P0401 and P0420.

[steveo]

97 Contour 2.5L 67,000.

I have had a chronic check engine light over the last year and when I had the codes pulled last year there was only a P0420. Now I have both codes, P0401 and P0420. And of course, its emissions testing time.

After some research here on the forum I was guided in troubleshooting the P0401 code. I used a small vacuum pump that I have for bleeding brakes and put 10psi vacuum on the egr valve, vacuum held steady but engine did not hesitate at all. Pulled out the egr valve and made sure it was opening and not clogged. Led me to believe the exhaust gases were not making back into the intake due to the intake passage being clogged. I pulled off the throttle body and sure enough the passages were completely packed the some sort of carbon sludge debris. After a good cleaning and putting everything back together the engine now hesitates while performing the suck test on the egr valve. I feel this should take care of the P0401 code but now I have to finally deal with my P0420.

I have done a little research so far and am considering the anti-foulers and other such eliminators. My concerns are that with the relatively low miles on the vehicle and such carbon/sludge debris clogging the egr system, I am sure that the car is not running as efficiently and cleanly as it should. I am concerned that the p0420 code is causing the vehicle to run poorly causing a lot of debris the in exhaust therefore causing the P0401 code. I have only had the car a year and have been averaging about 26mpg. My concern is does the use of anti-foulers trick the pcm into thinking everything is ok, or will they actually change the o2 sensor inputs the pcm and therefore how the car is running? Has anybody noticed the use of such devices caused there car to run differently, rich/lean, mpg difference?

Also, does anybody know how long I need to drive for all test parameters in the pcm to ready so when I test I can pass. I've heard they can tell if the codes were recently reset and will not pass you.

TIA.

 

[steveo]

After doing some more reading here I think I will try the anti-fouler firx on the oxygen sensor. Can someone confirm that P0420 is for the rear bank, and I want to add it to the downstream sensor not upstream. I have never gotten the P0430 but if I am doing one side should I do the other? Are there any clearance issues for the downstream sensors?

Also read that when an P0420 or P0430 code is present the ecu goes to a rich mode which might explain why there is so much carbon sludge that was blocking the egr passageways. Can someone confirm this? I have been driving with the cel on for over a year. Maybe I will even notice a mpg increase if with the code gone the ecu leans it out a little!

 

[Monkay619]

Can someone confirm that P0420 is for the rear bank, and I want to add it to the downstream sensor not upstream.

Yep, just like you said, Rear bank (which is called Bank 1 for some reason) and the second of the two O2 sensors.

That is as much as I can tell you, I'm sure someone else can answer your other questions

 

[AliasJerk]

the duratec is notorious for having carbon build up in the upper and lower intake manifold your CEL isnt cauing that issue. the carbon build is also going to be on your uppler and lower intake ports inside the motor, some people pull apart the intake manifolds and clean everything up to revive some horsepower in the motor.

as for your p0420 code, some people (and I personally) have tried to run berryman's B-12 through the gas tank with a low tank of fuel, this results in a gas that runs through the CATS and in many cases cleans them out to a point where it "fixes" this issue. although if that doesnt fix that issue MIL elminators will.

 

[steveo]

Thanks for the info guys. I will plan on picking up some B-12 this afternoon and give it a try. I am having second thoughts about the anti-fouler install. I have not found a lot of good reviews on this type of fix like I have the MIL eliminators. Seems only one guy here that keeps recommending the anti-foulers. I am just worried that by moving that sensor from its original position it just might induce more problems. I am just not sure how it will affect the f/a ratio. I have read some threads were guys have had new cel's come on and dramatic decrease in mpg after installing the anti-foulers. If some of you guys have used them successfully I would love to hear it or if someone can point me to a thread I would appreciate it.

 

[Tony2005]

My good experience is with Mileliminators and I have had them for 4 years.

Bank 1 is rear (firewall side) and the O2 sensor to install the fix is the lower or 2nd sensor. This is after the exhaust manifold (precatalytic converter). It should be somewhere inbetween the front seats (below the floor panel, of course).