Re: High idle, LOW mileage, '79 733 (archive)

Please help my wallet. Now that it is cold weather here, my '79 e23 has gone from 10-12mpg to less than 8mpg. Also, the idle runs between 1100 & 1700rpm in neutral, cold or warm engine. Additionally, unless the outside temp is above about 50 degrees, the engine never gets the temp guage above the first notch above the bottom. In warm weather, if I let it sit at idle(high idle) for more than ten minutes, the temp guage would get within a notch of red line, but that is with no aux fan operation. It cold & warm starts perfectly, always has. Being a '79, it has on the thermostat a temp switch, not a temp sensor, according to the shop manual, and I have not heard of these switches being a problem. Given the idle & mpg, should I suspect the temp switch, the cold start valve leaking, or something else?

Sounds like your 02 sensor is acting up (near the cat off your exhaust pipe). If your 02 isn't working, the computer or fuel-flow management system will just keep pouring in the gas rich (which the car normally does until it reaches op. temp.) To have that replaced might cost you a few bucks. Haven't heard of any bypass you could rig for your 02 sensor if in fact that is what's causing your heavy fuel bill. Before the 02, there was the manual choke !) Let us know what you find.

-Ralph.

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Re: High idle, LOW mileage, '79 733 Stephen Sank 01:36 12/08/2000 (0)

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