Catalyst Problem? I Need Help!

[JyRO]

Howdy!

My 1990 Celica has developed a problem and I can't tell if the problem is the catalyst or if the catalyst problem is a by-product of some other problem.

Since I took over this car from my wife, I've noticed an occasional miss, maybe only once or twice a drive, at lower rpm's as I'm accelerating through the gears. I thought that it may simply be time for new spark plugs. So over this weekend, I had the oil & filter changed, then bought some spark plugs and a new air filter.

Once I put the new plugs in (gapped and torqued correctly) the car did OK, until it got fully warmed up. It kept getting worse during the day Saturday, then I put the old spark plugs back in and it still ran cr@ppy. Later I drove it to the gas station and it barely made it, it only ran on 2 cylinders, and stunk when I got to the gas station. Then I drove it back home (2. 5 miles) and it stunk and smoked when I pulled in the garage.

I got a flashlight and looked under the car at the catalyst to see if it was smoking, and even with the flash light on the catalyst I could see it glowing red. Glowing red is not normal, is it? I wouldn't even think when a car is in proper running condition it would glow red while driving.

Here's my questions:
1) If 2 (of 4) cylinders weren't working, could the unburnt fuel be collecting/burning in the catalyst causing the glowing? Thus the problem is before the catalyst?

2) Or is this typically how a stopped up catalyst will act? Severe loss of power, and stinky, smoking, glowing catalyst. It is the original catalyst with 172,000 miles.

3) Is it possible that the new spark plugs created a hotter burn that accelerated the clog of an already clogging catalyst, and that the missing I was feeling, before the new spark plugs, was the onset of the catalyst clogging?

4) One last monkey to throw in here to confuse the subject. I cranked the car in the garage, and pulled off each spark plug wire at a time (this was before I took it to the gas station when it wouldn't fall out of a tree). While idling in the garage it had a definite miss. Pulling every spark plug wire except the #3 wire, made the miss worse. Is it just a coincidence that at idle the #3 cylinder wasn't firing?

While the spark plug wires were pulled off, I put a 5th spark plug on the pulled wire. All 4 wires with the 5 spark plug in them would arc to something metal while the car was idling/missing.

Now, I'd bet at idle, since the miss is worse, there'd be 2 spark plug wires that could be pulled and the miss wouldn't get worse (I. E. 2 cylinders not firing). But its dark and cold now, so I'll deal with it in the morning. I could sure use some help here. Sorry for the long post and thanks.

- JyRO

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Y2K 2500 Cummins ETC/DEE, SLT+, 4X4, Quad, LB, Intense Blue Sport, 3. 54 LSD, rear aux. springs (camper special), sliding rear window, all options except cab clearance lights including agate leather, totally stock engine, silencer ring removed, "stealth," mod to run fogs with high beam. (20. 8 mpg @ 70 mph) Since everybody else listed their toys, I will too.

2000 Toyota 4Runner SR5 4X4, 5-speed, 3. 4L V6 (25. 5 mpg @ 65 mph)
1995 Kawasaki ZX6-R, 97 H. P. @ Rr tire, 6-speed, . 6L I-4, 410 lbs. wet
- (60+ mpg @ 65 mph, but who can do that?) (For Sale)-[SOLD]
1990 Toyota Celica STX, FWD, 5-speed, 1. 6L I4 (36+ mpg @ 65 mph)
1983 Mazda RX-7 GSL Limited Edition RWD, 5-speed, 1. 1L Wankel (For sale)
No auto trannies in my home! Just say, "No!" to auto trannies.

 

[mbrolin]

Definetly sounds like your on track. The converters will disintegrate on the inside and plug up. This will cause tremendous back pressure and heat buildup

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2001 HO 6spd,Quad cab,LWB,4x4,Flame Red,all options except for leather,Westin Brushguard/Push bar,Painless wiring,Radio Shack CB,my own design CB mount,Smittybuilt nerf bars,NW Custom rocker covers,Custom built stainless rocker light bars,DeeZee bedrails,Isspro pyro and boost gauges,Jacobs ebrake,Reese 20k 5er hitch(more to come)

 

[illflem]

Your cat could be clogged, but I'm more concerned with the lack of change when removing the #3 spark plug wire. Unburnt fuel can then make it down to the cat where it burns, heating the cat, if that doesn't happen you have a fuel injection problem. Time to do a compression check, #3 will probably be low, if is squirt some oil down the spark plug hole if the compression then goes up it is a ring/cylinder problem. If the compression doesn't go up it's a valve problem. It could be as simple as a valve that is severely out of adjustment.

If the engine needs a valve job or rebuild it is easier/cheaper to buy a 25,000 mile Jap engine and replace it. I replaced the engine in a Tercel that was doing much the same thing, the Jap engine was $475 delivered to my door with a one year warranty. It was totally complete, even had the power steering pump, alternator and box with new oil filter, belts and gasket set. I've replaced many Jap engines( Honda, Toyota, Nissan) with these low mile engines, Toyota is easiest, the only special tool you need is a hoist, which can be rented. The whole switch requires no special knowledge. The replacement takes about 5 hours, a little more with AC, but the AC system stays intact. Hardest part is unplugging electrical connecters, they can be a buggier. Every engine has started on the first crank and run perfect, haven't even changed the plugs or even had to adjust the idle. Good idea to replace the clutch/pressure plate/throw out bearing at the same time. Good luck-Bill

 

[Doc Tinker]

I'm not sure what kind of ignition system that year Toyota uses, but I suspect that you have a bad coil to one of your plugs.

The new distributorless ignition systems (DIS) use coil packs that run one or two cyclinders.

A miss in the engine increases the temperature of the catalist since unburned fuel reaches the cat and burns there. The cat is just doing it's job and functioning as intended.


Doc




[This message has been edited by Doc Tinker (edited 04-01-2001). ]

 

[Tom W]

Illflem, where did you get the engine?

Thanks, Tom

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Tom W in Austin Tx 98 24v 2500 Quadcab, auto, 3. 54, lsd, Rhino, white/driftwood, Banks Stinger Plus, 275 injectors, Manix grill, nerf bars , DTT's TC, valvebody, cooler, Smartbox, Mag-hytec trans & diff, Pac brake, Bilsteins.

 

[Champane Flight]

JR, I would definitly dump the cat for a new one. It is most likely clogged. Your #3 cylinder is probably a little weak. This cylinder would be the first to fail if back pressure is increased(from shall we say clogged converter or potato up the exhaust). I would say get a new cat(if you live in comunist area). If you don't send the cat to the trash can,replace it with a section of straight pipe,pour a can of fuel injector cleaner in her and drive it out.

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95 Dodge 2500 Luverne grill guard,headache rack,running boards and Amzoiled. Soon to be mildly bombed. 84 Dodge d-150, 318 Hooker headers,Edelbrok intake,mallory ignition,Carter Afb,Accel coil,and Custom dual exhaust. Boat,fifthwheel,motorcycles,and shop. 72000 as of 3/1/01,not even broke in yet. Old Dodge 126000 miles and running better than new.

 

[illflem]

Tom, I've been getting Jap engines from an outfit in Coeur d' Alene, Idaho called Foreign Engines 800-552-1559. They are part of a larger importer based out of Seattle, I wouldn't doubt if they are nationwide. They've always had the best prices, engines are steam cleaned, clear coated, have a computer compression check attached and are guaranteed to have 25k or less on them.

The story I've heard is that in Japan, being so small, it takes most people quite some time to put on 25k. After the engine has 25k the registration fees go up so much that it is cheaper to replace the engine with a new one. Quite a deal for us since most Jap engines are good for at least 150k. I have found it is cheaper and easier to replace the engine yourself than it is for a mechanic to just replace the timing belt, something that needs to be done on most Jap engines before 100k.

[This message has been edited by illflem (edited 04-01-2001). ]

 

[JyRO]

Champane Flight - That was my thinking. I was thinking maybe the #3 cylinder was getting, "picked on," by the clogging cat. Now when I go outside and crank it, it's only running/idling on 2 cylinders. It's pathetic.

Everybody - I like the thought of the new motor, but if it is indeed the cat, surely I can replace or do away with it for cheap.

How could I talk someone into straight piping it? Does anyone know anyone in the southern area of Michigan who might be willing to help me out. I don't have the equipment to do this job. Have any of you guys pulled your cat (on your truck), if you had one from the factory?

 

[Shovelhead]

Jyro
I have seen two different vehicles doing this due to a defective distributor cap. Carbon tracking in the old cap combined with moisture in the air creating a serious missfire and related heating of the cat due to unburned fuel accumulating in the converter. (which has an operating temp of approx 1000 deg. ) You can remove disconnect the cat temporarily and try to see if the cat is clogged. (will it run/rev normally?)Also would recommend checking the oxygen sensor in the exhaust tract cuz raw gas tends to wipe them out pretty quickly. (Man I sure miss the old points distributor & carburated engines!)

[This message has been edited by Shovelhead (edited 04-01-2001). ]

 

[Doc Tinker]

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