Tb-42e lumpy under accleration

I concur always a Y not a T.

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Originally Posted by Pezzer

Hey guys I really appreciate the help, that's one reason I joined this forum also to to add any experience that I can offer to assist other members, its how we keep our vehicles on the road without going to big brother all the time emptying our wallets.
The Maverick has gone back to the LPG workshop for a tune and he is going to check a few things, the miss is definitely more apparent on fuel than on Lpg but its there. Reading other threads spiral leads seem to be the go with a cooler plug, the head has had lots of work done to it and mechanically all compressions are spot on. When I checked the vacuum lines I did not detect any leaks and no stray arcing was seen or heard at night, the vacuum operated fuel regulator shows no signs of seepage either. It does take 3 turns of the key to fire up, system always selects fuel to starts on.

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1-Confirm fuel pressure
2-confirm fuel supply rate of flow

Does it start better if you prime the High pressure pump by cycling the reds on and off 3 or so times?

Does it start better when warm?

When warm no problem.

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Originally Posted by davo94

1-Confirm fuel pressure
2-confirm fuel supply rate of flow

Does it start better if you prime the High pressure pump by cycling the reds on and off 3 or so times?

Does it start better when warm?

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Pezzer said that the miss goes away with higher revs. Would a fuel supply or pressure issue do this or would it get worse the higher the revs?

How old are the plugs pezzer?

Not sure on the plugs, but we have done 3000kms on them, I reckon on around 5000kms

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Originally Posted by taslucas

Pezzer said that the miss goes away with higher revs. Would a fuel supply or pressure issue do this or would it get worse the higher the revs?

How old are the plugs pezzer?

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Depends if they run a dual speed fuel controler. You could also try and crimp the return line to run full line pressure and isolate the pressure reg (just for testing)

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Originally Posted by davo94

Depends if they run a dual speed fuel controler. You could also try and crimp the return line to run full line pressure and isolate the pressure reg (just for testing)

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Is this what pezzer has done below?

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Originally Posted by Pezzer

Yes I checked this, I believe now possibly dirty injectors, I crimp the return fuel line and it rev'd which to me shows a lean running motor pressures seem good vacuum on fuel regulator strong with no signs of petrol seepage. crimped and blipped it a few times now lumpiness is a slight random miss. Idle is 900 as this seem the best for lpg and petrol to load up and pull away.

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Originally Posted by taslucas

Is this what pezzer has done below?

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Seems he has.

Get a compression test to rule out the mechanical aspect then we can isolate it to the ignition system.

yes I crimped the return line and also removed the vacuum line to the regulator, no noticeable difference.

What brand of plugs and gap are you running.
Lpg likes a smaller gap around .2 less.
and more advance on the timing 12-15 deg not 10 as per petrol specs.
go to advanced and petrol runs out of puff at a much lower speed and ping/det becomes a problem.

My experience found NGK iridium plugs work better and last longer.
Design is a much finer electrode to concentrate the spark,
also helps expose the spark better to the mixture, m2c.
but 3 x times the price.

Have read some where, maybe this forum.
LPG = NGK plugs, more reliable.
quality or something
I'm sold on em.