my van is a faliure AGAIN :(

[mr_clarkson]

some of you may have read my last faliure post 2 or 3 weeksw ago, since then i have done the work on the van and tody booked it into somewhere else for mot, it failed AGAIN this time on.....

1 brake line corroded - (the one that goes front to rear behind fuel tank - done that this afternoon, just need to bleed brakes in morning.

2 handbrake imbalance/little or no effort on pass side - not sure about this, i have just fitted new shoes to the rear (handbrake wasnt working before either, i thought it was ok but not on this side, going to have to take drum off and check i spose but not sure whats causing that.

3 this is the last thing.....and the hardest to sort for me, it failed on emmisions, the van has not been running right at all, there doesnt appear to be an air leak but wont idle properly and doesnt sound smooth, when he did the emmmisions it passed co at just 0.16 wich he said was very very very very low and it failed on hydrocarbons? im sure when i looked at the screen it was saying 470/480 ish but he said it was 1600ish and the limit is 1200 he said the van was running really lean(in fact another mechanic there said it smelt lean) so..........

i have been looking at the carbs and have a few questions and pictures.....

1) should both carbs be exactly the same? mine are slightly differant at the back, one of the (left side) has a bit at back with idle screw and breather pipe, the other one (right)doesnt have this they are both solex (then 4 letters buut cant remember) the -2 and -3 respectivly

2)if the carbs are correct, is the idle controlled from just the left carb with the bolt/screw by the breather?

3)there is a small screw in the side of each carb by the throttle adjusting screw, is this for mixture? (see pictures on next post)

my aim is just to try and get it running a bit smoother and get it through the mot so i can take it to someone to have it tuned properly.

hope this post makes sense and you can help

many thanks
jon

(pics to follow)

[mr_clarkson]

ok first up is an engine bay pic, after looking at other peoples pics i notice mine is missing what i think is a throttle damper? is this needed?



the next pictures show the top of the left (passenger side) and right (driver side) carbs so you can see the differance (not the best pics i know sorry, but should be able to identify if they are right or wrong (i hope)

left....

right....

finally here are a couple of side pics the left carb first, the red arrow points to the screw in the side that i am wondering if this is the mixture screw? it doesnt really make any differance when adjusted...
the blue arrow is what i think is the idle adjustment screw? but is only on this carb so is that the only one used for adjusting idle?
and the yellow arrow points to what the haynes says is a mixture adjusting thing, but this carb there is noscrew, just got some kind of yellow hard seal type stuff/thing in the hole but looks standard (i.e. not like someone has bogged the hole up)



and the right carb, just the red arrow that points to the same screw as the left one, again, is this mixture?





thanks for reading, sorry about pic quality

cheers
jon

[mr_clarkson]

please, someone must have a 2.0ltr a/c to compare? cu i think

[kit]

Cant help I have Diesel, sorry but someone will know I feel sure.

[meggles]

Sorry but can't make out the pics too well. From memory (I now have a diesel) my A/C carbs were similar but there were differences in mixture screws etc. The damper for the carbs should make no difference to the mixture. Have you carefully checked for air leaks in the many hoses? Also, bit obvious (sorry) but have you checked the air filter? Do you have a VW expert/specialist near you? He could advise you better. Maybe that's a tamper proof seal you have found (yellow arrow) and you just need to prise it out. Why did you not go back to original tester?
Good luck!

[mr_clarkson]

yeah have checked all over for airleaks and all seems ok to me, the airfilter is pretty clean although to be honest the airbox is off at the moment anyway whilst i am trying to get it running right. the yellow arrow i have tried prizing out but doesnt seem to be a cap just like a solid substance if you see what i mean and bits just chip off.

i have had the carbs off and cleaned them, put new leads ect and it is still running like a bag of rubbish, and when revved hard is backfiring out of the left carb, i have tried adjusting the timing (only by ear) but not making any significant differance other than raising/lowereing the revs.


i tiook it to a differant mot place becasu the last guy went well over the top with the van and made it clear he hated old cars and would go out of his way to fail them! i took it to my usual guy this time who is strickt but fair

[CovKid]

Had a very early type25 that had this engine (as well as a bay) and in both cases the throttle flap spindles were totally worn out leading to air sucking in all over the place and downright impossible to tune. Amazed theres many of these engines still around now. Tough one as you won't have the lower grill at the front and it would be hard work to convert to water cooled. If you still think theres life in the old girl yet, check the lower throttle flaps for movement and if its bad, get those sorted first or you'll never get it tuned. Ideally you want a guy proficient with a lathe. Loads up here in Coventry and a top man down in Clacton, Essex, that knows these carbs well. Once thats done you can better ascertain what actually needs attention.

Oh and yes, they look normal to me. Definately check hoses. Theres a 'balance' pipe/hose between the two if I remember.

[mr_clarkson]

thanks for the reply,

the balance pipe, is this the pipe that runs between the manifolds and up to the top of the left carb?

on mine there is rubber pipe joining the metal pipe to the manifolds/carb are they ment to be jubilee clipped as well?



there is a little side to side moivement obn the small butterfly at the bottom of carb but doest seem to be any play in the spindle that the butterfly is on.

[meggles]

Backfiring out of left carb!!! Just gave my brain a kick start. Replace your condensor!! Seriously! I replaced mine and the van ran like a bag of sh!!te, so I replaced it with an old, known good, one. Cured it! Its only a couple of quid so worth a try. I had had trouble with a blockage in needle valve giving similar probs so naturally thought it was same thing again. Took me ages to get around to thinking of ignition problem Why it backfired through left side carb I don't know. It's gotta be worth a try!
Good Luck!

[CovKid]

thanks for the reply,

the balance pipe, is this the pipe that runs between the manifolds and up to the top of the left carb?

on mine there is rubber pipe joining the metal pipe to the manifolds/carb are they ment to be jubilee clipped as well?



there is a little side to side moivement obn the small butterfly at the bottom of carb but doest seem to be any play in the spindle that the butterfly is on.

Long as its a snug fit, clips not crucial. You can get all this pipe still though. Check those throttle flaps. Squirt of WD40 around the spindle ends when engine is ticking over will show if they leak or not as engine speed will pick up. If they're original and never been touched, I'll bet they're worn. Really affects those twin carb set ups.

[mr_clarkson]

meggles, thanks for reply, but it is electronic ignition so no condensor!

covkid, thanks, i have tried and its not really picked up, HOWEVER...............

something just told me to look in the haynes at the firing order (not sure why i thought this but looked) it is down as being 1-4-3-2 i checked my dizzy cap and going clockwise from 1 it is/was 1-3-4-2 which would explain why it was backfiring from just the left carb as this is the one that feeds cylinders 3/4 i have swapped the leads over and it started nicer than usual but immediatly started revving its breasticles off, although it definatly sounded alot smoother!!! i think the revving will be because it has been like this for ages and i have been messing around trying to get it to tick over so a bit of adjustment tommorow (bit dark out there now) will HOPEFULLY see it ready for mot again.

roll on tommorow.

thanks for the replys and sugestions allmuch appreciated, hopefully it is sorted now but we will see

[meggles]

Yes, no condensor Mine should have been electronic but had been changed over! Sounds like you're getting there though. good luck.

[fullsunian]

Reading through this lot, It sounds like to me that you are diving in far to deep when something like the HC is usually two things...missfire or an air leak (I'm a tester by the way) and if I had to put money on it I would say an air leak. Don't start turning screws on carbs you could just make things worse. Air leak..
If you want me to try and help... no garrantees, give me a call..
IAN
07740344341

[meggles]

Nice one Ian! I'd rather trust an expert than missen!! Wonder why mine was spitting back when condensor went though Still, It's a diesel now so whole new ball game.!

[fullsunian]

Nice one Ian! I'd rather trust an expert than missen!! Wonder why mine was spitting back when condensor went though Still, It's a diesel now so whole new ball game.!

I am by no means an expert, but I'm learning very fast but I do know how to read a gas analyser
IAN