DIY co-meter

[350zwelgje]

Found some old posts, and still considering to get a CO-meter.
Why you ask? Like to tune my cars myself. Have a resoldered ECU, and a spare ECU. Rising rate and standard fuel pressure regulator. Last MOT the mixture screw nearly had to come out (even after a good blast) to be <4,5% CO (don't you love Holland?). Probably the ECU that gave up (and now resoldered) probably caused the high (8%) CO. Concluding: All things can very, but would like to have the final touch of tuning in my own hands. Only found gunson.

Any good other good stuff out there? Is it worth getting a tool like that? Please, let me know your opinions.

Thanks in advance,

Rob

[leorest]

The Gunson one is cheap and cheerful. With care it can give good readings but it takes time.
A wide-band lambda sensor is the Roles Royce method IMHO. The Megasquirt website is a good place to find out more.

[honourablepickle]

i found with the gunson thing that you had to repeat your adjustments half a dozen times and take the average as the readings varied so much - can't beat a rolling road .....

[rev-erend]

I was so un-inpressed with the reports on the Gunson that I bought
something better..

A hand held portable 4 gas analyser.

I had it at the wedge fest - just never had the time to use it

[dw350i]

The gunson I got worked fine for two measurements on the same day then would'nt calibrate again. Gunsons won't fix it as they claim it must have been contaminated.

[wedg1e]

I think the Gunson unit is best used for before/ after tests; I can't say I've had any issues with mine but it does definitely show the effects/ trends of adjustments which is the main reason I bought it...

[shpub]

Get one that measures all the gases that will be tested for the MOT. In the UK, that means CO and HC for pre cat cars. Just seeing CO means that you can still fail with the HC. I have a SUN unit that I got of eBAY for less than a Gunson.

[chunder]

I have just fitted wideband O2 sensor (Innovate Motorsports www.tuneyourengine.com) with programmable analogue outputs.

The intention being to use one to drive an AFR guage and the other as feedback to a megasquirt ecu. The sensor was a pain to fit and won't be coming out in a hurry (fitted in the top of the centre silencer - which doesn't silence anything) but the wiring was straightforward.

Fitted a guage on velcro just to the left of the speedo in order not to drill any holes - if it works ok I'll remove the radio and fit the guage there instead as I never turn it on anyway.

Haven't connected the gauge yet so not sure how accurate the sensor is going to be but by all accounts it should be as good if not better than any tailpipe exhaust gas analyser.

[350zwelgje]

shpub said:

Get one that measures all the gases that will be tested for the MOT. In the UK, that means CO and HC for pre cat cars. Just seeing CO means that you can still fail with the HC. I have a SUN unit that I got of eBAY for less than a Gunson.

I would like that.
CO-testing in Holland is only for CO at the moment (and max is 4,5%....), so no need currently for HC.

After reading the posts, I am not so sure of the gunson one anymore due to it being 50/50 ok or not...
Thanks for posting the information.

What type of Sun equipment do you have Steve?
Any other stuff out there worth to get second hand? What are the things to consider if buying secondhand, after reading that it can become 'contaminated' etc.

Don't have a clue what the CO is at the moment, too many parameters changed/played with, but assume too low and don't want to wreck the engine.

Rob

[s.hogan3]

i have a good working profesional co meter just calibrated if your intrested please e/mail me its now spare as ive just got a sun cripton tunner/co meter system.

[wedg1e]

I keep hearing stories that the Sun gear has a date in its software so that it won't operate once the calibration has expired and that's why they keep appearing cheaply on Ebay; anone know if this is so?
I guess the older systems probably don't or are easily bypassed...

[jchase]

I have an AFX wideband (made by NGK) and display on my 390se. It has an output for my Megasquirt ECU - which I need to install. It keeps me driving safe as the mixture leans out over a certain road speed, and I wanna keep my pistons un-melted.

-Jim

[shpub]

wedg1e said:

I keep hearing stories that the Sun gear has a date in its software so that it won't operate once the calibration has expired and that's why they keep appearing cheaply on Ebay; anone know if this is so?
I guess the older systems probably don't or are easily bypassed...

Depends on the system but is one of the questions to ask. Basically any ex MOT systems may have this problem as it is part of the effort to ensure calibration. I've got a SGA9000 which is pretty small and compact. I looked at AFRs but they really didn't help me with the task of meeting the MOT regs. Knowing what the AFR was didn't really provide me with any real data on the Co and HC readings.

[dickymint]

I'm after one of these babies www.testo330.com/Control?locale=UK_en for my new career as a gas bod.

Shpub as well as calibration don't you also have to replace the gas sensor cells?

[adam quantrill]

I have a gunson and it works OK, have had it for over 10 years now.

Jim has a lambda sensor which is great fun, but you need a (willing and brave) volunteer to call out/write down the readings as you gun it and the tacho rises.....

[rev-erend]

adam quantrill said:

I have a gunson and it works OK, have had it for over 10 years now.

Jim has a lambda sensor which is great fun, but you need a (willing and brave) volunteer to call out/write down the readings as you gun it and the tacho rises.....

Surely you could use a longer wire and not have the brave volunteer sitting on the wing

[shpub]

dickymint said:

Shpub as well as calibration don't you also have to replace the gas sensor cells?

All depends on how the readings are done. The SUN unit I have uses IR techniques which tend to need less maintenance.

[350zwelgje]

s.hogan3 said:

i have a good working profesional co meter just calibrated if your intrested please e/mail me its now spare as ive just got a sun cripton tunner/co meter system.

Thanks for the offer. Definately would consider it, if only I was in the UK.
Unfortunately not, as I live in Belgium....

Rob