Mechanics

CATALYTIC CONVERTER

2000 Toyota Sienna

Engine Performance problem
2000 Toyota Sienna 6 cyl Two Wheel Drive Automatic 70000 miles

The " check engine" light came up on our minivan. My wife noticed it was running slightly rough that morning and when the light came on, she was right around the corner of a service station we often use. She drove right in. They told her they didn't have the time to check it out right then but it was safe to drive. She drove it home (less than 4 miles) and it stayed in the garage until I took it in two days later for a thorough check. They told me it would take about an hour but it took about 2 and a half hours. I was told it needed a tune up and I scheduled it for the next day. I couldn't wait any longer. It took about half an hour for the mechanic to put it back together and he assured me it was safe to drive. All the way home, it rode horribly rough. It seemed to get worse as it was going on. It was bucking and jumping with acceleration and didn't get above 30-35 mph. At first, I thought it was just cold but half way home, I realized it was getting worse. I called the shop when I got home and the mechanic told me he " didn't put it together completely.&Quot; My wife brought it back the next day and it drove the same way (maybe worse). She and my children also noticed a heavy fuel odor that she told the mechanic about. They did the repairs they talked about but check engine light came back on after a week. I took it to a Toyota dealer and they told me the catalytic converter is fried. I have done a significant amount of research about this and all of the mechanics I talk to are convinced that between the diagnostic appointment and the repair work, the 8 miles of driving in the poor condition caused the damage to the catalytic converter. They have told me the wires were not placed replaced correctly when they did the diagnostic check and the 8 miles we drove allowed unburned fuel to be dumped into the catalytic converter and that most likely caused the failure. When I told this to the service station, the told me the Electric Control Module would prevent any such damage. Toyota says it will handle minor amounts of fuel but that the driving condition I described would not be prevented from causing damage. Can you help in sorting this out?
Avatar
Bob4994
April 1, 2009.



Ok Toyota is correct. The cat was probably the problem in the first place and by not putting the plug wires on right it made it worse by far. If you told the shop that the warmer it got the worse it got that is the first thing to check and it isn't hard to do. I use to remove the upstream O2 sensor and drive it and if it ran better then the exhaust is pluged. Now as Toyota told you the computer will help with minor amounts of unburned fuel but not to the tune of more then one cylinder not firing it just isn't made to do that.

Racefan966
Apr 1, 2009.
I think you misunderstood something. The car only got worse when it warmed up after they did the diagnosis step. Until then, the car was a little rough until it warmed up and then it was fine. In other words, the changes they made when they ran the diagnosis created the situation causing the car to run worse when it was warmed up.

What makes you think the catalytic converter had any damage before they worked on it? Was it the issue of how it ran when it was warmed up?

Thanks again.

Bob

Tiny
Bob4994
Apr 1, 2009.
Ok so what did the mechanic shop do? Did they cross some wires or what? If so then Toyota is correct this will cause the cat to go bad as it can only burn off so much raw fuel. As for you original problem don't know have no history and don't know what the first shop did. If it were in my shop I would have checked it out pull a couple of plugs and checked wires and determined if a tune up was needed or not and then went from there. I also would have done a live scan to see what the sensors were reading at the time of the running problems to have a better idea of what the car was doing when it was cold. I hope this better answers your question.

Racefan966
Apr 2, 2009.
That's the question. What did they do at the diagnostic appointment that caused the car to run so bad and did it cause the damage to the catalytic converter. I'm fairly certain they either crossed wires, as was suggested by one mechanic, or didn't connect the wires correctly in another way.

Tiny
Bob4994
Apr 2, 2009.
So is the car running right now? What did Toyota say that they found? With out this info it just guessing and pointing fingers and that never works. Also carb cleaner sprayed through the throttle body in large amounts can cause problems and so on. With out the info needed it is just guessing. So get back to me about if the car is fixed now?

Racefan966
Apr 2, 2009.