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[BigCat]

I've started a new thread as the other was getting confusing. The old one is here: http://www.omegaowners.com/forum/YaBB.pl?num=1314397990/all

I've been experiencing hard starting with my 3.2V6 which had an OMVL Dream XXI LPG kit fitted about three or four years ago. New coil packs were fitted at the time and it had new plugs fitted a few months ago.

The car runs fine on petrol (although it does suffer from the pre-cat issue - codes 420 and 430), but if I run it on LPG, it won't start easily. Rather I have to crank it for at least ten seconds, sometimes more. I've also had some poor running issues with it misfiring regularly (always codes 302 and 306) on LPG only.

I had a severe misfire which turned out to be oil in the plugwells; the camcover gaskets have since been replaced.

I've had problems with the multivalve which was replaced about nine months ago. The LPG running problems seem to have started around the same time, although this may be coincidence.

I'm just waiting for a new live data reader to arrive so I can have a look at what is happening.

Dominic

[Elitenut]

You might find these links useful. http://www.fesautogas.co.uk/dreamm.htm
http://www.fesautogas.co.uk/21Nnoneobd.pdf

[BigCat]

Thanks, I ordered the cable today and the OBD2 cable arrived this morning.

[BigCat]

Tonight I tried to connect up the OBD cable with little success. The leds come on when I plug it in, I connect it to the laptop and fire up the software which recognises the cable/OBD unit but it constantly searches for the ECU and never finds it. If I change devices e.g. Transmission, it still doesn't see it.

This is really frustrating as I had the same problem with the £350 UKOBD unit. We went back and forth with the unit and in the end they reckoned I must have a faulty wiring loom i.e. cut wires.

That may well be, but why then can Vauxhall talk to it with their Tech II? and why does a cheap £20 unit talk to it and clear codes?

Am I using the wrong communications protocol? say OBD II instead of Can Bus. Just grasping at straws here!

[feeutfo]

It is obd2 compliant.

[feeutfo]

Does cable need a proper com port on the lap top, maybe?

[BigCat]

It's OBDII and Can Bus compatible and the laptop can see it and talks to it, but cannot talk to the car's devices.

[tango]

hi
cuople of things id like you to check i might know where problem is

firstly
if you start the car on petrol drive it on petrol and then turn it off whilst still on petrol
does it then restart normally

secondly
your gas conversion has a regulator ( a big unit to wich the gas from the tank comes into and then feeds it to the engine )
this has water (coolant) pipes coming to and from it.
can you check from the original cars plumbing where these pipes have been fed from

[tango]

hi
just read through this again sorry my fault for not reading your original post

ok your problem is definitly down to 2 things
i have a 3.2 mv6 wich had similar issues

the problem is either your injectors are leaking gas ie not closing
so when you start your car it should start on petrol and switch over to gas when warm but the injectors are letting gas through so now your engines getting gas and petrol causing a major mixture issue wich isnt leeting it start properly
if the gas injectors have failed you will get a misfire in certain cylinders all the time

yuour other problem could be the seal in the regulator has warn and is letting gas through when it shouldnt
this has the same effect but youll get a random misfire
but the ones closest to the feed will show up more often as the gas is being fed from there

this is a very cheap fix as its only a rubber seal that goes
theres a gas instaler in birmingham who i know installs the same system as you have so he would have the parts in stock and i can get you a price of him for supply and fit or supply only

[zirk]

Just out of interest what happens if you force start it on gas?

[BigCat]

If I force start it on gas after it has been running on petrol it starts much quicker (it still takes a few seconds for the gas to start flowing and hit the injectors i guess).

When I discovered that, I thought it ruled out the leaking injector or regulator. However - the misfire is constantly on cylinders 2 and 6

[cem_devecioglu]

If I force start it on gas after it has been running on petrol it starts much quicker (it still takes a few seconds for the gas to start flowing and hit the injectors i guess).

When I discovered that, I thought it ruled out the leaking injector or regulator. However - the misfire is constantly on cylinders 2 and 6

either lacking fuel or spark .. (assuming correct ignition timing) ..  in a friends case we soldered the injector sockets and all was well.. (landed on the subject with parachute )

[tango]

if you look thrugh my previous post last year
you will see i had the same problem
i was also getting 2 & 6 most of the time but then i would get a random misfire  i would also not often but on the rare occasin get a misfire on cylinders 1 3 or 5
when this happened i went back to the gas installer who checked the regulator and the seal was leaking
i dont know why 2 & 6 show up first thats what happened to mine