[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index] Re: O2 Sensor Diagnostics
> If the O2 sensor is wrong, the ECU will be deceived, and the final > mixture will also be wrong, which will cause all sorts of drivability > problems. > >> > A better test, paul, is to grab the diagnostic plug (2 prongs green/purple > and brown) up near the fuel filter.... That gives you the duty cycle of the > O2 Freq Valve...... You can use a DC meter or a dwell meter (90% X DC = > Dwell angle on 4cyl engine), the factory spec is 50+/-8 DC, you want to set > at 42DC or 38dwell..... A warn O2 will show great fluctuations in reading, a > new one is more steady for a given reading.... To adj, a 3mm t-handle hex in > the port between the FI boot and the fuel dist lines.... A turbo car will > eat an O2 faster than a N/A car, and a bad fuel mixture can eat the O2 as > well.... 60k is pushing it, me I can tell when mine goes south, cuz the gas > mileage takes a 5mpg plunge, usually 30k or so.... > > HTH > > Scott Scott- Thanks for the good tip, but after looking for the diagnostic plug, I found I didn't have one. The 20v turbo did not have them. This is for the old CIS system (as I'm sure you know). However, you have given me a good tip. You mentioned loosing gas mileage. When I first drove my car home from Chicago, I got 28 and 25.5 mpg (actual by calculation). My car started to surge much more not long after that. My gas mileage is now about 21-24 MPG. However, I did put new tires on at about the same time, Dunlop D60 A2's. I'm sure that could also change the mileage, but I keep them at about 35 psi. Don't know. Paul 91 200q (probably getting a new O2 sensor) ************************************************************** Paul Waterloo TEL: (860) 267-7714 HydroAire Incorporated FAX: (860) 267-7387 875 Old Hartford Rd Colchester, CT 06415 EMAIL: 74543.407@compuserve.com **************************************************************
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