VX Berlina backfiring, stalling and other weird stuff ( LPG)
Hi everyone, I am at my wits end and I am hoping that someone here can help!
I have a VX Berlina S2 with after market LPG fitted on it approximately 3 years ago. I take it back to the installer for all things mechanical (except for one time recently when I went to Holden...oh how I wish I didn't!).
My car has been in and out of my mechanics for almost 2 months now, I took it in after it backfired so it could be tuned and checked over. I had it in the Holden dealership a couple of weeks before that and they said they gas serviced it and I say bull$hit! We replaced the oxy sensor in it, and that seemed to stop the stalling issue (until yesterday!), but the backfiring was still happening. I have blown anywhere from 3 filter boxes to pieces in the last 2 months and I have had plugs and leads replaced, multiple trips to the emissions meter and yet the problem isn't resolved. I am also sure he said he replaced the coil packs too, but the problems are still there.
I took it in yesterday morning, as it was running lean again so they tweaked it and I left. I got on the road again for my usual trip to pick up my kids and it started to fade, done it's little starving for gas dance and almost stalled until I switched it to petrol. Once I was parked and idling I changed it back to gas and it was fine for a little while until it died on me as I was turning a corner and an intersection and I had to roll to a stop and try and fire it up on petrol to get home! It was also hard to start a couple of times yesterday too, the gas just wasn't getting through to where ever it needed to be to start idling. Now, I am no expert on this whole LPG thing but if it is un-tuning itself in such a short space of time and distance (less than 100k's traveled since picking it up), wouldn't the converter or mixer thingy be the first part to be looked at or even replaced?
It has backfired several times, the very first time it did it was just after I had the LGP installed. I took it back, new leads were installed and I didn't hear it again until after Holden had their filthy hands on it in January this year.
I need my car to run smoothly, I am about to donate the damn thing to science and go shopping for an ancient car that has stood the test of time. My mechanic says that it's not only my Holden that does this, he has one other, a VY that comes in with the same issues and apparently a change of coil packs have resolved the problems there...but it has only been drive for 700k's, if it were me and my car, 700k's isn't a lot of driving for me to feel comfortable saying it was resolved.
I have read through old post on this site, some with very similar issues to mine, but it seems I am either really unlucky or someone is trying to pull a swifty on me! My husband is home tonight, so I am taking the car back in tomorrow, I want them to pull the thing to pieces and fix it instead of stuffing me around some more!
Can you take a LPG kit off your car and have it run like the good old days again?
So much for saving money on fuel costs!
Serija
wooow....sounds like a true drama.....
ok....i dont have a lpg fitted in my holden but i have had it in other cars with drama and without..
ok you done the plugs and plug leads
and tested the coil packs...
and done the sensor for the o2
i am thinking of 2 possibles.....ok...faulty gas vapor convertor or ... stuffed up air mass metre..
now it could be the vapor unit is not making fule a true liquid and could be due to not heating correctly..so look for frozen parts in and arround the vapor unit..when its playing up...
it could be the air mass unit is not knowing when and how to lean the engine off...this could be due to the vapor unit playing up or it could be..
so check the unit out
take back to a lpg --tuning specialist...prefered is the installer...
ok
GRA = REAL HP
what type of spark plugs you using and what gap ?
Originally Posted by Serija
Hi everyone, I am at my wits end and I am hoping that someone here can help!
I have a VX Berlina S2 with after market LPG fitted on it approximately 3 years ago. I take it back to the installer for all things mechanical (except for one time recently when I went to Holden...oh how I wish I didn't!).
My car has been in and out of my mechanics for almost 2 months now, I took it in after it backfired so it could be tuned and checked over. I had it in the Holden dealership a couple of weeks before that and they said they gas serviced it and I say bull$hit! We replaced the oxy sensor in it, and that seemed to stop the stalling issue (until yesterday!), but the backfiring was still happening. I have blown anywhere from 3 filter boxes to pieces in the last 2 months and I have had plugs and leads replaced, multiple trips to the emissions meter and yet the problem isn't resolved. I am also sure he said he replaced the coil packs too, but the problems are still there.
I took it in yesterday morning, as it was running lean again so they tweaked it and I left. I got on the road again for my usual trip to pick up my kids and it started to fade, done it's little starving for gas dance and almost stalled until I switched it to petrol. Once I was parked and idling I changed it back to gas and it was fine for a little while until it died on me as I was turning a corner and an intersection and I had to roll to a stop and try and fire it up on petrol to get home! It was also hard to start a couple of times yesterday too, the gas just wasn't getting through to where ever it needed to be to start idling. Now, I am no expert on this whole LPG thing but if it is un-tuning itself in such a short space of time and distance (less than 100k's traveled since picking it up), wouldn't the converter or mixer thingy be the first part to be looked at or even replaced?
It has backfired several times, the very first time it did it was just after I had the LGP installed. I took it back, new leads were installed and I didn't hear it again until after Holden had their filthy hands on it in January this year.
I need my car to run smoothly, I am about to donate the damn thing to science and go shopping for an ancient car that has stood the test of time. My mechanic says that it's not only my Holden that does this, he has one other, a VY that comes in with the same issues and apparently a change of coil packs have resolved the problems there...but it has only been drive for 700k's, if it were me and my car, 700k's isn't a lot of driving for me to feel comfortable saying it was resolved.
I have read through old post on this site, some with very similar issues to mine, but it seems I am either really unlucky or someone is trying to pull a swifty on me! My husband is home tonight, so I am taking the car back in tomorrow, I want them to pull the thing to pieces and fix it instead of stuffing me around some more!
Can you take a LPG kit off your car and have it run like the good old days again?
So much for saving money on fuel costs!
Serija
i feel for ya. im on the same boat as you right now. same problem with my vs 5 litre. just had , leads,plugs and dizzy replaced. its stopped backfiring but constantly stalling on gas. i bought the gas kit, purely to save a few bucks, now i lose money everytime i have to take it back to the gas fitter. He cant see me for a week now, its raping me in fuel. the guy reckons its caused from a bad electronic signal somewhere. good luck
Thanks for the input. I will be taking this to my guy tomorrow and I hope he can check these things for me.
In regards to the plugs, he said that he regapped them. I have no idea to what measurment. I don't know what brand they are either but I am sure they are NGK's as that is what he put in it when it was installed.
I am so over it. I am forced to drive my husbands exceptionally thirsty land cruiser ugh!
make sure he checks the distributor cap and rotor button. ive got ngk plugs on mine and since then ive had no backfiring whatsoever. Also had distributor cap, spark plugs and leads changed.
My old car had issues with leaning out the LPG, and blew up the air box. 2 different mechanics played with it no luck. Ended up back with the original installer (who was retired) he checked it over and found the inline lpg filter hadn't been touched and as a result the mixer was in poor condition internally. He adjusted it and said if it continues to play up I will need a new mixer. Ended up driving it for a couple of years with the same mixer before selling it.
QldKev
You will find wiht LPG systems, they are initially tuned too lean to impress people on mileage, we go in they tune it properly and no dramas. My Vx used to switch off in the 1st few months, once while i was on the monash freeway in peak hour ! Anyway, it was tuned too lean. Many peope have had this, even with new injector systems, mates vy turned off when reversing, due ot lean gas. Anyway after 6 years on gas and many other lpg cars in the extended family its excellent ! The tune is most important. Do it every 10,000k's initially. Only costs $15 or so. Now, i have had 2 backfires in that time, once using NGK plugs, and second time asss mechanic broke my lead and stuck it on loose, i drove home 50k's on the monash and east link no dramas. I got off, gunned it up a hill and boom, there went the air box.
My preference for plugs are Champion Gold, Bosch or Denso plugs. Many say NGK are best, but for me i have only had backfire when they were in the car. You also need Stainless steel leads, Scorcher or Ice Ignition being the best, with Bosch Eagle, Gasmaster leads are excellent. Must be Stainless steel. I am currently testing some Bosch LPG plugs, they made them especially for lpg cars, a new design, not just a colder plug. Get your coil pack tested from ignition specialist. Also clean the air filter and MAF. Lean air flow coming in can also effect and lean out the mixture. Also your radiator cooling system should be checked as it it important to the function of the mixer.
Also the systems work better as time goes on, the diaphragm in the mixer works properly etc. As i said, most have drams in the beginning, how may taxis etc after hundreds of thousands of kilometres on lpg ?
Thanks again for your insight, I really appreciate it.
My car is still at the gas fitters, he is going to change out the converter and see how it goes.
I have had the gas on for 3 years now, and in the beginning it was funky, and now since it was last serviced it has been all out of whack.
I have GasMaster leads on it so that is one good thing I guess! I am expecting a call today to come get it so I hope that the change of parts will do the trick. Good thing it that he isn't charging me until he gets the car working properly, but I am not looking forward to getting the bill when it finally arrives!
how did it go? did they solve the problem?
how did it go. i have similar problems(((
Where do i start
Ok, I have just stumbled across this thread. Reading through it I cannnot believe the responses that SERIJA has recieved. Nearly all them are factually wrong.
Firstly, I have many automotive qualifications and have been in the trade for 32 years.
I have a VX commodore that I converted to gas 3 years ago (2007), yes I am a licensed installer, although it is not what I do as a day job.
It has NEVER back fired!! it is a sprint gas system which is pretty well run of the mill on Commodores. What they call a complex convertor and simple mixer. (which i will assume is what you have) Vapour injection is more expensive and at the time you say your car was converted, Vapour injection was withdrawn from market because of reliability issues with injectors.
Spark plugs and leads are VERY important, I use NGK plugs and factory holden leads. Generally you go one heat range colder than standard (for Holden V6) and gap down. NGK recommend .1 of a MM and Bosch gas specific plug recommend .6 of a MM narrower. I have always settled at .2 MM, IE standard gap is 1.5MM, i set mine at 1.3MM. I also only replace them every 20,000KM. I have only fitted one set of leads in that time and that was because I have never put leads on the car from new. Original holden leads are more than adequate for LPG. However, Bosch, Topgun ETC will do the job.
9 times out of 10 a gas backfire is a result of crossfiring in the ignition system, this could be promoted by lean mixtures as it takes more current to fire a lean fuel mixture. Once you have the plugs and leads sorted and that can include separrating the leads to prevent cross fire, although shouldn't be necessary in VX, you can then look at setting the gas mixture. This is a straight forward job for a competent mechanic and a scan tool.
Don't get fooled into replacing every engine management component. If it runs well on petrol then they are all OK.
The gas is metered by a device in the vapour line, so once you have set the max gas flow restrictor the vapour line controller takes over. The vapour line controller is controlled by the gas control unit which takes feed back from the oxygen sensors in the exhausts LH and RH pipes. The right hand sensor is just a reference, the left does the work. To say they are set up lean is BS. With the proper scan tools you can road or Dyno test the vehicle and adjust gas mixtures to the ideal setting. I have always had a return of around 10.5 lts per 100 (hwy) and 12lt per 100 (town) on gas
It is possible that the convertor needs cleaning (depending on Kms travelled), gas residue can make the diaphram "lazy" and therefor may be slow to respond to throttle opening and that promotes a "lean backfire". An indication of convertor condition is starting. A sticky convertor will be harder to start when cold than when hot. If the starting characteristics are the same hot to cold the convertor is OK and shouldn't need cleaning.
No real answers there but hopefully addressed some of your questions.
Regards,
John
GRA = REAL HP
start with base engine tune check for vacum leaks at the manifold injector seals vacum lines , cracks in exhaust manifold up stream of the 02 sensors , check ground connections and leads for resistance , check if the lpg processor has been grounded at the engine block or just tek screwed to the body earth , spark plug choice i would use would be NGK BP7EFS gapped to 1mm ,
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