Hi guys and gals, I hope someone can help. I have an 85 mk2 golf gti 8v. It does not want to idle on a cold start. It will idle very low and want to cut out unless I give it throttle. When it's warmed up it idles fine. I have checked the resistance of the warm up valve is 26 ohms. I'm getting 9v from the plug going to the warm up valve. The haynes manual says it should be at least 11v. Would this be the issue or should I look elsewhere? Thanks.
I'd take a look at auxiliary air valve , it is probably closed all the time, not letting in extra air needed for higher cold idle speed.
check the voltage to the aav as well, as its fed from the same power feed as the WUR. Also if you check from the red/white direct to the battery is the voltage higher? if so the earth is bad. if not check between battery live and brown, if better the power feed is bad. look for any obvious bodgery in the engine harness, the plugs should have wire seals on if missing or damage water gets in and starts corroding the copper these wires run to a female spade behind the fusebox which should be plugged into a male spade on plug E pin 14, which is the black one for the rear wiring loom. check voltage here too, see if theres an issue with the feed directly out the fusebox or if its a problem somewhere along the wire.
That's great info. This gives me some things to check thank you. I will check over all the wiring and clean up connections etc.. I will post up what I find.