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[Omegacraig]

Hi Chaps,

I have an Omega V6 fitted with a bigas LPG system, ive only had the car a week or so but it appears that it had a problem on the gas system.

at idle it was a little lumpy but bearable, and normal driving it appeared generally ok but with the odd misfire, however at 50mph+ when trying to accelerate it would misfire quite badly and only by changing down could you speed up.

I did some research and it appears any weakness in the ignition side could be causing my issues, so i have replaced the DIS pack, HT leads and sparkplugs with high quality items (plugs are platinum and are gapped to .7mm) i did find a poor connection on the DIS pack that would definatly cause a weak spark in 1 cylinder and so i thought the problem would be cured, however the problem remains, where should i look next as to the cause of the problems?

Regulator? filters? all the injectors appear to be working correctly, i have had an LPG car previously but never encountered any issues with it so dont have much experience testing/repairing gas systems.

any advice is much appreciated!
Craig

[Entwood]

Hi

I think you are the guy I pointed here from the LPG forum, with any luck Kevin or one of the other LPG experts will pass by shortly and assist 

[Dazzler]

How old is the system?
May need a new filter.
May need the pressure turning up a bit.

[feeutfo]

How do craig, welcome too oof,

Does your system come with any software? if not with the car then via download from the makers site.

The stag system some of us have on here comes with software that allows automatic calibration and some map fiddling via usb.
 Also shows lambda readings and inector duration etc, if your system has similar it should be possible to see whats going on re the state of tune.

 Although im still getting my head round this as my install is only just complete.

In the absence of any other info i would check ignition as you have. Plus coil, lambda, ignition, battery and injector connections. Change the lpg filter as said....and then..... wait for Kevin Wood or lazydocker to answer your question properly i aint no "expert" 

[Lazydocker]

Ooh... Deemed and "expert" now 

Firstly, hello Craig and welcome

Right... As you've correctly said, the first point of call is HT but you've covered that!

As Dazzler said... How old its the system and has it been serviced? Bigas is a reasonable make and should be OK for the car so you need to check the history. If I were to hazard a guess (and it is a pure guess from the information so far) I would say the system probably needs a good tune up and filter change

Please update your profile with a location as someone with a little knowledge may be near enough to have a look for you and give some "eyes on" advice.

I can tell you that if you need Bigas software/spares you can get them from http://www.tinleytech.co.uk and the guys there are very helpful

[Omegacraig]

thanks for all the replies

ive been going through the history i have with the car and cant find anything regarding when the lpg was last serviced, its been fitted approximatly 2 years, so id be willing to bet never!

Ive found a copy of the ecu software as suggested i just need a cable use with it, ive updated my profile im from preston up north 

would it be worthwhile getting a reconditioning kit for the vaporiser whilst replacing the filter? or do they last longer before needing maintenance?

first things ill replace the inline filter & aquire myself an ecu cable (unless anyone has a suitable one they can loan me whilst i diagnose for some beer tokens?) and see how i go from there.

I have noticed in the ecu software many options are changable, but others are not without a dongle, fingers crossed i dont need one as ive come across software before that wanted one - and it was a real pain!

cheers for the help so far chaps

[SteveD]

If it runs fine on petrol and the software enables it, I'd try running with each cylinder on petrol in turn. You might be able to narrow it down then to an individual cylinder. If you do get down to one it will make troubleshooting a bit easier. The software should also let you keep an eye on the gas pressure under load so you can see if it's not supplying enough.

Software permitting, you could try a bank at a time too if pressure drop looks to be the issue.

Good luck!

[Omegacraig]

The car does run fine on petrol, im not quite sure just yet of what the software will allow me to do just yet as ive only today started having a look at it.

It does seem to have live diagnostic readouts so once my cable arrives i shall see what i can find out

[Lazydocker]

That's a good start Craig

Get the lead first. As I said, Tinley Tech are good, although not the cheapest, and will be happy to offer advice over the phone too

[Omegacraig]

Good to know thanks 

Ive been looking at cables from various suppliers & im a little unsure between the 2 types that are available.

seems to be a cable with a serial plug, some sort of interface box, then the ecu connection

or a usb>serial>ecu cable without an interface box, im presuming both are suitable and the interface is just required for the serial cable?

Id rather make sure before i splash out £40

Having a modern laptop im exactly 1 serial port short of... well having a serial port    so it would be useful to just be able to get the usb one

[Omegacraig]

forgot to place this in my last post, if your on msn feel free to add me on to your list, comp9801491@hotmail.com

always happy to chat to fellow omega owners, especially if i can pick their brains!

[JamesV6CDX]

LPG? What's that?

In all seriousness - the main thing to remember with LPG, is that it will detect any underlying running issues that may go un-noticed for longer on petrol, especially with HT related stuff

A miss under load on LPG, but not petrol, is often the sign of a failing ignition component.

As I proved today 

[Lazydocker]

LPG? What's that?

In all seriousness - the main thing to remember with LPG, is that it will detect any underlying running issues that may go un-noticed for longer on petrol, especially with HT related stuff

A miss under load on LPG, but not petrol, is often the sign of a failing ignition component.

As I proved today 

Agreed... But he's already replaced all the ignition components so the software will enable him to check the feed side before looking for a needle in a haystack with the potentially faulty plug/lead etc

[Omegacraig]

at last!

my filter & ecu cable has arrived today, as its nice ill be off out on the motorbike this evening, but before that ill get the new filter on and give the rest a cleanout with some carb cleaner, fingers crossed!

[Omegacraig]

well i didnt get chance to fit my filter last night as it was to dark by the time i got home, however i did break out the laptop to check some figures via the diagnostics

most of it looked ok from what i could see however 2 things were bothering me.

the gas pressure seems to hover around 0.8>0.9 bar, yet ive seen text on the internet that says it should be more like 1.8>2.2bar is this correct?

Also there was a setting for operation at low gas & high rpm
both were set incorrectly in my opinion but i couldnt change them.

operation at low gas was set to continue on gas rather than switch back to petrol, and high rpm was set to cut back to petrol at 2.5k>9k rpm - but i can still hear the gas injectors running over 2.5k if i rev it whilst stationary?

any thoughts anyone? the new filter will be going on when i get home so that at least takes that out the picture.