: DTC P0174 and P0420



krusty917
07-13-12, 12:57 PM
Hi, every couple of days I get both 174 and 420 while driving.

I can't seems to zero in on the fault.

1. I've cleaned the MAF sensor with Contact Cleaner. Which made the throttle response a little more snappy.
2. It appears that both codes set at the same time.
3. Idle is always smooth. Lots of power.
4. I've checked for intake leaks around the top of the motor with Benzene gas while monitoring: rpm and all 4 O2 sensors. No change detected while idling smooth.
5. Intake clamps are tight.
6. The Service Manual mentions the EVAP system plugged.

How does the EVAP system being plugged cause extra air to enter the intake?

7. I haven't check fuel pressure in the rail.
8. I might have a leak at or around the header.
9. I did the cat cleaning with a gallon of Lacquer Thinner and a 1/2 tank of gas trick recently.

Wayne.

Submariner409
07-13-12, 02:08 PM
Straight question: Where did you get the idea to run lacquer thinner - in any amount, much less a gallon - through your engine ?

krusty917
07-13-12, 04:23 PM
The lacquer thinner idea came from a mechanic on YouTube..."Fixing Bad Catalytic Converters With Inefficiency Code P0420"

He claims that you can gain up to a 5% cat efficiency by running lacquer thinner through it. Everyone who tried it claimed it worked for them. I don't really know if it does anything. The difference in cost was $20 for the lacquer thinner or $1400 for a new cat. The question is can a catalytic converter get dirty and can it be cleaned.

He also suggests removing the cat from the car and soaking it in soapy water over night.

Hasn't help my cat failure yet.

Submariner409
07-13-12, 04:40 PM
The reason I ask is because lacquer thinner is one of the most powerful solvents on earth. As you now know, it will eat the oils out of your hands until they turn snow white from dryness. You should see what it does to some plastics..........

Think of what it did to the oil film on your cylinder walls.

In my 57 years of building and rebuilding engines I have run some questionable snake oils through them, but this is a first.

KRSTS
07-13-12, 05:19 PM
Emissions warranty should still be good on a 2006 unless you have over 80,000 miles

Ranger
07-13-12, 10:50 PM
The reason I ask is because lacquer thinner is one of the most powerful solvents on earth. As you now know, it will eat the oils out of your hands until they turn snow white from dryness. You should see what it does to some plastics..........
It will also eat the insulating varnish off of the fuel pump and injector windings.


The difference in cost was $20 for the lacquer thinner or $1400 for a new cat.

Now add the cost of injectors and fuel pump.


He also suggests removing the cat from the car and soaking it in soapy water over night.
Does he also suggest an exhaust system flush? Is his name Bubba by any chance?

dkozloski
07-13-12, 10:56 PM
His name is Bubbles.

krusty917
07-14-12, 12:36 AM
Hey Submariner 409, thanks so much for your input.

How long do you estimate the engine will last with the cylinder wall damage?

It seems to have more power now than before.

krusty917
07-14-12, 12:43 AM
Hey Ranger, I had no idea that lacquer thinner was so corrosive.

How long would you estimate I have before the fuel injectors and fuel pump fail?

It's too bad cause the engine seems like it has a lot more power and is running so smooth.

Could you post the link to the corrosive matrix you used to predict the fail of my injectors and fuel pump? I would like a copy for future procedures.

Ranger
07-14-12, 09:58 AM
I have no estimate or link. I just know that lacquer thinner is a very strong solvent. Same goes for "fuel injector cleaner". It should only be used (if at all) in the concentrations listed on the bottle, which is something like one 12 oz bottle per 10 gal (or something close to that). A gallon of lacquer thinner in a 1/2 tank (9 gal) is a VERY strong concentration. No sense in worrying about it now. If any damage was done, it's already done. Then again, maybe you got lucky.

EChas3
07-15-12, 12:32 AM
You may be able to get a dealer to honor the emissions warranty longer than 80k miles. There were some bad cats being produced. There's a TSB & many N* owners got letters stating the extension.