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non-cat Lucas means no O2 sensor
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Posted by Siegfried (more from Siegfried) on Thu, 18 Aug 2011 09:30:38 Share Post by Email
In Reply to: Re: 900T16 CO 10%, vvack0matic [Profile/Gallery] , Thu, 18 Aug 2011 08:58:25
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Freddy,
actually, it's very simple issue. As you can see (but hardly read) from the picture below a high CO value means you're running rich. This can happen if:
- AMM goes bad
- electric signal from AMM is distorted on the way to ECU (or bad ground connection, or bad reference voltage to AMM)
- AMM measures more air that engine actually gets (an air leak somewhere between AMM and engine intake valves)
- ECU assumes the engine to be cold and goes with warm-up fuel maps (bad NTC sensor)
- ECU is bad
- fuel injectors are stuck open mechanically (or even only one of them)
- fuel injectors are stick open electrically - signal from ECU to fuel injectors is distorted (e.g. wire insulation is shot and since injectors are driven by negative pulse from ECU then if it's grounded to body then... ECU no longer drives injectors; additionally since Lucas goes with low-impedance injectors and uses additional ext resistor then if that resistor is shot then injector drivers inside ECU can be overloaded and can give pretty wired issues)
- FPR (fuel pressure regulator) is bad - the differential pressure between the fuel line and intake manifold is no longer 3bar as it's assumed by ECU fuel maps

As you can see it's pretty simple, not smth like space math or LHC physics.

Zig

P.S.
A breakdown for the diagram below:
fig #1 on the top goes for the emissions BEFORE the TWC
fig #2 in the middle goes for the emissions AFTER the TWC
fig #3 goes for the O2 sensor signal
horizontal X-line means A/R (lambda) value: rich to the left and lean to the right

High CO AND CH (HC for westerns) values mean you're running rich. Normal CO and high CH (HC) means ignition misfire. High NOx values mean very high combustion temperatures or overheated TWC. TWC stands for the cat (three-way catalytic converter).

posted by 77.37.1...

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