What is the best way to tell if my car is running rich or lean ?

Its a my96 uk spec, with hks dump valve, itg pannel filter, and full TSL dcat system, with a TSL backbox.

 

I was reliably informed that a black sooty tailpipe is an indication that it's running Rich.

Stefan

 

My exhaust is black with soot, but on a recent visit to PE, they showed my car as running 4%co at full power. The MAF unit is faulty on my car. It has similar mods to your car, although mine is a grey import. I would suggest that you get it onto a rolling road for piece of mind.

 

Does any one have any pics of what a sooty tail pipe should look like please ?

 

Bruce,

So what else were they able to tell you at powerstation ?
Could you tell that it was not running right before ur vist, if so how ?

 

Dawes AFR from performanceexhausts.net is a good cheap simple tool - lights LEDs to show you the lambda sensor voltage which gives a rough indication of mixture - enough to see that it is safely rich in most circumstances. The black sooty exhaust I would have to disagree on - what if you had a lean spot from 4000-4400 RPM for example?

 

Hardy,

I've taken some pics of mine just now. Give me time and I'll post them up for you. Basically, the tailpipe will be all black, like its been burning coal

Stefan

 

Hardy,

Johns correct. You would need to see the Lamda voltage throughout the rev range and only a AFR meter, Deltadash or SM would tell you exactly what's going on.

But, if your tailpipe is sooty, then it'll give you an indication if it's running Rich most of the time. That's all, it won't tell you if the car has certain lean spots. You'd need a custom remap to sort those problems

My O2 sensors sha@gged and my tailpipes as black as an Afghanies hairy crevasse

Stefan

 

John,

Have been to performanceexhausts.net, but it seems they are out of stock, any more url's please ?

 

If the mods listed are all then I would just wait for stock of more as performanceexhaust.net are the UK distributor for Dawes devices products. If you are in a hurry you could buy the lambda link from brdevelopments.com or scoobymania.co.uk

Or you could buy a cheap digital voltmeter from Maplin for about £10 and link it to the lambda sensor wire - get it wrong and you blow the sensor though - this goes the same for fitting an AFR meter so proceed with caution.

With your current mods if you air flow meter is working you are exceedingly unlikely to be lean.

You could also get a check of the lambda voltage on a select monitor - run a drag from 1500 to 7000 RPM in 3rd gear and then look at the trace.

 

Hardy,

Here's a pic of my tailpipe.



Stefan

 

Stefan,

Yeh thats the same as mine, so I would assume its ok then ?

 

Hardy,

I wouldn't trust it though. Mine's running too rich, since my O2 sensors buggered. You really need to get it checked properly to be 100% sure yours is running OK.

Stefan

 

Ozzy,

What would be the best way to get it checked out then?