two questions...

1) has anyone played with running EGR at low RPM's (around 1200)? I recently failed a smog check and I'm pretty sure it's due to two factors:
a) the tech ran the car in 2nd gear at 15mph resulting in ~ 1200 rpm,
b) after an extensive datalog, I discovered there is little to no EGR that low.

I am going to try and suggest to the tech that he keep the car in 1st gear for the 15mph portion of the test, but I'd like to have a back up plan (run some EGR down at 1200rpm around 40-50kpa).

I'm curious how much EGR I can run or if there are going to be other tuning issues.

2) I noticed in the datalog that my commanded AFR at one point went quite lean (15.1:1), learn mode went off, and port AIR was on, and O2 was stuck < 100mV with no BLM/INT updates. This went on for many seconds.. Is this normal? I've never spotted this before, and I thought highway mode was completely disabled in production GM BIN's (I'm using AXXD). I'll have to re-check everything, I certainly don't remember enabling it...

thanks!

 

HWM is enabled in some bin, check yours...

Sorry cant help you on the EGR stuff.......

/N.

 

Which portion of the test failed you? Was it the NOx or HC or CO?
If it was the NOx, then you should look at your EGR working at that RPM. Or knock down your spark a couple degrees. (Or eliminate hiway spark, if it's enabled)
If it wasn't the NOx, I'd be looking more at your fuel. Get it smack on 14.7 in those cells and you should be ok.