Rich for emissions but blms ok???

[alwaysneedmore]

Sorry guys, had this posted in emissions tech, but maybe it really doesn't belong there....

Hi,
I finally passed my Canadian emissions test, but here's what's happened.
Red's 93 chip about 1995 vintage.
Bluetop injectors
run 1
Fuel Pressure @ 41#
Hydrocarbons limit of 106. Actual value at 40 kph was 112. Passed the idle HC portion of test

run2
Fuel Pressure @ 37#
HC=108 at 40 kph,

Run 3
Changed Cat.
Fuel pressure 32#
HC=106 at 40 kph

What I noticed is that at highway cruise (120 kph) with fuel pressure correct @42, the blms are 127 - 135, which I thought was pretty good, even at idle they're about the same. This says to me that the car's in pretty good tune. Turn the FP down to 32# and the blms get driven up to 160 which also makes sense to me (the ecm is compensating for less fuel given the pulse width), but why would the e-test be showing that the car is running "rich" (showing hydrocarbons way high) I would have expected the blms to be compensating low if the car was actually running rich.
Even at the track, through the trap, the O2 number is in the 800's at 12.87.
Sorry this is so long, but any suggestions? I think I need an updated chip for starters, but what else is going on here?

Nathan

 

[gofstbuick]

Excess HC does not equate to rich, unless CO is increasing as HC increases. HC is unburned fuel, and CO is partially burned fuel. CO will be excessive if the mixture is rich, but for High HC, it is possible that there is a ignition or misfire problem (as the fuel is not being ignited).

 

[alwaysneedmore]

Veeeerrrry interesting.
My other 2 measured parameters (NOx and CO) were very low relative to the HC numbers. Would you suggest that I have a look at my coil pack and plugs then? Would wires have that much effect ?
I know the plugs have very few miles on them (about 6000 km in 2 years), but I'm not too sure about the coil pack.

thanks.
N

 

[gofstbuick]

Another thought may be that your fuel injectors may be partially clogged, and consequently there will be too much air for the amount of fuel being injected. And it will lean misfire, instead of ignition misfire.

 

[Reaper]

contact scott simpon of thrasher, he will get you a chip to pass. he burnt mine and i passed with ease in AZ.

have you done the basic emissions tuneups?


Dahtan

 

[alwaysneedmore]

If you mean by emissions tuning putting the cat back on, yes, I did .
Other than that, this is only the 2nd e-test, and I didn't do anything really special except clean the k&n and change the oil.
What else should I know about? I though the fuel was pretty well under control because the blm #'s were pretty darn close to 128 under cruise. While I was adjusting the FP, I watched for leakdown, and the system held pressure no problem.

 

[alwaysneedmore]

If anyone's interested, based on Grim Reaper's question of basic emissions tune ups, I checked things out a little more thoroughly with the ole scanmaster on the weekend. IAC was @ 00 !!!
Resetting it sent the blm's to around 140 - 150 at idle with the iac at around 20. I guess I'll be looking for an exhaust leak this week.
Thanks for the suggestions.
N