What does this idle issue mean? New problems!

[Jay23Sx 0]

Hello Everyone,

 

Well a little update for you. My 1.8 valver now has a new fuel distributor courtesy of Shaun. My mechanic fitted it yesterday while I was in Edinburgh and didn't even find out until this morning

 

Popped outside as soon as I got home and although the replacement part means my car now starts (it had died completely after his last visit) I'm back to square one with the engine failing to idle properly. It'll tick over, with difficulty, but as soon as you increase the rev's it'll die as soon as you release the throttle.

 

I'm going to add a video clip to illustrate what I mean and give you an idea of what it sounds like.

 

In the mean time check out this idle adjust screw - strikes me as being to far out? I tried adjusting it (a little) and it just made the car cut out sooner!

[Jay23Sx 0]

After listening to this again it does sound like I may have a Vacuum issue - although when the problem first developed no one could find a leak. You might be able to hear an ... airy, sucky, strange noise .. or maybe not .. while you watch this.

 

[CorradoVR6-Turbo 0]

make sure you have no air leaks between the throttle body and the fuel head,when you fited the replacment,did you set the mixture?

[Jay23Sx 0]

make sure you have no air leaks between the throttle body and the fuel head,when you fited the replacment,did you set the mixture?

 

I haven't set it since the mechanic fitted the unit yesterday. Don't think I've got anything here suitable for altering the mixture but I can solve that one quite easily.

 

When the car originally died I had the RAC out (thanks Barclays) and they tested for leaks using a can of .. something. There was a small split but it didn't seem to be drawing anything in - it's been wrapped up in tape just in case though.

[Valerian 0]

There's is no way that idle speed screw should be srewed out that far.

You either have a vacuum leak , mechanical timing is out,or , ignition timing is out.

Seeing as the car seems to rev freely i'de put my money on a vaccum leak.

[Toad 0]

How about the piping to the ISV? or the ISV itself?

[Jay23Sx 0]

I've just been reading up on cleaning the ISV. I will check that.

[Jay23Sx 0]

Quick question now that the rain has stopped!

 

If I disconnect the wiring for the ISV (located near the coil I think?) and the engine starts to run normally would that indicate the ISV is at fault? And likewise if disconnecting it does nothing should I discount that as my fault or still look at cleaning/replacing it anyways?

[boost monkey 0]

Yeah that TB screw is miles out! If you like, I can wind mine all the way back in and then tell you how many turns it should be? Mine idles at 900 now and revs properly.

 

Also check the ignition timing like Valerian said. Although if it's been working fine before the metering head died, then ll the timing should be fine?

 

With the vacuum hoses, you really do need to have eagle eyes to be able to spot a dead one sometimes! Definitely worth making sure they're all intact and connected properly.

 

If the ISV is dead and you unplug it, the car will probably still run as it is now. Just unplugging a dead part won't solve anything? They are always worth cleaning though, get some carb cleaner into it.

[Jim 2]

I was getting similar sorts of bouncing revs with my ISV when it was playing up.. I'd definately try and source another to rule it out!

[Jay23Sx 0]

If the ISV is dead and you unplug it, the car will probably still run as it is now. Just unplugging a dead part won't solve anything? They are always worth cleaning though, get some carb cleaner into it.

 

My Haynes manual (Golf GTI KR Engine) seems to suggest that without the ISV connected the engine will almost settle into a default mode.

 

It's at this point that the idle speed adjust screw really makes any difference.

[boost monkey 0]

the brass screw will always make a difference, I'm on my 4th KR engine now :salute:

 

The Red Mk2 Golf haynes is a good book to have though for sure. I didn't know the car would settle in a default mode with it unplugged though, interesting stuff.

[Jay23Sx 0]

Disconnect the wiring plug for the idle stabilisation system. This is located near the ignition coil.

 

Allow the engine to idle then check that idle speed is 1000 +/- 500 rpm If necessary remove the cap and turn the idle speed adjustment screw.

 

.. insert bit about also checking mixture at this point ...

 

Reconnect the wiring plug and remove all test instruments. Note that after reconnecting the wiring plug the stabilisation system will return the idling to the specified speed

 

I thin what I tried to suggest earlier that if the ISV is screwed then it could be the "specified speed" is going up and down like a yo yo. Without the ISV it goes more into a manual mode .. if that makes sense.

[boost monkey 0]

Unfortunately, I don't have my haynes to hand, that quote sounds quite odd though:

 

the plug for the ISV is nowhere near the coil, it's near the distributor if anything :scratch:

what is the "cap"? :scratch:

 

Are you definitely looking at the 16v ISV stuff and not the 8v?

[Jay23Sx 0]

Unfortunately, I don't have my haynes to hand, that quote sounds quite odd though:

 

the plug for the ISV is nowhere near the coil, it's near the distributor if anything :scratch:

what is the "cap"? :scratch:

 

Are you definitely looking at the 16v ISV stuff and not the 8v?

 

I've put the book away but there is definitely a plug by the coil as per the illustration in the manual (it's a whilte plug on quite a short lead right by where the HT lead plugs into the coil - a red wire from memory). The cap it refers to is the cap that's supposed to be over the idle speed adjustment screw - although I imagine most people have since lost it.

 

According to the haynes manual the plug that is directly conencted to the ISV goes off to either the brake or clutch cyliner - can't remember which now, and yes -it confused me to the first time I read that.

[boost monkey 0]

weird stuff. oh well, hope you get it sorted, get your magnifying glass out and check those vac hoses!

[Jay23Sx 0]

I should add that I know the plug is where it's supposed to be as I've just been out and unplugged it.

 

On first start it seemed to have solved the problem - the car idled perfectly. And then it started to get slower and slower until it cut out. Still, an improvement on before. If anything this has convinced me more that I should get a replacement ISV.

[boost monkey 0]

do you know that the 3 1-pin sensors on that end of the engine are working? One of them is the thermotime switch for the ISV.

 

The plot thickens...

[Jay23Sx 0]

Don't give me more to check .. !

 

I was able to cope with the 1-point-nothing engine in a little Polo I used to have but that was as simple as a hamster on a wheel :) At this rate I need to find myself a local expert .. well, someone who knows more than me anyways.

[Toad 0]

If the ISV is dead and you unplug it, the car will probably still run as it is now. Just unplugging a dead part won't solve anything? They are always worth cleaning though, get some carb cleaner into it.

 

My Haynes manual (Golf GTI KR Engine) seems to suggest that without the ISV connected the engine will almost settle into a default mode.

 

It's at this point that the idle speed adjust screw really makes any difference.

 

When I unplug my ISV the engine dies, and I would have to wind my idle screw out to get it to run.

 

I'd try cleaning your ISV out and see how the car runs then. Then go through the fueling system cleanign the throttle body, to make sure it doesn't stick, carefully remove any oil from the metering head flap to make sure that moves freely. refit all the piping checking thoroughly for cracks, small holes, perishing rubber. Look at the inlet piping, connections to the ISV, and vaccum lines. Then check throttle body and inlet manifold gaskets, check your injectors are seated properly.

 

Then check your timing, idle speed, and mixture, and see how it goes from there.

[dirtytorque 0]

with no power attached the isv will just remain in a semi open state and so it could stabilize the problem if it is sticking under normal operation.

[Jay23Sx 0]

Well I've had some progress !

 

My local corner shop mechanic called in a friend from the local franchise of Tune Up - he instantly found that a) the mixture was wrong b) both bends from the metering head to the throttle body had splits in and c) the injectors are weeping.

 

He originally thought he'd made enough adjustments to get the car to run while I sort out the parts, and yes, for a whole 5 minutes I went cruising round the town to test it. Unfortunately after the 5th minute it started stalling at every junction (about 200 yards from a roundabout say) and then is a bit hesitant at starting because of the weepy injectors.

 

He thinks I can compensate by winding out the idle speed screw 3-4 turns. In the mean time it's back to sourcing parts!

[marshole82 0]

hey dude, had the same issue with mine. with the ingnition in position 2 are you getting a buzzing noise from the isv? if not then there is something wrong with either isv, the wiring to the isv, or the coolant temp sensor that sends the signal to the isv.

 

also try checking that the throttle touches back on the idle microswitch on the throttle body. this switch also sends a signal to the isv so could be contributing. i've just solved this issue on my valver but am relatively new to this sort of thing.

[marshole82 0]

haha didn't realise you had updated! might be worth checking these bits anyway whilst you source new bits for the other issues

[Jay23Sx 0]

Right, a few things tried this weekend ..

 

ISV cleaned out with carb cleaner

ISV continuity checked with multimeter

Temperature sender resistance checked (1,000 Ohms at 20 degrees)

Splits in air intakes sealed (until parts can be sourced)

 

And it still runs rough and cuts out as soon as you start to move. Although it's now developed a new fault - reving up to 6,000 rpm with nothing on the throttle. Once it's started doing this it keeps on doing it until about the 3rd attempt at starting.

 

So .. any more ideas before I get fed up with it and send it to the scrappers ? :)