Mk2 16V poor cold running

[tobz.]

Hi I'm hoping somebody might be able to suggest some solutions to a problem with my MkII 16V Gti. It's a 1990 model on a H plate with 117k on the clock. The problem is as follows: Very spluttery from "cold" start (doesn't actually have to be cold it displays the problem even on hot sunny days when I leave work). The car starts first time but wont tickover and stalls straight away. To get it to fire properly you have to kind of tease the throttle a bit (push it down too far and the engine will stall). Once you have managed to get it revving for a few seconds it will then tickover albeit a bit rough. The car will then require excessive revs to pull away without it starting to misfire again. For the first couple on minutes driving it will misfire a couple of times following a gear change and if any junctions are encountered excessive revs will be required again to pull away (also it's a bit guttless while cold). Once the engine has warmed up it will happily sing its way to the redline all day with no problems (not that I do that all day before somebody suggests that could be the cause of the problem!). It has recently been to the garage where the following was carried out: Idle valve cleaned Idle switch found not to be working and rectified Mixture set up after found to be running very weak Bypass valve cleaned (I believe) Please help it's starting to get embarassing! Thanks in advance for any suggestions. Toby

[shawn]

snap
i've got the exact problem with my car, i've cleaned all the breather pipes and the taken out the idle screw and cleaned that as well, but it still runs the same, interested to know if anybody has cured this problem.
Sorry i can't be of any help.

[richandhazel]

I'll try and dig out the warm up regulator electrical tests for you tomorrow evening.  

[tobz.]

Just thought I'd update the thread. I measured the bimetallic strip in the warm-up regulator and it measured 23ohms (bang on what it should be). I also measured the supply to it and it had a blip of 12v when the ignition was switched on and then constant 12v when running so this seems fine. This morning I unplugged the warm-up regulator before switching on the ignition, started the car and it behaved exactly as it always does (if anything it was a little bit better but I'm dismissing that as a coincidence). I'm strongly suspecting the regulator as a result of this, does anybody know the usual failure condition of the regulator? i.e. is it normally the bimetallic strip that goes open circuit or is a mechanical failure more usual?
Thanks for any help guys it's going into the garage next week to have a rattly camchain fixed and I'd rather tell them what to change on the injection system than fork out for hours of fault finding which I can do myself!
Cheers for the suggestion golfvr6 I have a spark plug window from back in the dark old days when I was a...........ahem...........ford driver. I'll dig it out and see if its long enough, chances are it'll be a larger diameter though.

[richandhazel]

Unplugging the regulator when starting up from cold won't make any difference, initially. That plug provides power to the heater in the regulator. Been having a look around and found this in a thread elsewhere:-

Q
'Still having cold starting woes. It will stall a couple of times when starting cold, then not be able to rev for about 20 or 30 seconds.. you open the throttle, and the engine bogs down. Open it wide, and the thing cuts out. I had this trouble before I got the unit replaced (with a second hand unit, mind you dammit). Hmm... thinks I. I disconnected the plug from the unit and started it from cold again. Same crap. So the unit may as well not even be there, because it's not controlling the pressure at cold temps. This could be the wiring, i suppose. What should I be looking for in terms of voltages, etc?'

A
that electrical plug is there to energize a heater that will make the regualted pressure go up as engine warms up (when it is lowering pressure to begin with).
A fault in the electrical part would make it run rich for an extended period past when engine gets warm, not cause any trouble with initial start performance.
It sounds like your CPR is not regulating, they can be adjusted but it is complicated and tedious to do and not always successful. It requires a fuel pressure gauge setup to measure the control pressure to get it back to the right level at a given temp.

[richandhazel]

Also found this:-

Starts hard cold- This is almost always the warm up regulator. High cold control pressure will make the mixture very lean. The cold start valve will still spray and you will likely fire up for a second or two and then die. In order to see what your control pressure is you will need a set of special gauges which are available at most auto parts houses. Keep in mind that you have fuel pressure at all times, even with the engine off, so be careful when attaching fuel pressure gauges.

at: http://ncr-pca.org/tech/tech-cis.htm

[wayneprice]

Hi I'm hoping somebody might be able to suggest some solutions to a problem with my MkII 16V Gti. It's a 1990 model on a H plate with 117k on the clock. The problem is as follows: Very spluttery from "cold" start (doesn't actually have to be cold it displays the problem even on hot sunny days when I leave work). The car starts first time but wont tickover and stalls straight away. To get it to fire properly you have to kind of tease the throttle a bit (push it down too far and the engine will stall). Once you have managed to get it revving for a few seconds it will then tickover albeit a bit rough. The car will then require excessive revs to pull away without it starting to misfire again. For the first couple on minutes driving it will misfire a couple of times following a gear change and if any junctions are encountered excessive revs will be required again to pull away (also it's a bit guttless while cold). Once the engine has warmed up it will happily sing its way to the redline all day with no problems (not that I do that all day before somebody suggests that could be the cause of the problem!). It has recently been to the garage where the following was carried out: Idle valve cleaned Idle switch found not to be working and rectified Mixture set up after found to be running very weak Bypass valve cleaned (I believe) Please help it's starting to get embarassing! Thanks in advance for any suggestions. Toby

Sounds exactly like my problem. I've replied to a few tonight. I tried everything on mine including a full VW setup. Changed every valve and sensor you can think of. I then went back to basics and checked the fuel filter. It turned out to be clogged. Mine was a 1989 16v with 102,000 miles. Due to the age of the car there was a lot of muck in the petrol tank. I flushed it out and replaced filter, It now runs like a dream. Hope it helps. I Know exactly how you feel

[msond]

I have had the same problem with my car.  Mine also stalls (even when warm and running fine) when approaching roundabouts/junctions etc. If I depress the clutch with the revs above 1500rpm, it normally dosn't stall. But if I depress the clutch with the revs below 1500rpm, the car stalls.

I've changed the plugs, replaced the warm up regulator (second hand unit), and had the engine tuned.

The engine runs much better when warm, but still stalls and is only slightly better in the morning. I'll try changing the fuel filter next.

Any ideas about why the car keeps stalling would be appreciated.

[red16v]

Hi msond,

I had exactly the same symptoms on my 1992 16v. I took it to two Main VW dealers and one specialist Bosch fuel injection specialist. All of them diagnosed it to be the slow idle adjustment. All of them adjusted this and all of them had the same result - no change and no improvement.

Out of desperation I took it to a local independent VW/Audi service outfit and after listening to me declared that the 'slow idle adjustment' needed setting up - NO I said, and explained that everyone else had adjusted that with no change. No, they said, we think its definitley the slow idle adjustment. They took the car into their workshop and undid the slow idle adjuster and inspected it - it was 'clagged up' with all manner of deposits presumably from many years of use. They cleaned the clag off the end of the needle, re-inserted it and started her. 100% success and I've never had a problem since.

Needless to say they look after my car now and I never take my car to a VW dealer anymore, if only the lazy so and so's had bothered to inspect and clean the part they were adjusting.

 So, if you want to try it yourself I suggest you locate the slow idle valve which is (I think) adjacent to the slow idle microswitch (looks like a 'brassy' material), undo it - carefully counting how many turns it takes, clean the end of the valve with a suitable non-aggressive cleaning fluid and re-insert it to the same amount of turns as you took it out (obvious that bit I know). I hope it works for you, certainly the stalling symptoms you describe were exactly like mine. Kind regards, yt.  

[golfvr6]

slow idle valve? never heard of that one before