No ERG Valve - Failed Emission Test

[94RangerVa]

Greetings,

My 94 4L 4x4 Ranger (158K miles) failed the emission test today due to elevated NOX. The CHECK ENGINE light comes on after a few miles of driving.

My truck was never equipped with an ERG valve system. It does have the original catalytic converter. I'm going to replace it, as well as the fuel filler neck (small leak) and gas cap. The coolant level is ok so that isn't the cause.

Any other thought on how to get the truck to pass?

Thanks.

 

[Andy D]

How close to passing were you? The Rat doesn't get smog tested in MA because it is OBD 1. So this is generic advice. If the mixture is lean, it could be a vacuum leak or a bad O2 sensor .Pull a couple plugs, If the insulators are white not brown, its running lean. O2 sensors range between .2 and .9 volts. They should dither in that range fairly rapidly. A good one will make a digital meter dance . A steady .45- .55 is a default state, no good . CRC, makes this stuff called Guaranteed to Pass .Any parts store will carry it. Good luck

 

[shane96ranger]

You can also run the tank pretty low, and buy a few bottles of Heet fuel line anti-freeze. It's alcohol, and will burn clean clean clean.

 

[adsm08]

If you don't have EGR the cat is about the only thing on the vehicle for NOx. As already said, make sure she isn't running lean. NOx is produced at high temps and lean conditions make the engine run hotter.

An intake cleaner may also help. Carbon deposits retain heat and make hot spots in the cylinder.

 

[shane96ranger]

You'll need to purchase a 3 way converter, or it will not do much for Nitrogen Oxide. A 2 way is meant to only reduce hydrocarbons and carbon monoxide.

 

[Andy D]

You'll need to purchase a 3 way converter, or it will not do much for Nitrogen Oxide. A 2 way is meant to only reduce hydrocarbons and carbon monoxide.

any cat that you put on will die shortly if you don't fix the trouble that killed the original one. AMHIK

 

[94RangerVa]

Thanks all for the input.

 

[Andy D]

Please report back how you made out. TIA. The Rat is pretty much the same truck. As a 4.0 newby, I like to read about their care.