Club 80-90 Forums

Hi everyone,

I appreciate there is thousands of threads on this - we've read a lot (and tried an awful lot too!), but hoping someone has a bright idea for our particular symptoms. Apologies for the essay - just trying to give you as much info as possible.

We've got an '86 1.9 watercooled, that's is struggling to start in cold weather, let's say anything colder than 4 degrees...

The issue isn't actually starting, it will turn over and fire up fine but runs on a very slow idle. As soon as I touch the throttle, even the tiniest amount, it will stall. If it helps, we can see on our solar controller that the alternator doesn't seem to be kicking in either - normally when the engine is running we see a reading around 13.8V but on this slow idle it's only around 12.4V. Does this mean the mixture is too rich?

Eventually after letting the engine warm up for a while on the slow idle, and starting it a few times with the gas pedal down it will start properly on a nice strong idle - it also gives us a nice squeak from the belts too, and we can see the battery voltage reading as 13.8V. The van is always a bit sluggish for the first couple of minutes when we start while it warms up - just need to be heavy on the gas pedal - doesn't happen in summer.

When the weather is a bit milder (8 deg+) the van starts and runs fine (sometimes a belt squeak on start, sometimes not).

We have had stalling issues before from blocked carb idle jets, so we always make sure to give them a spray when we're having difficulties - so I don't think it's that.

Recently, we had a coolant leak from the thermostat housing - so we've replaced the whole housing, with the new thermostat too - though this all appears to be functioning correctly, when the weather is not very cold...

We've got new fuel filters in there, and also replaced fuel tank and about a year ago. The mechanic changed the fuel pump too - we have recently realised it's the cheapest one from brickerks: https://www.brickwerks.co.uk/fuel-pump- ... l-wbx.html - is this an issue?

Alternator also new (less than a year) - starter & leisure battery (less than 9 months). Belts seem "tight but not too tight".

Any help or pointers would be gladly received - we definitely don't mind getting our hands dirty, but definitely still beginners!

Have your read the thread on the pierburg cold start - the choke flap may be an issue for you as well.

I know its easy to check but I couldn't tell you how any more as I have changed the engine for the gti.

Have a read and look at the pictures

regards

Em
x

Quite possibly - I can hear the click in the engine bay when depressing the gas pedal, is that the click i'm looking for. Apologies - we are new to this!

Do I need to take the pancake cover of the carb, and watch flap to see if it moves when gas pedal is depressed?

Sounds like the fan belt needs adjusting / replacing to stop the screeching.

On the cold start, I think you should be looking at the cold start system as suggested above and check the ignition timing

[quote="937carrera"]Sounds like the fan belt needs adjusting / replacing to stop the screeching.

On the cold start, I think you should be looking at the cold start system as suggested above and check the ignition timing[/quote]

Will have a look and take some pics of the carb tomorrow. Wondering whether it's worth me buy a timing gun and tachometer (ours doesn't have one) and having a go myself. Do you recommend setting the timing at 3,000 RPM: http://www.gowesty.com/tech-article-details.php?id=162 - or is this a load of nonsense!

https://scontent-lht6-1.xx.fbcdn.net/v/ ... e=5B49E589" onclick="window.open(this.href);return false;

Photo of the carb before starting or touching gas pedal. Flap is fully open is that correct? It did actually start OK today, but weather was a bit warmer!

I just installed a tacho in my T25 - quite easy and very cheap

https://club8090.co.uk/forum/viewtopic.php?f=39&t=163521

It's always handy to have a decent timing light.Having read the article I wouldn't follow the suggested approach, idle timing is supposed to be done with idle stabilisation and vacuum advance disconnected. Furthermore the approach suggested depends on centrifugal advance and vacuum advance in the distributor being in good condition and operating in normal parameters. Of course, others may have a different view.

I looked at your photo now - the choke flap should be closed and it is open, so that needs fixing for cold start and idle when cold. Others on here have much more experience than me with the carbs so I'll leave them to advise the likely problem. There have been a couple of relevant posts recently so I suggest you research those threads too.

Great, we also took a video, I repeatedly pump the gas pedal and the choke flap slowly closes, when it's nearly closed BAM it fires up.

Read in this thread: https://club8090.co.uk/forum/viewtopic.php?t=139262 I should only be pressing the pedal once. A VW mechanic in Germany told us twice when it's cold, once when it's warm!

We'll be a bit more scientific about it tomorrow and get another video.

Thanks again for your help, reading the other threads and just working out what I can try without removing the carb - not quite confident enough to do that yet...

Thank you also for the thread on the tacho, we've heard the so called 'buzzer of death' so going to check whether it's already wired up.

OK bit more investigating today, and feel like I'm making progress.

1. When cold, the choke flap is fully open.
2. The van will start eventually when this flap is open, but will cut out as soon as we touch the gas pedal.
3. We tried depressing the gas pedal once didn't move the choke flap.
4. We tried depressing the gas pedal twice, which also didn't move the choke flap.
5. If we push the choke flap closed, it starts up beautifully.
6. We're not sure if the small spring in auto-choke mechanism looks right (not the coil, the one that controls the flap), here's a video https://www.youtube.com/watch?v=AafE-x5 ... e=youtu.be
7. Another video playing around with the mechanism thought it might help diagnose some issues: https://www.youtube.com/watch?v=FN4JhPVn4Wg (ignore the throttle cable we noticed that after the vid..)

So one question hope someone can confirm, the choke flap should be closed when cold, and slowly open up as the engine warms up?

Question two: does that spring look OK? If it needs replacing is it going to be tough to get that part of a carb?

The choke flap should be closed when cold.

It opens due to heat on a bimetallic strip on the carb (can you see the round bit with an electrical connection). That has a bi-metallic coiled spring inside. Heat from either the electric current or conducted heat from a warm engine opens the choke.

Make sure the bimetallic spring is in good condition and connected inside the round bit.

My WBX has a different carb so my pictures won't help. There is a good one posted recently on here with an elastic band holding the operating finger in position.

[quote="937carrera"] Heat from either the electric current or conducted heat from a warm engine opens the choke. [/quote]

On a Pierburg the choke unit has a water feed from the hose blow the header tank ...

[img]https://www.brickwerks.co.uk/media/cata ... 21108j.jpg[/img]

and then to the manifold ...

[img]https://www.brickwerks.co.uk/media/cata ... 21060a.jpg[/img]

Ian

Thanks Ian, too much history on Aircooled not enough on WBX yet.

[quote="937carrera"]Thanks Ian, too much history on Aircooled not enough on WBX yet.[/quote]

No worries mate

Don't over tighten belt, mine was squeaking when I first bought the van, overtightened it and the water pump started leaking at the impeller, pump was possibly on the way out anyway, but learned from it.