How can you tell if a converter is going bad?

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  #1  
Old 05-14-06, 06:55 AM
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How can you tell if a converter is going bad?

I have a 1994 Chevy 4x4 pickup, 4.3 motor. My gas mileage is really getting bad and the truck seems to have lack of power. The converter on this truck is still factory installed, never been changed. Is there anyway of telling if the converter is getting plugged? This converter is welded right to the cross-over pipe, and I don't really want to spend $250.00 on a new one if this isn't my problem.
 
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Old 05-14-06, 07:31 AM
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I'd start looking somewhere else
The converter could get plugged, but usually takes another problem to cause the converter to fail
Ex: Running too rich, over heating, etc...

First thing I'd do is a full tune-up including all filters just as a good starting point
And check the computer for any codes

Then if the oxygen sensors are original, or have over 60 thousand miles on them, I'd replace those
 
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Old 05-14-06, 12:16 PM
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What are u calling bad fuel mileage?I'd expect 13-17 mpg.
 
  #4  
Old 05-14-06, 12:27 PM
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How many miles are on your truck? A bad convertor will cause loss of power but you should rule everything else out first.
 
  #5  
Old 05-14-06, 01:15 PM
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To see if you have slipage you need an rpm gauge. Does your truck have one? You can calculate your speedo with the tire size and gears you have at a certain speed. If the RPM is higher than calculated then it is slipping.
 
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Old 05-14-06, 03:19 PM
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Originally Posted by chevydrivin
....you need an rpm gauge. Does your truck have one?
A tachometer?...in case someone doesn't know what an rpm gauge is?
 
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Old 05-14-06, 03:24 PM
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Originally Posted by bigguy05641
What are u calling bad fuel mileage?I'd expect 13-17 mpg.
What does the 4.3 convert to in cubes? I had a chev 79 305 and got (9.5 city/highway even mix; 12.5 summer)...pulling exactly 6000 pounds gross weight with all my tools/supplies under the topper in the 1/2 ton auto 2WD pickup. I was thinking of resurrecting that truck. With the gas prices today?; forget it!
 

Last edited by DaVeBoy; 05-15-06 at 05:28 PM.
  #8  
Old 05-14-06, 04:57 PM
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Originally Posted by chevydrivin
To see if you have slipage you need an rpm gauge.
Unless mistaken I believe grantiman is refferring to a catylic convertor and not a torque convertor.
 
  #9  
Old 05-14-06, 05:09 PM
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Originally Posted by marksr
Unless mistaken I believe grantiman is refferring to a catylic convertor and not a torque convertor.
As it is "is welded right to the cross-over pipe" that's what I assumed
 
  #10  
Old 05-14-06, 05:22 PM
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"My bad". I am not all there since yesterday. been working 3 to 4 hours up and asleep for 2 hours for the last two days (i think) I read to fast and thought he was refering to the transmission slipping.
 
  #11  
Old 05-16-06, 04:26 PM
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Just gave it a tune up, motor runs smooth, it just seems to have a lack of power. It seems like you always have a tail drag, something holding you back. If your driving it when it's a little windy out, you have to hold the gas down almost half way just to get it going at 45-50 mph. Heading into the wind it never wants to shift into overdrive, it wants to stay in 3rd gear. You give it the gas, the motor seems to want to take the gas, but it feels like something it holding the truck back. Its not like the transmission is slipping or over reving. It feels like your always towing something heavy behind you.
 
  #12  
Old 05-17-06, 02:40 AM
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about any exhuast shop can put a small hole in the pipe before the convertor and measure exhuast back pressure and determine if its excessive usually only takes about 10 minutes for them to check and some places will do it for free or for a very small fee would probably suggest you see an exhuast shop to see if it is your problem.
 
  #13  
Old 09-06-06, 12:35 AM
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Stall Test

pull in drive put foot on brake . run rpm up to 1500 to 1800 rpm . if the rpm fall short 0f 15 to 18 . torque conv . bad.
 
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