Hey Guy,
I have a problem with our RX7 and I hope you might shed some insight.
About August 1998 I replace the precat as I found it to be collapsed.
Everything has been fine except in retrospect we may have been burning oil at
a rate of 1/2 quart in about 3-4 events and 180 street miles. At an event in
November, Beth was by herself and 1/2 way through a course the car started
running rough and putting out a lot of smoke. She brought it over to the
trailer and it stalled. She started it and kept it running for 5-6 minutes
while some people tried to figure out the problem. I started on the trailer
for 30 seconds to see what was up when she got home. The problem was the hose
to the boost sensor on the driver side of the firewall had blown off. We put
it back on and have run another event. The car didn't feel quite as fast and
was not pulling the same numbers on our boost gauge. I thought maybe another
hose had blown off or was leaking so I went and replaced all the hose with new
that I could find (20 feet or so). The car transitions from 1st to 2nd turbo
smoother but still is not pulling the same boost as it used too, and when we
got back from testing the precat (even after cool down and after a long idle)
was glowing a bright orange. I noticed a lot of oil in the intake when I
changed the hoses. Also some oil into the aircleaner assembly. There is oil
leaking off of both turbo, but it may be from the oil feed attachment seals.
When we start the car cold it seemed to smoke (oil type) a lot more than I'm
used to seeing (large cloud). I took off the precat and from the front does
not appear collapsed or melted (honeycone intact). It did shed a small pile
of grey dusty and slight formed material that I can see coloring the front
side of the main cat honeycone mesh. Also, the front part of the precat
manifold area seems to have a black 1-2 millimeter thick coating (maybe burnt
oil as it is irregular in texture and not the smooth powdery carbon black). I
have taken off the turbo assemblies. The turbo shaftes seem to have a bit of
side to side play in them. Nothing else looks out of the ordinary, but this
is the first time for me to see this stuff.
The car has 55,000 miles
The questions I have:
1. Do you think that the problem with the catalytic was caused from the
vacuum hose popping off for a short time and a rich mixture sent into the
catalytic or are the turbos worn out and sending more oil into the combustion
chamber and allowing the mixture to burn to hot or clog the catalytic.
2. If the problem is caused from too much oil, will the precat be ok
once a clean mixture is sent back through the system or is it trashed. (It
only has maybe 200 miles on it).
3. Would you rebuild the turbos or buy a new ones$$$$$?
Any help would be greatly appreciated.
Thanks
Erik Strelnieks
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