wlw-19958

Hi There,

I agree that the fuel pressure looks correct (at least as far as I've tested).

Yes, the system was in closed loop (or as my scanner displays Loop Status: Closed).

HO2S's were showing typical rapid up-down voltage fluctuations.

I ran a few more scans trying to capture the problem when trying to
maintain a steady throttle position (hard to do when the car bucks like
it does). One funny thing I see is when I slowly advance the throttle,
I see the Mass Air Flow slowly increase, The Manifold Absolute Pressure
slowly increase (like they should) but the RPM's go down and then start
to increase (bogging down).

I also noticed that the Spark Advance curve is roughly the inverse of the
Throttle Position, Manifold Absolute Pressure, Mass Air Flow curves (i.e. spark
advance declines as the others incline).

Is this any help?

Good Luck!
-Blue Chips-
Webb

wlw-19958

Hi There,

I know it has been a long time and I haven't been keeping up
with the progress.

I just wanted to let you know that I did finally figure out the issue
with my son's Camaro. It turned out to be the catalytic converter
had become blocked at the inlet (where you can't see into it). The
exit was clean and looked normal.

I discovered it when I removed the "wye" pipe assembly and noticed
a rattle inside it. I turned it so the inputs were down and some pieces
of the catalyst came out (along with some dust). So, I figured the pieces
have been vibrating against each other and making this dust and it was
plugging the honeycomb passages in the rest of the "cat." So, I took a
long chisel and broke out the rest of the honeycomb so the cat is now
a resonator. This was done as a "quick check" to see if this had any effect
on the problem. I re-attached the wye-pipe with disabled cat and "Nirvana!"
The old girl ran like new. I have since replaced it with a Walker wye-pipe with
cat.

This happened shortly after my last post. Unfortunately, I have suffered
a series of catastrophes that have consumed my time (like my house burning
down, my mother being diagnosed with cancer and dying and then my sister
dying of cancer too). So, my mind has been consumed by other thoughts
and I just forgot to post my results. Please forgive me.

Anyway, I figured that I would let you know that the problem is solved
and you now know what the answer was.

Thanks for all the help and,

Good Luck!
-Blue Chips-
Webb

flht99b

Sorry to hear about your family losses and loss of your home. As a new member to this forum I had read your posts as I am interested in troubleshooting these cars and had wondered what the outcome was. I've seen other cases with similar drivability issues turn out to have clogged cats requiring replacement. Glad to hear you were able to fix the Camaro and hope all is back to normal with you life. Thanks for your update.