I had a similar problem with my TR3. The problem turned out to be the
positioning of the sensor on the Crane electronic ignition. It was so
far off, that even though I could set the timing correctly, the rotor
was not in the correct position when the sensor fired. As a result, it
often arced across to the wrong cylinder, firing the mixture in that
one.
Careful adjustment, following the directions, corrected the problem.
"Bromiel, James E (Jim)" wrote:
>
> Listers
>
> I need help solving my 74 TR6's backfiring through the carb problem . I've
> had the car
> since Nov. I've rebuilt the carbs and added Pentronics Ingnitor electronic
> ignition.
> I've also replaced a leaking vacuum line. The EGR valve is off and plugged
> by previous
> owner. The one vacuum line goes from the distributor to the bottom of the
> back carb., all
> other vacuum lines are capped. The timing is set at 4 degrees ATDC at idle.
> I notice the backfire under acceleration / lower RRM or when
> cruising at a constant speed.. Under heavier acceleration /higher RPM I
> don't notice any
> backfire. My first thought was I need to lean out the mixture. I did that by
> turning the mixture
> adjustment tool clockwise, hence lowering the needle into the carb body,
> letting less
> gas through. Is this correct?
>
> Is there a way to know if my carbs have the correct mixture needles?
>
> Should I check my valve clearances?
>
> Any suggestions will be greatly appreciated.
>
> Jim Bromiel
> 74 TR6
> bromiel@lucent.com
--
George Richardson
Wyvern - '57 Triumph TR3, TS15559LT -
http://www.merlingroupinc.com/tr3.htm
Griffin - '71 Triumph Stag - undergoing restoration
Pikachu - '75 Triumph TR6 - undergoing repair
Kitty - '83 Jaguar XJ6 Vanden Plas - Daily Driver
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