HCCO readings from 88TR

I am playing with my new gas analyzer. Here are the readings on my TR, after the car has been driven for 25 miles and completely warmed up, taken while the car was idling. I have no cats.....the O2 sensors were left connected, because I heard that they didn't work at idle.

Left bank: HC=380; CO=.70; NOX=63; O2=1.3

Right bank: HC=580; CO=1.08; NOX=49; O2=1.8

That is all I did so far. Any comments?

Looks like the banks aren't balanced by looking at the numbers (HC too high, should be 150ppm).

Do a vacum gauge check & get both banks to 15-16inhg..then dial the CO (O2 sensors disconnected, it's the air pump that doesn't work at idle)to .7%-.9% both banks..then double check inhg...then rehook O2sensors.

When finished all things working well, you should see .8%-1.1% CO & 150-175ppm HC.

NOX ???

You got a 5 gas ...;-)

Thanks. When a better model of analyzer comes along in a few years, I will be able to sell this analyzer quicker........besides, they had a sale on it......hence it wasn't much more than the 4 gas.

The manual gives two procedures: one for getting the idle dialed in, with the use of the vacuum gauges; then another procedure for dialing in the CO, with the fuel adjusting screw.

Since CO and HC seem to go together, while bringing down the HC, won't the CO become too low?.....in the right bank, the CO is already where it should be. Is this because of the O2 sensor?

Henryk,

situation is this..HC represents unburned hydro-carbons or in shop talk> missing... essentialy one can't change the HC as such...however when a bank runs perfect..no miss = low HC = 150-175ppm...

now when both banks are spot on CO and inhg , which means they are no longer fighting each other or dragging each other along..the HC naturally falls on it's own...if HC's don't it's usually a bad plug, plug wire, connector, injector, air leak, etc. still causing some anomolie at the combustion level preventing full and thourough burning of the mixture.

This is what 'tuning' is all about. Insuring each and every cylinder is doing it's full share of the work. You'll know when all 12 are doing their share when the HC is around the 150-175 range, as this means they are firing strong and burning most of the fuel being supplied to each and every one. At this point the idle will be glass smmooth and the engine will have full power off the line and through the rpm range.

HTH's