The Renix goes brain dead every time you shut your Jeep off. No need to reset.

 

I thought it mapped parameters and saved them just didn't save error codes. Ya know it was actually a very very advanced ecu for its time. I'm pretty sure it has parameter memory. Nm..... just Googled it.

 

You need a new cat and check your vacuum lines. You may not have an EGR. But if all else you need a new cat. NOX is eliminated by the cat. it will lower you NOX enough if not more to pass. Don't spend a crap load of money trying to diagnose this and try quick fixes. I did it already so you don't have too

 

I agree it was and still is a good system. Just stores nuttin.

 

Do the 4.0s have timing marks like other engines ,I was thinking about how to retard the timing . I know that the distributor is locked in place, but i have some ideals that might work

 

do not try and adjust the timing manually. It's locked in place for a reason. The PCM controls the timing as it gets information from the sensors.

Trying to adjust it will only screw things up worse...way worse

 

Yea I had not thought of how the system might react ,but is there a way to verify that everything is in time . I know like if the rotor is off by like a fraction that's like a couple of degrees right there. You never know about manufacturer's tolerances.

 

It has regular timing marks that you can see with a timing light. Expect to see about 12* at idle. Timing is not your problem though.

 

If the engine is running, the distributor is correct. 1-2* of base timing being off on these engines results in a no-run/no-start condition.

 

I'm gonna have to disagree with you here, Dukie. The ECU controls te timing from the CPS. The distributor can be off a tooth or more and it will run.
Here's something that could be a problem though. The sync generator inside the distributor gives a signal to the ECU so it can fire the injectors in sequence of firing order. If the sync generator is bad, the injectors batch fire all at once and this could contribute to poor emissions.

 

Sounds like I really need to check the timing just to ease my mind ,because It's one thing I can do that's doesn't cost anything,who knows the flex plate might be off !

 

Once upon a Jeep....Failed the test. The guy recommended an O2 sensor. Put it in, took it back, and this time left the guy alone so there where no witnesses. It passed and I paid him. I assume he put his sensor in my exhaust, but really, I don't know.

A really easy check:
There is a gang of wires coming up the front of the engine that run up around the manifold heat shield to the injectors. The edge of that shield can cut into those wires, sometimes causing all sorts of things. Sometimes nothing, sometimes a little sometimes allot

 

Only way I know of is indexing where you will move it a tooth.. good luck with that :-(

 

you really need to forget about the timing being off...you're wasting your time. Timing off on straight 6 engines results in either the engine not starting, or a MASSIVE power loss and poor running. Basically you would see a lot more wrong than just failing an emissions test.

The fact that both your NOx and CO are high usually points directly at a bad cat. No other running conditions would cause both to occur at the same time on this engine.

I have a very important question for you though. Did you get the converter good and hot (eg: did you drive for at least 15-20 minutes (some at highway speed) before the test and keep the truck running while waiting in line)? This is very important to pass sniffer tests.

 

X2 x2