CO and MPG question 16v 9a

[radness 0]

Hi guys, I recnetly went for an emissions test and it came back with 0.490% vol, i've been doing a bit of research and I have seen some people suggest that 2.0% is the ideal mark for 16v's.. Any truth in this?

 

I'm also getting poor MPG....20-25 around town at night.. On another point, if my CO is too low, that would mean im running lean, so surely my MPG would be better not worse or have i missed something?

 

thanks for any assistance :)

[horney 0]

20-25 is what I get out of mine to mate, will look up the last emissions reading from the MOT over the weekend for ya.

 

Nick

[radness 0]

thanks mate, would be interesting to see, also worth noting, when i accellorate close to redline then drop into 2nd it gives a backfire...but up top it seems to lean out a bit more than expected..i have kr cams

[horney 0]

Humm I have KR cams to but don't have any backfire issues. That said I haven't had the fuelling or timing checked since the cams went in.

 

Nick

[Kempy 0]

around town you'll be lucky to get over 20mpg. I from south wales to north london on tuesday and managed 33.2mpg which i was happy with. Try a Ecotek valve, I have one on my other valver and its says on it mfa up to 38-40mpg on longer journeys..

[davidwort 0]

Try a Ecotek valve, I have one on my other valver and its says on it mfa up to 38-40mpg on longer journeys..

well seeing as an ecotek is nothing more than a manifold air leak and the mfa on a valver calculates mpg from manifold vacuum I'm not surprised you get dodgy figures.

[Kempy 0]

its should make it more economic though, right? thats why i fitted it any way

[Toad 0]

It might make it seem more economic, but it's tricking the ecu (on cars with MAFs) into getting the mixture wrong, which is clearly going to harm the engine in the long term.

 

If you want to improve your fuel economy, drive more smoothly and at 60 rather than 70.

 

There are countless threads on here of issues with idle and running issues caused by air leaks in the inlet trunking, and this is what you're intentionally introducing to the car.

[colinstubbs 0]

Valvers do 38-40mpg at 60mph out of the box. Best I had was 48mpg on a motorway run with a spacesaver fitted -- only hit 65mph once or twice, not a good idea! I was trying to stick to 50mph, safe, economical and boring!

[radness 0]

20-25 is what I get out of mine to mate, will look up the last emissions reading from the MOT over the weekend for ya.

 

Nick

 

Hey man, where you able to find your last reading at the MOT? :)

[Supercharged 2]

Ekotec valves - lol, they are still around then!

[radness 0]

OK, i have since found out that your CO reading on the 9a cannot go above 0.5% as it has a lamba which controls this.

 

I was doing a bit of research and have heard a lot about the BLUE CTS (not sure what or where this is) but it basically controls fueling when your engine is cold it causes over fueling, aparently this can go wrong and cause over fueling when the engine is warm. Is this correct? I've done a bit of searching on here and only see the BLUE CTS mentioned in relation to the g60.... does it not affect 9a?

 

if i do have a blue cts, could it be affected due to my engine never going above 80c coolant temp? Since i got the new thermo it's never gone above 85c and always sits around 80c, engine oil is always around 90c, unless sitting it goes upto 100c and no further.

 

(last edit)

 

During running my idle can randomly go upto 1500rpm and sit there until i turn the engine off and on again, sometimes turning the engine off and on again doesn't help it.... anyone know why this would be ? ISV?

[davidwort 0]

there's two sensor on the side of the metering head IIRC, down the left hand side (looking from the front of the car) from what I remember from a few years back at stealth if you unplug both the car will run in average temp etc settings from the ECU. There was a car that wouldn't idle at all (9A 16v) and a pattern lambda was suspect, pulling both these sensor connectors and it idled OK, presumably that was enough for the ECU to give up on the lambda signal too.

[radness 0]

there's two sensor on the side of the metering head IIRC, down the left hand side (looking from the front of the car) from what I remember from a few years back at stealth if you unplug both the car will run in average temp etc settings from the ECU. There was a car that wouldn't idle at all (9A 16v) and a pattern lambda was suspect, pulling both these sensor connectors and it idled OK, presumably that was enough for the ECU to give up on the lambda signal too.

 

What is the downside to having these sensors removed? Should there be anything to be careful of, is there any advantages apart form fixing the idle problem? sorry for the newbie questions :confused4:

[davidwort 0]

there's two sensor on the side of the metering head IIRC, down the left hand side (looking from the front of the car) from what I remember from a few years back at stealth if you unplug both the car will run in average temp etc settings from the ECU. There was a car that wouldn't idle at all (9A 16v) and a pattern lambda was suspect, pulling both these sensor connectors and it idled OK, presumably that was enough for the ECU to give up on the lambda signal too.

 

What is the downside to having these sensors removed? Should there be anything to be careful of, is there any advantages apart form fixing the idle problem? sorry for the newbie questions :confused4:

 

it just makes the ECU run in 'average settings' rather than reading values from the sensors, sort of 'get-you home mode'

best not to leave it like this for long though or it could eventually damage the cat. It's just a crude way of narrowing doen what might be causing the problem.

If you had a vacuum leak or something mechanical being the problem, then the problems would persist at idle.