CO2 prob tool

I am a huge advocate for exhaust gas analyzers and have for many years had 4 gas analyzers in my shop but I really do not consider them all that useful or needed on carburetor engines. As opposed to fuel injection I just do carbed engines by ear.

Id much rather have a manometer.

The rear bank taps might actually still work but if the tubes are still present on the front bank, for sure they are clogged past the pint of ever being used.

 

I use an Innovate LM-2 for my 1965 Fuel Injected Corvette. Only way to get it right. The old manometers are apparently very difficult to use.

 

you can use a thermal probe (coupler, laser gun or thermosteric) to read the temp at the exhaust pipe out of the head to see if the cylinder is running hotter or cooler than the ones next to it. if you the emissions disconnected (air pump cats etc.) the CO is not as important because you are not going to damage the cats, putting in a WB O2 at the collector on both banks will give you an overall reading of that bank so you still have one or more cylinders running to lean or rich which will damage your engine.

if your car has CIS injection then having access to the CO ports is really good because you can set the flow rates for each injector at the fuel distributor, that's why some people find that their cars run rough low power etc. after replacing the injectors even if the fuel pressure is in balance its the flow rate through the injector is not set, have a CO reading you can balance the flow to all injectors, but that to can be done with temp probes just take practice.

 

On the CIS system, how exactly would you be able to change each injector flow rate at the distributor? Is this not something that is calibrated into the unit in the first instance?

 

on top of the fuel distributor next to each of the fuel lines there is a plug that covers an adjustable pin at allows the metering plate to either open more or less this plate works on a bias from fuel pin as more fuel enters the upper half the plate moves down letting more fuel flow to the injectors, there is a small spring at each port that helps the bias and because the injectors are always flowing if one or more are not at the same flow rate it will unbalance all the rest
there is so much more too it, i just try to make quick and easy. the last time i did one i bench balance with the injectors that were going into the car it's not hard just takes time and once that is set up you can adjust the CO screw to have the system come on richer or leaner to the air plate (how soon the plate reacts to air flow into engine) again this is just touching to surface and takes time, but i would never replace just one piece either fuel distributor or injectors i would send all of them out to be check and replace together.


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yes, it is set up the first time the system is put together but when the manufactures still need to make adjustments to meet emissions and performance for each model as we all know not every engine will adjust the same way even modern ecm's are making adjustments on the fly

 

Interesting, thank you for the information. So the key is this all needs to be set up on a test bench. Did the factory really do that itself, seems hard to imagine but maybe so.

 

as far as i know the systems came from Bosch as a match set (fuel distributor and injectors) all the lines are turner and twisted so that they are as close to the same length the furthers being the straightest. once in the car and running there was a station at the factory that made the final adjustments to meet emissions standards, and there's where most either got a good tune with power or just good enough to run lol (i bet a Tuesday Wednesday or Thursday car got done the better way)