Speaking of the ol' EGR code - cold temp has banished it. (1 Viewer)

[IdahoDoug]

In late October or November, I got set up to chase that thing by moving my EGR components a bit. It went on a couple times after this, but has not been seen for months now. So, I'm guessing the "EGR insufficient flow" code I have is activated by a temp reading that's too high but the winter temps here have kept the temp from rising to that threshold. Anyone else observe this with their vehicle?

DougM

 

[Vitesse_6]

I thought my code 71 was due to just the opposite, But I havent had a code for a few days, and the temps have been up locally...Maybe mine is something else?!? VSV or something.
Good luck

 

[kup99]

I would also say the same... mine has came around early Oct. .. and has popped on when the tems have got warmer.. but has been gone for a long time now that the weather is a lot colder!!

 

[KliersLC]

Must be nice.

Mine came on when it got cold, and I've been fighting it ever since....

 

[Tools R Us]

Must be nice.

Mine came on when it got cold, and I've been fighting it ever since....

X2, my P0401 comes on when it's cold out and off in the summer.

 

[baumber]

I had the P401 on for a couple months. Rather than due diligence I just upgraded the modulator to blue. This was no help. I've also had other things in the works including sliders. I had an exhaust shop reroute over the frame rail and go to a single MagnaFlow cat.
The code was on for aproximately 2 days after this work and has since dissappeared! I've been running now for 3 weeks sans code in temps ranging from 12 to 55F. I was so skeptical at first I made sure my CE light was still operable.

Deductive Reasoning question: Due to the inherent "Insufficient Air Flow" that gets triggered with the 401, is it possible that my stock cats were the culprit for the code being triggered due to gunk build up and insufficient flow?
baumber

 

[Beowulf]

Time, vehicle speed, and operating temp are part of the drive cycle. You have to have 2 complete back-to-back drive cycles with a failure to trip the P0401. I would have to look it up to be sure but I guess it is possible that ambient temp (or maybe intake temp) is also part of the drive cycle. That might explain what some of you are seeing.

-B-

 

[Beowulf]

Due to the inherent "Insufficient Air Flow" that gets triggered with the 401,

It is not "air" it is recirculated exhaust gas. This is pulled from the exhaust side of the head, not downstream of the cats.

-B-

 

[baumber]

It is not "air" it is recirculated exhaust gas. This is pulled from the exhaust side of the head, not downstream of the cats.

-B-

Ok, but wouldn't an insufficient flow translate on both sides of the cats, and wouldn't this lack thereof translate into higher temps in the exhaust, which would then affect gas/exhaust ratio? Or are you saying that this is only measuring recirculated gas? I'm rereading FAQ soon. It was just too convienent to think that was the culprit.
Thanks,
Baumber

 

[Beowulf]

Baumer,
Read the copious amount of information we have here in the 80-Section on the EGR system. I will try to find you the simple explanation of the system on one of the tutorial sites. It isn't that complicated and, to answer your question, the insufficient flow is detected because the EGR temps are not high enough. Your above logic is reversed.

Here ya go.... http://www.autoshop101.com/forms/h61.pdf

You will notice in this generic diagram, that the EGR system is fed directly from the engine; basically an extra exhaust port on the head that feeds the EGR valve with exhaust gas.

-B-

 

[baumber]

You will notice in this generic diagram, that the EGR system is fed directly from the engine; basically an extra exhaust port on the head that feeds the EGR valve with exhaust gas.

-B-[/QUOTE]

Aha, I see said the ignorant, blind man! In order for my thinking to make any sense the damn modulator would have to be 3 ft away from where it is. Thanks for the lesson and the link Beo.

So where does that put me and my nonexistent 401? I think the answer is :It'll be back. Sorry for the hijack Doug.

 

[Beowulf]

So where does that put me and my nonexistent 401? I think the answer is :It'll be back.

Bank on it.

-B-