b1ackhawk

Ok, so i just completed timing belt and waterpump on my sc400 and those 2 things seem to be fine. However, a couple things have popped up, at idle, the engine seems to run a little rough. When i give it a little gas, sometimes it stumble a bit at first, but when the rpm's are up a little you can't notice the roughness. The other thing is that i noticed that my drivers side cat it glowing red hot! the pass side cat does not look like its red hot. Trying to figure out if theres a connection between the two. like poor spark in one of the cylinders allowing unburnt fuel to get to the cat causing the cat to burn hot???
I don't know hopefully someone who knows more than me has some ideas.

O. L. T.

iTrader: (17)

obviously raw fuel and obviously the rough idle. Check your harness's and connections.

Enigma8246

one thing that can cause cats to get hot is if they are clogged. Check the pipe upstream and downstream. If it is hotter upstream than down, it may be clogged.

I don't know if a clogged cat would generate enough backpressure to cause rough idle but its one thing to look into

O. L. T.

iTrader: (17)

The cat didn't clog while the engine WASN'T running. The problem is a result of the actions taken, so look over the actions taken and check everything in that area for connection. He's missing because he isn't firing on that bank and raw fuel is in the cat.

b1ackhawk

thanks for the quick responses guy's, i wont be able to work on it until tomorrow, but i did notice that the pipe after the cat was getting red hot as well. So i am confident the cat is not clogged. I hope nothing has gotten damaged.

b1ackhawk

ok, found the wire causing the problem. However, even though the driver side cat doesnt heat up nearly as fast, eventually, both cats do get red hot, including a little of the piping after the cats...

I just attempted to take a test drive and definately something isnt right, while it runs, there is a serious lack of power. Im thinking possibly timing issue with the new belt on, things not lined up. but i gave it a few revolutions before reassembling and everything looked dead on....

CuLayTur

iTrader: (1)

I had the same problem after I did the timing belt and water pump on my 400.... Turns out that I didn't get all the plug wires into the holders correctly and the cam gear cut thru a spark plug wire.... Once that was replaced it was back to the smooth idle.....

b1ackhawk

pulled everything off... again. everything looks lined up perfectly, cam gear markers, crank gear. I'm scratching my head at the moment. maybe one of my coils is bad? Some coolant got on my L coil.

kanderson

Sorry to say that possibly if raw fuel dumped into the cats then at least one if not both of them could be toast. It melts the honeycomb on the inside of your cat and now it will not allow the exhaust to flow properly. This will cause the back pressure and lack of power that you are describing. I hope I'm wrong but I have seen this before.

b1ackhawk

how long would this take? its was starting to smoke before i figured out the problem....

kanderson

A friend of mine had a plug wire break on the freeway. He drove it for about 5 minutes to work and his cat's were already clogged. It can take just a few miles. Sometimes the material inside the cat will break apart so you can tap on it to see if it rattles or remove the cat to see if the honey comb is melted or broken apart. Not an easy job to remove the cat. The exhaust nuts are usually rusted up. Don't know if that is what is wrong with yours and I really hope I am wrong. Just thought I would pass our past experience on to you. If they were glowing then they got really hot and COULD have melted the insides.

StiCk3

iTrader: (5)

try adjusting the ign. timing? something is misfiring causing the fuel to get dumped into the exhaust and eventually the cat. Rough idle means something is misfiring.

b1ackhawk

rough idle seems to be fixed since fixing the ignition wire.
Still have issue with low power, seems like it could be backpressure in exhaust. need to diagnose that.... if 5 minutes can melt the catalyst, than that probably happened, it was running for prob twice that before i figured out the cat was getting hot, plus running on and off for a while trying to diagnose.

sc-driver

iTrader: (7)

did anyone say the ignition coil? Sounds like it to me.

b1ackhawk

You still think its a coil after resolving the rough idle issue?
I suppose it could be, but i have no reason to believe that the coil is bad really, however, that cat smoking on the other hand, would prompt me to think it might be damaged now.