YJ Rich Mixture Emission Problem

[90growler]

OK....I cannot seem to figure out what is up with my emmisions. Carbon deposits shoot out of my tailpipe and streak up my driveway. I cannot get it to pass emmisions. Here is a list of what I have replaced....can't figure it out.

Oxygen Sensor,Air Temp Sensor, Map Sensor,Catalytic Conv.,Ignition Coil and ICM,Spark Plugs

1990 2.5L TBI YJ

 

[monkeyman]

You could make sure all your emissions related vacuum lines are in good shape and have vacuum where they should. I had a Datsun 280Z that would not pass and it was a simple vacuum line.

 

[tint_rookie]

what state do you live in?

 

[Bounty__Hunter]

Is the exhaust manifold cracked?

 

[90growler]

TN.........All lines are good and have been checked..........no cracks visable on the manifold.

 

[geopig]

Check the fuel pressure regulator, I was having the same issue, replaced everything I could think of and the pressure regulator ended up being the issue.

 

[90growler]

If you have a '91 than you have Multi-Port Injection which the fuel system is always under pressure. I have Throttle body injection(not under pressure unless running).......do you think that would still be the case?

 

[geopig]

I'm not 100% sure but someone can correct me if I'm wrong since I do have a 91 with MPI. But there is still a fuel pressure regulator on the TBI systems and if it is faulty then this could be the cause of you running rich. I checked my Haynes and the pressure for the TBI engines should be at about 14-15 psi. It says to use a 0-30 psi pressure gauge to check. Wouldn't hurt to check it out I think.

 

[slo-wrench44]

here's a thought. i know in new york that if you get and estimate for repaire to the emissions system that states it costs over $400 to fix it, just in parts no labor, then you can get an emissions waiver. check with you laws for your state. sounds like you bought a bunch of expencive parts . get an estimate and see where you stand. my yj hasnt passed inspection yet and its on the road legaly . later guys