I hope that someone can help me! Any ideas? Thanks!

PIC1:

Where goes that hose?? Nowhere?

PIC2:

Website · Post by **antiekeradio** » 05 Aug 2005 11:35 pm

- no revs difference (N or driving) when the low gear switch is on or not. The bulb inside the switch is good but it never illuminates the switch!

OK.. this leads me to think the following; (educated guess)

the tacho relay sends current to the EMVK's 'downshift' side if;
- full throttle - kickdown
- hard braking
- low gear hold switch ON

if the bulb in the low gear hold on switch doesn't light, that means one of the other functions is already active.

conclusion;

either the High pressure brake switch, or the throttle cable switch (most likely!) have a bad contact.

the 3 switches are wired in series. if one is open the entire circuit is open -> low gear high revs.

the throttle cable switch (kickdown switch) is located above the accelerator pedal. if you floor it, the switch is pulled down.
sometimes the contacts get a bit corroded. a cleaning/WD40 action may be all that is required.

- When I put the car in D and press at the same time on the button of the gear selector, when I try to accelerate, the car doesn't shake at all and it accelerates totally normally!! >> not normal! (if it was working good, it would be the same effect as selecting a wrong gear on a 340 with manual gearbox)

this is a entirely different issue from the high revs.

it's about the clutch limiter (valve is on 2nd image)

most common problem with that system is the wire connection at the bottom of the gear lever. it flexes when you move the lever, and after years it breaks near a soldering joint.

good luck!

Post by **Duvel78** » 06 Aug 2005 12:50 pm

Thanks for your reaction concerning that problem!

antiekeradio wrote:either the High pressure brake switch, or the throttle cable switch (most likely!) have a bad contact.

the 3 switches are wired in series. if one is open the entire circuit is open -> low gear high revs.

the throttle cable switch (kickdown switch) is located above the accelerator pedal. if you floor it, the switch is pulled down.
sometimes the contacts get a bit corroded. a cleaning/WD40 action may be all that is required.

Oh! I know that the throttle cable has been replaced by someone (not a Volvo specialist, and I didn't recognize the genuine mechanism in the motorbay); maybe there's something wrong there, I should check all the contacts near the accelerator pedal!

Where is the high pressure brake switch?

antiekeradio wrote:most common problem with that system is the wire connection at the bottom of the gear lever. it flexes when you move the lever, and after years it breaks near a soldering joint.

Ok, I'll check that too...

Thanks for this good explanation! I really want to rescue that Volvo 340 vario...

Website · Post by **antiekeradio** » 06 Aug 2005 02:06 pm

Oh! I know that the throttle cable has been replaced by someone (not a Volvo specialist,

OK that makes the diagnose 99% certain

there is only 1 wire going to the kickdown switch. If you cannot find a volvo CVT throttle cable, connect it to mass.
this will kill the kickdown fuction, but most of the time elder people never use that anyway

about the high pressure brake switch, it's on the master cilinder

Greetings Wouter

Post by **wjp01908** » 07 Aug 2005 08:57 am

Hi Duvel

That pipe fits on to a nipple on the base of the air filter.

Might be unconnected but the 4 way valve on your pic is wired differently to mine (incorrectly?). Mine has the yellow/green and brown wires reversed.

Will

Post by **Vario Si** » 07 Aug 2005 11:54 am

Started the car from cold this morning, and had it running with choke, in Neutral, I pressed the low gear hold switch - and the revs rised a noticeable amount, and fell when I turned it off...

After driving for a few minutes to the petrol station and it was warm, I tried this again in neutral (with and without choke) and it didn't seem to have an affect

That to me is pretty confusing

Simon

Post by **wjp01908** » 07 Aug 2005 11:56 am

Hi again Duvel

Just had a bit of a check with my multimeter and that green/yellow wire goes 12v when the low hold is on. Is it possible that reversed connections are telling the transmission to change down the whole time?

Try switching them and see if this sorts it. It`s maybe a long shot but it may be the problem.

Regards

Will

Post by **wjp01908** » 07 Aug 2005 11:59 am

Mine does that too Si as I`ve just found out while checking wiring for the above post. Weird.....

Sure it`s OK!

Will

Post by **Duvel78** » 07 Aug 2005 12:32 pm

antiekeradio wrote:OK that makes the diagnose 99% certain

there is only 1 wire going to the kickdown switch. If you cannot find a volvo CVT throttle cable, connect it to mass.

OK, I know what I have to do now... Thanks!
Shame that the car isn't here (80 km far away) because I would like to test it immediatly. I'll maybe ask to the owner to take some pictures under the dashboard...

wjp01908 wrote:the 4 way valve on your pic is wired differently to mine (incorrectly?). Mine has the yellow/green and brown wires reversed.

This is strange, I've find another pic with another 340 vario and the wiring is the same as the one on the car with the problem. I'll check on my own 340 variomatic too. Vario_si, how is it wired on your car?

Vario Si wrote: After driving for a few minutes to the petrol station and it was warm, I tried this again in neutral (with and without choke) and it didn't seem to have an affect

This is a good sign! When the engine is warm, if you can't hear a revs difference when the switch is on, just a little change when you turn it on, it means that the carb mixture is good. Higher revs when switch on = mixture too rich / Lower revs when switch on = mixture too poor. Will and Wouter can correct me if I'm wrong!

Website · Post by **antiekeradio** » 07 Aug 2005 08:40 pm

right you are.

difference will mostly be audible, only with bonnet open..

Post by **Duvel78** » 31 Oct 2005 01:19 pm

Throttle cable changed with a good one (with the kick down mechanism), wire connected to it and...... there is NO difference!!

And the bulb in the low gear switch still doesn't work!!

I go crazy...

Website · Post by **antiekeradio** » 31 Oct 2005 04:09 pm

aymat,

sounds like you're having a hard time solving this puzzle. you may call me(use skype; i'm 'antiekeradio') perhaps we will find the answer much faster than by typing everything out here.

Gr. Wouter

Post by **Duvel78** » 03 Nov 2005 09:44 am

Hello Wouter!

Thanks again for your phone call when V3M was down...

On Skype, that's an idea... when I will install that program lol!

If only I could find a solution for that variomatic problem before the end of the year...

Post by **Vario Si** » 29 Dec 2005 09:20 pm

... I finally got round to looking at the car, covers off the transmission... On Boxing Day!

(Whilst there the belts looked okay and the surfaces looked fine)

I saw... an unconnected pipe from the primary side - I connected it, and there is now no longer the air leak when you blow down the right-side pipe of the two parallel pipes leaving the 'thing' under the bonnet.

Starting the car, it did not take as long to start, which was interesting.

These seems to soe improvement in the acceleration with the switch on, but no noticeable difference when the switch is operated whilst driving. Revs are the same on/off.

I guess the pipe which was not connected was the one which gets a vacuum when on low gear hold... I tried running and revving the engine in Neutral a little to see if this pipe sucked, but nothing.

As I said it pulls a little better I think up to 50mph with the switch on, but thats just speculation.

Can someone clarify if that pipe should be sucking when low gear hold on, or maybe this doesnt occur in Neutral?

Hmmmm!

Si