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[richard]

Hope you good people may have some clues for me to follow

2.2 lpg/petrol 115000 miles 2003

Runs like a dream on LPG but a dog on petrol. Its been on tech 2 and Kevin cannot see any issues. Really hard to start but flips eventually to lpg and all ok..

Does it use the maf or O2 sensor when on lpg ??

Its got worse recently.. it was a niggle its now a real pain in the arxx.  Tried redex to clean injectors etc. but seems to make no difference. The fact that all ok on lpg seems to suggest the spark etc is good as lpg normally much harder to ignite.

Every now and then it disappears and runs really well but that is getting less and less.

Any suggestions would be great even if the only make me smile as I am sad at the cars temperament

Ta 

[Lazydocker]

Shed some more light on the setup please Richard. Single/multi-point, make, age of system etc...

Kevin is very knowledgeable on these things and I'll be surprised if any of us come up with a solution he hasn't thought of but it's worth a go

I assume that you've checked the obvious things like fuel filter/supply? I agree that the fact it runs OK on LPG makes a HT fault highly unlikely.

[TheBoy]

Did he notice anything abnormal on the trims?

[tidla]

Did he notice anything abnormal on the trim?

say it was a fuel problem not a hair cut one

[feeutfo]

would suggest a petrol supply issue i guess? cant think of anything Kevin would not have covered, but if the issue is now worse it ma y stand out a bit more on tech 2 now?? :-/

[Kevin Wood]

Sorry I forgot to reply to the PM, Richard.

My best guess was that the fuelling is way out on LPG, so block learning is adjusting so far that it won't then run on petrol.

I think, IIRC, we tried resetting the block learn and only running it on petrol and it was fine on petrol, but it was a while ago. :-/

Can't recall seeing any obvious problems with the MAF. Everything was fine except for the running.

I do remember that we switched between fuels on a run and the pre-cat Lambda was hard lean on one fuel and hard rich on the other.

To answer your questions, Richard, the MAF and Lambda sensors are used on both petrol and LPG.

Did we ever discover what LPG system it had on it? I would certainly like to get into the LPG system and see how it's tuned.

Kevin

[tunnie]

if its fine on gas, but nackered on petrol could one of the petrol injectors got clogged up from not being used?  :-/

Cause normally any problems are magnified on gas, such as poor spark plugs  :-/

[richard]

its a Pharos system (LPG) nobody seems to have the software.
The ecu for it looks exactly the same as the vogas unit but its got pharos on it.
The only guy thats ever looked at it has disapeared but I cannot believe I was just lucky and he had the software.. Maybe he made a generic adjustment ??
I believe he made a adjustment to the lpg mixture but as i said he's gone.

[PhilRich]

I assume you checked the plugs/dis pack for water or oil ingress Richard?, solid plug connection on dis pack? Are the petrol injector plugs tightly fitted? Just seen a similar thread to yours (same system, same symptoms) on LPG Discussion Forum & it was a dis pack fault. HTH 

[richard]

Thanks for the info about LPG forum.. Just had a look but cannot find it. What was its title or could you pop a link

Ta

[PhilRich]

Sorry, don't know how to post HTML link If you PM me your email addy I can sent it that way as an attachment?

[richard]

pm sent

[PhilRich]

pm sent

Replied via e-mail (twice! ) it wouldn.t send first time then went twice HTH Regards, Phil.

[richard]

Thanks for that...

But my car runs a treat on LPG but rough on petrol which everybody says is round the wrong way for a ht problem as the lpg is much more fussy than petrol when it comes to spark etc.

[Ken T]

If its OK on petrol sometimes but bad other times then something is changing which causes the problem. Something like bad electrics (to the fuel pump ?), crap in the fuel line/tank/filter that shifts about, or an air leak that comes and goes (a pipe split/crack ?).

Trouble is if you reset the petrol ECU, you may not be able to retune the LPG side without the software and lead. A garage would concentrate on getting the petrol working right, but you might end up with an LPG system totally out of tune.

Ken