1.3 Driver hesitates

Still not right

Still hesitating coming back onto the throttle

Convinced it was to do with timing, not fuelling, I've just checked the timing again with a strobe light - it was out (timing mark was lining up with the angled part of the timing bracket, not the straight part). I've set it properly again and gone for another quick spin - definitely better, but still there.

This leads me to think that what's actually happening is "over-advance" - when I hit the throttle, the vacuum advance (along with over-advanced static setting) is causing the car to stutter.

Does anyone know how far the ignition should advance due to engine speed? When I blipped the throttle with the strobe light on, I was quite surprised to see how far it advanced - maybe 30+mm away from the timing mark (not sure what this equates to in degrees)

Getting there (very slowly)

Did youi check for crap in the tank? Can't remember if you said or not

Madferret said

Did youi check for crap in the tank? Can't remember if you said or not

Haven't done - there's an inline fuel filter that's perfectly clean and the car fuels perfectly everywhere else. Car had a new filler neck not long before Matthew bought it - not even started to get rust on the outside yet.

I had rubber sealant in mine, everytime I floored it, it sucked it up and got stuck in the end of the pipe, then when I released the loud pedal it dropped back out of the pipe into the tank, worth a try.

mmmmmmmmmmm

OK - after LOTS of thinking, my latest theory is that the centrifugal advance in the dizzy is sticking, leaving too much advance at low revs (which would explain why disconnecting the vacuum advance made the hesitation better, not worse.

it also explains why I'm constantly finding the timing has slipped - I set it, then the mechanical advance moves and sticks in a different position

just need to strip and rebuild the dizzy now

Hows it going? I'm curious to find out what it actually is

Madferret said

Hows it going?

Didn't get to try it this weekend - much too cold outside AND I can't remember where we put the spare dizzy  :dontknow:

According to the Haynes manual, the dizzy can't be stripped to service the mechanical advance, so its a case of swapping over with a known good unit

still haven't got round to changing the dizzy, but I think I've confirmed that the mechanical advance/retard is sticking

I can set the timing using a strobe light - rev the engine and it doesn't always return to the same setting

If I can't be sure the ignition is fully retarded at tickover, I can't be sure its set right, which means it could easily be over-advancing when it comes back on the throttle

This also explains why it gets quite a bit better if I disconnect the vacuum advance (although it then hesitates coming off tickover, which is even worse)

Annoyingly though, it would appear we're also suffering quite badly from carb icing - despite reconnecting the vacuum to the airbox thermostat, it stalls readily when its been driving for a while - if I park up and let the heat soak around the engine bay, it'll tick over just fine.

Bloody carbs - does anyone know if there's an injection-equipped VW that I can do a straight swap? - eg a later Polo. I guess the lumps are quite different - probably went over to hydraulic tappets or some other change that will make a straight swap impossible

polo engines do o pretty much straight in need to do a custom gearbox mount unless you keep the original golf box and a faff with doin th wiring and your away i'd send yeha a pm for advice ass he seems to know a great deal bout the polo lumps. or check out www.clubpolo.co.uk

hope that helps.

Doesn't the manifold have water heating on that model?

Anyway the airbox thermostat maynot be working properly, you could always route the hose toward the engine for winter use to solve that problem for now.

As for the mechanical advance if its a vacuum one then just suck on the pipe it should spring back of its own accord. I think you can replace just the vacuum part on it anyway.

Madferret said

Doesn't the manifold have water heating on that model?

Anyway the airbox thermostat maynot be working properly, you could always route the hose toward the engine for winter use to solve that problem for now.

As for the mechanical advance if its a vacuum one then just suck on the pipe it should spring back of its own accord. I think you can replace just the vacuum part on it anyway.

Nope - 1.3 has an extension on the exhaust downpipe to heat the manifold - the 1.1 is water-heated.

the vacuum advance works fine (now I've replaced the actuator diaphragm) - I reckon its the mechanical advance (centrifugal weights) that isn't returning properly to the base setting, which explains why it doesn't hesitate when coming back onto the throttle at higher revs, but when the revs drop low, the mechanical advance is staying too advanced, then when it gets a chunk of vacuum advance as well, its WAY over-advanced.

Its still all theory though - need to test it. Matthew is going to find the spare dizzy in the shed on Saturday, so I'll probably do a swap on Sunday

Damn - Matthew can't find the spare dizzy (although he didn't look for very long )

Didn't much fancy working on the car today anyway - MUCH too cold !!

I'm pretty sure it has both, water and off the exhaust, mine did. The water is pumped through the manifold between the inlet holes, theres two 'bridge' parts, *anyway* (ie. two extra holes on the manifold)

Probably a good idea to re-build it, might be obviously 'something' once it's dismantled

Good luck anyway

Hmmm - I'll go and check it out, but I'm fairly certain there are no unions for water pipes - we had the manifold off to replace the gasket, and I really don't recall seeing anything other than the exhaust union

Ar$e - seems we put the spare dizzy "somewhere safe" :roll: :roll:

Has anyone got a good dizzy for a 1983 1.3 Driver?

right - I've now bought:-

A new dizzy, with leads
a new airbox (in case the temp sensor vacuum thingy is broken)
some Wynn's fuel treatment

Between that lot, I'm hoping I can sort the hesitation (which I reckon is ignition over-advance caused by a sticky mechanical advance) and the carb icing.

I WILL NOT give up until this car is running perfectly

I just hope Matthew remembers this when his dear old Dad needs some help tuning his mobility scooter

Ar$e, Ar$e and Ar4e again  

Got hold of a secondhand dizzy, which I've just spent half a day trying to fit

It still has points and condenser, so I had to make up a couple of wires to the coil (existing dizzy has some form of electronic ignition, with two wires going to the coil)

The first surprise was that the new dizzy has three mounting points, but the existing one only has two. They are the same part number though - weird

I stripped the new dizzy to fit the vacuum advance unit off the old one (didn't work on the new one). While I was there, I gapped the points and fitted a new condenser.

However, it just won't start - not even a glimmer

I've obviously done something wrong

I've connected the terminal on the condenser to the +tve terminal on the coil - is this right?

Matthew wasn't around today, so I haven't been able to check the system for sparks - its pretty obvious that the plugs aren't firing, but I'm struggling to work out where the break is - I've stripped and rebuilt the dizzy to make sure the lead to the points wasn't earthing on the dizzy body

I've tried both rotor arms, although I've yet to try the dizzy cap and leads that came with the new dizzy (can't see why they should be different)

any ideas?

scratch that miss read sorry.

Ah well - after stripping and rebuilding the new dizzy twice, including a new condenser, I fitted the old dizzy back on and it started (bit rough, as I'd fouled the plugs trying to start it on the new dizzy)

I traced the problem - the coil was giving a spark (although it was very weak). However, the plugs weren't sparking, so I simply fitted everything back as it was.

However, I took the opportunity to strip the old dizzy right doen and clean it all up inside - there was quite a lot of caked-on oil residue, so I cleaned it all up and re-greased the moving parts

Its definitley a bit better, but it still hesitates

I'm going to try dropping the size of the accelerator pump jet,as I 'm now wondering if its too big and its choking the engine as the throttle is depressed (although its fine coming off tickover, its only when I come back on the throttle from a trailing throttle - say 1,500rpm)

ah well - the joys of classic motoring…..