Running problems

[klapwijk]

I recently had some problems with my 1.8 16v KR Mk2 Golf that I sorted. A vacuum hose came off and was causing the car to idle at 3000rpm and run like a bag of .... Sorted that and then the car was hunting very badly and idling very badly, cutting out a lot. Set up the CO to 2.05% and the idle to 1000rpm. Now that I've sorted those problems I've run into some more.

The car doesn't like starting from cold unless I feather the throttle. The car had been running ok for two days until this morning. Car started after a few seconds of feathered throttle and then about 5 miles down the road the car started to idle where I last had my foot on the throttle. Turned it off for a few minutes and then it just started hunting very badly again but the throttle didn't stick.

Got to where I needed to be and then turned the car off. Came back an hour later started it and it was ok, then suddenly it started hunting again. Then I disconnected the ISV and the revs dropped a lot and the hunting went away. Reconnected it and then restarted the car and it was fine?

When I disconnect the electrical connection to the ISV, the revs drop and then when I reconnect it while the car is running; should the revs return to normal or should I have to reconnect it? Should the car cut out when I disconnect the electrical connector on the ISV, like it does on my other golf?

Also, when adjusting the CO on the metering head with the allen key should I be able to move the VAF/metal dish in the head as well. When I was setting it up, if i pushed down the car would cut out. I presume this is because the car isn't getting any air. Is this movement of the VAF normal?

The problem seems to be very intermittent, and hasn't come back yet on my return journey home.

Thanks

[klapwijk]

Quick update. Just been out in the car and it was fine for a bit before it started to hunt again and then very slightly kangerooing at low revs and low speeds. Again it didn't like starting from cold and idled quite poorly for the first few minutes. When it started hunting again I pulled over an disconnected the fifth injector and it made no difference. Then I disconnected the ISV while the car was running and it idled fine and no longer hunted. Reconnected it and them restarted the car and it hunted again. Drove home with it disconnected and it drove and idled perfectly fine. I'm going to try and test the temperature sensors for the ISV and see if it has any impact on it, tomorrow.

If the ISV controller was playing up what symptoms would it give?

Thanks

[clipperjay]

Like you said mate its the controller or the ISV but I would borrow another ISV or even a controller to rule them out before spending money.
Other things are temp sensors by the side of the block check the contacts are in good order no corrosion on them!
Another one could be throttle switch is damaged near the TB hear if it clicks okay!
Final issue fifth injector could be over fueling but thats usually when under load.
Give the ISV and TB some wurth carb cleaner when its running to burn off any crap left in the systems!

[klapwijk]

I've cleaned out the isv and tried another known working one that I gave a clean as well. Idle switch is working. The temp dash light has been lighting up so I'm going to give all the contacts a good clean and try three known working sensors. I don't like throwing parts at a car but unfortunately I need to fix the car ASAP!

To replace the isv control box is it literally just behind the centre console? TB looks to be in good condition. It I will give it a clean anyway. Checked that it is closing everyone and checked the cable to see if it's sticking at all

Thanks for your help!

[clipperjay]

Well I've had loads of parts that looked brand new but sadly they have failed before.
It might be best to double the earth to the gear box as a future isssue you might have just bolt another earth cable to the gearbox any ring connector that fix on the bolts.
Also get some washing up liquid get the foam and spread it around the vacum pipe joints to see if you have any air leaks?


 

[klapwijk]

I'll try that trick when I get home. If I didn't set the CO with the red lead disconnected do you think it would cause this problem?

[clipperjay]

If you have multi meter there is a way to test out the ohms on the Co2 but best is to search for it on here I can't remember the rating off hand but I would do a search for it.
If you get stuck come back to me as I'm off in awhile to pick up a bike 

[klapwijk]

I've checked all three temp sensors on the side of the head. One was faulty so I've replaced it. Tested them by using the wire for the dash gauge. Cleaned all the connections for the sensors. Idles better now. The fault is still occurring but I can get rid of it by just revving the car high a few times. I'm running out of things to check now! Didn't get round to doing your washing up liquid trick!

[clipperjay]

Well I've had the Hall sender play me some grief, but that was on a Digi?
16V should be much easier to sort?
Are you sure the ISV you have is for 16V and not 8V?
Did you change two of the sensors out near the distributor? there are two that control the ISV.
3 single pin black sensors on the side of the head which are all the same rating, blue/white for ecu, green/.red for isv controller and red/yel for the dash gauge
when was the plugs change out last?
 

[klapwijk]

The ISV i changed it for is off my other 16v, which was working ok. Cleaned it our before I fitted it. I only changed one as it wasn't giving me a reading on the dash. I then double checked that all three gave a reading on the dash. The plugs haven't been changed in a while, nor has the oil. I'm thinking of disconnecting the crankcase breather and allowing it to vent to atmosphere to see if the problem is better. Only because I don't get paid until Thursday and cannot do an oil or plug change. I've heard that some people have solved idle problems because their dirty oil was allowing fumes into the air box via the crankcase breather.

Thanks for your help once again!