ME7 kicks when changing gear

[cookiec70]

Hi guys, my 99 C70 ME7 has started to give a strange kick/jolt when it's coming off boost, mainly when changing gear, it's like the cars trying to jump forward. Theres no fault codes or lights on, but if you cycle the ignition off and on then it goes back to being normal. Am I right in thinking this could be a faulty TCV?

[stribo]

Does it do it when you floor the throttle as well, sounds like transmission shunt, if so your top mount, or bottom torque mount could be knackered.

[abdul]

Could it be the propshaft

[JamesT5]

Could it be the propshaft

The C70 is FWD, only the RWD cars have propshafts but I like your theory.

[cookiec70]

No it's just when coming off full boost, mounts are all mint but it must be an electrical issue for it to clear when the ignition is cycled off and on again?

[M-R-P]

Mine used to do it a lot, I never pinned it down tbh. It's only done it once in the last year. I found pulling the battery for a couple of hours sorts it for a while.

[cookiec70]

Well I've bit the bullet and decided to change the TCV anyway, as looking at it i'd imagine it's the original one, and the cars got 104k on it so definitely due a change. I disconnected the battery for a few hours the other day as you suggested M-R-P and it's been fine since then, but then again it did only ever happen now and again anyway. I've bought a genuine Volvo TCV but I've heard that it has to be taught in, what's the best way to do this?

[stribo]

Well I've bit the bullet and decided to change the TCV anyway, as looking at it i'd imagine it's the original one, and the cars got 104k on it so definitely due a change. I disconnected the battery for a few hours the other day as you suggested M-R-P and it's been fine since then, but then again it did only ever happen now and again anyway. I've bought a genuine Volvo TCV but I've heard that it has to be taught in, what's the best way to do this?

On the S60R I just fitted it, and carried on driving as normal.

[Dream3r]

An ECU reset (battery off) would reset any adaptations, if your TCV was behaving poorly before then tthey can overboost when swapped.

[M-R-P]

An ECU reset (battery off) would reset any adaptations, if your TCV was behaving poorly before then tthey can overboost when swapped.

Good heads-up mate. Had the same thing when I fitted the IPD tcv.

[cookiec70]

An ECU reset (battery off) would reset any adaptations, if your TCV was behaving poorly before then tthey can overboost when swapped.

So how do I avoid any overboost then, is it just a matter of taking it easy until it re-learns itself?

[Dream3r]

If you were getting overboost, an ECU reset would clear adaptations (battery off), then just drive it normally.

[cookiec70]

Ok thanks that's a great help, I shall do the swap tomorrow and see how things go :)

[cookiec70]

Right guys, I went to change the TCV today and realised that the vac pipes are all quite badly perished, pretty sure there not bad enough to cause any leaks but they need changing none the less. Now as I have removed the airbox so that the do88 intake pipe and cone filter sit nicely, there is nowhere for the TCV to clip onto, I've ordered some new vac pipe and I was wondering if I could make a bracket and mount the TCV somewhere different, neatly out of the way, or would changing the lengths of the associated vac pipes cause me any amount of trouble? I've ordered 6mm vac pipe as that is the diameter of the solid pipes connected to the TCV, will this be ok or is this no good either? I'm not too fussed if not as it was only a few quid off the bay

[stribo]

I used 4mm vac pipe, but if you clip it or cable tie it so it won't blow off you should be fine. Length of the pipe isn't too crucial, so you can relocate it, mine's just cable tied out of the way.

[M-R-P]

You'll struggle getting 6mm to stay on, you'll be wrapping the ports with tape before long.

[cookiec70]

Ok stribo nice one ill see how it goes with the clips but if it keeps falling off like M-R-P suggests then ill have to order some 4mm.