LPG conversion yesterday, Car stalling!!

[L67 Calais]

Hi, Got my VP 5 spd put on gas yesterday after spending the weekend getting her running sweet, Went to pick it up and the mechanic starts it up and its running like an absolute bucket of S#*t! He says that the gas system needs to "bed itself in" And that any issues should be sorted at the first 1 month tune (free) Drove it for 30kms last night & it stalled on me twice!! Lost power steering & brakes at 90kmh (foot on clutch changing gear, stalls) Now mechanic says i probably need new leads and to re-gap the plugs to 1.2mm. Is any of this right or have i been taken for a ride?? And what can i do?? Cheers

[georgeonboost]

Im not 100% sure about the gas system "bedding itself in" but usually on gas it will run a little ruffer compared to petrol.

But when running on gas, the plugs need to be gapped closer. factory specs(no gas) from memory are 1.5mm and i gap mine down to around 1.2mm(as close as i can get really). Heavier duty leads will help prevent backfiring aswell. I also run a slightly colder plug BPR6EFS-13 is what im running at the moment.

hope this helps

-George

[L67 Calais]

Actually since it got done yesterday it actually runs worse on petrol, Which i expected because he put a new chip in with the gas system but it runs shocking on gas too (slightly better than petrol though). Checked codes this morning and it gave me code 24 speed sensor? Not sure if that has any bearing on why the car would stall while changing gears but maybe if its not keeping the revs up like it should....?

[L67 Calais]

Also if i gap the plugs to 1.2 will this affect how it runs on petrol? Seeing as theyre bought at 1.5...? Will this have any adverse affects at all?

[georgeonboost]

how bad is it running on petrol? and he changed the memcal?

i havn't seen any problems with gapping my plugs down to 1.2mm.

[L67 Calais]

Its running shocking on petrol, Coughing missing on idle, Surging alot when its cold, Worse than the gas. Yeah he said he put a gas memcal in or tuned it to gas? One of them 2 anyway. But why is petrol so bad now when it went in running fine? He also changed the O2 sensor while it was in which cost me $100!!! Couldve done it meself for 60......

[delcowizzid]

he would of put a memcal in that turns the injectors off when on gas it may not be right for the vp or something .the speed sensor issues may not help either it will think its idling all the time .

[Cheap6]

There may be more than one issue:

The VP memcal is likely to be the factory LPG one intended for auto. trans., which would not normally be an issue with everything else working.

Anything learned in the ECM, including the starting IAC motor postion for idle, will have been lost when the memcal was changed and the ECM will not be able to relearn properly without the speed sensor signal.

When the sensor failed, the ECM would have been using what it had learned with the sensor working. Reset the ECM and the problem becomes noticeable, explaining the problem now occuring on petrol.

Bottom line: fix the speed sensor fault and then see if there is still a problem with stalling/idle on LPG.

Plugs gapped at the standard 1.5mm will be fine with LPG if it is working correctly.

[L67 Calais]

Thanks Cheap6 You're a champ!!! Replaced speed sensor & Reset the Ecm & Shes running %100 better!!! Im a happy man now! Time 2 do a skid :-) Still a little bit of a miss tho but heaps better. I'll change my cracked exhaust manifold & the plugs n leads tomorrow and let you know how i go. Thanks again!

[Phat VN]

my VN 3.8 (GAS) stalled YESTERDAY in drive. i started it again went down the driveway then it stalled again. my mate in the back noticed that my gas reading wasnt coming up as anything managed to start again then stalled going about 200 metres up the road then it just wouldnt start at all but runs ok on petrol Any way cut a long story short this morning and last nite doing about 100 kms flicked it over to gas ran for about 20 seconds then stalled and i dont have a clue wat it is can any 1 help me asap thanks

[Vt-Brrrlina]

from someone that has owned a vp commmodore on gas - mate my ran perfect on petrol and gas - maybe try where local taxis get theres done - there gas fitter will have done hundreds of em - get em to have a look for any obvious things wrong -

with mine though car had to be in tip top shape to run on gas - coil packs good, leads good , correct spark plugs, fresh air cleaner element

[padrickz88]

also check for any vacuum(sp?) leaks....