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Re: CIS Injection: O2 output questions Posted by Dana [Email] ![]() ![]() In Reply to: CIS Injection: O2 output questions, Todd 83-900T, Sun, 20 May 2001 21:25:30 Members do not see ads below this line. - Help Keep This Site Online - Signup |
A couple of things to explain first....
1. The O2 sensor really doesn't work until the engine is nice and hot..
2. When it is hot, it starts to put out a voltage based on the O2 content of the exhaust. Until it gets hot, the car goes thru a "locked" 60% elevated pulse rate to the modulating valve to enrich the fuel mix by increasing the fuel pressure. The warmup regulator is also giving it little boost too of enrichment for the first minute or two...
After the engine warmup temperature switch says the car is warm, it turns off the fixed pulsed ratio and the CIS tries to control the fuel mix by monitoring the O2 sensor for a set point of .5V...but it will vary up and own as an average around that number...nothing you can really measure well.
The modulating pulse rate will go to what ever it has to...to keep that .5VDC at the O2 sensor....wether that is 50% modulating pulse or not will depend on the proper functioning of a lot of items...such as the warm up regulator, the fuel pressure regulator, air leaks, etc. etc....but if they are then it should settle at 50% average pulse rate at warm idle....
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