1990 1.8lt, 8v donk? It's idling high

[Golf Loon]

Got Pm`d this by a newbie, Ryan. Thought I`d let you lot help too.

"Can you help me with this 1990, 1.8lt, 8v donk? It's idling at 1100-1200rpm when warm!?!?!?"

What does it idle at when cold? Try turning the idle down at the screw on the front of the inlet manifold. If it stalls when cold, ISV or Cold Start Valve.

Is it Kjet or Digifant? Auto or Manual and does it have AC?

[Ryan]

Well guys it idles about 800+- when cold, not to bad by the sound of things.(with AC turned off)

As is slowely warms up - so do the revs, when running temp is reached the RPM has climbed to about 1300+-.

Okay I tried turning down the idle screw on the back of the inlet manifold when hot but starts sounding unhappy and stalls even with the AC disconnected.

I think it's Digifant but i'm not sure, currently trying to post some picts but don't know how to with bigpond!

And yes it's a 5spd manual, what this has to do with the prob I don't know.

The idle stabilisation valve and/or the cold start valve have been mentioned and I think this is quite a likely cause because earlier investigation leed me to the cold start sensor which I tested and is fine.

If someone knows anything pls write it down or msn me or whatever im going nuts,

[Ryan]

this betta work!!![img][/img]

[EndlessMKI]

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is this the beasty engine from mat?

dam in the car already? fark.

[Ryan]

Mat may have plenty of parts but this one aint from him yet!

[Ryan]

okay, after waiding through the russian vw site I have found that my golfs engine is a JH out of a Caddy
The Ignition System is: Hall-sender electronic, 1985-89
Digifant came on the 2H from 1990+
So even though mine is 1990 it has a JH Engine Code = how odd!

[Golf Loon]

Your car is kjet, not digifant.

I dunno what a JH engine code is, but that doesn`t matter, are you sure its not a JN engine code? Check the block, not the papers. JNs are from an Audi 80.

The bit you have labelled as the cold start valve is in fact an ISV idle stabilisation valve. Try unplugging the electrical connector to this and see if it makes any difference. I believe this is a secondary unit, which ups the vacuum when you have your air on, or if the car is auto.

Also check all the hoses from the manifold to the valve for rips, vacuum leaks will cause chaos.

Is there another valve with an electrical connector mounted on the back of the manifold? This is the primary ISV.

The bit you call a pump is the fuel metering distributor. Leave that alone, it either works, or it doesn`t. Tinkering makes it not work

From the fuel metering head, there are hoses to the injectors and two others which run down to a unit on the block. This is the cold start valve. A very common fault on kjet motors. Check wiring to it and then change it for another. lots of cars have em, early saabs and volvos are cheap donors if you cant afford a vw audi one

Do all that and tell us how you get on.
Cheers
Matt

[Oneofthegreats]

It sound's to me like the aux air valve (the valve on the back of your intake manifold with an air tube running up to your cold start valve.)isn't closing up totally. But I maybe wrong!
Also, how long has this being happening for?
Mine used to do this all the time as the electrical plug was broken and kept falling off and it wasn't closing the valve off.
With the engine running at operating temp and idling high, crimp the hose from the aux air valve to the intake manifold and see what happen's, hopefully the idle will come down and you will be able to here it closing off air supply. If not you may have an air leak somewhere.
Give it a go & let us know.

[Ryan]

Cheers guys I'll get right into it and keep you posted
thanks
Ryan

[Ryan]

GTI20V, Yeah i've tried closing the hose between the ISV (on the back of the intake manifold) and the intake-manifold, makes no diff...

Mat, It's a fair-dinkum JH donk with K-Jetronic, it's also used in the caddy, going off the russian site! sounds like they grabed all the pieces around the work-shop and banged it all together

All hoses checked, tightend and checked again but found FA I had replaced some not so long ago trying to rectify this situation.
Examined electrical connections on both ISV's (look in good condition) and disconnected them but no diff...

It's started about 1 month ago progressivly getting worse.

I guess all is left is the cold start valve are you sure it's on the end of the two lines comming off the Fuel Metering Distributor? thought this was the fuel pump? Not doubting you so i'll try find a replacment for the test tomorrow. Oh the connector to this looks fine aswell.

Cheers

Turning lights off in work shop
Goodnight....

[Golf Loon]

Mat, It's a fair-dinkum JH donk with K-Jetronic, it's also used in the caddy, going off the russian site! sounds like they grabed all the pieces around the work-shop and banged it all together ....

The VW way, goto the parts bin and build a car.

Examined electrical connections on both ISV's (look in good condition) and disconnected them but no diff.......

Are they both working they should hum when power is going to em. Touch them and they should feel as if they are pulsing.

I guess all is left is the cold start valve are you sure it's on the end of the two lines comming off the Fuel Metering Distributor? thought this was the fuel pump? Not doubting you so i'll try find a replacment for the test tomorrow.....

Its a rectangular thing with two hose connectors and a couple of wires. The fuel pump is under the boot floor, or in the tank.

Good Luck

[Ryan]

Replaced the Cold Start Valve with another of a Volvo today and it made no change at all, so we can count that one out. I'm still doing tests on the Aux Air Valve, not satisfied with it yet!

[roccodingo]

this is the Auxillary air regulator, which allows extra air into the engine when the coolant temp is below 35 Deg C.

When you start the engine, electrical current is passed through the regulator which heats the electrical coil inside the unit closing the valve. the valve should be closed after 5 minurtes running time.

from the symptoms you have of high idle speed, this is likely to be the culprit at first glance. U can try the hose pinching method to see if the idle speed will drop.

Electrical resistance for the unit is 30 Ohms. check to see if you are getting 12 volts at the wiring terminal when the fuel pump is running.


HTH.

[Ryan]

Hi Roccodingo, thanks for that just what I was looking for, okay did a few tests seems like it's faulty (not closing fully) but I didn't know what the resistance should be. you said 30 Ohms and I got 44.5 Ohms so I think it's the culprit and yes i'm getting 12.5 VDC from the electrical plug so this should be fine

Now where on earth can I find an Aux Air Valve/Regulator?
Definatley none here in Cairns i've looked everywhere! and the VW agent can't find any from his sources either.

Is their a good parts place down south somewhere???
Please let me know, cheers
Ryan.

[roccodingo]

If you can hang out til the weekend i can likely dig one up out of my collection..

You may be able to remove the unit and find the BOSCH part number so you can cross reference with any other car manufacturer that uses Kjet ( volvo, saab, merc etc..)see how ya go..