Poor Idel running

Hi
I'm trying to work out the reason why my car keeps stalling out while it's ideling. It runs for a while the just gets really lumpy then stalls out. Checking the plugs there black which I assume it means that it's running rich..
I've checked the alinement which looks good and it looks like the timing is right with disty set to -6 TDC.
You rev it and it runs. Don't take too much to start the car with it needing to have the peddle pushed to get it working

It's a 1.8 DX K Jet..

Ideas ? Pointers? 

What year is your car as later cars (mostly cabriolets) have a idle stability valve.

Have you try to increase the idle speed?
Get the car warm then increase the idle up to about 1200 rpm then blip the throttle a few times, then lower the idle speed to 1000 rpm.

Also worth checking the rubber O ring on the idle speed screw, (back of the throttle body for the idle speed screw)

The O ring goes hard over time and can cause an air leak or the idle screw to slowly adjust it self…

If your car has only been on short journeys or just been started and stopped a few times this can blacken the spark plugs as they don't get hot enough, after checking idle speed take it out for a good run and some revs then park it up over night and check the colour of the spark plugs in the morning.


Are you using super unleaded petrol?

It's a 1985 DX 1.8
I've had a look at the Idel screw but not a lot changes the ideal rate.. don't look like the screw lifts the Idel rate nor lowers it.

Does take a good turn of the key to get it running while dipping the pedal.

The engine just runs and then get lumpy and finally stalls out.. 

It's running in normal unleaded so that 95.

Personally I would avoid normal unleaded now it's got twice the amount of ethanol in it, Super unleaded is still only 5% ethanol and higher rated RON 97 to 99 depending on where you get it as the DX engine is designed for 98 RON petrol.

You are adjusting the idle screw ?
View topic: 1800 DX idle low (Update Now Sorted) - The Mk1 Golf Owners Club

Yep the idel screw made no difference.
I am going to get a new washer for it to see if this makes any difference.

O ring for idle screw - https://www.ebay.co.uk/itm/292537424199

paceman said

O ring for idle screw - https://www.ebay.co.uk/itm/292537424199

Thank you.  Will come back in a day or so once i have fitted it.

Has this just come about or has the idle been lumpy for some time?
The 5th injector playing up would give you a rich mixture, also the warm up regulator if the electrical connection is not good.

Not sure if it helps but bently has this listed under the CIS Troubleshooting. Item 4 sounds like it might be what your looking for.


 

Well some update on this process.  Well i think not.

New O ring done on the idel screw and set it back to were i should be.

Car was a little hard to start but got it going but was still a little lumpy.  Since it mostly spent the last couple of weeks been started / stop etc i took it out for a drive. Little smoky on running but this look like most burn off in the first couple of minutes.  Well then the following fun played out of the car selling out as the rev kept dropping out while the car was moving.  The only was i could keep it running was to keep it in gear while driving a little hard to to at juncations.

It did stall out and then took a good age to get it going again however it back home safe.

Now to get to the bottom of this..

The bottom line now is it really hard to get it to start & when it does it revs low.
I did try unplugging the clod start valve but this made no difference.
Aux value has a nice 30 Ohms over it but i need to have a look at it.
 

Well after last night I took off and checked all pipes around the auxiliary valve.. made sure everything was tight and it burt into life with minimal efforts
Revs we’re a little low so I tweet the idel valve once it warmed up
Feels better now no drip and stalls but it’s hunting around at idel a little..
Is this a mixture thing or am I still looking at something else..

Clean up the spark plugs and take it out for a good run then recheck the colour of the spark plugs once they are cold.

What is your idle speed?

paceman presumably the 5mm I.d x 2mm that comes up on the link is the right size for idle screw?

Ignore me, it doesn't give the option to change the size anyway, duh 🤦‍♂️

No worries, that is the right size though. I stuck a smear of vaseline on when I fitted it as new ones are a tight fit in the barrel!

So todays instalment.

After the advice on plugs I decided to get a new set which have been fitted. I also did drop the oil and replace the filter as I could remember what oil I put in it when I rebuilt it

Started first time which was positive with no leeks too. Check the timing and made sure ignition timing was 6BTDC.

Had a little turn of the injection screw but this made no difference to it.

Looks like it running ruff with black ish smoke from the exhaust.. as I’ve got the VAG gauges which shows the engine pressure which just above one bar but drops as the engine starts to stall out.. but the the aux valve clicks and kicks the revs back up..

This has got me stumped now..
Not too sure what to do next

Well after some time i have taken the car to the garage, i know.  Also i hope this information helps someone too so i'll keep this updated to the final fix.

They have worked out that the mixture was still to high and put it on a CO2 meter so have turned this back to what it should be.  This would have explained why it was running the way that it was.  Due to this was masking over another issue.

When the car warm runs fine, however still has the issue were it would not allow over 3000RPM.  On the CO2 meter the reading go very high at this point, so it over rich.

Cold start is a complete pain, hard to get it going and then runs like a bag of nails till warm.  So going to have a go at changing out the cold start valve for a eBay one to see if this makes any difference.

I think what you really need to do is to check the fuel pressures and go from there.

Something else, if it has been retro fitted with a WUR with full throttle enrichment and the vacuum pipe is not connected it will run rich, have a look at that, they're a bit taller than the standard WUR and have a pipe to connect to. 

Nope it not got one of those ones.  Just the normal one that the K-Jet has.
I checked the pressures were as advised in the manual all were ok.