So there was one item on my rebuild that I was hoping to use from the original engine, that being the EGR valve. Anyways I passed the smog check with everything working normal but I'm noticing that I'm getting EGR error% of -20 to -40 when idling. So should I keep my EGR valve or get a new one.

 

hot idle is when we get max EGR. You went with the non-scoop pipe, right? Take a look at your Intake Air Temp and IAT2 readings at idle. I don't think there is any other device in place to measure EGR flow other than inferred from the temp increase in IAT2 over IAT.

So my thought is: Lucky You Not getting a ton of EGR flow like the rest of us are stuck with

As long as it doesn't throw a CEL, you are golden IMO...

 

IAT2 with no scoop

 

Ya' got me: that looks like max EGR and temps in line with it working. I'll be honest, I hadn't heard of the EGR Error % before now, so have no clue what it relates to...

 

I did a little googling and it appears the EGR Error % is a generic OBDII PID. Found one thread on here from back in 2014 and the bottom line from that thread is it is something the PCM calculates, and nobody knew much about how it did that. I don't think there is any other feedback for the PCM to know if its commanded value for EGR opening, is being delivered other than the IAT temps...

Maybe another member can help...

 

You've got a rock solid 6.0 powerplant if you've got the time to worry about an EGR position error that doesn't throw a CEL.
I thought there was a position feedback mechanism for the computer to know where the valve is versus where it was commanded, but I could have dreamed that up. Like DD said, your temp spread indicates your putting exhaust back in. I don't look at IA2 much but I recall seeing a similar spread after running it unloaded on the interstate for a bit.

 

Thanks you guys, going slightly of tangent: Any of you ever notice how close IAT2 and TRANSMISSION TEMP (see picture posted above) are? This little observation could be huge if those sensors are using the same output method. Does anyone get what I'm talking about. Purely for science of course. Send Tranny temp to IAT2 PCM input and now ERG flow is golden.
What do you think about that concept? Again purely for science theory.

 

Yes, at that point it was... I'll humor you a bit: what if the PCM asks for more EGR and your trans is running cool, so the PCM doesn't see the rise in IAT2, which actually would happen fairly quickly versus a rise in trans temp... Hmmmm, would it throw a code??

Or you could move out of CA like we are thinking of doing, and not care....

 

I seem to recall that my temps follow closely most of the time, sadly now that my 6.0 is in mint condition, I'm not going to mess with it, hopefully someone with a beater will give it a go and give us some feedback.

OTOH New Hampshire would be my first choice but I like living above freezing temps all year.