Guys,
I've got two service manuals at home with two different lists of codes.
Evidently the meanings changed at some point. I will try to type it all in this
weekend. Here's what I have discovered after owning a '91 505 Turbo SW8 for
2-1/2 years:
o When I first owned it the light would occassionally flicker when driven hard
as the owner's manual suggests. However, I found out several months later that
the thing could knock loudly and the light would not even flicker. Go figure.
o About a year ago it started flashing four and two at me practically every
time I started it. It would do it as soon as I started the engine, before the
engine even exceeded idle speed. This caused me to dismiss the explanations of
code four and code two in both manuals. Both code lists indicated that 2s and
4s were knock related or knock sensor problems. At idle after a cold start? No
way.
o I discovered the that shutting it off and restarting at the fist stop sign or
traffic light would clear the light. This usually kept it off until the next
cold start but sometimes it would come back on again.
o Once it begins flashing it will stay lit during accelleration or steady
cruise. It will only flash at idle.
o I did not notice any performance or drivability problems at first when the
light was on or flashing. Several folks suggested I disconnect it. Eventually
I discovered that I was not receiving full boost when the light was on.
o Eventually I discovered that my idle speed was too slow and that speeding up
the idle slightly prevented the light from ever coming on at all!
Mind you, I could not get the idle up to the 950 RPM or whatever it's supposed
to be with that silly little screw on the side of the manifold and the throttle
closed switch adjustment screw is not supposed to be used for adjusting curb
idle. Eventually I took the throttle housing off and drilled out the
anti-tamper plug and opened the real throttle stop further. I don't think I was
able to do it precisely by the book. I'm pretty sure my throttle is open wider
at idle than the procedure says it should be. But everything else checked out
okay and it was the only solution.
Idle speed is mostly okay now except that it is still occassionally
inconsistent. Sometimes it idles dead on. Other times it races. When the AC
is on it runs too slow. It's not the AC idle solenoid either because I replaced
that. I attribute it all to poor design, inadequate testing, etc. In other
words, the usual Peugeot story.
For what it's worth I will add a couple of other observations about the yellow
light. Under some conditions when it comes on performance and drivability will
be severely affected. When I disconnected my knock sensor, for example, the car
would begin to accellerate normally and then just kind of die. Apparantly the
control box expects to hear something from the knock sensor just before the
first shift and it puts the motor in a limp home mode if it determines the
sensor is gone. I had a similar experience once or twice when the ignition
wires and distributor cap got wet. Shutting it off and restarting solves that.
Hope this helps. I suspect this is a very common problem.
Don Nordenholt