Only 2 plugs on each bank firing ?

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tom'o
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Only 2 plugs on each bank firing ?

Post by tom'o »

Hi there, I'm new here so finding my feet.
I've got an SD1 3.5 low compression V8 with twin SU's on, it was working fine until a week ago I came back from a drive, parked it up and left it for 4 day's, when I next turned it over it would only fire on 2 cylinders from each bank, the outer 2 on one bank & the inner 2 on the other bank?
I have cleaned, gaped & checked the plugs, all firing, fuel is getting through, timing seems fine as it runs smoothly on only the the 4 cyclinders, well a smooth as it can, any ideas please, as I do not know where to fo from here.
Thanking you in advance for any help, ideas you may have.



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Ian Anderson
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Re: Only 2 plugs on each bank firing ?

Post by Ian Anderson »

Is that not how the SU manifold divides the flow?

In which case one of your carbs is not fuelling

That would be my guess, check float levels and see if one is stuck would be my first port of call

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DaveEFI
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Re: Only 2 plugs on each bank firing ?

Post by DaveEFI »

If you remove the air filter and elbows to the carbs, on a dull day, at idle you can see the fuel being drawn up through the jet with a torch. It should look similar on both.
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ged
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Re: Only 2 plugs on each bank firing ?

Post by ged »

I had the same exact thing happen with a stromberg carbed SD1. Turned out to be a rubber elbow on the fuel line near the carb had kinked with the heat & shut off the fuel supply.

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ChrisJC
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Re: Only 2 plugs on each bank firing ?

Post by ChrisJC »

Definitely a problem with one of the two carbs.

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tom'o
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Re: Only 2 plugs on each bank firing ?

Post by tom'o »

Thanks for the information guy's, I'll get on to checking my carbs out a.s.a.p. :D

tom'o
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Re: Only 2 plugs on each bank firing ?

Post by tom'o »

Thanks guy's, needle jet not seating in one of the carbs, now sorted, but maybe a good clean & service of them is well overdue.
Now running great :nw :nw :nw

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