Here is some info on air/fuel meters & sensors that I have used in the past.
Starting from the best to the worst (IMO)
Innovate LM2, using a wideband sensor in the exhaust, I own one, I thinks it’s great & I use the logging feature all the time, the SD card makes it easy to use. The LM2 also has OBDII for post ’96 US cars (& many other makes)
Innovate LM1, using a wideband sensor in the exhaust, I borrowed one off a mate & it convinced me that wideband was the only way to go.
This Hawk unit came from the local Police garage via Trademe. it is a bit safer than the older unit below as it only has wires going into the car from a sniffer panel that you attach to the back of the car. I tried it out on my partners stock '38 Chev & it worked fine, it is designed to be used while the car is being driven so the engine is tested under load.
An old Vane unit I borrowed, it could be found in tune up shops 20-30 years ago, it has a pipe that goes up the exhaust & another that expels the gas back outside the car.
Colortune, the little glass sparkplug that lets you see the colour of the flame inside the combustion chamber. It is a bit tricky to use this under load unless you have a dyno but what a great thing! I have used mine on cars, chainsaws, weedeaters & lawnmowers.
Holes in the hedder pipes just out from the heads, this was an old Smokey Yunick trick that let you see the colour of the flame as it left the head, once again not great without a dyno.
Exhaust gas temp, I may have been the problem on this one but I bought a good quality high temp probe & I just couldn’t get consistent numbers or for that matter exactly what they should be, everyone had a different opinion & things such as valve or ignition timing made a huge difference so I gave up.
Narrow band O2 meters, yea I suckered for one of these, I paid the bucks & got the 3 wire heated sensor, fitted it as close to the engine as pos etc etc. Narrow band sensors are exactly that, narrow band, they read fine at 14.7 & read crap everywhere else! They may look cool, the numbers do change but unless you want to go slow or lean burn your engine do not use one for tuning.
Plug reading, since they took the lead out of our gas it has become so hard to read plugs on pump gas it is not worth the effort & who wants to take the plugs out of an engine that has just been thrashed & shut off anyway?
Notes:
Here is an interesting instruction I found in the NGK AFX meter instructions-
The sensor should be mounted at least ten exhaust diameters upstream of the exhaust exit (ex. for a 3” exhaust pipe, that is 30”). If the sensor is mounted between one and ten exhaust diameters from the exhaust exit, the AFR measured will be leaner than the actual AFR by as much as 2 AFR at low engine speeds (i.e. less than 3000 rpm).
Some meters have the option of a fitting that goes up the tailpipe, we & others I have spoken to have got bad readings from doing this so I think the instruction from AFX is right on the money. With the old Vane unit that went up the tail pipe we had to funnel most of the exhaust into it to get a good reading at low rpm.
The only air/fuel adjustments that should be made in a garage without a dyno are idle & idle in gear in an auto, wheels chocked, person behind the wheel etc to adjust the carb from going lean under the pull away load. All other testing/adjusting should be done under load, on a dyno, dragstrip or the road. You should be able to get things very very close without too many lights & sirens if you use your head, load the car with weight, test in a lower gear on a steep hill, even if you don’t get perfect results at least you were out driving your Mopar & that’s all good.
Oxygen sensors do need some special care.
Anti-freeze will damage the sensor so a sensor would need changed after a blown head gasket.
RTV silicon fumes will damage the sensor so if you use silicon anywhere near a sensor make sure you get the sensor friendly type of silicon. Most good auto suppliers (rather than hardware shops) should carry it in stock.
Leaded fuel also harms sensors after a time so only fit the sensor for tuning then remove it.
so I'll look through my saved files later today & see what I can dig up, I thought I posted it on GoFastNews as well but can't find it.
Me too. Thanks!