420 420 420

[brus brother]

I'm under the impression Techron gas treatment might actually help with injectors. Maybe experiment with it in a 'test' vehicle as well.

 

any rumors from other shops about this epidemic of 420s?

Any case histories with good ole' Seafoam?

Threw some in the tank a month or so ago and then threw the code again. I wish I could see a pattern as it's now been around 300 miles since I last cleared the code. This has been going on (and off) for about 2 years. I've read too many stories here and on other sites about "did this... did that" without success.

[1 Lucky Texan]

Any case histories with good ole' Seafoam?

Threw some in the tank a month or so ago and then threw the code again. I wish I could see a pattern as it's now been around 300 miles since I last cleared the code. This has been going on (and off) for about 2 years. I've read too many stories here and on other sites about "did this... did that" without success.

 

I used seafoam too recently. It has a huge following on the boards and I had a weird issue with my WRX. Dunno if it actually helped - or coincidentally the problem hasn't returned.

 

It's hard to know for certain with most of these 'mechanic in a can' solutions.

 

 

Ivan, have you checked for old fuel filters or for some kinda partial failure of the fuel pumps - low pressure/volume? Maybe weak fuel pressure regulators?

[ivans imports]

all over the feul syestems new fillters and iv'e done the pump on almost evry subie around here it seems to easy for it to be somthing simple i used the lucas feul treatment because it also has a lubracant that whould help a sticking injector havent seen the test pilot since fingers crossed I had a thought about moving the rear cat and o2 forward to get them hotter but i still think its a lean problem or posibly a carbon on the intake valve problem the carbon is working like a sponge and soaking up the gas making it run lean still driving me nuts

[1 Lucky Texan]

Ivan, while I understand RIGHT NOW may not be the best time to learn some new software, I'd bet you could really use the FreeSSM occasionally.

 

check out this thread when you have time;

 

http://www.subaruoutback.org/forums/65-parts-accessories-performance/39426-freessm-complete-access-your-ecm-tcu.html

 

 

you could maybe find some smooth/normal running cars, take a look at all the sensor readings etc. - you know, get a 'baseline' set of figures, then use it to check real-time reading from sensors on a car with a problem. Also looks at transmission parameters too.

[torxxx]

We've been getting P0420 codes like crazy lately too. Weird to see it in the summer, I would assume the Cats/O2 sensors would be the hottest in the summer, and not set codes.

 

One thing I thought about after looking underneath my 98 Outback last night. Wrapping the front cat and about 2 inches upstream and downstream of it? Should help hold heat in the Cat causing efficiency to go up correct?

 

Header wrap if done right, shouldnt hold too much moisture. The idea of it is that it gets hot and the moisture evaporates out. If you are that worried about your exhaust "rusting out" it should already be replaced.

 

My lifted 86 had header wrap from the exhaust studs to back behind my drivers seat for a few years. I took it off when changed the configuration around and there was a slight bit of surface rust, but no pitting. And my car does not stay out of the water, its in water to the bumpers almost every weekend, does not get washed off when I get home. Rally it, Park it, Rally it, Park it for the last 10 years and my tubes are just fine.

 

On the other side of things, couldnt one remove the cats, replace the 02 sensors with EGT sensors right at the manifold plate? It would require some reprogramming, or a custom ECU but I still think using the idea of controlling EGT per cylinder could overide the need for a cat and o2 sensors. I'm not anywhere near a fuel injection guru, but I've heard of guys running GM engines in mud trucks, and they get rid of the cats, put the o2 sensors way down stream and they dont set o2 or cat codes.

 

There has to be a software side of this issue that we can cure?

[1 Lucky Texan]

has anyone tried an old-style tailpipe test to see if there's really anything(and what?) 'off' about the emissions?

[ivans imports]

not many people around with exhaust gas anilizers anymore i dont have one but i know the smell of lean and they all got it or nox if you perfer if you follow one of theese cars up a hill with drivers foot to the floor no cat smell not rotten eggs and if it was anythig else whould stink like catts not enuff feul way to lean burning subaru droped the ball one feuling there engines trying to make milage standards I still think its callibrated way to lean and the o2 hitts a wall trying to get the feul trim ritch enuff and setts a code for what it thinks is wrong I think a catt is like a engine needs feul to work

[uniberp]

not many people around with exhaust gas anilizers anymore i dont have one but i know the smell of lean and they all got it or nox if you perfer if you follow one of theese cars up a hill with drivers foot to the floor no cat smell not rotten eggs and if it was anythig else whould stink like catts not enuff feul way to lean burning subaru droped the ball one feuling there engines trying to make milage standards I still think its callibrated way to lean and the o2 hitts a wall trying to get the feul trim ritch enuff and setts a code for what it thinks is wrong I think a catt is like a engine needs feul to work

 

You guys do a lot of engine braking up there in the mountains. Altitude may also be a factor. Plus the possibly weird gas and humidity.

 

maybe?

[brus brother]

You guys do a lot of engine braking up there in the mountains. Altitude may also be a factor. Plus the possibly weird gas and humidity.

 

maybe?

Reporting here from the flatlands of CT (no engine braking) where my mechanic is also stymied... 0420 for the past two+ years on my 05 OB.

[torxxx]

I'm really starting to wonder if its a ECU issue that causes the code. I've seen the cat code pop on a car with a new installed factory cat. (I installed it on a customers car, verified the cat was intact before I installed it)

 

I honestly think that someone with a programming background could rewrite the software in the TCU to make it so the test it runs for P0420 with less strict parameters. I've seen too many EJ25s run just fine and have cat codes. And the poopy thing is having the fuel cut on a 5 speed or fail safe on a 4EAT and not being able to shift all 4 gears... All because of a silly false positive code..

[ivans imports]

yes they are realy efected by elavation everytime they climb the pass or go up in elavation it seems to affect the auto cars more my test 03 turns on the light when they pull the hill on way home is a substantial elavation increse but i still think its lean and just shows up more on hills anyway is still driving me nuts will keep trying

[brus brother]

yes they are realy efected by elavation everytime they climb the pass or go up in elavation it seems to affect the auto cars more my test 03 turns on the light when they pull the hill on way home is a substantial elavation increse but i still think its lean and just shows up more on hills anyway is still driving me nuts will keep trying

OK then back to my pondering how my 05 OB appears to throw code more often with my versus wife's driving since I am more of a stomper?

But doesn't the loop (closed or open, I forgot) change during heavy acceleration and therefor make the question irrelevant?

Coincidence?

[ivans imports]

have a five speed 99 forester and the 03 auto both live up the same hill both set 420 going up that hill it makes no sense they also have a 97 auto but it sets the 420 on evry 3rd or forth trip but on the same hill is a 6 km very steep hill with slow corers on it the other fifty car set light all over the place have not been able to find a cure yet and i cant get the 420 to show up when i test drive takes some miles for it to turn on the one car she drove it 1500 kms after i shut light off before it came back on average is about 500- 1000 kms to turn light on the least ive seen is 100 kms but all over the place and many cars with 420 i dont think thiss problem will fix easy

[1 Lucky Texan]

have a five speed 99 forester and the 03 auto both live up the same hill both set 420 going up that hill it makes no sense they also have a 97 auto but it sets the 420 on evry 3rd or forth trip but on the same hill is a 6 km very steep hill with slow corers on it the other fifty car set light all over the place have not been able to find a cure yet and i cant get the 420 to show up when i test drive takes some miles for it to turn on the one car she drove it 1500 kms after i shut light off before it came back on average is about 500- 1000 kms to turn light on the least ive seen is 100 kms but all over the place and many cars with 420 i dont think thiss problem will fix easy

 

OK

 

I can think of 3 things that relate to a vehicle going up a hill;

 

increased load on the engine

 

tilting of the gas tank/vehicle

 

reduced barometric pressure

 

 

so, suppose one of the suspect vehicles could be put on a dynomometer to see if load would trigger the code (use an auto maybe with the FWD fuse installed for 2 wheel dyno)

 

 

maybe idle the car and carefully jack-up the front to see if tilting will set the code

 

 

I dunno, maybe idle the car on the back of a flatbed and drive to higher altitude?

 

 

(desperate times call for desperate measures - lol!)

[brus brother]

OK

 

I can think of 3 things that relate to a vehicle going up a hill;

 

increased load on the engine

 

tilting of the gas tank/vehicle

 

reduced barometric pressure

 

 

so, suppose one of the suspect vehicles could be put on a dynomometer to see if load would trigger the code (use an auto maybe with the FWD fuse installed for 2 wheel dyno)

 

 

maybe idle the car and carefully jack-up the front to see if tilting will set the code

 

 

I dunno, maybe idle the car on the back of a flatbed and drive to higher altitude?

 

 

(desperate times call for desperate measures - lol!)

Nah, I'm not going for barometric or angle. As I said, I'm here in the flatlands of CT and I'm leaning towards heavy load. My observation is that the code shows up more frequently if I have been driving than when either my wife or daughter are driving. I definitely am a more aggressive accelerator.

[brus brother]

To Ivan, GD Shawn and the rest of the uberwrenchers,

I found the following video on 0420 on an old Toyota.

As I have mentioned, My 05 OB seems to get the code more when I am the main driver than when my wife or daughter are lightfooting around. They have however gotten the code when on extended highway roadtrips.

Could this be the answer to the P0420??

I don't have the tools to do the diagnosis but I guess I could borrow a Autozone scanner to check.

Just askin...

[Fairtax4me]

One of the many problems that can cause a P0420 code.

Autozone scanner won't show you MAF or Fuel trim graphs. You'll get a numeric value that may give some clues IF the scanner they have can read Freeze frame data.

[drdan52000]

In our area (Orgone) there running 10% Ethanol in all our gas.

Ethanol, dosen't have the same BTUs at real gas, so would that make the cat

run cooler.

Just an idea.

[mikaleda]

i have heard you can get higher ethonal content depending on how long the gas has been in the tank and how low the tank is because the ethonal and the gas don't mix and will separate after time and will also deteriorate faster . i have run into problems with my older cars running bad if i get gas from certain gas stations that don't get alot of customers. just a thought

[brus brother]

One of the many problems that can cause a P0420 code.

Autozone scanner won't show you MAF or Fuel trim graphs. You'll get a numeric value that may give some clues IF the scanner they have can read Freeze frame data.

What sort of scanner do I need to get?

It seems like this sort of information is vital to getting an accurate and individual diagnosis and end the speculation?

Do retailers such as Autozone sell scanners that will give this info?

I have seen OBDII readers that connect to laptops for readouts. Does anyone have any idea which is best to use?

[1 Lucky Texan]

personally, I think a DIYer would do fine with a $100 scanner. If you plan to maintain a lot of cars, or you plan to NEVER let a dealer or mechanic do anything to any car you maintain - you may need a $250 piece of equipment or some fancy software.

 

I have an old Innova 3100. It gets used by coworkers more than I use it. It won't get transmission codes, but gets CAN and all 4 OBDII protocols. I think it can be flash updated, but I've never connected it to the computer since i bought it.

 

I think you can get more features for the same money nowadays. I guess check Amazon for good ratings on Innova and Actron.

 

A laptop and cable is very awkward - but there are wireless Bluetooth adapters now and apps for smartphones - so, lots of choices.

[brus brother]

I have a a very basic scanner that I paid less than $20 that reads the codes and readiness and clears codes so that I can slide by emissions when I need but nothing about freeze frame graphing trim/o2/maf etc. that will aid in a deeper understanding of this P0420 gremlin.

The reason I asked about the laptop (or BT as you suggest) is that I am guessing there would be more info available with that interface.

I am still curious if any of the heavy wrenchers like Ivan (who seems to be in the middle of an epidemic of these) have run these tests.

[1 Lucky Texan]

Ivan, I tried to search the thread for EGR but didn't spot it.

 

I wonder if there's an EGR that might be weak or dirty?

[ivans imports]

no egr on a 251 and the egr sets its own codes funny thing the test car stoped turning on the light about 300 kms after the lucas feul treatment it hasent turned on the light in 3 trips up the hill so back to feul injector problems bett they get pluged or sticky or just dont move enuff feul

[brus brother]

no egr on a 251 and the egr sets its own codes funny thing the test car stoped turning on the light about 300 kms after the lucas feul treatment it hasent turned on the light in 3 trips up the hill so back to feul injector problems bett they get pluged or sticky or just dont move enuff feul

Anyone grabbing freeze frame data with these codes?

I just got the code again yesterday after highway driving.

I'm going to get the freeze frame data before I clear the code this time and see if someone here can interpret them for me.

In the meantime, Lucas is a pretty cheap fix! (fingers crossed)

Keep us posted Ivan on your hill climbers.