Mk1 16v throttle position switch question

I've been fiddling about trying to get my mk1 to idle correctly, the CO is 2.1 and it seems to rev cleanly enough but it idles at 12/1300 rpm. When revved it doesn't come back down to an even idle but drops down to a splutter and then picks back up to 12/1300rpm. Other times when the fan is running and it's revved before dropping to idle it dies. I think the extra load from the fan is causing it to die?

Further it didn't have a throttle position switch, the wiring is there which looks like this -



And the plug on the end looks like this



I'm guessing its a pretty obvious answer but this is the route cause of the idle issue?

I did try to fit the throttle position switch off my 90 spec valver but it has the following connection so doesn't fit-



So would that mean I have an early spec loom in my mk1 and I need a particular type of tps?

Any help appreciated as I'd like to get all these little issues that I can sort out myself resolved before I take it to a rolling road.

Thanks in advance,

Nic

 

I am sure RJ will be able to give an informed answer. But just as a quick response, the throttle switch needs to be working for the ISV (idle stabilisation valve) circuit to be working correctly.

 

That makes sense, I think we've adjusted the idle screw to stop it stalling to compensate.

 

Still haven't got anywhere with this.

Now it'll idle when cold but wont when warm, every other throttle switch I've checked is like my later valver plug? Will probably go in to the dealer in a bit to see what they have on etka.

Also I'm not running a brake servo so besides the two thin vac hoses which run I think to the ecu and clocks the others are blocked off. Is this correct? The one from under the metering head is plugged, the one under the intake boot connecting the throttle body and metering head is also blocked and besides the two thin vac hoses from the back of the inlet manifold/head they are also blocked.

Was told yesterday that I still needed to connect the metering head vacs to the inlet/head?

Have unplugged my cold start valve as it's causing it to flood. Shame there are no real k jet specialists down my in south west Wales!

 

Ideally you need the MK2 KR idle speed controller, wiring and valve to run closed loop idle control.
The controller has dashpot built into it to dampen the engine speed drop when the throttle is closed.
This of course is based on your base idle ( i.e. ~1000rpm).
The fuel mixture will have to be set "optimum" to achieve this.
KR engines have a 3 pin throttle switch as they allow control for the cold acceleration extra injector enrichment and flagging when ISC is required.
The conversion of the KR engine to a MK1 sounds to me that the wiring to the cold start injector may be mixed up and is being activated, hence the flooding.

 

Thank you for that Toyotec.

I've been having a read about and this seems to make sense -

Source 16V Conversion on VWgolfmk1.org.uk

So there are 2 pin TPS, this makes me feel a bit better rather than looking at my car thinking WTF? Have messaged a couple of people to see if they have one, they are no longer available from VW.

Going on from what you've said about the idle speed controller, this was mentioned to me yesterday but I had forgotten about it already, I don't know if mine has one fitted or not, I presuming it hasn't as I haven't seen the controller box.

It's pretty frustrating having the car sitting there and not being able to use it

 

Just to clarify, this isn't a new conversion, it used to run fine and idle fine before it was pulled apart, just didn't seem to rev as it should have hence the engine refresh. I can't ever remember the TPS being there, but it's obvious it should be there.

 

Cheers John, I'm starting to get somewhere now, hopefully be able to get it to E38. Are you going?