Only firing on two cyliders???? help please.

Post by **Sinclair** » 01 Aug 2006, 19:40

I've just picked up my first wedge

a 1980 1900 water cooled. Mot failure on emmitions. I was told it ran fine to the mot station but has only been on No. 1&2 pots ever since.
So far I have tried:
Checked for spark. 4 is a bit weak.
checked the plugs. 3 and 4 are black but not really wet.
substituting the rotor arm, cap and leads with my 1600. I take it the firing order is 1432 like the old ones.
adjusting the timing.
checked the fuel pump.
Adjusted the tappets (are they hydraulic)
still no joy. starts fine with no smoke, but i can take 3 &4 leads off with no difference to performance.
I'm a bit stumped now. any ideas would be greatly appreciated

Post by **andysimpson** » 01 Aug 2006, 21:43

First thing to do is a compression test.

They did'nt make water boxers in 1980

Post by **Sinclair** » 01 Aug 2006, 21:52

andysimpson wrote:First thing to do is a compression test.

They did'nt make water boxers in 1980

That makes sence, I'll give it a go although I would have expected some smoke or crank case pressure probs.

As for the engine. it looks like a beetle lump without the fan shrouds. better check it against the documents.

got to say, the engine access is so much better than a splitty. think i'm going to weld in a top access from a wedge

Post by **deepdale** » 02 Aug 2006, 17:11

dunno why everyone jumps to a compression test!!
Start at the beginning with basics, if you only have a weak spark check your dizzy components ie/ points condensor rotor arm and more importantly plug leads.
I had the same fault but only with one cyl (no3) and it was the lead. If they are the same as mine which were Vw parts the dizzy end is crimped and it had not penetrated the insulation to the core. re make the end striping it back and folding the core back on itself then but ya crimp back on.
Also check fuel is getting through, might sound daft but if its been stood at all theres a chance ya needle valve could be stuck.
Even if compression was low it would still run on all four!!!!

Post by **Sinclair** » 03 Aug 2006, 19:44

OK. I have 150-160 psi on all four cylinders cold.
I have new leads, plugs, rotor and cap. ignition is electronic and i have a fat spark now. But still it only runs on 1&2 ?
3 & 4 cylider makes no difference if the leads are on or off or transposed. plugs look dry

I've taken the carb off for a clean, bus as it's a single how can that be the problem. I can't see any adjustment on it either.
The previous owners tell me it ran fine until they tried to get the emitions on the MOT and has never been right since. i'm cluching at staws now. I'll clean the carb and then I have an old 009 dizzy I could substitute.
Any and all theories much welcomed

Post by **toomanytoys** » 03 Aug 2006, 21:31

if you have a fat spark then hows changing for a crappy 009 gonna make a differance? I presume sparks are on the "non firing" cyls? at the lead ends?

May sound stupid, but are you absolutely sure the leads are on the right way round? double check it....

Post by **airhead** » 04 Aug 2006, 00:16

Id be inclined to go with toomanytoys on this one. It sounds like youve got the leads on arseways. Try just swapping the 2 that arent working!

Post by **Sinclair** » 04 Aug 2006, 05:28

toomanytoys wrote:if you have a fat spark then hows changing for a crappy 009 gonna make a differance? I presume sparks are on the "non firing" cyls? at the lead ends?

May sound stupid, but are you absolutely sure the leads are on the right way round? double check it....

like I say, cluching at straws with the dizzy. Tried transposing the leads. I take it it's 1432 firing order and that the firing piont for No. 1 is the notch on the dizzy body. I ought to buy a manual really.