LPG Discussion Forum

Hi all

I have a 2006 Saab 9-3 with factory fitted dualfuel.

She is currently running rough when on gas. On petrol she is perfect.

When on gas she has a slightly rough tick over and is down a little on power when driving. Although she has a full service history from new, i'm not sure that the gas side has been
serviced as required.

I'm based in Normanton, Wakefield and need a specialist to give the gas side a service and health check.

Cheers - mike

Simon (LPGC on here) is close to you (South Elmsall) and worth getting in touch with. Might be worth giving it a fresh set of plugs though if it hasn't had any recently as well as they can cause poor running on gas whilst being fine on petrol as they get worn.

Wasn't aware Saab did a factory conversion although they do convert well. I had a '96 Saab 900XS with a conversion on it, NGK Iridium plugs used to last around 40,000 miles.

I did wonder about that actually as well, Would be an idea to identify the system fitted if you can as well if you can.

While the earlier 900 was Saab through and through (with GM only having a very small input), the later 9-3 was very much GM influenced and shares a lot of parts with the Vectra, so it might have been the same system as fitted to the similar vintage Vectra?

That would be Necam/Koltec I'd guess. Which it would be better if it wasn't!

Landi-Renzo was a "factory-fit" for a few makes (theres another brand as well that was commonly used but I can't remember the name of it at the minute). Which is at least a bit more friendly to get on with.

hi all

its a Koltec system

Its a factory fit system and has worked well.

I have picked up a new set of plugs for it so will pop them in tomorrow.

I have sent Simon an e.mail, I have used him before around 8 years a go.

Cheers - mike

The Kolec system is fine when its working - they worked well. Just when they do go wrong, some bits for them are scarce now and expensive as well. Simon is probabbly your best bet with that system and where you are though.

hi all

I have started doing some work on the saab this morning

First thing I found was the oil filler cap o ring has failed so there's effectively a vacuum leak so I will replace it.

I have pulled the plugs and numbers 1,3,4 are all perfect but number 2 is sooty. I don't think lpg leaves sooty deposits ? so it may be the
petrol injector that's leaking. The car runs well on petrol and I think the leaking injector does not show up but when on gas its adding extra fuel
and messing up the mixture.

I'm going to renew the plugs and read the fault codes.

Cheers - mike

hi all

have done a bit more in this

I read the fault codes which showed misfire no2 cylinder which confirms what I saw on the plugs.

Popped it all back together and got it running on gas. I then clamped the petrol feed to the injector rail so that it could not get petrol and she immediately smoothed out on gas and ran fine.

So it looks as though number 2 petrol injector is leaking.

Going to order one later today.

Cheers - mike

Don't you just love an easy fix, well done.

Very good!

If the problem is much worse at tickover than under load it points more toward the petrol injector leaking a little constantly even when not being pulsed, if the problem is consistent throughout the load range it points to the petrol injector still being pulsed when running on LPG. The question is, is the problem mechanical (leaking petrol injector) or electronic (not shutting off petrol injection on cyl2 when running on LPG).

I've replied to your email but pleased to read it seems sorted. What did I do for you 8 years ago?

You might get some luck with some injector cleaner if you run it on petrol for a bit, the factory fits tend to swap over at a very low temperature, so very little petrol goes through the system. If its mechanical issue, as said above it could be electrical (unplugging it would tell you more if thats possible to do, can be a pain to do without snipping wires on some cars, though thats easy to fix if you have a soldering iron).

hi all

the problem persists even with the injector un-plugged so its definitely leaking. The car changes to gas within 60 seconds even on a cold
start so the petrol injectors see very little use.

I added some injector cleaner to the tank and did 40 miles on petrol yesterday so will see if its any better today.

I have ordered an injector to replace the faulty one and may have them all ultrasonically cleaned whilst they are out.

cheers - mike

Hi all

have done a few more miles on petrol today with the injector cleaner in and I think she's now soerted.

She's running really well on petrol and ok on gas with now mil light etc.

She's 95% ok on gas so I will change the filters and give here a check over once the new filters arrive.

Cheers - mike

Nice one

Hi all

have done a few more miles on petrol today with the injector cleaner in and I think she's now soerted.

She's running really well on petrol and ok on gas with now mil light etc.

She's 95% ok on gas so I will change the filters and give here a check over once the new filters arrive.

Cheers - mike