My 80 Failed emissions this week

[Overlander]

It was time to get it checked out so I too it in mid-day and... it failed by a smidgen: the CO GPM Reading was 20.81x while the limit was 20. Also, the Gas Cap 'integrity' failed. The CEL is on ... probably the PO401 that it had when I got it.

I'll to get a new Gas Cap today. I got it until next week to sort it out and try again without another charge. Was thinking to drive it real hot and then immediately try to get it tested. Solving the PO401 can be a real pain from all the threads that I read...

Anything else anyone can think of?

 

[jps8460]

Can you post up photos of the failed report?

 

[Overlander]

Here it is: https://photos.app.goo.gl/mdWsFaoTuBbYTdHu6

Hope you can see the image

 

[Inukshuk]

Did you read all the threads here? 2 cans heet, oil change, cap, dacono.

 

[Overlander]

Yeah, just spent couple of hours reading the threads. Sounds like it could be: EGR, EGR Vacuum module, VSV, TPS, MAF, Fuel Pressure Regulator or Cats.... it blows my mind.

I couldn't really find that one thing that consistently points to reducing NO numbers which I happen to have.

Guess I'll start with the simple recommendations first as Inukshuk mentioned above.

 

[ccslider]

Do you have exhaust leaks?

 

[60wag]

Your CO2 is low and your CO is high, I think the cats are weak. The NOX is good so its not the EGR. However, they won't pass you with a check engine light on. You might have to do some EGR work to get the light out, if the code points to that.

 

[Overlander]

I've reset the PO401 code with UltraGauge. I don't know if I have exhaust leaks... how can you tell?

 

[RayRay27]

Make sure to double check your timing. Are you lifted at all or running larger tires? Also I know it sounds like snake oil but if you buy a bottle of cataclean and run that through a few days before it might drop your CO's enough for you to pass cause your just barely over. I have had success using it and it's a lot cheaper than trying to replace a bunch of components in a weeks time frame.

 

[RayRay27]

Yeah, just spent couple of hours reading the threads. Sounds like it could be: EGR, EGR Vacuum module, VSV, TPS, MAF, Fuel Pressure Regulator or Cats.... it blows my mind.

I couldn't really find that one thing that consistently points to reducing NO numbers which I happen to have.

Guess I'll start with the simple recommendations first as Inukshuk mentioned above.

Your fuel pressure regulator is really simple to replace if you have to replace one of the following components above. Also a dirty air filter could cause high CO's so double check your air filter and replace with a new one if needed. I recommend just getting a Toyota air filter if you need one since you can clean and reuse them.

https://www.smogtips.com/failed-high-carbon-monoxide-co.cfm

 

[Overlander]

I've read about checking the Timing but I don't know how to do that. How many bananas on that one? I'm running slightly larger tires: 285.x.x

 

[jps8460]

I can’t see the photo, can you post it directly?

Also, confirm the code. Any parts store will read the code for free.

 

[RayRay27]

I've read about checking the Timing but I don't know how to do that. How many bananas on that one? I'm running slightly larger tires: 285.x.x

It's not really difficult but may be a bit confusing if you have not done it before. It involves using a paper clip to jump two connection in the engine bay. If you pop the hood of your truck and look for a sticker on the bottom side of the hood it will tell you what your timing should be set at.

 

[RayRay27]

Here's a few threads that talks about timing.

https://forum.ih8mud.com/threads/adjust-ignition-timing.794555/

https://forum.ih8mud.com/threads/how-to-adjust-or-advance-timing.874078/#post-9877573

 

[Overlander]

I can’t see the photo, can you post it directly?
Also, confirm the code. Any parts store will read the code for free.

Yes, My UltraGauge read PO401 before I reset it.

Photo...

 

[jps8460]

Yes, My UltraGauge read PO401 before I reset it.

Photo...

Did they give you a sheet with a bunch of graphs on it?

 

[Inukshuk]

Like @nuclearlemon always said: 2 cans heet, oil change, cap, dacono.
Until that fails, enjoy making your lives complicated! I'm out!

PS. I'm happy to loan you my emissions gas cap.

 

[jps8460]

Like @nuclearlemon always said: 2 cans heet, oil change, cap, dacono.
Until that fails, enjoy making your lives complicated! I'm out!

PS. I'm happy to loan you my emissions gas cap.

While that’s sage advice, it doesn’t find root cause. A good function/running 1fz should be around half of those limits. The above was not adequate to get me to pass.

After properly diagnosing my erg valve, glitchy tps, and weak cats, I fast passed at 485k miles. 😉

Oh and putting some 265 highway tires on at 50psi.

 

[Lastresort576]

Fwiw, I have been passing for a few years now with the bad flow egr code. I just clear the code on a $10 scanner, and run it hard up to the dacono station. Always passes even though I have that code.

 

[Overlander]

WHoo hoo - new gas cap, tires at 35psi, clean air filter and two cans of HEET (red) in Decono - and I passed. THx all. 'till next time...