Failed smog NOx high

[JIMMYRIG]

Just failed smog in my 89 4.0 Hoping its not the cat but my NO numbers were way high. Guy said it could've been EGR too but idk if it would cause this big of a spike. I attached the results from the test below... Any recommendations as to what I should do?

 

[Salvagedcircuit]

It looks like you linked to an email in your inbox. Try taking a photo / screenshot of the report you got so we can try to help you. Thanks!

[JIMMYRIG]

 

Let me know if this works

[Ωhm]

Your results show your running LEAN.

[JIMMYRIG]

I know the o2 is a little high but thats not related to NO right

[Ωhm]

Both are related through combustion. As O2 climbs, so does NOx.

[JIMMYRIG]

Could it just be an o2 sensor causing the ecu to tune lean?

[Ωhm]

It's hard to say without knowing if you're in Closed or Open Loop.

[fiatslug87]

Do you have a Renix Engine Monitor? If not check the resistance between A & B of the O2 sensor reading should be 5-7Ω. You can also check EGR function?

 

https://comancheclub.com/topic/73480-21-–-renix-egr-valve-test/#comment-769327

From the FSM is in this post.
https://comancheclub.com/topic/38225-egr-solenoid-renix/

 

[pizzaman09]

As you are running lean, it's worth checking to see if your manifold bolts are tight at the head.  Checking for any vacuum leaks before trying to chase emissions stuff is a good place to start.

[JIMMYRIG]

If it were EGR would a symptom be high idle at startup? 1 in 10 times I start up it revs to ~3k rpm. I don't have a renix monitor. I'm not familiar either

 

Ill check the o2 aswell

[JIMMYRIG]

Just now, pizzaman09 said:

As you are running lean, it's worth checking to see if your manifold bolts are tight at the head.  Checking for any vacuum leaks before trying to chase emissions stuff is a good place to start.

I checked vacuum leaks yesterday by spraying brake clean around all hoses and connections to try to get it to rev up. Nothing

[89 MJ]

It’s common for the bolts holding the intake manifold to the head to loosen up.  Be sure to check on the underside too. 

[JIMMYRIG]

Will do

[JIMMYRIG]

So I'm not getting vacuum signal to the transducer or the EGR. I'm getting vacuum to the inlet on the solenoid. I'm gonna check the connection to the solenoid with a multimeter but I'm thinking its the solenoid. Likely causing the high revs at startup and after freeway driving and also running lean. But tell me if I'm missing something

18 hours ago, fiatslug87 said:

Do you have a Renix Engine Monitor? If not check the resistance between A & B of the O2 sensor reading should be 5-7Ω. You can also check EGR function?

 

https://comancheclub.com/topic/73480-21-–-renix-egr-valve-test/#comment-769327

From the FSM is in this post.
https://comancheclub.com/topic/38225-egr-solenoid-renix/

 

 

[Ωhm]

33 minutes ago, JIMMYRIG said:

So I'm not getting vacuum signal to the transducer or the EGR. I'm getting vacuum to the inlet on the solenoid.

 

EGR Solenoid needs to be de-energized, with engine RUNNING, so vacuum can flow to Transducer or the EGR valve. Disconnect EGR Solenoid electrical connector, then test.

[JIMMYRIG]

 

5 hours ago, Ωhm said:

 

EGR Solenoid needs to be de-energized, with engine RUNNING, so vacuum can flow to Transducer or the EGR valve. Disconnect EGR Solenoid electrical connector, then test.

I thought it stops letting vacuum through when it’s de-energized. 

[rokinn]

I had a high Nox situation with my last emissions test which failed.  REM says my vac is about 3/5ths of what it should be.  Tested all of the lines with vac tester - all good.  Knew the manifold bolts were good because I tightened them when I had the head milled.  Again when I replaced the clutch and slave swap.  Finally replaced the front tube on the valve cover with new.  Viola - VAC up to 15 - 16 inHG.  Passed emissions with flying colors.