Hi all.
Poor Andy is feeling the worse for the journey round the country again!
We have been through Kakadu and are now in Katherine heading south.
Andy ('77 bay kombi, dual carb 2L) is feeling a little sick.
The symptoms so far are poor/no idle when cold (runs on 2-3 cylinders).
Once he's warm the idle sit's on ~1400rpm with an occasional miss.
He's generally lacking power from idle to ~2500rpm, but fine above that. He also back fires intermittently on a trailing throttle.
I have also noticed the cyl. head temp is ~50degF cooler than normal since the problem (it's on No 3, 4 head). Oil temp is normal.

It's hasn't stopped us continuing on, or affected fuel economy etc but is being a real pain.

Each night I have been trying a new theory as to what it could be, so what I have tried so far in no real order are (none of which have made any real improvements):

New points, condensor, cap, rotor. Swapped in my spare distributor, and coil. Checked plugs and plug leads, all look good (except for No 2 plug, more later).
Checked timing, dwell of course. Timing seemed to vary a bit at idle, but most likely due to varying idle speed?

Checked compression, all good.

Fuel pressure OK, new fuel filter fitted, carbs removed and cleaned (no dirt in them).
I also disconnected the central idle circuit on carbs with no change. The chokes also function correctly.
Air cleaner still servicable (done ~5,000km)
Double checked valve clearence, all OK.
Also checked battery, alternator working well.
Exhaust is tight, and no apparent leaks.

I will also add the probelm I had in Perth (No 3 head gasket leak, and was fixed) has turned up on the other side, I guess in No 2 cyl hence the slightly black No 2 spark plug, where the others are all fine. It isn't noticable on a compression test and hasn't affected power so was planning to make it home like this.

ALSO, does anyone know what the mechanical advance curve should be on the stock distributor?
The "good" distributor I have has one very light spring, and the second, heavy spring doesn't have any effect until the weight is ~1/2 way out.
The "bad" distributor I have I have dogied up some springs to fit on, so probably doesn't advance properly. Niether distributor fixes the problem

It really has me stumped.
Does anyone have any clues as to what else I should check?
I will try and get back on the net tonight/or in the morning to check answers.
Otherwise I can be reached on 0416137163.
As I said it is not stopping us, but is very annoying.

THANKS for any input.
Cheers,
Richard
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[Edited on 28-7-2004 by Andy]

bump

timing shoul;d not vary at idle unless your revs are varying considerably. Does the clutch effect the idle/timing? if so then the problem is endplay and you are in some trouble. Other than that i'd be looking at the exhaust system as VW are very sensitive to exhaust problems.

the revs were varying between 1200 & 1400 at same time timing was varying, I just duplicated this situation on my engine, so not that, exhaust system is A1

before I go home, I should clarify the vehicle was running normally & approx 850 revs idle, first awareness of the problem is they pulled into a town & suddenly found the engine idling at 1400 revs

OK thinking on the fly here

sound lean?? - high revs and a occasional miss???

How about a loose manifold or split gasket???

Quote:

Originally posted by Kombi M@D FOUND THE PROBLEM......oops my bad the vacuum line from the manifolds to the brake booster had a crack in it. There you go that simple.

A couple of ideas:

- is it running on all cylinders? Sounds like one is not contributing. The one with the CHT sensor on it would be a good starting point if it's running cooler. Try checking the spark and compression.

- is the accelerator stuck slightly on? Check if it the idle adjustment screw goes completely back to the stop when idling. I got the problem you described by completely removing all slack from the accelerator cable!

Hi Andy....hope you find the problem....I just had the SAME with my engine!!!!! I've busted my brain for 2 weeks to try and solve it. I've had the engine out and checked EVERYTHING----new coil/leads etc etc....Ended up being a leak in the brake booster!!! Not the hose at the engine side. Damnm it had me stumped. Have you tried blocking off the brake booster outlet and trying that theory?? Just a thought. Hope all your travels have been interesting so far and you've taken lots of pictures for us less fortunate. Keep well and drive safely.

running crap when cold and idling high when hot, and being doughy low in the rev range definitely sounds like an air leak somewhere.

Hey thanks guy's!!!!
It's always the things you forget.
Mick, I can really feel for you, luckily I never pulled the motor, but had the same problem.
A perrished connection on the brake line check valve, cut the end off the hose and a new hose clam and all is back to normal. It's great to have 18" again (vacuum that is )

A big thanks also to KombiKim and Wes for the calls.

I really had to kick myself afterwards, I should have known myself.

Anyway, I hope you all have fun at Valla without me as we will still be on the road.
Till next time,
Cheers,
Richard

Ahhhh! That's one worth remembering!

Yay, "all problems are minor"! Have a good trip.

Its good to hear everything is fixed and running well Andy, the other thing that it could have been is the welsh plugs in the back of the left hand carby (there are 2 plugs).

So when are you due back?

Yeh....I should have known as well!! Unfortunately for me I picked it up too late and had to drop the donk to replace a head due to a dropped valve seat:cussing It took me ages to find the leak as I was so ticked off at the time I couldn't think straight. It is a good way to destroy a new head!!! S#it happens....good luck with the rest of your travels!!!!!:thumb

Hi Man
Glad to see you found the problem. Nothing worse than being away from home and the Kombi is playing up. After reading those replys, I now know what to look for if mine dose the same thing. Good luck for the rest of your travels.
Rob......