DIY_EFI Digest Tuesday, 26 December 1995 Volume 00 : Number 013 In this issue: RE: O2 sensors See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: Jim Pearl Date: Mon, 25 Dec 1995 18:08:33 -0600 Subject: RE: O2 sensors Do a YAHOO search on the WEB for this subject. There is some good = information out there and someone actually took apart an MSD unit and = found the construction to be something less than ideal. The probable = reason why the K&N unit took so long to warm up was probably because it = wasn't heated (?). The advantage of a heated sensor is that it can be = placed further down the pipe and will stay "cleaner" and not clog as = easily. If I have a chance I'll track down the WEB site that has the = info and post it.. - ---------- >From: BradyEng@xxx.com] Sent: Saturday, December 23, 1995 9:40 PM To: diy_efi@xxx.edu Subject: Re: O2 sensors In a message dated 95-12-23 18:35:27 EST, you write: >I need some info on oxygen sensors... I have installed two O2 sensors >in my header collectors (350 V8). These are attached to two LED >bargraph meters for monitoring purposes only at this point. The >readings I get from the sensors are not really agreeing with what I >see from engine operation. > >The sensors show basically full lean (<100 mV) at almost all throttle >openings, which I cannot see because the engine runs fine, has lots of >power, etc. The engine has 30000 mi with no problems, if it was >actually running this lean it would have eaten head gaskets or pistons >long before now. The only time I really get a change in O2 sensor >output is under deceleration (throttle fully closed) at which point >the bargraphs show full rich (>950 mV). > >2. the engine is running on propane fuel, is it possible that the O2 >sensor is not responding with the correct reading for rich/lean >because of the different stoich point for propane... > >With regards to this point, if this is the case, is it possible to >correct the O2 sensor output to reflect the correct voltage with >alternative fuels such as propane? Any info on how to calculate a >correction factor (if necessary) would be appreciated. I would like to second this question on O2 sensors. It appears to me = that the garden variety used in production autos are basically go-nogo gauges = for rich-lean. However, meters with O2 sensors are sold which are reported = to be useful tuning aids and accurate to ~0.5 A/F. Does anyone have comments = on prices, sources, and performance of the sensors used in the aftermarket systems? To answer a question in this query directly Bob Behn wrote an article in Turbo Bike Volume IV Number I on air fuel ratio meters that included = data for alchohol and propane. Turbo Bike is available from Joe Haile Enterprises, PO Box 8000725, = Valencia, CA 91380-0725, Tel 805-255-3426. Bob Behn sells an A/F meter @ RB = Racing 1625 W. 134th St., Gardena, CA 90249, Tel 310-515-5720. Meters are also available from K&N @xxx. I've seen the K&N in operation on a street KZ1000 (4 cyl air cooled 2 valve motorcycle) with a header. It = took a while to warm up, but sure speeded up the jetting process. The short version is that stoichiometric is stoichiometric on the gage = or O2 sensor, although the actual A/F ratio changes with fuel . Rich and Lean = Best Torque are between about 86% and 92% of stoichiometric. The problem is = that O2 concentration just doesn't change much below stoichiometric. CO = becomes a much better indicator, but I havn't heard of real time sensors for this. I'm sure this topic has been covered before in this forum, but I would = very much appreciate it if it was discussed again.=20 Thanks SBrady ------------------------------ End of DIY_EFI Digest V0 #13 **************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. A non-digest (direct mail) version of this list is also available; to subscribe to that instead, replace "diy_efi-digest" in the command above with "diy_efi".