Thread: Read my plugs please

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No, unfortunately I don't have access to an A/F ratio meter. The engine only has 1300 miles on it too, fwiw (well, 1300 post initial break in miles, so more like 1800 miles after the first bed-in running - no I'm not only doing a 500 mile break-in, but the first 500 miles were done with different oil and some mixture and timing differences) . I know before the engine went in, some dunderhead had blocked off the warm up regulator (which also does high throttle enrichment)...what I don't know is if someone other than me replaced it or not (I thought someone had, then that person indicated that he hadn't...so now I have to figure out if someone else did). I could just adjust the main mixture screw at the top, but my understanding is that on Bosch CIS, that is mostly just for idle mixture, and given the one black ring I'd say idle mixture is good where it is.

I'll take a better shot tomorrow.

Any ways , what are you running? You know type of car and motor, timimg maybe.



You can buy a pretty cheap air/fuel monitor for cheap from Summit, about 125 dollars the last time I bought one.

Even cheaper but just as good ,maybe better, you can make your own. You will need to get a O2 sensor bung (5 dollars) and get it welded into you exhaust (20 bucks). Then get a O2 sensor (65 dollars) plug in some 12 volt power and the other wires go to your volt meter and thats it. One thing to keep in mind though is if you are running headers you need a heated 02 sensor . For anything running a 02 sensor and headers the sensor need to be heated. A heated 02 sensor will give you consistant results since the tubing of the headers are thin. The exhaust will cool down quicker and give false readings .

If you have a newer system and have a 02 sensor in the vehicle just plug in your volt meter.

Heres a basic guide http://www.cfm-tech.com/oxygen_sensor_tuning.htm

Originally Posted by BigTruckDriver

Any ways , what are you running? You know type of car and motor, timimg maybe.

You can buy a pretty cheap air/fuel monitor for cheap from Summit, about 125 dollars the last time I bought one.

Even cheaper but just as good ,maybe better, you can make your own. You will need to get a O2 sensor bung (5 dollars) and get it welded into you exhaust (20 bucks). Then get a O2 sensor (65 dollars) plug in some 12 volt power and the other wires go to your volt meter and thats it. One thing to keep in mind though is if you are running headers you need a heated 02 sensor . For anything running a 02 sensor and headers the sensor need to be heated. A heated 02 sensor will give you consistant results since the tubing of the headers are thin. The exhaust will cool down quicker and give false readings .

If you have a newer system and have a 02 sensor in the vehicle just plug in your volt meter.

Heres a basic guide http://www.cfm-tech.com/oxygen_sensor_tuning.htm

It's a modified Mercedes 117.968 motor (1986-1991 560SEC/SEL), which is an overhead cam, 5.55liter V8 (though mine is 5.65 liter, has lumpy cams, and 10:1 pistons, and everything else to match. Timing is 10 degrees BTDC at idle). The exhaust (jet-hot coated tri-ys to downpipes, to cats, to a single pipe - set up by a nextel cup shop this way to make the most area under the curve though peak power is a little lower than a dual exhaust to the end system would have been). It does have O2 sensors...in a way. The factory set up has O2 sensors that do nothing other than give you a convenient point under the hood to check the voltage. Currently, there are O2 sensors but they do nothing other than plug the O2 sensor bung holes.