MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

TR parts and Triumph parts, TR bits, Triumph Car Spares and accessories are available for TR2, TR3, TR3A, TR4, TR4A, TR5, TR6, TR7, TR8, Spitfire and Stag and other TR models are available from British car spares and parts company LBCarCo.

Triumph TR6 - 02 senser

I installed a air fuel moniter in my 76 tr6 can anyone tell me why after a half hour on the highway it quits working. After sitting for a little bit it ok again?
Tim

Tim- What type and how many wires?
Don
DON KELLY

one wire. the cheapist one the auto store had.I think it is for a honda
tim

My guess is that it is not getting warm enough at speed to get a reading.
Don
DON KELLY

You should have installed a heated Sensor, especialy if it's not close to the head!
If you use either a three or 4 wire sensor. The extra wires are for an internal heater that keeps the sensor at the correct operating temp.
Colin Wilson

Don and Colin are correct. The O2 sensors begin to function at 600F, and your exhaust does not maintain that kind of heat. That's why a heated sensor would do the trick. However, if you're using a conventional sensor designed for a modern car, then all it really does is report back a voltage signal based on the heat (oxygen left over). The voltage will move between 0.1 and 0.9 volt. On a computer controlled car, the programming is looking for the sensor to trip over and below the 0.6v threshold something like once per second. When the voltage is high, the injection pulse will be shortened, and vice versa. By constantly moving back and forth, a nearly perfect ratio of 14.7:1 can be maintained. On our carbureted cars, I'd expect that you'd see a fairly steady signal, which would really be of not much use to know since you cannot do anything about it.
old paul

With a good sensor with imediate feed back,(very expensive ) you can take that knowledge and use it for changing jettings and such. If you run webbers or SUs it is a helpfull tool especially if it is downloaded to a lap top. With split headers you can get a direct reading of each carb if 2 sensors are used.
Don
DON KELLY

Paul, I guess you could pull the choke or turn it off..hehe. Seriously, you can modify jet settings, consider changing needles for different loads at different revs, the O2 sensor sounds like a fun tuning tool.
Tom

thank you. Thats what I thought might be happing. At highway speeds the sensor must be cooling off. It is in the header collector.I installed a supercharger and just wanted to make sure it did not run lean under boost or any any other time for that mater.
Tim

Tim _Contact David Johnston of this post. He has a bit of knowledge w/ super chargers and lean rich scenarios.
Don
DON KELLY

Tim - the "narrow band" sensor that you have gives accurate readings only very close to the "ideal" stoichmetric ratio of 14.7 to 1. (air to fuel ratio) Even if you get a 'heated' narrow band sensor you'll only get accurate data if you are already very close to that 14.7 to 1 area. If you're that close you probably don't need the sensor at all! Most narrow band sensors indicate rich all the time then at full throttle -- rich,rich LEAN . My heart jumped into my throat, but the guage is wildly inacccurate. (Proved that on the dyno. The dyno uses a very good O2 analyzer to figure ratio strength.. Very frustrating. Similar to a cheap radar detector that is always going off as you pass strip malls -- yuk.) What is much better from a tuning perspective is to buy a "wide-band" sensor and special guage. These are much more expensive but they are accurate in a "wide-band" between 10 to 1 to as high as 20 to 1 ratios.
Made by PLX Devices
http://www.plxdevices.com/M-Series_productinfo.htm
OR Innovate Products
http://www.plxdevices.com/M-Series_productinfo.htm they offer accurate tuning info . As Don mentioned I'm trying to get my supercharged TR6 running at optimum - which would be a 12.5 to 1 ratio at full throttle on full boost. Cost is approximately $300 -$400 for a complete set-up . I have a PLX M300 and haven't even used it yet. I'm finishing a motorcycle project right now. For a good technical article on wide band sensors and these guages get a back issue of Grass Roots Motorsports magazine October 2004 - nicely written article. Have fun.
Oh- this site has good info also : http://www.performancetrends.com/wide_band_uego.htm#Remote
David Johnston

This thread was discussed between 17/05/2005 and 21/05/2005

Triumph TR6 index