V8 (with LPG) Problem....

Lack of power, even though I've had the LPG tuned up professionally, if I put the throttle to the floor in top gear 50 mph she pull away fine, at 40 mph top gear it's ok, not as good as she used to be, but anything less than 40 in 4th and 5th gear she takes ages to go anywhere......

coil pack is loose and new one going on soon as well as new magnacore blue leads, new plugs are in, lambda sensors are "lazy", sometimes one doesnt give any reading when the diagnostics are connected up,

Any ides whats wrong?

the problem is solved slightly when running on petrol but not much better

yup - its the ides of march!

TWEETS said:

anything less than 40 in 4th and 5th gear she takes ages to go anywhere......
Any ides whats wrong?

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Have you considered changing down?

yes, but when I first got the car she would drive the roads im driving now how im driving now, just now she isn't coping

if I pull out of a junction turning up a hill I end up with a string of irate drivers behind me until I get above 50 when she is fine, and believe me she takes her time getting to 50 and is screaming it's head off in every gear on the way

Pity you aint got a dizzy, you could advance it a bit. Maybe you could move the crank sensor and fool the ECU ..

bit beyond me

TWEETS said:

bit beyond me

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Is this more you then?

TWEETS said:

lambda sensors are "lazy", sometimes one doesnt give any reading when the diagnostics are connected up,

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You need info from both lambda sensors to go to the ecu so it knows what is going on.
it might be that one half of your engine is on tap as it should be, but the other half is shut back as the ecu hasnt go the info it requires to adjust the fuelling or the spark.
Just an idea - I may well be wrong - I prefer the older V8s.

think I might just bang on two new front ones for the sake of it, do it before the new coil pack and leads go on that way if it needs any tuning I can have it done whilst am at the garage having the coil pack done

ratty said:

Is this more you then?

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ha ****in haha

Tweets,I wouldnt just buy new parts - esp oxy sensors until they have been tested.If they are not switching it could be that the engine is running so lean, (or rich if they are stuck at .8v output.) that they cant switch.Has the garage done an adaptive reset on the petrol ecu ? When the engine is running on LPG the petrol ecu is still functioning but not injecting petrol,BUT if the fuel trims it decides on dont give the correct feedback the ecu will be confused.When was the LPG last serviced/tuned ?

LPG was last tuned the other week, because the garage I was at before that said it was running too lean on the LPG (fine on petrol) it improved things but only slightly

at both garages when the diagnostic equip was connected up one of the lambda sensors wasnt reading anything at all, then after a few minutes it came alive and did as it should (reading jumped about all over the place) on my disco the rocker cover gasket is dripping oil onto the yellow plug connector for one of the lambda sensors and is running down the cable to the sensor, could this be causing problems?

EDIT: the guy that tuned the LPG didn't have an exhaust sniffer to tell if it was still running too lean or rich, im waiting until we put new coil pack and leads on then tune it again before I go to the garage to have the exhaust sniffed..... the guy that tuned it said "that's as best it's going to get" whatever that means....

Some more detailed info for you hear Eightinavee....... http://www.landyzone.co.uk/lz/f37/saga-continues-61954.html

Just read the other bits,sorry I didnt respond but I was on holiday in the South of France with no TV,phone or computer - Bliss !
Couple of things,an exhaust gas analyser is not a good way to tune an engine,it only gives an overall picture as it is too slow to respond to whats actually going on,plus its after the Cats,ie treatment of gases.
The proper way to do it is either with a scope or by watching the oxy sensors as live data on Testbook.I do it with a scope to test the sensors then Testbook whilst the car is being driven,with a second laptop looking at the LPG software and tweaking as necessary.
No decent LPG place will touch the LPG settings till the engine is perfect on petrol.Where in the world are you ?

Reet, heres an update, meant to do it earlier but had to dash out

I want back to the garage I know that does LPG and is an LR specialist to have an adaptive reset done (as you mentioned earlier) despite it being tuned up on LPG it's still just as bad as it was before hand (lean) the guy that tuned it did as you did, I drove along and he tuned it whilst I was driving, he said "thats as best its going to get" if that's the case and the engine is running lean then is some of my LPG componements knackered?

As for petrol they say she is spot on, they asked if I had actually drove any distance on petrol (I hadn't, just flicked back and for between petrol and gas to find the petrol just as bad as gas) was advised to drive back to Aberdeen (30 miles) on petrol :O and he was convinced that the further I drove the better it would get, and boy was he right, it's just like driving the car when I first got her (spot on) just not on gas the say there is nothing mechanically wrong with me engine and they diagnostics shows no misfires so they advise taking me coil pack back to get me money back as it aint really need it, but is I have it and were taking the inlet manifold off to do the leads then i be as well sticking it on anyway (probably save 3 hours labour at a later date)

I'm in Aberdeen, quite some way from you but if I can't get any resolve with the LPG tuner I'm going to at the moment it might be worth a trip to you. I don't know if you noticed a post I made when i first joined, I had an accident when I was 12 and broke my hip which never healed correctly got two ****ed ankles and one dodgy kneee, sadly DLA won't give me the level of DLA I need to get a free car, but after years of busses and walking I can't go anymore and need a car, reason i chose a disco is I can slide in and out rather than climb in and out of a small car, so yeah, i really need me car, and after having it I don't think I could ever go back to lugging shopping on and off busses again

Ok,so if its fine now on petrol and the LPG cant be adjusted rich enough its probably in need of a kit for the vaporiser and new filters.Running lean on gas will rapidly harm the engine so you need to get it sorted,if the bloke was setting it up you you say did they not offer to go through the gas kit for you?
BTW you can do the leads without taking off the top of the inlet - its a bit tight but depending on where your LPG injectors are drilled into the manifold I'd do it with the manifold on.

Just going to run on petrol the now until it's sorted, kit for the vaporiser? I put new filters on myself not long ago, albeit I had then on the wrong way round for a few hunddred miles, could that have ****ed them?

Offer to go through the gas kit as in what exactly?

will post a pic, hold on

reason for taking top off of inlet manifold is to tighten down the coil pack as it rattling around loose at the back of the engine

post 15

http://www.landyzone.co.uk/lz/f10/anyone-fitted-bygas-lpg-kit-tinley-tech-62119.html

The kit includes a replacement diaphram for the vaporiser several other bits and pieces,everything needed to restore the output of it.Not familiar with the Bi gas system,most around here use Romano,OMVL Prinz or E-Gas.

is it the vapouriser that can freeze? or is that a misnomer?

The garage I was at up here does AEG kits, was considering earlier getting the nescessery bits to convert me system to AEG, that way I have someone local that can service/tune it every so often, if I was to go down that route, what would I need to buy? condensor, ECU and injector rails? anything else?

If push came to shove and i came down to you would you be able to tune it for me if a new kit doesn't solve me problems? and is it a job I can do myself if I got a new kit?