Stupid Volkswagens #2

[Jim]

I got rid of the baja bug, and replaced it with a manx buggy. Was out caning the arse off it on stockton on the weekend, having the best fun! All weekend it was a total bastard to start, getting worse as the day went on. Finally it started to cough and backfire and miss under revs (load didn't seem to be the problem).

Limped it home and went through the usual replacing with new stuff in the following order:

Points,
condenser,
plugs,
leads (incl bakelite ends),
check fuel filter,
check dwell and timing.

There's fuel in the carb, and the fuel pump seems ok, no torn diaphragms or other leaks or damage, seems to pump up fine too.

Still ran like a turd. Then checked:

Carby for crap in the jet or bowl (spotless),
swapped out spare dizzy, cap and rotor button.

Nothing appears to have an effect! This is the first time in a decade a motor has beaten me! I'm totally out of ideas on this bastard!

Any suggestions? No I won't burn it, and no it's NOT a fucking tumour!!

[Bitsamissing]

Fuel getting hot somewhere & evaporating ?

Needle & seat or float sticking in carby, (flooding). ?

By having no prob under load means it is using the extra fuel OK, playing up not under load then it's flooding & can't use the extra fuel.

[Jim]

nope and nope. it's doing it from cold now. if it was N&S it would be ok at revs, but choke on idle/cruise, and it's almost the opposite.

[Bitsamissing]

Plan B. Refer to your topic header

Stupid Volkswagons ! :D

[HoonBoy]

Compression?

[Jim]

hmmm... I did think of that, then put it in the "I don't want to know" category. I will check though. The only reason I don't think so is the problem was intermittent at first, and when it runs good it goes like stink.

[Uncle Arthur]

Coil is not on the list.

[Jim]

whoops! yes, now has a new coil too, forgot to mention that. I replaced the old one with the transformer type.

[Stix Zadinia]

was number 3 looking weird when you pulled it

whats the location of the fuel filter btw, i hope not where half the people leave them?

what motor is it? checked all the electrical stuff? (regulator/generator or alternator etc)

[HoonBoy]

Broken or craked wire going to the points? I had a 323 that broke the wire and was just holding on by a strand. Had enough power to give a spark with the cap off, but not enough to start the car.

[Stix Zadinia]

yeah, and don't use bloody silicone wires.

[Jim]

yeah the wire from the coil to dizzy is all new (new coil, new condenser). The only thing I haven't checked is that there's an earth strap from body to motor.

Russ, it's a 1500cc single port with stock carb.

[MrBishi]

Burnt out exhaust valve? A mate's dubber ran like turd for months & later found out it was a burnt out valve.

[Stix Zadinia]

is it a solid manifold or one with those rubber seals to the inlets over the ports?

checked those rubber things i've seen them run like shit 'cause of dodgy rubbers to those.

[Jim]

solid manifold (singleport).

thinking about it, Hoonboy and Mrbishi might be on the money *sigh* compression test coming up tomorrow arvo...

lucky I have a spare motor there.

[Che Castro]

is the manifold sealing properly? Had my one pull out one of the studs holding it down once and it ran like shit - that's with the pissy 6mm studs holding it into the heads.

[bahaimus]

Could it be crap inside the fuel tank blocking the pickup a bit?

The inside of my R100 fuel tank had a bit of rust and it would do this kind of thing intermittently until we cleaned it out.

[Jim]

has fuel in the carby so it doesn't seem to be a fuel supply problem. you can see it squirting in there even when it's playing up.

it's not a vaccuum leak, the motor does not speed up when you progressively block the carby.

[Jim]

ok, the fucker has 110 for 3 cylinders and number 4 has 130, which should be plenty to run.

It's hard to tell if it's getting spark as there's only me here and it's too hard to see the plug from the key. I could wire up a remote start again but frankly i'm totally fed up with it. crawling around under it to hook up bits of wire is more than I want to put up with today.

It's getting worse though, if you keep revving it while it's playing up it lets off a backfire like a fucking cannon.

I hotwired the coil straight from the battery which has 12V nominally and drops to about 8-10V cranking. No change whatsoever.

I am totally out of ideas, and not a little pissed off.

[Jim]

Looks like I have located the problem.

When I bought the coil I asked for a GT40 transformer coil, which they didn't have, and the pleb said they had another type of transformer coil. I went "duh okay" without thinking too much about it. It looks like the new coil is a high output EFI type and was causing the points to arc, so the points were never opening enough to break the circuit and collapse the secondary coil field, so no high voltage output to the leads.

I dug a ratty old coil out from under the house and while it's not running great, it's running and running a shiteload better than it was.

Sometimes I think I should give up on cars and collect stamps or something like that which doesn't require so much blood and brain power.

*edit*
Maybe Nero's magazine could do with a "Dirty Stuff" type column...LOL

[nui]

So was the problem the coil?

[Jim]

yeah, looks like it! Coil died, and I replaced it with a coil that wouldn't work with it. always something friggen stupid huh.

[nui]

always the case

[Uncle Arthur]

See, told you :)

[Jim]

no, you just said coil, which I had already replaced. You didn't raise the possibility of the wrong coil! :p

[tandy ass]

Secoh, it might be a long shot but have you checked the possiblity you might have an incompatible coil in there?

[Jim]

fuck! Bozz is right! thanks man! you really saved me -3 days!