16v kr running rough after start up then keeps losing revs

Need some advice please
I have a mk1 gti fitted with a 16v kr motor. Bought it as a non runner and fitted a new battery and fresh fuel and fired up no problem…doesn't like ticking over when cold but once a bit warmer will maintain revs ok, tried to take it for a run to see if it improved but it becomes really rough and dies. Starts again instantly and will drive again for 20 seconds or so and the same happens again. Am thinking fuel supply but am not familiar with these motors at all so looking for some advice on where to start….

Pop over to the Mk2 Golf Owners Club forum and in the technical section take a look at rubjonnys tuning guide for the KR engine.

It covers all the basics and more, plus bits that are easily overlooked.

Could be a vacuum/air leak among other things. When I had a Mk2 16v I had knocked without realising the pipe off the underside of the inlet from the metering head. It was a pig to start and hold revs, but an easy fix once found!

Hope this helps

Cheers for that will spend some quality time at work today searching for answers

Still not managed to get this running properly…checked out the suggested guide for the KR,  cold start valve working,cleaned up all earths etc.
Started car tonight, again not keen on ticking over until a bit warmer drove it for about a mile and behaved as it should with no hesitation,turned and headed back to the shed. Half mile further on and returned to spluttering  and drawing up. When switched off and then restarted throttle response is good but soon starts misbehaving again within seconds…it almost seems like its resetting itself when switched off? Does that make any sense?

Had problems like this myself on a 9A running KR injection, ended up going through the system bit by bit changing fuel pump and filter which were choked up (noisy pump will sometimes indicate this) so agree with sounding like fuel, probably best to start at the beginning and change fuel filter etc, could be a number of things depending on how well it was converted, you really need test equipment, gauge etc to check if the WUR is working properly, if the cold and hot control pressures are out it'll cause rough running, you can make up the test equipment yourself quite easily for about £40, there's loads of guides on the interwebs

did you check everything as per my guide, timing, base idle, idle switch linkage, wiring, injector spray patterns/volumes, splits in boots etc?

Have not removed the injectors yet was trying the more basic things…got a fuel filter coming this afternoon for it,sprayed all hoses etc with carb cleaner and made no difference,everything connected as it should be.Throttle switch clicking,cold start valve spraying fuel.Not checked the timing yet forgot my strobe.  The fact that it runs fine without a problem alll through the gears for couple of miles gives me the impression that something is breaking down or blocking up??

when it goes bad check the idle switch again, the upper linkage that hits the switch on mine was slightly sticky so it clicked most of the time but randomly it woudlnt maker contact

Cheers John will try that too...Having a night off from it tonight because it is doing my head in... Was looking into a set of bike carbs instead save all the aggro. Not good when your at work all day and all your thinking about is getting a bloody car to run right

Have you got the standard KR air filter box? If so then worth checking if the gasket under the metering head is leaking air?

Spray some carb cleaner around it whilst on idle, if revs increase then you've got a leak. That's another issue I've had before.

Part no 34 on here - partsbase.org

Tried that, had the whole thing swimming in carb cleaner,put a new fuel  filter on last night but it's not made any difference either. Something obviously sending a signal to the ecu telling it there is a problem as when you switch it off then back on the throttle response is spot on…like it is resetting itself