89' Iroc problems - Team Camaro Tech
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post #1 of 6 (permalink) Old Nov 30th, 00, 09:58 AM Thread Starter
Join Date: Nov 2000
Location: Lawrence, KS, USA
Posts: 5

I have an 89 iroc that used to get 14 to 18 miles to the gallon. It has a 350 w/ dynomax headers and flomaster exhaust. Not any emmisions on it whatsoever. After I did the exhaust it now only gets about 8 to 10 miles to the gallon. I timed it and it still gets crappy milege. It seams to be running really rich. And a watery substance is coming out of the tailpipe. Loss of power to. what sensor or what could be wrong to cuase this. Please help gas aint cheap and I must have performance!!!!
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post #2 of 6 (permalink) Old Nov 30th, 00, 10:11 AM
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Join Date: Mar 2000
Location: Dtown PA
Posts: 820

when you replaced your exhaust, you didnt cut the O2 sensor off did you? and if NO, then make sure that it is close to the engine as possible. the O2 sensor measures Exhaust Gas temp, and tells the computer to adjust the mixture accordingly. If you nuked the O2 Sensor, then thats why your runnnig ritch and getting Extra Condensation out the back.

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post #3 of 6 (permalink) Old Nov 30th, 00, 05:54 PM
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Join Date: Oct 2000
Posts: 52

Yep, definitely check the O2 sensor. When you changed exhaust did you use a free flowing replacement? did you change the location of the sensor? You may have to move it closer to the manifolds to get the temp back up.
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post #4 of 6 (permalink) Old Dec 6th, 00, 12:29 PM Thread Starter
Join Date: Nov 2000
Location: Lawrence, KS, USA
Posts: 5

How do you check the O2 sensor? Where do you get these free flowing o2 sensors? I need to know before I take it out.
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post #5 of 6 (permalink) Old Dec 6th, 00, 03:42 PM
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Join Date: Sep 1999
Location: Idaho
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The O2 sensor measures the amount of unburnt mixture in the exhaust. It does this by chemical reaction. This reaction causes the sensor to produce a voltage up to 1.1 volts depending on the condition of the exhaust mixture.

The O2 sensor must reach a certain temperature before it can create this voltage correctly. Until this temp is reached, the engine operates in open loop. In open loop status, the fuel mixture is enriched.(works like a choke system)

The problem that most people run into with headers is the O2 sensor doesn't reach the proper operating temp due to the nature of headers. To cure this problem, you need to install a "heated" O2 sensor. Rather than having 1 wire, you will have 2 wires. This design will heat the sensor electrically allowing it to give a proper measurement.

Most of your mail order companies will sell heated O2 sensors.

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[This message has been edited by cardude (edited 12-06-2000).]
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post #6 of 6 (permalink) Old Nov 9th, 06, 12:23 PM
Join Date: Oct 2006
Posts: 15
Re: 89' Iroc problems

GM newer design O2's are 4 wire sensors
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