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Hi revs when changing gear

Posted: 31 Dec 2014, 09:56
by nordberg
Hi All,
I have noticed over the last couple of days use of my van that the engine seems to be revving high when changing up the gears (diesel JX Westy engine) . I think its more an issue when the engine is warm, although I can't say for sure as I have only done short journeys to work and back. It seems to be OK when going down the gears but I guess this is due to the fact the engine speed is decreasing during deceleration as its moved from higher gear to lower (If that makes sense). Any pointers? :shock:

Re: Hi revs when changing gear

Posted: 02 Jan 2015, 10:18
by blacky
Clutch starting to slip ?

Re: Hi revs when changing gear

Posted: 02 Jan 2015, 11:29
by nordberg
Thanks for the feedback. When the clutch is depressed and I take my foot of the accelerator to change gear the revs should drop. If the high revs were then the clutch was engaged (in gear) that would be a slipping clutch.

I probably haven't explained it very well. :roll:

Re: Hi revs when changing gear

Posted: 02 Jan 2015, 16:03
by fairwynds
Check your accelerator cable, both ends, but start at the engine end. Common fault due to lack of lubrication on either the cable itself where it enters the cable housing or the spindle between the cables end and the carb body. Bit of grease there, oil cable and operate it manually with engine ticking over. This will cause revs to rise and fall accordingly and then you can make sure that it's returning all the way back to the stop point. It will make sense when you take a good look at it :ok

Re: Hi revs when changing gear

Posted: 02 Jan 2015, 16:55
by CovKid
Idle speed too high?

Re: Hi revs when changing gear

Posted: 02 Jan 2015, 17:24
by kevtherev
nordberg wrote:.........(diesel JX Westy engine) .
I don't recall Westfailure making diesel engines :D

Re: Hi revs when changing gear

Posted: 02 Jan 2015, 21:19
by nordberg
kevtherev wrote:
nordberg wrote:.........(diesel JX Westy engine) .
I don't recall Westfailure making diesel engines :D
Kev....good point well made :lol:

Re: Hi revs when changing gear

Posted: 02 Jan 2015, 21:24
by nordberg
fairwynds wrote:Check your accelerator cable, both ends, but start at the engine end. Common fault due to lack of lubrication on either the cable itself where it enters the cable housing or the spindle between the cables end and the carb body. Bit of grease there, oil cable and operate it manually with engine ticking over. This will cause revs to rise and fall accordingly and then you can make sure that it's returning all the way back to the stop point. It will make sense when you take a good look at it :ok
Thanks for the feedback fairwynds . Hopefully should get chance to check this at some point tomorrow and verify if that's the cause. At a camp site in Lincoln at the moment in the van. Got a can of WD40 so will spray a bit of that around anywhere that's looking lacking in the lubrication department :D

Re: Hi revs when changing gear

Posted: 03 Jan 2015, 10:06
by ghost123uk
Keep a careful / accurate (level ground) check on your oil level. It could be (to some extent) running on it's own oil. This can get bad, see = https://www.youtube.com/watch?v=rLzf3ItkbOE" onclick="window.open(this.href);return false;

Go on, do tell us the background behind the Diesel Westy

Re: Hi revs when changing gear

Posted: 05 Jan 2015, 18:06
by nordberg
Ok, so I have had a good look at my engine bay today in relation to this issue , which is only third time since I bought the van 3 months ago. All of the other classic vehicles I have owned I got to know the engine bay better than I did the interior so I guess it's a good sign really :D . Anyways, here is the engine......

Image

Very tidy if I say so myself :lol: . Anyways, I have inspected the cable and it doesn't look too bad. However, there it's a lot that sits underneath the van, and there are some signs of wear on the outer cable were it disappears through the aperture out of the bay. I have found this link to a new cable for £17 off Just Kampers.

http://www.justkampers.com/vw-t25-parts ... -1992.html" onclick="window.open(this.href);return false;

That doesn't seem to bad so I think I am going to take the plunge and order to eliminate that out of the equation.

Re: Hi revs when changing gear

Posted: 05 Jan 2015, 20:30
by fairwynds
If it's faulty, you should still be able to tell if it's not running smoothly, by manually operating the throttle at the carb end, as that will still 'pull' on the cable itself.....

Re: Hi revs when changing gear

Posted: 05 Jan 2015, 22:18
by nordberg
fairwynds wrote:If it's faulty, you should still be able to tell if it's not running smoothly, by manually operating the throttle at the carb end, as that will still 'pull' on the cable itself.....
I did spend some time operating the lever on the carb but couldn't tell for sure if the cable was dragging enough in the outer to cause the issues I was experiencing. The van is now back in storage and knowing there is some visual wear on the cable I thought I would change as a matter of precaution next time it's back home.

Re: Hi revs when changing gear

Posted: 06 Jan 2015, 09:19
by ajsimmo
Hi Nordberg
Is there much smoke when revving? If someone has opened up the fuelling screw on the back of the pump (not carb ;-)) in an attempt to get more power this can result in revs being slow to drop back to idle. It can also cause excessive white smoke (unburnt fuel).
I doubt it's the cable.

Re: Hi revs when changing gear

Posted: 07 Jan 2015, 17:24
by killerme
I think this is very similar to my post:
https://club8090.co.uk/forum/viewtopic.php?f=37&t=133843" onclick="window.open(this.href);return false;

My knowledge of engines is pretty basic so I expect I will make quite a few mistakes here but please correct. Lots of listening, reading and watching has led me to this conclusion.

When the pressure in the engine gets too high, this is reflected in the vacuum wastegate actuator (see red circle). Pressure here will push the rod (see yellow circle) which in turn opens the wastegate and releases pressure. You can test yours with a bicycle pump. Attach it to the actuator and pump it and you should see the rod move. Mine moved a very little bit. Too much movement and too little is bad. After checking it, I pushed and pulled the rod, added a bit of WD40, did more pushing and pulling and hey presto, when I took it out for a run it was much, much better. I can only assume that either the actuator or the rod was sticking. Every time I have the engine lid off now I give it a good going over. It seems to be working much better now.
I would like to replace the actuator but I haven’t had any joy sourcing one. Anyone got any ideas?
Incidentally, my engine is a 1.6 TD but can anyone tell me where the turbo is….answers on a postcard to….

Re: Hi revs when changing gear

Posted: 07 Jan 2015, 19:12
by nordberg
killerme wrote:I think this is very similar to my post:
https://club8090.co.uk/forum/viewtopic.php?f=37&t=133843" onclick="window.open(this.href);return false;

My knowledge of engines is pretty basic so I expect I will make quite a few mistakes here but please correct. Lots of listening, reading and watching has led me to this conclusion.

When the pressure in the engine gets too high, this is reflected in the vacuum wastegate actuator (see red circle). Pressure here will push the rod (see yellow circle) which in turn opens the wastegate and releases pressure. You can test yours with a bicycle pump. Attach it to the actuator and pump it and you should see the rod move. Mine moved a very little bit. Too much movement and too little is bad. After checking it, I pushed and pulled the rod, added a bit of WD40, did more pushing and pulling and hey presto, when I took it out for a run it was much, much better. I can only assume that either the actuator or the rod was sticking. Every time I have the engine lid off now I give it a good going over. It seems to be working much better now.
I would like to replace the actuator but I haven’t had any joy sourcing one. Anyone got any ideas?
Incidentally, my engine is a 1.6 TD but can anyone tell me where the turbo is….answers on a postcard to….
That's very helpful. Lots to look into. I am getting the impression it's highly unlikely to be the throttle cable, but I have a new one so will change and keep old one as spare. My van is back in storage but should be able to investigate further towards the end of the month :D