Failed e-check Nitric oxide test

[throb]

I have a 92 Dodge Caravan with a 3.0 engine. I failed the Nitric Oxide test. I replaced the faulty radiator cooling fan,had the vehicle re-tested and still failed. The first test showed the n.o. level at 1493 ppm. The second test showed 1383 ppm. The limit is 955 ppm. The only trouble code i am getting is 37 which has nothing to do with emmisions. The vehicle does have a hard time starting when it is hot(usually 3 or 4 cranks). Please help!!!

[lakeman]

Check the EGR valve, could also be timing, cat., converter or even O2 sensor. Check EGR first. High NO is indicitive of high combustion temps., and plugged EGR will cause this as will a lean mixture caused by a bad O2 sensor.

[throb]

Originally Posted by lakeman

Check the EGR valve, could also be timing, cat., converter or even O2 sensor. Check EGR first. High NO is indicitive of high combustion temps., and plugged EGR will cause this as will a lean mixture caused by a bad O2 sensor.

Thanx for the info. I was told that this vehicle does not have a egr valve. Do you know if this is true? Thanks again.

[lakeman]

That's possible, I'm most familiar with the 96' and later. Try this:http://autorepair.about.com/ see if they have an answer. Also get a Hayne's or Chilton manual, they will save you a lot of looking and quessing.

[throb]

Thanx again

[paulsi]

I have 93 3.0l Caravan but bought in 1992. Mine does have EGR valve. I would suspect a clogged EGR tube or the pessages.

-Paul

[B33p3r]

Check the emissions label under the hood. This should show the EGR if it has one

[Cobra_Sam]

Originally Posted by B33p3r

Check the emissions label under the hood. This should show the EGR if it has one

When last was the catylitic converter replaced ?