Posted: 12/20/2004 1:12:12 PM EDT
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Okay guys. What's the best way to tell if my catalytic converter is plugged on my truck? Symptoms are a serious lack of power, really rough idle. If I stomp on the gas it seems like it's choking out and it won't rev. Refuses to go over fifteen mph. Advice? |
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Checked the fuel filter? Does your exhaust smell funny? Like rotten eggs? Go back to the exhaust pipe, where the exhaust exits the system and feel, see if it feels like the exhaust flow is less than normal? I'd check the cheaper items first, then try the converters |
Smell like rotten eggs? How old is the car. New cats are MUCH improved, and I doubt you could damage one without burning 2 stroke fuel. I seriously doubt it's the cat based on your description. Sounds like you have a vaccum leak. I had a '91 Lumina that would lightly reverse backfire when it didn't start properly. This would overpressure the intake and blow out a large vaccum fitting that held 3 separate lines. The result of this is EXACTLY as you describe. I couldn't tell you if the leak itself was the problem, or the computer was registering so many problems, that it didn't know what to do. Either way, the vaccum fitting blowout is what caused it, and reinstalling it was the cure. This wouldn't happen to be a GM 3.1 would it? |
Take it off and do a test drive, if you have the means, replace it with a test pipe, or not. |
Could be a ton of things. Year, Make, and Model? Engine? EFI? Carb? Could be as simple as a warm air riser flapper valve issue to an air cleaner, exhaust heat gate (older smog systems) and a ton of other things. Any other symptoms? |
Sorry to disagree with Driftpunch but my 2001 ford van just had to have both cats replaced. I'll admit I have high mileage on it at 130K but I've never had this kind of crap with a GM. My symptoms were loss of power, and sounds as if marbles were in the exhaust. I know this isn't exactly the problem Desertrider described but cats are not what they used to be |
So far this sounds similar. It sounds exactly like a bunch of marbles rattling under the truck. '93 7.5L F350 gas engine with fuel injection. I'm gonna run outside right now and have the wife crank her up while I sniff her tail pipe. The truck that is. Thanks guys, I'll check in later. |
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Started it up and checked the tail pipe. There's exhaust coming out, but not as much pressure as I'd expect. Definitely running on the rich side as evidenced by the black soot around the tips of both pipes. I slid underneath to listen, and the loud rattling does seem to be coming from the cat. Sounds just like someone through a handfull of ball bearings in there. I had the truck running for a few minutes and the pipes/collector just before the cat was hot, while the single tube exiting the cat was much coller to the touch. Don't know if this is an indication of anything though, as the cat didn't have enough time to reach normal operating temperature. The exhaust does not smell like rotten eggs. I originally thought that the E4OD automatic tranny had taken a dump on me because the truck wouldn't go any faster than 15 mph. I pulled the tranny dip stick and the fluid was neither frothy nor smelled burned. In fact I changed the tranny fluid and fiklter less than 10k miles ago. The truck has 109k miles on it and was running strong up until this incident. I'm thinking maybe I'll remove the cat and have someone at work weld up an adapter for me to mount to the four bolt collector and see how it runs. I noticed that there are two tubes running up to the engine compartment from the cat. I'm assuming these must be emissions lines for something. I sure hope it's the cat and not the damn tranny. |
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You should be able to run with out the cat to check. The tubes are probably pre heat tubes to help bring it up to temp quicker. I would just unhook the exhaust at the collectors/ where they attach to the rest of the exhaust. I would have guessed the truck would have dual exhaust, but if not, you should have a single point that connects up before the cat. If it is a plugged cat, and just exhaust back pressure, just disconnecting it should be enough to verifiy it. There will be a gasket in there so make sure you take that out so you don't lose it. I would think that it might even still be covered as emissions I think are 10 years. |