Club 80-90 Forums

I think my distributor is causing starting issues on my 1.9DG.

When looking at it today, I noticed that the vacuum unit on the
dizzy is taped up! I'm pretty sure that's not meant to be like that and I'm guessing that could? cause starting issues as there's no or poor vacuum?

So, is it possible to replace just the vacuum unit? Or do I need a new dizzy?

If a new dizzy is needed, I'm not sure which one I need.

Attached a picture of the dizzy with number. I've checked JK and Heritage but not certain which one I need.

So you have a distributor with the VW part number 025 905 205 Q which is correct for a manual 1.9 DG engine upto chassis M 105000 and which supercedes to 025 905 AE so either of these would be okay for you if you are looking to replace the disi but it is more likely you might need a vacuum unit, but have you the vacuum pipework still from the distributor or is that missing and is the spigot on the disi blocked or open and sucking in air ?

The vacuum unit for this distributor is 025 905 271 C, currently out of stock at Brickwerks, but showing in stock at Heritage and likely available elsewhere and very cheap so won't be original Bosch part anymore but as long as it is the correct unit should do what it is supposed to

You can try testing the vacuum advance by sucking on the spigot and if the diaphragm is intact you should feel vacuum resistance, if it is perforated you will just feel fresh air and you would want to replace it, which is pretty easy to do

Hi Aidan,

All pipework is still there, it's just the vacuum unit is taped up, so Im guessing as it's taped up it's letting to much air in or not enough air in.

I haven't tried to see if it has gone, so will try that tomorrow.

As the vacuum unit is cheap, might as well just replace it to be sure.

Thanks

Andy

Taping the vacuum unit up will do nothing. Is the pipe plugged?

The reason they get bodged is because the vacuum diaphragm splits and causes an air leeak into the inlet manifold resulting in poor running . Blocking the pipe helps the running but with no advance thespark timing will nto be optimal.

Rob

Hi Rob,

Not checked if the pipe is blocked off, is that the same pipe that Aiden talked about in his post?

As for the vacuum advance being taped, not sure why the previous owner did thsi, as I have a receipt for the distributor being refurbished,. not sure why they had it refurbished, when it would have been easier just to replace with a new one.

seven months in of being Nellie's custodian and issues which were not present at time of purchase are now starting to appear!

Thanks

Andy

When was that refurbished as it looks original, unless the refurbisher was lazy?

Hi Rob,,

Not sure as I have to dig the paperwork. I know that she had a replacement engine about 1999, so unsure if the dizzy came off the original engine or.on the replacement engine.

On a side note, most of her is original with limited external and internal parts replaced and updated.

Andy

Also checked the vacuum advance and that's got no vacuum. So have ordered a new one from Heritage, also going to replace all vacuum pipes as well as the one from the pulldown has a leak.

Yeah , its worth just replacing them as they may have also gone porus ove 40 years.

TwinTurbo wrote: ↑01 Feb 2025, 19:49 Yeah , its worth just replacing them as they may have also gone porus ove 40 years.