KR 16v sticky revs

[mrbeige 0]

Got a KR 16v that is doing something a little odd. The engine revs seem to hunt a little bit and when you 'blip' the throttle, it takes an age to return to idle. The throttle butterfly seems free enough, as does the paddle on the metering head. It does seem to run a little rich too at start-up, so it doesn't rev up cleanly.

 

Any suggestions?

[davidwort 0]

ISV I reckon, that's what my old one did, I'm running a mk3 8v VDO ISV that has a permanent small air bleed (that's just the design on those ones), it's not perfect, v slightly higher idle but it pretty much works fine, certainly spot on at start up and they seem very easy to come by, plenty about.

[quicky1980 0]

tight accelerator cable?

[mrbeige 0]

ISV I reckon, that's what my old one did, I'm running a mk3 8v VDO ISV that has a permanent small air bleed (that's just the design on those ones), it's not perfect, v slightly higher idle but it pretty much works fine, certainly spot on at start up and they seem very easy to come by, plenty about.

Hmmm, ok. I tried disconnecting the ISV, to see if it was that but it stalled pretty much straight away. I also tried squeezing the pipe from the ISV back to the inlet and same happened.

tight accelerator cable?

Nah, does it when operating the throttle body directly

[Erny 0]

You take the isv off while the car was running?? It would stall if u did that, I would have checked the isv first, would guess stickin/or slightly stuck from what u say, take it off, fill with wd-40, wrap in a plastic bag n give it a good shake, or let it soak in it over night if u have the time.

[mrbeige 0]

I just wondered if it was stuck open or closed. I now suspect stuck open.

 

[...]take it off, fill with wd-40, wrap in a plastic bag n give it a good shake, or let it soak in it over night if u have the time.

Would brake/clutch cleaner be a suitable product to clean it with?

[CazzaVR 0]

I just wondered if it was stuck open or closed. I now suspect stuck open.

 

[...]take it off, fill with wd-40, wrap in a plastic bag n give it a good shake, or let it soak in it over night if u have the time.

Would brake/clutch cleaner be a suitable product to clean it with?

 

Should be fine, Stu- I usually use carb cleaner. Also worth a spray of PTFE stuff such as 3 in 1 after you've cleaned it.

[blaarado 0]

had same prob with my kr. I cleaned everything with carb cleaner Quiet a lot of dirt came out of the ISV but i also cleaned all conected parts IE. tb, airbox, pipes but also the overrun cut off valve was almost full of oil (tbh their was a lot of oil through the whole system) so i emptied that and used the carb cleaner on it. Cant really pin down what helped but there was definetly an improvment

[Erny 0]

Yeah should be fine, bit of petrol, owt realy, if it can soak for a while, that helps the most, it's shocking how much oil and shit clogs up the airlines, oil catch tanks are worthwhile

[mrbeige 0]

Well, I don't think its the ISV. Gave it a good clean and checked it's operation by powering it directly off the battery, and it made no difference. I think I might just do what blaarado did and clean everything, although it'd be nice to know the reason.

 

Feels a bit like over-fuelling to me. Warm-up reg??

[davidwort 0]

Well, I don't think its the ISV. Gave it a good clean and checked it's operation by powering it directly off the battery, and it made no difference. I think I might just do what blaarado did and clean everything, although it'd be nice to know the reason.

 

Feels a bit like over-fuelling to me. Warm-up reg??

 

It might still be the old ISV, mine has been cleaned, soaked in petrol, you name it, but it still hangs on to revs, you really need to swap it with another one to rule it out.

[mrbeige 0]

Ah, ok. I need to find a known good one to try. Anyone??

[davidwort 0]

Ah, ok. I need to find a known good one to try. Anyone??

Like I said before, one of a digifant mk2/3 golf (as long as it's the same electrical connector) will work, it might idle a tiny bit higher due to the permanent bleed they have but it will otherwise operate just as the KR one and will at least rule out your old one.

I really mentioned this because they are so easy to come by compared to the 16v ones as they're fitted to so many cars, passats etc, so I thought you might know someone with one you could borrow off their car for 5 mins just to rule it in/out.

[CazzaVR 0]

Dave, would the ISV of an 8v Corrado work on a KR?

[davidwort 0]

Dave, would the ISV of an 8v Corrado work on a KR?

I'll check the part number against the ones I have, if it's a VDO one with the same connector and pipe connections in roughly the same place it should be OK, the bodies of the 8v ones are slightly thicker at the pipe end, but fit in the mounting rubber fine.

It's prefereable to have the correct KR/audi 100 one though as the digifant ones do have a permanent air bleed like I said, they'll do as a temporary fix though.

[Erny 0]

If sheffield isn't too far from ya stu, ya more than welcome to have the isv Ive had sat on my back seat for the past 2weeks

[mrbeige 0]

Ah, Sheffield may be a little too far (about 2-3 hours away) dude, but many thanks for the offer :)