HELP - Continuing poor running saga of my 1800 kombi

I'll try and keep this brief.... 🙄

My '75 1800 kombi is running poorly - I have previously described this as a 'hesitation' problem but can more correctly be termed 'stuttering'. In the initial acceleration period of each gear, with the throttle open just a little, the van jolts and doesnt pick up speed as expected. It can be made to stay jolting/kangarooing without picking up speed. When floored, it takes off (but neither as strongly as you would expect from an 1800, and it seems to struggle to get over 100kph).

My carbs have been apart, tuned, cleaned, checked, etc... I think this is a problem with the distributor, but i'm clutching at straws now.

The dissy is a single vac with elec ignition... number 021-905-205P... Old volks home suggests this is a 76-78 2litre dissy, but i have a feeling it should be compatible (are others running single vac dissys on these engines?).

I have been correctly timing this at 7.5deg BTDC, and have watched it advance smoothly with the strobe up to a max of 28deg advance when revved. The vac advance works fine also.

When driving, it feels to me like the timing is too far advanced... but i dont understand how this can be. I had a go at retarding the timing a little and it smoothed it out a bit but the power was lacking.

Any more suggestions/ help? What dissys are others running on these engines?

I'm going insane (we've almost put him up for sale several times over this, but i'm trying to hold my nerve!)

Sam

Hi , 28 Deg Total sounds a little low for a type 4 motor .
But
Also you might think I'm crazy but how old are your rear Tyres ?
Are they still round?

cheers

i run a 009 on my 2L. is there any wear on the dissy shaft ie can you move the shaft sideways. hows the condition of the base plate in it

Tyres are in good nick, wheels are square

I mean round 😀

28deg is the mechanical advance only.... the vac advance is added on top 😉

There is a little wear in the dissy shaft but as i said its on electronic ignition so the timing mark is very consistent.

This may sound like a dumb question but which bit is the baseplate and how do i check its condition? I've taken this dissy apart completely and cleaned it all up in the past.

Sam

[ Edited on 19/7/2006 by Samblers ]

the baseplate is the plate under where the rotor goes that controls the advance

Check the dwell , is it steady? (that will eliminate the base plate thing)
Type 4 can take up to 34 deg total mech ! vac hose disconnected , sound like the mech advance may be a little lazy

Theres two plates under the rotor on with the little/ball thingy at the top and the bit in the bottom where the weights sit. What am i looking for? Wheres the wear?

I dont have a dwell meter... doh

the mech advance is working to spec according to the old volks home website... shouyld i try advancing it more ???(others have told me that 28deg is the max mech advance for these engines)

S

this site is good for a general overview of checking and rebuilding a bosch distributor http://www.glenn-ring.com/010/

ok reading straight out of the gregory's manual
uneven wear on distributor cam
faulty ignition coil
vaccum advance mechanism sticking or excessively worn
vaccum advance unit inoperative

the only other help i can offer is to try and buy or borrow another distibutor and test it in the van.

good luck your determination to persevere with this problem deserves a win.

I have the same problem it seems. Does it go away mostly when the engine is hot?
Cheers

No, its worst when the engine is hot! When its still on the chokes it runs a bit better!

Will report back in a bit 😉

Had a similar set of symptoms yonks ago. And after checking vacum hose from dissy to right hand carb, Current to carbie solinoids (really important).I guessed it must have something to do with that 30 year old distributor. I posed the question?,Do I continue to drive whilst the engine stammers through t intersections and when forced to overtake? or eliminate one problem on a long list of to do's.
After inspecting an empty wallet I eliminated the distributor as the possible source of my troubles and decided to focus on possible soutions within my budget.
Three more days followed of intense technical research followed and wishful thinking that perhaps come morning my beloved bus may have, during the night, cured itself of all its aliments and I would not have to contemplate the likelyhood of a brake down and subsequent tow equivlent in cost to a new distributor!
2 brake downs in peak hour traffic later( both physically and mentally), everything clicked. KONDENSOR.
And for a while at least I had revived my big loveable dud.
and my Ta"uschung Iron clad once again.

Excellent reply dude...

except i dont have a condensor!!!!!!!! (electronic ignition doesnt need them!).

I will stick it back on points again and see if that helps though 😉

S

:o Alrighty then, Get ahold of a Gregorys manual for your bus. I know they aren't the most comprehensive manuals ever written. However turn to the carbies bit. Its quite clear and has the least amount of contradictory terms for a single object in one paragraph. do that bit. but make sure you've done all the other bits before that bit,to make sure the crucial bit counts. Do the crucial bit properly using all the right stuff. Or that will bugger up all the other stuff and well.... I suppose, you'll probably have to get the bus?

Oh and if that proves futile, Its time to assume an advanced yogic position under the bus and replace the busted fuel pump diaphram(assumeing your running mech pump). You'll need 12 point key to suit as the top bolt is frankly a shit to remove with the engine in and the bus on the ground. A good idea is to remove the bottom fastener on the warm air stove pipe to the air filter so you can get a turn on that top bolt.
and if that fails take the bus to a mechanic, They will sort it out,decide if they like you and charge accordingly.

maybe i'll just set fire to it ?

No, by doing that you may throw the entire East/West coast vw equalibrium out of balance. Resulting in an Affront to the Great volkswagen gods.
thus bringing down their vengeful wrath in a dark and dreadful time of annoying car repairs which will plaque us all and will continue until such time as you, and only you have conquered this infernal...?, "hiccup", in an otherwise realatively careing relationship you seem to have with the Van.
Ps, Dont curse them or threaten them. It hurts their feelings and they always have their way in the end.
Sure you'll feel great for amoment or two, But then it will dawns on you that, Betsy or Mertle or Bud or whatever has had the last laugh as you realise that in your arson frenzy you've left your house key in the ignition and wallet on the dash. And the volks gods will look down and frown upon their once faithful deciple and how silly he looks on the long walk home with the empty jerry can.

I admire your wisdom dude... and your spare time 😉

Where's the matches?

REPLACE YOUR FUEL FILTER!!!!! Happened to me in the beetle, easy fix..

the jolting ride between gears on acceleration suggests the accelerator pump is not squirting enough fuel. the only other thing to check are the vaccum lines including the one to the brake master cylinder i have replaced the rubber part of that line on 2 of my kombies because of cracks, hard to check because its under the vehicle up behind the rear passenger side wheel section.
I've had the same sort of problems with my 2litre kombi camper, i rebuilt the carbies replaced the solenoid valves, removed the choke plates (i always do that with solexes) replaced all the vacuum rubber hoses new plug leads and plugs new air filter then i started to turn out the accelerator pump screws and after it has fully warmed up it is very smooth on acceleration but never a world beater for performance.
at the moment it has a inlet valve seat gone on the no4 cylinder so i'm going to replace the head and then i am going to put a set of alfa 36mm webbers on it.
don't give up believe me when you strip these vw motors down to their innards they are very very simple machines.

Yup, have already stripped this one to its innards once, doh!

I dont think its the accelerator pumps or fuel related...I think the vacuum leak theory sounds like a likely cause (i havent checked this all yet cos its miserable outside!)... I'll give you my reasoning:

Say i'm cruising in 4th gear at 80kph. The throttle is JUST open so i'm slowing down slowly. If i veeeeerry slowly start to push the accelerator pedal down, to keep the speed constant, it kind of does nothing for a bit and then thats where it gets bogged and starts to stutter quite harshly.

Observations:

1. The speed hasn't changed so the MECH advance shouldn't have either

2. The accelerator pumps aren't in play because i havent stamped the throttle

3. The load on the coil/ plugs etc hasn't changed so they should be alright

4. What i should be getting is more VACUUM advance to get the speed going. I know the vac advance on my dissy works... so???

Are we agreed?

Did you check the FUEL PUMP DIAPHRAM ?
If it is split it will cause this type of impedement. ps, As suggested vacume hoses should be replaced.

havent, but will do 😉

Samblers wrote:Say i'm cruising in 4th gear at 80kph. The throttle is JUST open so i'm slowing down slowly. If i veeeeerry slowly start to push the accelerator pedal down, to keep the speed constant, it kind of does nothing for a bit and then thats where it gets bogged and starts to stutter quite harshly.

When barely under acceleration (cruising) the fuel swirls around the fuel pump and fuel still gets through.. When the fuel pump pushes fuel through the outlet under slight acceleration the outlet gets clogged with rust bits and shit from the bottom of the fuel tank and causes bad stuttering. Have a look at it, and it only costs $5...

My VW guy says my fuel pump has low pressure (like 2.5 pounds when it should be 5)... so hopefully thats it

Start pulling it apart 😉

S

Fuel pump diaphragm had small split - replaced pump

Still runs shit

:cry :cry :cry :cry :cry :cry

Good. now with the air filter assembly off whilst running give the bus some throttle and make sure the accelerator pumps are working on both carbies. They should squirt equal amounts of fuel into the venturi.. Eliminate this. Then Re-tune your carbies start with the old worn out linkage, compensate, then go step by step. you would be amazed at the range of flat spots that can be acheived through the revs. If each step is not followed. A carbie synch takes out the biggest guess work In the equation. If not carbs then back to ignition, timing. Do a compression test and eliminate the valves/guides.

My 2L Kombi had much the same problems. I tried for ages to tune the carbies.

I went through all the checks

-vacuum leaks
-plugs
-coil
-points
-condenser
-leads
-timing

I finally fix my problem.

I replaced the carbys with other pair of another Kombi.

The carbies now on it are the dirtest looking carbies, but once I bolted them on, connected everything it run great.

Its like a different car to drive. I wish I had done it sooner.

Maybe hunt around for a second hand set of carbies.

Had exactly the same problem (hasnt everyone lol). Ended up being the throttle synchroniser. Adjust your throttle linkages (coming down from the cross bar). You want both throttles to move at the same time, otherwise one side of the engine will try and do all the work the whole time (run like shit)... its going to end up being one of those little things you thought it couldnt be... just slowly keep checking things off the list.

Well, my accelerator pumps are working ok, i know that... and its just been into my local air-cooled place and had a carb balance and settings tickle-up

It either ignition or carbs, but without seeing a fault in either i dont want to replace them 🙁

Never buying another dual-carb engined VW... twin port 1600 is the go

Don't give up. You will be all smiles when you have got it running spot on.

:P:P:P:P:P

The battle only makes it more satisfying! I picked up a set of reco'd duel solexs for $100ish... worked a dream, bargains are out their. You should be able to pick up a dizzy pritty cheap aswell.

did you check your throttle crossbar adjuster??

To be fair i only paid $5 for the dissy (plus one free), so i could just pick up another and put that in... its the carbs that scare me.

Struggling for motivation sorting the damn thing out though - my heart sinks every time i lift the engine lid

There should be a stickied thread for 1800 dualcarb faultfinding. I always feel angry when I think of them.

I'm leaning toward an unspecified carby fault. It's amazing. They can be completely ratted and keep chugging just fine, or have the tiniest thing out and make the motor run like a lawnmower.

Still trying to faultfind mine too. The carbs usually seem to be the issue though. If not, have you tried swearing at it _really_ loudly? Even if it doesn't help the engine, it'll make you feel a whole lot better.

If i havent died first!

Every time I think "Hey, I know! It's (x) that could be causing it to run badly", I build up the determination to have a look. Sadly enough, every idea of a problem I had was true. I'd fix it, and cross my fingers. Start it up. Still runs wrong (Too damn hard to explain easily).

Others may know, Is there an easy way to dynamically check vacuum? I thought of the whole loop of plastic hose with water etc. But it seemed a little clumsy.

A thought. Are you absolutely sure the top gaskets of the carbies are perfectly seated? They can easily stuff up the running of the motor.

hey General_Failure, good 2 c ya bak man.
Samblers, i get shitted very frequently at my bus, dont think your the only one lol.

Just keep trying to cross one thing off the list at a time.

Okay.. this may be off topic, being as you said the carbies had been looked at... but here goes..

I have a Nissan Patrol (1984)... don't laugh. About a week ago it started doing *exactly* what you describe. It'd go to 1500-2500 rpm, then just cut out.

Fortunately, the Patrol has a second choke that is pretty much like a second accelerator pedal. I had a party trick I'd do at times, where I'd drive from the running board, by leaning in thru the window. Pulling that choke out halfway solved the problem.

Anyway, after checking the timing, doing almost everything you've described, someone suggested it was crap in the main jets... can I say crap on this board? So I took em out, blew through them, and hey presto! No more kangarooing or driving with the choke half out..

Hope this helps.. I'm a new member.. trying to build up some karma 😉

Let good karma be upon you child!

Thanks for the reply... crap in the jets (see, i said it too!) would explain the problem... but i've blown them through twice, along with every other carb bit, so ive kind of discounted it.

I'm thinking its just one of those inexplicable things that will just magically go away after spending $X00 on some more carbs, a fuel pump and a distributor... but being an engineer (dont laugh) i HATE just replacing parts until the problem goes away. I like to see the proof!

Grrrrr!

Is there anyone in Perth who's got lots of gauges and stuff who wants to come round and have a tinker for a crate of beer ? 😉

mate where the hell were you when i was selling my last 1800 out of my 76' bay,

that was a perfect engine with comp tests and full rebuild receipts
came with all carbs n dizzy n everything cos iz doin engine conversion...

ended up sellin it all to VW shop for $350

ah well........

Okay... back to the drawing board 🙂

I've read through Muir's "Compleat Idiot", and Haynes '72-'79 Manual for 1700/1800/2000.

The only suggestions they have for your symptoms are that either the accelerator pump is not working properly, which you've eliminated, or the idle adjustment is incorrect, but hey, books - what do they know??

Muir says that for a 1975 Type II, the ignition should be at 5 degrees ATDC. Haynes say that 7.5, 10, or 5 degrees BTDC is correct, depending on if the engine is from Europe, US (auto) or US (manual).

Hope these help.

If it were me, I'd give each of the ignition settings a try, then have gander at the carbs. How's it running, with regard to idle speed, and temperature?

I know from experience how much fun (not) it can be squeezing around the 1800, but chin up! 🙂

[ Edited on 6-8-2006 by mpbriggs ]

Its not really acceleration thats the problem, its just maintaining any kind of cruising speed without flooring it.

As far as ignition settings go, i've got a single vac dissy with mech advance which i've looked up as requiring 7.5deg BTDC... I've currently timed it to about 10deg at idle because i think the mech advance isn't too hot and it runs a little better (smoother)... the other settings mentioned will be for alternative dissys i guess.

I'm still expecting about 10-20% more power than i'm currently getting though. Grrrrr

As for the dude who sold his entire engine for $350... thats just fackin nuts!

If anyone wants to sell me another set of twin carbs for this puppy then U2U me 😉

Sam

I have done this trick a couple of times to help clean out any dirt in the carby jets, and it works sometimes.

With the engine running and the aircleaners removed rev the engine to about 2000-3000 rpm

Cover the mouth of one Carby entirely with the palm of your hand.

The engines revs will die off but then give it 100% open throttle to try to keep it running.

The engine revs may still die down but ensure that you remove your hand before the engine stalls as it is then flooded and hard to start.

Repeat with the other Carby.

You only need to keep it covered for a few seconds (3-5seconds)

The reason this can work is as you block off the air supply the engines vaccuum draws large amounts of fuel through the jets and can dislodge any dirt particles

The other benifit is that with the palm of your hand feel the different vaccuums through each carby and also how well the other carby runs the motor while one is blocked off. Each side should have the same changes.

It is a bit of a bush mechanics procedure but it may show so differences between each carby or vaccuum and may even solve your problem.

Jeremy

Dude, I feel for you. I had a very irritatingly misbehaving dual carb stock 1800 too. Similarly, when she was playing up, I could very very very gently increase pressure on the acclerator and she would slowly but smoothly speed up. Then I'd hit a bump, or press a little too quickly, or a butterfly flapped its wings in Chile, and all of a sudden the bus would stutter, shudder, slow down and I'd have to PUMP the pedal to get anywhere. Picture driving across South Aus near the Flinders Ranges, 35degrees outside, heater stuck ON (it'd burn yer hand if you held your hand above it, until I disconnected it one day), and doing 40km/h. Not that much fun. And I could never figure this thing out!

The problem was intermittent. Some days she'd be fine, cruising at 85km/h for hours on end. Other days she just wouldn't want to go. And once the problem started, it'd almost never go away until the next day.

I noticed that it often happened for the first time on any particular day after we'd stopped for a break. So, the engine was hot from driving happily along, then we'd say, get fuel or stop for photos. Then after starting again, she'd be fine for a minute or two, a few km, and then wham, stutter, oh dear me! Back to shuddering along. I noticed that in this cripple mode the engine was shaking like mad. I therefore did a quick check: pulling the leads of cylinder 3 or cylinder 4 or from BOTH 3 and 4 resulted in absolutely no change in engine speed (OK, going by ear). Pulling off either of cylinder 1 or 2's leads resulted in instant death. This might be something you could try too, it's pretty quick and easy hey. And the tingling feels nice... Oh uh lets move on.

Of course, every morning when I booked her in to see a doctor, she'd be fine again. After paying $70 to be told there was nothing wrong (because at that time she was behaving of course) I realised I'd have to sort this out myself.

So one day she buggered up while driving along, and I happened to have my tools along with me (heh, in an old VW, never! :P) Anyway, I had by this stage decided that It was fuel related. So I opened each carby and lo and behold, the one feeding cyl's 3 & 4 was bone dry. I filled it up, put the lids back on, and drove home with not another issue. Now clearly I didn't actually DO anything there. The carby-full of fuel wouldn't have lasted all the way home, so I still didn't actually know the root cause. There are several reasons why a carby might not have fuel in it.

1) fuel pump buggered. Nah, other carby has plenty of fuel.
2) fuel line blocked downstream of T-joint. Nah, replaced earlier by me.
3) sticky needle valve. maybe!
4) freaking moronic dumbass finicky idle cutoff solenoid broken. maybe.
5) simple little piece of wire to cut-off solenoid having a loose contact.

Well, I replaced the cut-off solenoid with one I have lying around which has it's top cut off. Apparently that's pretty common. I also replaced the wire. Now I didn't replace the needle float valve thing just 'cause I haven't got a socket that'll fit in there to unscrew it.

I am not actually convinced that the solenoid cut-off valve was THE problem. But in the last year and a half she has not ONCE let me down. Absolutely no problems at all. I love that bus!

So it may very well be something small and simple. Try pulling the leads off, try checking the fuel level in the carbs, don't yet reach for the matches.

Hope that helps dude, cheers, Aurel.

Aurel,

cheers for that dude... tech help is so much easier to read when there's a story behind it! We too found the flinders ranges as hot as hell... and beautiful 🙂

I tried the whole gig a couple of times taking the lids of both carbies and seeing if fuel was present. There was (is)... but the float level is like 17/18mm from the top of the carb body on both sides, when its supposed to be 13mm. The books say you're supposed to be able to adjust this float level height by adding/ removing washers from underneath the needle valve.

Since I only had one washer underneath my needle valves i decided that i couldn't get the float level any higher and anyway i couldnt work out how it make a difference to the running of the van... the thing has fuel, right?

When I was putting the engine back together after our Bribie island disaster (so far from home!) we snipped the ends off the fuel cut-off solenoids and put in fixed jets where the 12V ones are supposed to be. Make sense?

Anyway, its driving a bit smoother now i've advanced the timing but its still lacking the power that i know it should have, grrrrr

S

What colour are your spark plugs? I don't suppose you've got a CO meter have you? I was just thinking that perhaps the plug colour would tell you whether it was running rich or whatever on one or both sides, but you said that you had the carbies tuned... Hmmm, interesting...

the low level of fuel in the float bowl could? be your problem.
i've just measure a spare float bowl i have and the 17/18mm fuel level comes very close to the inlet of the accelerator pump circuit in fact it only just covers it.
so basically you are driving down the road on the idle circuit or the main jet circuit either one is consuming fuel and it is possible that the accelerator pump intake is above the level of fuel left in the carby hence no transition just a big flat spot ?maybe?
I guess a way of increasing the fuel level would be to carefully bend down the tab on the float which closes the needle valve.
the fuel level of 12 to 14mm must be set correctly for the carbies to work properly.

you may be a genius

i shall look into this and post some beer if it turns out true 😉