Club 80-90 Forums

Might be a daft question but have you checked (when bending/twisting) or replaced the ht leads?
David.

If I start the engine with the adv/ret connected then it’ll idle if I keep the throttle pressed for a while and gradually release after 5-mins or so, the idle speed is set at about 950. If I disconnect the vac pipe it’ll die immediately.
If I start without it connected it’ll run after the same procedure and then pick up a bit if I reconnect it, but running is rough and exhaust note popping.
Whatever the case I cannot start without tickling throttle to get it to stay running.

David, the ht leads were all renewed not long ago and they all appear good.

Have you tried the ignition module? Might be worth seeing if there’s someone local who will swap it over with you to check.

Seem to be a couple of things going on

Firstly choke / warm up not working as it won't idle without opening the throttle a bit

Secondly, it won't idle when warm with vac disconnected. Going back to my second suggestion earlier, is the timing set at 5 degrees BTDC with vac pipe connected or disconnected, I'm guessing connected ?

Choke is working fine. If I start from cold with one press on the throttle then it’ll idle at high revs until the choke comes off and then it dies if left alone.

It will idle warm with the vac disconnected if I start it and kep the revs up and then gradually decrease over about 5-mins. If I manage to get it to idle in the same manner with the vac connected but then remove it,then the engines dies immediately.

And yes the vac was connected when the timing was at 5deg btdc. I reset it without connected at 5deg btdc and then reconnected it and it didn’t make much difference.

Timing should be set at 5 deg BTDC with vac disconnected (and the hose should be plugged)

Reason for asking you to check the timing earlier was to see where it was set and what effect the vacuum advance component of the dizzy was having.

I don't think that's all your problem, but it won't harm to get this bit set right, and see how it works then

937carrera wrote:Timing should be set at 5 deg BTDC with vac disconnected (and the hose should be plugged)

Reason for asking you to check the timing earlier was to see where it was set and what effect the vacuum advance component of the dizzy was having.

I don't think that's all your problem, but it won't harm to get this bit set right, and see how it works then

thanks 937 Carerra, I’ll re set again tomorrow and report back!

Still think air leak.
Had similar.

PeteandNikki wrote:If I start the engine with the adv/ret connected

How many vacuum connections do you have on your dizzy, one or two

Crap in carb, blocked jets??

PeteandNikki wrote:And yes the vac was connected when the timing was at 5deg btdc. I reset it without connected at 5deg btdc and then reconnected it and it didn’t make much difference.

That might be a big clue. It should make a huge difference when you reconnect the vac advance. It should advance the timing by around 7° and pick the tickover rpm up considerably. Have you tested the dizzy vacuum can? Can you suck fresh air through the pipe connected to the dizzy, or does it hold a vacuum?
You mention retard too. Is it a dual vac unit (from a df or cu?). It should only have one port (SVDA - single vacuum dual advance) on a DG.

Sent from my ONEPLUS A3003 using Tapatalk

Sorry my mistake, I should have just referred to it as vac advance! There is only one pipe which I’ve renewed the 2 flexi sections and ‘suck’ tested for soundness and also that sucking moves the advance in the dizzy.

I’ve spent so much time yesterday trying so many different options that I’m finding it difficult to remember exact details now!
I’m going to re-set the timing with vac adv disconnected and plugged today. I’ll then see what happens when re-connected.
I have a feeling that it’ll pick up a bit but then stop dead when disconnected again. I’ll report back.

Thanks to everyone who’ve made suggestions

Try disconnecting the brake servo vacume take off on the manifold and plug the manifold, I had this pipe break down it's a braided hose that looks sound but can go porous causing the engine to run lean.