Guys,

I need you to save me again!

My wife's '92 LX 5 Speed failed State (NJ)emmisions for NOx. The max reading they allow is 1006 and we got a score of 2504. The wierd thing is that the HC and CO are both well within specs. (HC reading is 107, they allow 132 and the CO reading is .69, they allow .73). On other cars I've had that failedemmisions, ALL the numbers went through the roof and required new Cats and/or O2 sensors to fix.

Here's what I know: The check engine light is not on! I jumped the ECU terminals and got no flashing codes, only a steady check engine light that does not go off. I'm guessing that theO2 sensor is ok due to the lack of codes. The Cat is an after market unit (probably Bosal) and only a few years old.

Any ideas on howI can get the NOx numbers down?

Rich

 

Spark timing too-far advanced?
Carbon buildup in cylinders?

 

try cleaning your egr ports.

 

I removed the EGR valve and checked it out. I cleaned the accumulated carbon and checked it to verify that it will hold vacuum and that the switch works. Timing seems OK. Any other ideas out there?

Rich

 

you could try seafoaming it to remove any carbon buildup in the cylinders, although it sounds to me like it could be the cat.