Failed smog high NOx then seafoam smoke in bay . .

[V70R]

Faile d smog with everything normal except high NOx
15mph was 2xs the max and 25mph was over but close


Did a seafoam through the throttle body and got smoke out the exhaust but also from the engine bay (don't remember seafoam smoke from the bay before).

Could this be a leak causing high NOx? or is seafoam smoke expected from the engine bay area?

 

[440Magnum]

An exhaust leak is the only reason you'd see smoke in the engine bay from a seafoam abuse^H^H^H^H "treatment."

An exhaust leak could conceivably mess with the catalyst, which *might* increase NOx if it interferes with the reduction stage.

This might be the worlds first example of Seafoam *actually* helping with an emissions test, since it at least pointed you to the real problem ;-)

 

[spasm3]

if the engine has and egr system thats where i'd look first. Nox is a symptom of high combustion temps. Lean mix or non working dgr system.

 

[Bluestream]

As mentioned:

Higher than normal NOX emissions may be caused by:
-an overheated engine
-Lean air/fuel mixtures
-Vacuum leaks
-over advanced ignition timing
-Defective EGR system


Seafoam wont help you son

 

[V70R]

Originally Posted By: Bluestream
As mentioned:
Seafoam wont help you son

If high temps are being caused by carbon deposits then seafoam is the cure
(2000 ls1 engine)

also, I can't find any info on how to test the egr valve

 

[mopar_monkey]

Originally Posted By: V70R
Originally Posted By: Bluestream
As mentioned:
Seafoam wont help you son

If high temps are being caused by carbon deposits then seafoam is the cure
(2000 ls1 engine)

also, I can't find any info on how to test the egr valve


what yr,make,model are we talking here? may not even have an egr system so some info would help.

 

[V70R]

2000 Firebird Formula V8 5.7 Ls1
Does have egr

 

[OVERKILL]

Originally Posted By: V70R
Originally Posted By: Bluestream
As mentioned:
Seafoam wont help you son

If high temps are being caused by carbon deposits then seafoam is the cure
(2000 ls1 engine)

also, I can't find any info on how to test the egr valve


AC Delco Combustion Chamber Cleaner/Top End Cleaner is a more effective solvent.

 

[paulo57509]

Originally Posted By: V70R
Faile d smog with everything normal except high NOx
15mph was 2xs the max and 25mph was over but close


Did a seafoam through the throttle body and got smoke out the exhaust but also from the engine bay (don't remember seafoam smoke from the bay before).

Could this be a leak causing high NOx? or is seafoam smoke expected from the engine bay area?


If you're going to fail, you'll fail NOx at 15MPH. Predictable as the sunrise.

Just for info purposes, if you kept the test print out from two years ago, compare the measured numbers and the max allowed limits then vs. now. I'm going to guess that the state lowered the max allowable limits.

 

[ltslimjim]

Originally Posted By: OVERK1LL
Originally Posted By: V70R
Originally Posted By: Bluestream
As mentioned:
Seafoam wont help you son

If high temps are being caused by carbon deposits then seafoam is the cure
(2000 ls1 engine)

also, I can't find any info on how to test the egr valve


AC Delco Combustion Chamber Cleaner/Top End Cleaner is a more effective solvent.


I agree, locally Chrysler/Dodge/Jeep daelers should have Mopar's version in their parts department. OR just order some Amsoil Power Foam.

That is, if the idea is to clean top-end for deposit removal.

 

[V70R]

Originally Posted By: paulo57509
Originally Posted By: V70R
Faile d smog with everything normal except high NOx
15mph was 2xs the max and 25mph was over but close


Did a seafoam through the throttle body and got smoke out the exhaust but also from the engine bay (don't remember seafoam smoke from the bay before).

Could this be a leak causing high NOx? or is seafoam smoke expected from the engine bay area?


If you're going to fail, you'll fail NOx at 15MPH. Predictable as the sunrise.

Just for info purposes, if you kept the test print out from two years ago, compare the measured numbers and the max allowed limits then vs. now. I'm going to guess that the state lowered the max allowable limits.


Limits did not change only just the NOx readings

 

[V70R]

Originally Posted By: ltslimjim
Originally Posted By: OVERK1LL
Originally Posted By: V70R
Originally Posted By: Bluestream
As mentioned:
Seafoam wont help you son

If high temps are being caused by carbon deposits then seafoam is the cure
(2000 ls1 engine)

also, I can't find any info on how to test the egr valve


AC Delco Combustion Chamber Cleaner/Top End Cleaner is a more effective solvent.


I agree, locally Chrysler/Dodge/Jeep daelers should have Mopar's version in their parts department. OR just order some Amsoil Power Foam.

That is, if the idea is to clean top-end for deposit removal.


I used seafoam as a top end cleaner

 

[V70R]

Just to add my AFR on the smog test was 14.4 @15 mph and 14.3 @ 25 mph
So not running lean

 

[tommygunn]

You got a leak somewhere, if seafoam/smoke was coming out of the engine bay.....

Definitely check your vacuum lines.....

I recall a youtube "How to Seafoam" video, and the poster had this symptom, the comments were jumping about exhaust/vacuum leakage somewhere.....only thing that will cause the Seafoam to smoke up the engine bay.......


When was your last oil change, air filter change, etc...? Have heard it's a good idea to change out both prior to smog testing....maybe even wires...


Do you have a check engine light on or anything?

 

[OVERKILL]

Originally Posted By: V70R

I used seafoam as a top end cleaner


We know. We are saying there are better products for this task.

 

[Bluestream]

Your problem is not dirty pistons!!!

 

[OVERKILL]

Originally Posted By: Bluestream
Your problem is not dirty pistons!!!

Agreed.

 

[ltslimjim]

True, leak of some sort, try to find where it does leak. Probably exhaust leak or vacuum hose somewhere not being seen. What is the idle RPM when hot compared to the factory specified value?

 

[V70R]

Idles perfectly

Had a shop use a smoke machine from the back of the exhaust and smoke came out from behind one of the cats at the rear of the cat bolted to the exhaust.
gasket needs replacement there.

I'll seafoam again when the gasket is placed.
However this is behind the cat and 2nd o2 sensor so not sure this is the Nox cause

 

[ltslimjim]

Introduction of outside air might be leaving some undesirable compromising somehow(depends on how close to the rear 02 I suppose, but generally that sensor doesn't control a/f ratio)...

I'd figure there would have been a leak in the engine bay with talk about smoke coming from the engine compartment???