| Author |
Message |
phil hooper (Wolftalk)
New member
Username: Wolftalk
Post Number: 26
Registered: 5-2002
| | Posted on Friday, July 19, 2002 - 1:35 am: | |
hey ken,
in the interests of science, I disemboweled the
cat. internally, it was just a hunk of material
kindof like a honeycomb, but the cells were square and pretty small - around the size of a window screen. if you took a bunch of screens and stacked them up to make a pile a few inches thick (keeping the holes lined up to form tubes), that's pretty much what was in there.
they get clogged when crap fills up the tubes. the crap is the stuff peter and erik defined. |
Erik R. Jonsson (Gamester)
New member
Username: Gamester
Post Number: 31
Registered: 3-2002
| | Posted on Friday, July 19, 2002 - 1:13 am: | |
Also, leaded fuel, fuel additives, high oil consumption all attribute to cat clogging. |
'75 308 GT4 (Peter)
Intermediate Member
Username: Peter
Post Number: 1913
Registered: 12-2000
| | Posted on Thursday, July 18, 2002 - 10:14 pm: | |
Ken: "How can a cat get clogged?"
The internal matrix breaking down from heating/cooling cycles, vibrations and corrosion and clogging the passageway.
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Ken Ross (Kdross)
Junior Member
Username: Kdross
Post Number: 84
Registered: 2-2002
| | Posted on Thursday, July 18, 2002 - 9:34 pm: | |
How can a cat get clogged? |
phil hooper (Wolftalk)
New member
Username: Wolftalk
Post Number: 24
Registered: 5-2002
| | Posted on Thursday, July 18, 2002 - 9:00 pm: | |
ok, cancel the rotor concept - it can only go on one way. running out of ideas...
can the digiplexes be swapped? |
phil hooper (Wolftalk)
New member
Username: Wolftalk
Post Number: 22
Registered: 5-2002
| | Posted on Thursday, July 18, 2002 - 8:02 pm: | |
hi ed,
no good (but the car does now have a very free flowing cat :-))
suppose I did the stupid and put the rotor on wrong (give me a 50-50 chance, and I'm doomed. considering I thought I paid attention, I should have a 95% chance of having it right....but I seem to have a certain talent in overcoming those kinds of odds).
so what's the easiest way to verify the rotor position - the pm1-4 mark on the flywheel? pull a plug and turn engine until piston at top (50-50% chance of being on compression stroke, so maybe that's a bad idea)? compare against front bank rotor position?
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Edward Gault (Irfgt)
Intermediate Member
Username: Irfgt
Post Number: 1583
Registered: 2-2001
| | Posted on Thursday, July 18, 2002 - 5:48 am: | |
Your cat is definately clogged. Trust me. |
phil hooper (Wolftalk)
New member
Username: Wolftalk
Post Number: 21
Registered: 5-2002
| | Posted on Thursday, July 18, 2002 - 12:55 am: | |
tedious description of events follow....
I decided to plug an annoying oil leak around the rear bank cam cover, and while the smog pump was out of the way, fix the egr valve which was stuck closed. (CA emissions does like this).
I was in a hurry to get the thing reassembled since I had an appt. at an a/c shop to get it charged, and didn't clean out the egr valve as well as I could have. oh yeah, I had also just replaced the a/c lines, so the gas tank was out and in.
put it all back together, got it to the a/c shop (probably never exceeding 70mph, since it was 40 mph zones pretty much the whole way :-)) and didn't notice anything amiss. had the oil changed while it was there.
hopped onto the highway and at some point the engine stumbled - tach dropped in half and bounced back up, and engine ran horribly. it recovered and was fine, then did it again a couple miles later - tach fluctuated wildly. I was low on fuel, so I thought maybe I had sloshed the gas into the other tank and starved the pump. again it recovered, and I continued on. started running rough again just as I pulled into a golf course, so I hopped out and played 18 to let the thing cool down.
got home ok, and started looking. the egr valve was stuck open. removed it, completely disassembled and cleaned it, and put it back in.
heard a vacuum leak and found a split hose between the plenum and the electrovalve over by the oil filter. replace the vacuum lime (honda dealers have metric vacuum hose).
still a lack of power and throttle response. pulled the distributor cap again and checked plug wires. 3 bad, so replaced them temporarily with standard 7mm carbon core bulk wire (have an electromotive system from nick ordered). can now get up to 120mph@6K rpm, but it's still sluggish. I'm sure front bank wires are bad.
anyway, the main issue (finally)...the rear bank exhaust is glowing red. after poking around on the site, seems like ignition problems or exhaust. pulled the plugs - dry, sooty around the base of the threads, and tan/brown on the rest. plugs were changed less than 5K miles ago during a major service. plugs on front bank look the same. swapped coils, rear bank still glowing (all of it).
decided to look at exhaust. discovered that the thermal sensors had been removed from the cats and the holes for them welded shut. took off the cat for the rear bank, but it has a u-shaped pipe on the header end so can't look through it. blew some compressed air through, then blew air in opposite direction, then back in forward direction again. seems like flowed a better after the reverse step.
so I'm now staring a the cat wondering if it's partially blocked, plus I'd like to reconnect the sensors to both of them. I haven't looked at the sensor fitting yet, but I vaguely recall that it
wants to screw on.
at this point, what's the opinions on the exhaust vs. ignition, and can someone suggest a way to test the cat? also, any ideas on reconnecting the sensors (the original fittings are just globs of weld now).
thanks,
phil
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