Check Engine Light

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Re: Check Engine Light [Re: JeepMedic] #377920 01/21/04 05:26 AM

Anonymous

Unregistered

possible fuel pressure regulator failure?

Re: Check Engine Light [Re: JeepMedic] #377921 01/22/04 07:50 PM

Anonymous

Unregistered

if the exhaust manifold has a crack in it air (oxygen) will go in. The oxygen sensor (new or old) will read 'lean'. The ECM will add the maximum amount of fuel at all times, trying to make the O2 sensor go rich. So you will burn more gas than you would normally. The ECM will turn on the check engine light and give you the lean code 51 on pre OBDII systems

Re: Check Engine Light [Re: JeepMedic] #377922 01/22/04 07:57 PM

Anonymous

Unregistered

I'd like to add that the engine will run just fine, probably more power and smoother if the O2 sensor is reading lean. More gasoline, more power. It's easy to check the O2 sensor. Attach a digital voltmeter positive to the black/dark green wire, negative to the engine block. The voltage should swing between 0.1 and 0.8 Volts DC continuously.If the sensor is new and the reading is stuck at 0.1 Volts you have a crack in the exhaust manifold, end of story.

Re: Check Engine Light #377923 01/22/04 09:51 PM

Anonymous

Unregistered

i don't agree with more fuel more power unless the vehicle's stock programing is set to run under 14.7:1

also to tell if the O2 sensor is getting old it should switch voltage 8 times in 10 seconds minimum.

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