volvo 340 GL cvt high revving (HELP)

[macplaxton]

allright, i'll start with it then

Don't forget the metric to Imperial conversions too (but leave the metric in brackets for Irish viewers )

Mac's guide is excellent too, but you can never have enough CVT guides.

[volvodspec]

do you refer to this one?
http://www.volvo300mania.com/forum-uk/v ... =39&t=3803

our method from V3C is easier i've also integrated the tachometric-repair page into the diagnostics page. so on 8 pages (incl pics) all fault-finding info complete
together with a quick guide for adjusting/checking belts and cvt clutch+disengage servo system and that's all you need
info as in mac's article is allways interesting if you want to find out how the systems works, but seperating "how it works" and "how to fix it" works much better

[macplaxton]

Yep, I think that's link (not looking with the moby).

As I said two are better than one. More, more, MOAR!

[lewy]

Checked vaccum pipes today all seem to be good with a vacc gauge fitted to one end , but what i did find is that with the low gear hold switch on and the small and big pipe removed (primary gearbox side) the downshift side sucks very strong but the upside (the one with the diod) has probbaly half the suck IE: big pipe side 20bar the small pipe side 10bar.
any ideas on this?
took pipe from 4way valve to the manifold checked the vacc pressure from the manifold thats very strong like the big pipe side.
in the green book it says that the kpa should be about the same.
is there another part in the vavle thats got stuck?
Lewy

[volvodspec]

nope, that's ment to be; i wrote a little bit about that yesterday, i'll see if i can look it up again and post it here

[volvodspec]

The connections A and B are different, connection B the kickdown vacuum is unrestricted this is because for kickdown you want a quick response of the gearbox to select a lower gear so you can overtake.
Connection A the “gear up” vacuum is different. In the factory the EMV’s got a restriction on the A side to allow around 400mBar through, this is to make sure the car doesn’t want to go from 1st to 5th gear instantly when taking off and allows a efficient and smooth gearchange (1st, 2nd, 3rd, 4th, 5th) when driving, as far as this automatic wonder is comparable to a manual car offcourse!

If you take a look at the EMV the 2 sides have different wire colors, at side where hose A is connected, there’s a grey and a green wire. Where hose B is connected, there is a brown and a yellow/green wire.

To check side A, run the engine in N, press your finger gently to the connection on the EMV; now raise the rpm’s to above 1800, this connection should now suck noticeably by your finger.
To check side B, run the engine in N and let it idle, switch on the low gear hold switch inside near the gear lever and you should hear it suck noticeably.

[lewy]

yep ran the engine in N and the sucking is as you say, 1800 rpm the small side sucks on the finger slightly, and run engine on tick over with the hold switch on and the big side sucks stronger.
ok so the engine still revs to high 2500rpm @30mph.
what next?
lewy.

[lewy]

Does the main Vacuum Pipe connect to the Base Plate of the Carburator as in the manual and the engine Rocker Box Cover? I can see that there would be vac pressure from the carb, but isn,t the Rocker Box Cover inlet for a Breather Pipe, or is this pipe supposed to go back to the four way valve also as it does on this car?
Lewy

[morgan105]

Pipe from 4 way valve connects to a t-piece connector, then a tube goes from that to the base plate of the carb for vacuum, and the left over connection on the t-piece has a pipe connected from it to the connection on the rocker cover. This pipe has the 1mm restrictor in it.

[lewy]

Thanks thats good all seems in order.
How about the pipes to the clutch servo valve they seem to be diferent to the green book. one goes from the top of the 4 valve to the cluth valve, the a pipe goes from the cluth valve to the clutch servo, is that correct
lewy
nearly up and running

[morgan105]

The pipe that supplies the servo is connected to the same main vacuum pipe coming from the 4 way that goes to the base of the carb via a bigger t-piece connector. There are 2 t-piece connections in the pipe, 1 large and 1 small. What you will have is a larger diameter pipe from the 4 way valve (shortish piece) connected to a big t-piece, from this you get 2 vac pipes, one goes to clutch servo and other pipe goes towards carb base. The one that goes to carb base has the 2nd smaller t-piece connector which you will then have 2 more pipes. 1 small pipe goes to carb base and other with 1mm restrictor goes to connection on top of rocker cover.

[lewy]

oh ok! mines like that from the 4 way valve to the carb and rocker also to the clutch valve, but what pipe goes to the cluth servo? does it come from the clutch valve?
lewy.

[morgan105]

Yes a second pipe will come from the clutch disengagement servo switch to the clutch valve diaphram (vacuum release servo) that is connected on the clutch bellhousing.

[lewy]

ok that is the same as mine.
so all the pipes seem to be ok and not leaking. so i suppose its back to checking the electrics at the tach relay connector.
lewy.

[morgan105]

Have you checked the clutch plate gap? If this is to far away from the drive plate the revs will increase and also give poor top end power while driving. If gap is to wide you will have to remove a shim/s to get the correct gap.