FC 45

[John T. Martin]

hello,

for what its worth..

93 S/T-10 vin W cpi has a somewhat cronic problem with code 45's system
rich. usually  with slight rough Idle. It has been my experience this is a
CPI problem . When this system was introduced we had  lots of unusual rich
conditions. CPI's use one electrical injector followed by six poppet
nozzles. The poppets are use for distribution, the single injector for
metering. Under a lab condition this was investigated and found a portion of
the injector housing was shifting (we are talking .001"  's here) creating a
larger metering orifice. I can't fully visualize this myself, I've just
replaced more CPI's than I can remember and verified the fix. The new part
#'s have the latest design and are not prone to this failure. I'm not an
engineer, mearly adding my  $.02 and passing on some field experience. Have
also seen several leaky regulators (part of CPI assembly) and lots of
plugged poppets (lean and dead cyl.)

good luck, any specific Q's please E-mail me privately

john
gmman at eskimo.com

-----Original Message-----
From: Matt S Bower <m.s.bower at cummins.com>
To: gmecm <gmecm at efi332.eng.ohio-state.edu>
Date: Thursday, May 20, 1999 5:31 AM
Subject: FC 45


Hey guys,  I could use some advice on this.  I have a 93 s10 blazer with
cpi.  It's setting a fualt 45.  Using the scan tool I am seeing that
when I cruize at highway speeds the O2 sensor voltage will hold at .85
volts and after a couple of minutes it will set the code and kick it out
of closed loop.  It then holds O2 volts at .92 and will stay usually
until I go back to start stop driving at which point the ecm goes back
to closed loop and the O2 sensor starts swinging from .1 to .8 volts.
Any ideas as to what I am not seeing here?

Thanks Matt.