That sounds about right, CO when running on LPG is usually very low even though the limit is 3.5%. Mine came out at 0.3% and that is with gutted cats. Borderline to pass the CAT test for petrol but I could probably get it down low enough if I wanted with a tweak of the LPG system settings.

The problem with the CAT test is if you tweak the mixture enough to get it below 0.3, the "lambda" value fails instead as the mixture is too lean. You might manage to eeke thru with LPG though.

Its quite sensibly designed to be very difficult to pass without working cats.

A healthy petrol engine will run around 0.4-0.5% with no cats fitted, with lambda nailed at 1.00. Fit the cats and it'll come right down to zero if they're working well.

I'm actually quite impressed these cats are working, as they look like cheap aftermarket ones and are well rusted suggesting they're a good age, and have been bathed in unburnt fuel and oil deposits from the engine burning oil, and previous experience with aftermarket cats is that they really dont last that long!

Mine was 0.12% when I got it tested last week and that's with the two year old sport cats.

Well that lasted well.....

Taxed it today and decided to take it for a run to get pizza. It drove pretty nicely, everything working as it should, engine felt a bit peppier than previously even, collected pizza and headed home. Pulled into my street and all of a sudden it wouldnt rev. it idled perfecly happily, but any throttle input and it was coughing and spluttering. Switched LPG off and it was exactly the same on petrol. Tried revving in neutral and it was the same there too.

Grrr

Throttle position sensor......

You recon?

I've just tried it with the MAF unplugged and its exactly the same, so i think that hopefully tells us its not the MAF.

Gentle throttle input will lift the revs from idle upto around 1200rpm, at that point it starts surging, and any more input it starts really spluttering, almost sounds a bit like a rev limiter.

If it's the same with the MAF unplugged, then that could point to the MAF. Are you sure you haven't got an iffy connection? Although my MAF plug hasn't suffered, a couple of the others had wires that had broken where they go into the plug. I carved the plastic away and soldered the ends of the wires directly to the back of the terminal. That could explain the apparent appetite for MAF sensors if there's a dodgy connection and it works for a while after you've disturbed it.

When the MAF went faulty the first time round last year, it ran fine with it unplugged and drove normally, wasnt like this at all.

It ran so well infact that i put it in for an MOT with it unplugged by mistake (which it then failed for high CO!)

That's odd. Normally if the MAF is dead or disconnected they are a bitch to start and run really rough.

Well mine certainly seems to run fine without it normally. The first couple of starts are difficult until the ECU realises its not there, then its fine. Granted if you back to back it you can tell its better with the MAF plugged in, but it works well enough without it.

last week when i put it all back together i installed this new/used MAF and new plugs, and started it and it was running like a bag of crap and sounded very strange, then i realised i hadn't plugged in any of the passenger banks spark plug leads :P

With those plugged in it ran much nicer, revved up nice and cleanly, but i was scratching my head trying to figure out why the maf values werent showing on nanocom. Eventaully i noticed the intake temp was showing as -61c and that made me realise i hadnt plugged the MAF or intake temp sensor in either.

Plugged those in and checked the readings and it was reading the book values at idle at 2500rpm.

I'm fairly happy its not the MAF, could well be the TPS but i wouldnt have thaught that would affect the running so much, youd expect that to be more related to idle control?