idle and lpg problems

the engine runs fine on petrol except for slight knobblyness when idling.

on gas its pretty much useless(but never stalls)

after much trawling the forum i decided to have a look at the MAF.

with the faultmate plugged in the reading is around 40 idling, 130 @ 3000 neutral and over 330 @ 3000rpm in drive

i've seen some numbers on one post that suggests these numbers are too high.

do i need a new MAF? will that solve the poor running on LPG?

i also checked the lambda sensors and they seem to be working normally (flicking between around .1 and .8 every second or so??)

i've attached the video(i hope) that i recorded of the readings in case it helps. note that i never went above 3000rpm as i'm still running the new engine in.

Google Docs

hopefully that link will work...let me know if not

What these ones....

Idle 680rpm - 22Kg
1200rpm - 32.5Kg
2000rpm - 55Kg
3000rpm - 92Kg.

I would like to take the credit for readings but that must go to Eight NV.

These readings are for a 4.6 Thor engine (Bosch)

Hope they help.

rewmer said:

What these ones....

Idle 680rpm - 22Kg
1200rpm - 32.5Kg
2000rpm - 55Kg
3000rpm - 92Kg.

I would like to take the credit for readings but that must go to Eight NV.

These readings are for a 4.6 Thor engine (Bosch)

Hope they help.

Click to expand...

excellent thanks very much.

so if my readings are higher (by roughly 30) does that mean the MAF sensor is knackered?

That is a fair asumption, although I would have expected to see the figures down rather than up ? Stands to reason that a dirty or tired MAF would read low, but, hey these cars are a law to themselves.

Did you notice that the fuel pump is off ? I think this is a bug in the Vehicle Explorer software .

Do you have a video of the injector timings and the O2 sensors. Thats always a help. Warm idle, no revving.

rewmer said:

That is a fair asumption, although I would have expected to see the figures down rather than up ? Stands to reason that a dirty or tired MAF would read low, but, hey these cars are a law to themselves.

Did you notice that the fuel pump is off ? I think this is a bug in the Vehicle Explorer software .

Do you have a video of the injector timings and the O2 sensors. Thats always a help. Warm idle, no revving.

Click to expand...

yeah i did see that the fuel pump was off. thought that was odd - can't be true though can it?

i'll get a vid of the injector timings and the O2 sensors and post it here asap.

the o2 sensors looked normal to me but i'd like a 2nd opinion.

why is is useless on lpg, what lpg system is it?

gavbriggs said:

why is is useless on lpg, what lpg system is it?

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no power and backfires alot under load.

its an OMVL dream XXI

the dream doesnt use the maf, at least i dont think it does, so it wouldn't explain the poor running on lpg.

although the car will have to run correctly on petrol before you can set up the lpg to make the whole package as it should be, you could have a look into the lpg see if you can get it running well enough on that to help pinpoint the issue.

with it having no power and backfiring i would check the ignition system is in order. check leads are in the correct order. it sounds like the lpg kit is just amplifying the problem.

whats the lambdas doing?

gavbriggs said:

the dream doesnt use the maf, at least i dont think it does, so it wouldn't explain the poor running on lpg.

although the car will have to run correctly on petrol before you can set up the lpg to make the whole package as it should be, you could have a look into the lpg see if you can get it running well enough on that to help pinpoint the issue.

with it having no power and backfiring i would check the ignition system is in order. check leads are in the correct order. it sounds like the lpg kit is just amplifying the problem.

whats the lambdas doing?

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Gav (not being as arse) see my initial post...

lambdas seem to be working normally (flicking between around .1 and .8 every second or so??)

its a brand new engine with new plugs. we double checked the order when we put the leads back on

works fine on petrol( not stumbling, plenty of power & decent MPG) apart from slight knobblyness on tick over

Did you reset the adaptions when the engine was fitted?

skirabb said:

Gav (not being as arse) see my initial post...

lambdas seem to be working normally (flicking between around .1 and .8 every second or so??)

its a brand new engine with new plugs. we double checked the order when we put the leads back on

works fine on petrol( not stumbling, plenty of power & decent MPG) apart from slight knobblyness on tick over

Click to expand...

arse!!!

mmmm, was it a full engine?

my lambdas go from .1 to 1.2 i think but thats on a gems engine, tbh i usually use the lpg kit software for checking lambdas, its a simpler and more responsive software for some reason!

gavbriggs said:

arse!!!

mmmm, was it a full engine?

my lambdas go from .1 to 1.2 i think but thats on a gems engine, tbh i usually use the lpg kit software for checking lambdas, its a simpler and more responsive software for some reason!

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ha actually i am a complete arse! (when changing oil, it turns out you do need to put the sump plug back in before "filling" it up. :der: )

yes adaptive values reset

ran the auto calibration in the OMVL software too

yes its a "long" engine from RPI.

the lambda values i've already stated are from the omvl software not the faultmate

i will ponder this over night at work!!!

gavbriggs said:

i will ponder this over night at work!!!

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thanks! ponderment much appriciated!

i've ordered a new MAF sensor so i'll let you kow how that goes

skirabb said:

i've ordered a new MAF sensor so i'll let you kow how that goes

Click to expand...

Hope youve ordered a genuine one. There are some right old nasties on the Bay that are very tempting price wise, but are complete poop.

rewmer said:

Hope youve ordered a genuine one. There are some right old nasties on the Bay that are very tempting price wise, but are complete poop.

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ordered it from famousfour.

don't know that its genuine but i'll distance selling regs allow me to send it back even if its not broke so i'll have a look when it arrives.

Sweetos. Post up those figures as soon as it's fitted.