P0420 Again - Page 3

00GTP4ME · #31 01-21-2010, 09:58 AM

Well the check engine light came on again today. I guess going CAT shopping is probably a safe bet at this point. It never ends....

Thanks again for the help guys. Hopefully this takes care of it.

tblake · #32 01-21-2010, 10:08 AM

Quote:

Originally Posted by 00GTP4ME

It never ends....

Welcome to my world.

danielsatur · #33 01-21-2010, 10:24 AM

We buy our OEM cats @ www.catalyticconverterwarehouse.com

00GTP4ME · #34 01-21-2010, 11:49 AM

Quote:

Originally Posted by danielsatur

We buy our OEM cats @ www.catalyticconverterwarehouse.com

Thank you. I'll make sure to price them before I buy. Anyone else have any places for good deals?

Are the CATs on our cars weld on or bolt on?

00GTP4ME · #35 01-21-2010, 09:10 PM

Well, I spoke too soon. That SES light that came on today wasn't another P0420, it was a P0401 (EGR flow insufficient).

So one week I have a CAT code trip and the next I have an EGR code trip. What the heck is going on? Does anyone have any idea as to what this might be (besides needing a new CAT and EGR valve!

)??

maybe it's just a bad SES light solenoid coil adapter harness housing assembly converter bearing...

BNaylor · #36 01-21-2010, 11:33 PM

Quote:

Originally Posted by 00GTP4ME

What the heck is going on? Does anyone have any idea as to what this might be (besides needing a new CAT and EGR valve!

)??

Have you ever replaced the PCV valve? Check the condition of it and the o-ring seal to start. And check the vacuum lines at the MAP sensor and off the supercharger and throttle body.

00GTP4ME · #37 01-22-2010, 09:34 AM

Quote:

Originally Posted by BNaylor

Have you ever replaced the PCV valve? Check the condition of it and the o-ring seal to start. And check the vacuum lines at the MAP sensor and off the supercharger and throttle body.

Yes, I change the PCV valve every 15K I think (I'd have to look at my maintenance log). I'm pretty sure the last change was just this past fall.

I'll check the vacuum lines; that's a good idea.

tblake · #38 01-22-2010, 09:49 AM

15k on the pcv valve? wow, I'd be changing my pck valve every few months.

00GTP4ME · #39 01-22-2010, 10:11 AM

Quote:

Originally Posted by tblake

15k on the pcv valve? wow, I'd be changing my pck valve every few months.

No, no, no, you're right. I meant to say 30K; sorry.

BNaylor · #40 01-22-2010, 05:34 PM

The test to check the EGR flow is based on Manifold Absolute Pressure (MAP) and engine vacuum so that could cause the P0401 DTC. More so on the L36 3800 engine when the o-ring seal is missing on the PCV but sometimes on the L67 3800 engine too.

00GTP4ME · #41 01-28-2010, 11:50 AM

Out of curiousity, if the PCV valve is completely sealed off by the two-bolted plate above it, why would the o-ring make a difference? Where could a leak come from on the top side of the o-ring? (I'm not disagreeing with you at all, it's just the PCV on these cars has never made sense to me because it doesn't flow or open to anywhere but the sealed chamber it sits in....)

richtazz · #42 01-28-2010, 12:14 PM

the PCV valve acts as an air-flow restrictor, so the missing o-ring will allow too much airflow through that housing, throwing off the readings fed to the PCM.

00GTP4ME · #43 01-28-2010, 12:57 PM

Quote:

Originally Posted by richtazz

the PCV valve acts as an air-flow restrictor, so the missing o-ring will allow too much airflow through that housing, throwing off the readings fed to the PCM.

That is just weird. So do our cars have a crankcase ventilation system that actually routes fumes to the intake somewhere?

I know on my Jeep it has a PCV valve that feeds to the back of the throttle and it has crankcase breather tubes that feed in right before the throttle. I'm curious to know if our cars have something similar.

BNaylor · #44 01-28-2010, 05:46 PM

Quote:

Originally Posted by 00GTP4ME

Out of curiousity, if the PCV valve is completely sealed off by the two-bolted plate above it, why would the o-ring make a difference? Where could a leak come from on the top side of the o-ring? (I'm not disagreeing with you at all, it's just the PCV on these cars has never made sense to me because it doesn't flow or open to anywhere but the sealed chamber it sits in....)

Weird PCV setup but it works and is needed. Did you miss the small hole going back in to the intake (supercharger) so it is not completely sealed off? See pic.

Or try running without the PCV installed and let us know the results.

00GTP4ME · #45 01-28-2010, 09:27 PM

You have GOT to be kidding me!! I had NO CLUE that little hole was in there!! Now do you see why I was so confused??

It all comes together, the planets align! I seriously thought you guys were all a bunch of crack heads thinking that PCV valve did anything, but yes, that hole there changes everything. Every time I've opened that plate I'm always approaching from the driver's side so I've never seen that. Unbelievable.

It is a weird set-up, yes, but at least now I can conceivably understand how the thing works in there.

Bob = +1 GTP Point

For another GTP point, can anyone tell me the answer to this?:

Quote:

Originally Posted by 00GTP4ME

I know on my Jeep it has a PCV valve that feeds to the back of the throttle and it has crankcase breather tubes that feed in right before the throttle. I'm curious to know if our cars have something similar.

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