Emissions with megasquirt and supercharger

[eltax91]

Hi guys

I have a mk2 1.8i and it's currently sat at the mot station being given its usual once over.

It's come up as having CO emissions of 2.4, when the maximum is 0.3.

I've only had the megasquirt/ charger fitted around 10 months ago, so it's clearly soemthing in the kit I bought that's causing the problem as it sailed through last year. The kit was bought used from a guy running it on a mk2.

I fitted most of it myself but did have it trailered to nick at skuzzle Motorsport to have the megasquirt fitted, have it tuned etc and generally Finnish/ tidy the install. It came with a wideband O2 when I bought the kit, which I fitted.

So, having zero knowledge of how the megasquirt works, what the he'll do I do to lower the emissions so drastically?

Cheers folks.

[feef]

eltax91 said:

Hi guys

I have a mk2 1.8i and it's currently sat at the mot station being given its usual once over.

It's come up as having CO emissions of 2.4, when the maximum is 0.3.

I've only had the megasquirt/ charger fitted around 10 months ago, so it's clearly soemthing in the kit I bought that's causing the problem as it sailed through last year. The kit was bought used from a guy running it on a mk2.

I fitted most of it myself but did have it trailered to nick at skuzzle Motorsport to have the megasquirt fitted, have it tuned etc and generally Finnish/ tidy the install. It came with a wideband O2 when I bought the kit, which I fitted.

So, having zero knowledge of how the megasquirt works, what the he'll do I do to lower the emissions so drastically?

Cheers folks.

I don't know about the megasquirt's features, but with my Emerald ECU, I have 3 maps which are switchable on the fly from the dash. One is a full map, one is an adaptive map that uses the wideband sensor in a closed loop, and the other is a leaned-out 'MOT friendly' map to make sure it can pass the emissions test. Can the Megasquirt do something like that?

[J-Tuner]

I had similar fun and games the first MOT after supercharging. Was running horrendously rich. I had no wideband at that point.

I got Skuzzle to do some further tuning to bring everything into spec but if you know your way around tuner studio you could probably lean things out in the fast idle range on a temp map to get you through.

Mines due in May and I'm nervous about mine again. Gonna look on the laptop and see what the lambda is like this weekend.

I believe you can switch maps on megasquirts no idea how though.

[eltax91]

J-Tuner said:

I had similar fun and games the first MOT after supercharging. Was running horrendously rich. I had no wideband at that point.

I got Skuzzle to do some further tuning to bring everything into spec but if you know your way around tuner studio you could probably lean things out in the fast idle range on a temp map to get you through.

Mines due in May and I'm nervous about mine again. Gonna look on the laptop and see what the lambda is like this weekend.

I believe you can switch maps on megasquirts no idea how though.

Do you have a megasquirt too? I'm an IT guy by trade so should be ok with connections and uploading etc. intake it these things are just serial ports and the tuner studio software?

Do you have two maps then? One for mot time and one for normal running?

[skinny]

You are making it more complicated than it needs to be. All you need for emissions is stoich at idle and maybe fast idle. There's absolutely no reason you can't / shouldn't have that anyway in your one and only map. It's not like it's gonna lose you anything?
High CO means you're running rich. Running rich at idle is just wasting fuel. take some fuel out of the low speed low load cells until you hit 14.7 afr. Job done.

Edited by skinny on Friday 3rd April 11:35

[eltax91]

skinny said:

You are making it more complicated than it needs to be. All you need for emissions is stoich at idle and maybe fast idle. There's absolutely no reason you can't / shouldn't have that anyway in your one and only map. It's not like it's gonna lose you anything?
High CO means you're running rich. Running rich at idle is just wasting fuel. take some fuel out of the low speed low load cells until you hit 14.7 afr. Job done.

Edited by skinny on Friday 3rd April 11:35

Thanks for the advice. I'm a complete noob at this timing stuff, ive never touched the software or ecu before.

I did have the kit fitted and tuned 10 months ago by skuzzle Motorsport, who from reading on here and the nutz forum came highly recommended.

I'm Reasonably sure, although I need to ring nick on Tuesday to discuss, that he would have set it up and tuned it to pass an mot! This being the case, maybe something has broken in the meantime?!

What would the main suspects be? Injector faulty and opening too much? Wideband lambda sensor Failt?
Something else?

Cheers for the advice. I really appreciate it.

[eltax91]

Hi guys

I plugged the computer into the megasquirt today and found that the afr is running really low, less than 10. Which backs up the running rich theory. i posted a screenshot of the software readouts on a facebook group someone suggested it was not getting any input from the lambda and had switch the default values.

So, I traced the lambda cable only to find the multi plug has somehow come undone and was dangling loose under the car, which explains a lot! I wasn't dressed appropriately to get the car up in the air so left it for now. I reckon when I reconnect that my afr will shoot up and emissions will be great again!

Quick question, I coildnt see anywhere obvious from above (supercharger gets in the way) to reconnect it.

Anyone know whereabouts on the loom the plug fits back in to? Just to give me a clue for when I get chance to get it in the air again. Rest assured the plugs will be getting cable-tied back together securely this time.

[J-Tuner]

Sorry for the delay in responding I don't seem to get notifications?

I guess by now you know all you need is a functioning com port and either a usb>rs232 adaptor or a proper serial port if it's a dinosaur laptop TunerStudio will be happy as long as the port and baud are set to rate that the Ecu likes. Mines a ms2 and set pretty high.

Sounds like once you reconnect the sensor things might sort themselves out. In the event that they don't then as long as you back your current tune up to laptop you can adjust the map slightly in the Rev range to run at 14.7 (stoich) or 1.00 or so lambda.

I don't run multiple maps personally but I did have a wideband fitted specifically for MOT emissions tuning. First one melted and blew up (ropey install) and so far the second one seems to be ok but I think it's going to be an ongoing pain in the arse if it needs free air calibration every year....

I'm in IT also but ECU tuning is a steep learning curve. Especially if your car won't start on the drive like mine a few weeks back. I am winning though

[MX-5 Lazza]

I think the stock o2 connects to a socket near the back of the head. If its a feed to the MS it will probably be a wide band O2 that's been fitted so there will be another socket somewhere, probably also somewhere around the back of the engine that doesn't feed into the stock loom.

P.S. I'm in IT too

[eltax91]

MX-5 Lazza said:

I think the stock o2 connects to a socket near the back of the head. If its a feed to the MS it will probably be a wide band O2 that's been fitted so there will be another socket somewhere, probably also somewhere around the back of the engine that doesn't feed into the stock loom.

P.S. I'm in IT too

Hi.

I have not been under the car to be certain yet, but im pretty sure it only has one multi plug hanging off it and one single set of wires. It's over a year since I fitted my SC kit, and I tmember removing the old sensor from the exhaust and fitting what was I thought a wideband. Perhaps it's just a standard sensor afterall? Would that be possible with a charger and/or megasquirt?

I'm pretty certain it had only one cable and one plug on it. Will take some photos tomorrow.