Over-revving on gear change (and now tighten throttle cable)

[Jim 2]

My car has developed an interesting problem which only shows up from time to time. Sometimes if it has been standing for a few days without being driven, or in the case of this morning when it was COLD outside.

 

For the first 5-10 minutes of driving, when changing gear, as soon as your foot depresses the clutch the engine revs up about another 500RPM. Doesn't seem to happen at very low revs as much but when you are just getting up to under 3,000RPM to change gear it'll do it.

 

Something to do with the throttle sticking open or the throttle cable sticking, or an engine management / sensor or something type of problem?

[Kevin Bacon 5]

Does the problem go when the engine is heated up?

 

I reckon the solution is a simple one - drive it more often :lol:

[Jim 2]

Yeah - stops when its warmed up.

 

I drive it EVERY day damnit! How much more do you want me to drive it? :)

[Kevin Bacon 5]

You said it had been standing for a few days so I assumed you don't use it much.

 

Might be your blue temp sender?

 

I doubt it's the throttle cable if the problem goes when the engine's hot...

[buttles 0]

Does the G60 have a throttle damper like the VR6? Might be holding the valve open too long.....

[GazzaG60 0]

check the throttle cable aint sticking and when warm loosens up

[StuartFZR400 0]

Does it tick over at usual revs once warm?

 

Sounds like the somthing Automatic, like buttles says or maybe choke needs overhaul. Somthings worn or clogged up.

[dav 0]

I had a similar problem with my MK1 but it turned out to be the little O-ring on the idle adjustment thing on the throttle body which had perished and was letting air in. Symptoms were the same as yours, it would go away when hot, I suppose because the rubber would expand when up to temperature and sealing the gap.

It would only do it at mid level revs at first as the vacuum would be greater than at idle, but after a while it would do it then too.

 

Don’t really know if the throttle body adjustment screw on a G60 is the same or similar that of a MK1 (should be)

Just a thought, could be cheep fix.

 

D.

[h100vw 0]

The tickover screw on my Golf used to back itself out on trackdays. It would tickover at 2k, the ISV would try it's best to bring it back down. After the first time it happened, it was easy to spot.

 

My Passat plays up a every now and then. It tickover at 1500, if you open and close the throttle quickly it ticks over normally. I am putting it down to the closed throttle switch being a bit intermittent.

 

Gavin

[Jim 2]

Just some other info...

 

* Doesn't do it every day - has only happened about 4 or 5 times since buying it

 

* Blue temp sender was changed about... er.. 2 months ago?

 

* Idles, etc as normal - nothing unusual at all. Around 900-1000RPM when cold, around 800RPM when warmed up. No unusual surging, or anything like that.

 

Thanks for the comments and suggestions guys. I'm not tooo worried because of how intermittent the problem is, but I wanted to make sure that it wasn't going to turn into a scary moment like the throttle sticking open or something else equally entertaining ;)

 

Lots of stuff to check though. Cheers.

[Kevin Bacon 5]

Might be the idle valve on it's way out.... had a similar thing happen on MK2 16V.

 

It should be closed off idle but they can occasionally jam open, which you will only notice when changing gear or at idle.

 

Might be worth blasting it through with some carb cleaner....

[Slimbo 0]

Sounds like a problem my car had before I bought it. The previous owner had the gearbox rebuilt as a bearing had went in it. The VW dealer bill came to £1200 in total. Ouch.

[Jim 2]

Don't start with horror stories like that!

[Henny 0]

eh? Slimbo, how can a gearbox bearing effect the idle speed when changing gear?!? :?

[Slimbo 0]

"For the first 5-10 minutes of driving, when changing gear, as soon as your foot depresses the clutch the engine revs up about another 500RPM."

 

I don't take that to mean idle speed. Anyway, I'm just going off what it says on the VW invoice, that's what the reported problem was, they inspected it and that's how they fixed it. £700 labour charge. Ouch.

[Jim 2]

When I say depresses I mean as in when you press the clutch in.. so the gears shouldn't even be engaged at that point..?

[olly elworthy 0]

maybe if there was a really bad bearing as in slimbo`s case this would make the engine have to work harder with the clutch out so the idle stabilisation would compensate, and then on depressing the clutch this extra load is relieved and it takes a second or so for the idle to re stabilise? bit far fetched but maybe?

[Jim 2]

Just a bump for this now as this has reappeared in the past few days again.. I never got round to doing any of the work on the car before as it stopped doing it again after I made the post.

 

The only pattern I can recognise here is that it does it when its seriously cold outside (heavy ground frost today and yesterday, and has done it yesterday and today!)

 

So - worth checking / cleaning the ISV you say, and it could possibly be a sticking throttle cable?

 

Trying to drive it like this is.. entertaining. Have to kind of let off the gas, wait a second and then change gear, otherwise it makes you sound like someone who hasn't quite worked out how to use the clutch! :|

[RACK 0]

Mine was doing this on and off for months.

It turned out the be the throttle cable, for £20 and about 15mins fitting it's worth trying.

[Jim 2]

Thats my thoughts as well.. is it not a particularly awkward job to fit it? Just take out the under dash trays, and thread up through the engine bulkhead?

[bcstudent 0]

Thats my thoughts as well.. is it not a particularly awkward job to fit it? Just take out the under dash trays, and thread up through the engine bulkhead?

 

Pretty much!

[RACK 0]

Yeah mate that's it. Here's a step by step guide what Henny did for me:

 

"take off the lower dash shelf (drivers side ) and then get your head in down there... You'll see the cable on the left hand side of the pedal cluster - (YES, I DO mean left side! ) Unhook it and push it up a little bit.

 

In the engine bay, un clip the cable from the throttle, and feed it back. Now pull the cable from the cabin into the scuttle panel area and then through the bulkhead into the engine bay...

You should now have the old cable out...

 

Re-fitting is the reverse of removal [/haynes]

 

Just remember to make sure the grommets are all seated properly else you'll get water coming in next time it rains!

 

Should take no more than 15 minutes to do it and only requires a screwdriver to undo the lower dash and a torch to see what you're doing down by the pedals..."

 

Hope this helps.

 

One point though, make sure the stealer gives you the correct cable. The one I went to gave me one for a VR6. The G60 one has a hook on one end.

[Jim 2]

Thats excellent.. thanks very much for that mate! Will try and get the throttle cable in the next few days!

[Kevin Bacon 5]

Yeah that does sound exactly like a sticking throttle....my old 16V Golf used to do it until I changed the cable. It's only about 30 mins work to change out.

[Jim 2]

Should I be applying any kind of grease at any point/place when I refit the new cable?