Van running on 3 cylinders

[harper1980]

Hi everyone I'm hoping someone can help,I'm running a 1641 with twin empi carbs,
I can be drinking along fine and then it will drop down to 3 cylinders,if I switch it off and on again it's fine for about 5 minutes then it happens again,I've changed the fuel pump relay as it seems to be something electrical it was ok for a day but then it's happening again with it being an intermittent fault I don't think it's plugs or leads as when I switch it off and on it's fine again,
I'm really hoping someone can help me please?????

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[harper1980]

Sorry lads I ment driving along fine.

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[ozziedog]

First thing I’d do is to try and work out which cylinder it is so get your plastic pliers out and listen and pop off a plug lead to see if that can identify which one. My guess would be in the dizzy, either cap or button or possibly the wire under the plate, does also sound like it could be a condenser problem, as they can be proper little gits and lead you up the garden path.

Ozziedog,,,,,,,,, plus a condenser costs next to nuffink and a great ‘known’ spare :mrgreen:

 

[harper1980]

That's great thank you for that il try pulling the leads off today if I can get it to run on 3 again, I'm running electronic ignition aswel so I didn't no if that could be at fault as it's weird how when I switch it off and on again it's fine as if it's resetting something.

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[harper1980]

Just a quick update I've got the van to run on 3 and if I pull number 3 lead off the dizzy cap there's no change and When I put it back on it fires back on 4,so I think il change the plugs,leads and dizzy cap to see of there's any change,
Is there anyone else that's had these gremlins in there engine bay?

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[bac2ba6]

I had this last year and after loads of faffing turned out to be a dodgy electrode on my new (bosch) spark plugs. Binned them and fitted ngk plugs been fine since .
Each to there own but I personally think "new" bosch stuff is pants.

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[StuF]

Sounds like a dodgy lead to me too - might just be a poorly made join inside that has an intermittent connection.
Bet new leads sort it for you - your engine bay looks clean enough to eat off!!

 

[harper1980]

That's great thank you you for your advice,it seems to be the one of the plugs now you say that one of the electrodes does look wonky but il defo change plugs and leads thank you for all of your help and advice and thank you for the compliments on my engine.[emoji4]

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[Happystamps]

Swap 'em about first- try the plug and lead from 3 on 4, see if the misfire moves.

 

[harper1980]

Good point,I'm having a day on it tomorrow so il keep you posted. Thanks for your input.[emoji106]

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[harper1980]

Well I've changed plugs,leads,dizzy cap and rotor arm and it's still dropping down to 3 cylinders I'm beginning to think that's it's fuel or carb set up now as any lead I pull of the engine dies.
Does any body no if I need to turn the fuel regulator up?it's really doing my head in now, I just hope someone can help me.

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[vinvan]

Why dont you try a compression test on all 4 cylinders, just to rule out anything nasty going on with the valves or pistons

 

[jonboylaw]

Unless you are running 1 choke per cylinder (twin dual carbs) then it can’t be a fuelling problem as the fuelling is shared.
Could be lost compression it the valves need adjustment, or a lose head.
Someone suggested swapping the older number 3 lead cap with number 4 to see if it makes a difference, I’d also include the spark plug in that case as well. Then you can rule out ignition ( other than the cap/rotor)


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[harper1980]

Well my compression tester arrived today so il check the heads are tight and do a check,I'm hoping this will identify the problem,il have a look at it Friday so il keep you posted,
Thanks again for everyone's input.

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