1.9DG - cant get CO above .10%

[jonnyg]

I got me a 1.9 DG, a recon unit from elite VW. I have put it all in and gone to gas it to check its running right. The CO level is sitting at 0.10% and will not move even when adjusting with the mixture screw.

I have since checked the gaskets for leaks (after replacing them all again) and its all OK. The bit that confusses me is that even though i am playing with the adjustment i get nothing. This is leading me to think the carb is fubar'd. I have strip[ped the carb, blown out the jets and all other air/fuel ways i can see. I have done this a few times now and still no help...

So, im after help with ideas on how to fix it or where i can get a new/refurb carb

cheers

[Ian Hulley]

I'd speak to Elite if I were you ... after all the engine itself is covered by their warranty and you wouldn't want to invalidate that. They also install and service gas now (as part of Gasure) so know what they're doing.

Ian.

[Red Westie]

I thought very low emmisions were a desireable part of running on LPG....as in much cleaner and fewer polutants!
I C so it's not LPG then? just the way you worded your post by saying 'gassing'
There is a missconception here! Your mixture screw adjusts fueling at idle so has very little effect when actually running at speed. I would however say you may have a vacuum or exhaust leak causing this low idle reading.
Martin

[Ian Hulley]

OK, just looked our MOT test emission data out .... our 2.1DJ with DG carb was chucking out 916 parts per million of CO (1200 ppm being the pass limit).

How does that compare ?

Ian.

[jonnyg]

Ian, your looking at HC, not CO. Hydrocarbons (hc) is the unburnt fuel, yours sounds about right. The engine is fine, no faults there. Emmissions are all controlled by the carb, im using my original. Elite didnt fit my engine either so cant really bug him...

Martin - its not LPG, i meant i have gassed it as in gas testing, shoulda written it better me thinks.

[VWCamperfan]

The limit for CO emissions is 4.5%. If yours is at 0.10% then thats way below the limit and I would be a happy as a pig in poo!
How come you want to change the carb etc. when it would sail through an emissions test?

[jonnyg]

The limit for CO emissions is 4.5%. If yours is at 0.10% then thats way below the limit and I would be a happy as a pig in poo!
How come you want to change the carb etc. when it would sail through an emissions test?

at 0.10% it suggests that the engine is running very lean i.e. not enough fuel. This would in turn make the engine run alot hotter and risk melting a piston.

The spec for the DG is 1.5%CO +/- 1% so need it to be 5 times better than it is...

[jason k]

yup he is bang on, too lean is very very bad for your engine, can burn out valves if your lucky or melt pistons!!!

[VWCamperfan]

I would be tempted to check your meter, even with the mixture at very lean I would be surprised to find the readings that low because you should always have some CO output higher than you are getting.
Do the readings change when the engine is just started and the choke is closed or you restrict the airflow?
Have you got the air filter and associated pipework connected when taking reading as this would affect the emissions too?

[T'Onion]

Whats the reading on petrol ? could be that the gas system isnt working correctly ,not the engine or carb

[Mocki]

Whats the reading on petrol ? could be that the gas system isnt working correctly ,not the engine or carb

do try and keep up sleepyhead!
he hasnt got LPG........ it is only petrol!

[T'Onion]

ok I'm back off to bed to dream of snow balls

[VWCamperfan]

Other than that, check your float level. Could be too low.

[VWCamperfan]

Just something else I remembered! Check the vaccuum pipe to the brake servo unit. Any leaks here will draw air into the mixture after the carb has mixed the fuel and give a lean run.

Check the spark plug colour for an idea of what is going on too.

[asahartz]

Air leak sounds likely. My CO was ridiculously low at the last MOT (well over at first, then a tiny tweak and almost nothing. MOT tester couldn't even get a reading from one exhaust.)

Not long after we had massive problems due to an air leak. So it could cause that.