RESULT! CU running lean, what could it be?

[81AirCooled]

Another update in this seemingly endless saga. I took the van to an local ex-VW garage to check the timing. Well like advised it was out , it was set to 0° instead of 5° +-1° so they´ve now set it up correctly and adjusted the idle mixture. It´s no longer running lean apparantly but as far as I can tell without a proper testdrive there´s no improvement to performance and it may even have got slightly worse. Like I said I´ll need to test it on a hill and on the motorway to get a proper feel for it.

The garage said there are no airleaks, but they did notice that one of the vacuum hoses is disconnected from the dizzy and blanked off, but they don`t know why the first garage would have done this. Does anyone know what possible reason they could have for doing that and if I just reconnected it would I need to have the timing or anything else set up again? I still have the stalling issue when pulling off with a cold engine too, it´s also much worse in reverse. I´ve an auto gearbox so letting the clutch slip isn´t an option either.

Here´s a couple of pics of the disconnected vacuum hose. Board limit for uploads is full apparantly

[kevtherev]

You should use photobucket.com for pictures
it's free to join, just follow the on screen instructions

80-90 only allow a few pictures to upload
photo bucket allow millions

[BOXY]

It sounds like neither garage have set the timing up properly. If you disconnect both vacuum lines and blank them off the timing should be about 7 degrees BTDC (before top dead centre). If you then connect the one that's been disconnected that will retard the timing back to 4-6 degrees ATDC (after top dead centre). If you rev the engine to +3000 RPM the timing should advance to 30 degrees BTDC if the mechanical advance is working. Finally if you connect the second vac line from the left hand carb this should advance the timing up to 40 degrees BTDC at +3000 RPM.

The first garage may have set the timing at 0 degrees because the vac can retard isn't working, and they left it disconnected?. They should have set it at 7-8 degrees BTDC, the retarded timing at idle is only to reduce emissions I think.

The second garage have made it worse if they've set it to 5 degrees ATDC because your maximum advance will top out at less than 30 degrees BTDC instead of 40 and even less if the vac can isn't chipping in with its extra 10 degrees. If they've set it at 5 degrees BTDC then that's probably close enough.

If you take off the distributor cap and suck on each of the vacuum lines in turn you'll be able to see the sensor (black plastic bit) move clockwise & anti-clockwise this will confirm both sides of the vac can are working. If when you suck there's no resistance and nothing moves then the vac can is U/S.

[81AirCooled]

Thanks BOXY. The vac advance hose is still connected to the vac unit but the one from the air filter box isn´t. I´ll do the suck test in the morning and see if the vac unit is working. What I don´t get is why the first garage just not change the vac unit if faulty and why disconnect only 1 hose and still set the timing wrong I wich I had noticed the blanked off hose before, I´m going to have to go back to the garage again at extra expense and the wife is already using phrases like "I wish we´d never had bought the van"

In the meantime, with the timing now set to 4° ATDC and one of the hoses blanked off what damage could this do to my engine short term?

[81AirCooled]

Morning viewers I´ve checked the vac advance and it seems to be working, when I suck on the hose coming from the carb the sensor moves a little and clicks, when I suck on the hose from the airbox which has been disconnected the sensor moves more than the other way but doesn´t click. Resistance seems fine but then again I´m not an expert.

I´m wondering why the original garage did what they did?

[BOXY]

If it's moving in both directions it looks like it's working fine, so no idea why the first garage left it disconnected. If your timing is now set at 4 ATDC without the retard line connected it really needs to be re-timed with it connected. If you just reconnect it, it will pull the timing towards 20 ATDC.

Have read through this post about my 009 dizzie saga it'll give you some pointers on setting up the timing. If you buy / borrow a strobe timing light setting up your own timing is really easy.

https://club8090.co.uk/forum/viewtopic.php?f=39&t=79992" onclick="window.open(this.href);return false;

[kevtherev]

Two "professional" mechanics got it spectacularly wrong so it wouldn't hurt to do it yourself

nice link Boxy

[sarran1955]

Hello,

You have a pm.

Looks as though we are slowly getting there,

Strobe lamp say € 20, vac gauges say € 40. Test lamp say €10. tippex and a feeler gauge.

With the price of petrol doesn't take long to justify.

You will end up tearing off all the double can piping, any electronics, and dubious hoses to the aircleaner, and run at 7-8 btdc at 900 rpm hose off.

We'll get there


Cordialement,

[81AirCooled]

I'm still in two minds about trying this myself. I know someone who might have the necessary gear and if he does I'll give it a go. If not I´ll need to take it down the garage again.

Basic setting at idle

5° ATDC @ 950rpm (for automatic gearbox) with all vac hoses connected. IS bridged and crankcase breather removed which should advance to 30 BTDC @ 3000rpm

- is that right?

[81AirCooled]

Took the van back to the second garage yesterday, told them to re-attach the vac hose to the can, set to 5° ATDC and check it advances properly. BIngo! Drove the van 40km to work this morning, accerlerates well (for a CU) and comfortably reached a speed of 120kmh before I decided to get back down to 90kmh. Might have been another 5-10 khm in there but whats the point?

No overheating, dipstick very warm but can be touched without it hurting so I´m a happy bunny

I get the feeling the Van specialist workshop I took it to originally might have been trying to convince me I need an engine rebuild. They insisted the timing was right even though I asked them to check and said it´s an internal engine problem. Got to say I won´t be taking it there again.

THANK YOU ALL FOR YOUR INPUT! Without it I would have assumed what the garage told me was correct and would have probably taken it back for a rebuild in winter finances permitting. I OWE YOU!

[BOXY]

[kevtherev]

Thats great news
Now you can contribute back to the forum with that experience... Should anyone come looking for similar advice