The titles kind of self explanitory, and the truck's been bogging down a little on take off, so I was wondering how to tell if the convertors are getting clogged?

And what to do about it..


Thanks

 

when mine were clogged the exhaust smelled like something had died in there. also, the engine would not rev up as high as normal because of the restriction in the exhaust. good luck!

 

If the engine is bogged down it could be a clogged convertor, or even a clogged muffler. Also double walled exhaust piping can collapse inside and cause a restriction. The way i usually figure it out is to drop the exhaust before the convertor and drive it with the open exhaust and see if it feels better.

If you want to do it the right way you can test it with a vacuum gauge. Hook the gauge to a manifold vacuum source and hold the engine at high idle (2,000 to 2,500 rpm) If the exhaust is restricted the vacuum will slowly drop as the engine runs. BTW. Normal vacuum should be around 18 in. hg. or higher.

-Jon

 

When my cats. plugged up on my '87, it would slowly drop in top speed. One day, driving down the road, I was doing 110 kmph (65 mph). Then a couple of days later my top speed dropped down to 100 kmph then a couple of days later, it was down to 90 kmph. Eventually before it went into the garage, the truck would accelerate past 2500 rpm, no matter what gear you were in. It was just creating too much back pressure on the motor. Another way is to have some one rev it up to around 2500 rpm and you feel the exhaust if the pressure at the outlet drops off then the cat could be going. BE CAREFUL NOT TO BURN YOURSELF !!!!

Good Luck !!

Have Fun & Keep on Truckin'
Dean

 

mine clogged up . when i was ont he freeway doing bout 75 and punch it to around 90 it would load up and lose power til i got back to about 75 again . after i had it removed and exhaust work done, the problem went away

 

Ford4ever's suggestion of testing with a vacuum gauge is good advice. My suggestions are as follows:

With a vacuum gauge, there are two easy tests you can run to determine if your exhaust is restricted (cats clogged).

First test:
1) Attach vacuum gauge to manifold vacuum source.
2) Observe vacuum at idle.
3) Snap throttle to WOT and release, while watching the gauge.

The vacuum gauge should drop to almost zero when you hit WOT. When the throttle snaps closed immediately after, the vacuum should read 4" to 6" higher than what it did at idle. It should then settle back at the same reading it was at idle before the WOT snap. This whole exchange should go from idle reading to idle reading in 2-3 seconds, tops. If it takes longer for the gauge to return to the same idle reading, your exhaust is restricted. The longer it takes, the worse the restriction.

Second test:
1) Attach vacuum gauge to manifold vacuum source.
2) Warm up engine.
3) Observe vacuum at idle.
4) Leave engine idling for 10 minutes. Do not touch anything on the car during this time. In fact, go inside and fix some coffee.
5) After 10 minutes, observe the vacuum.

If the vacuum is the same or higher, you don't have any resctrictions. If the vacuum gauge has dropped, you do have a restriction. The more it drops, the greater the restriction. If it drops 1" or more, you have a serious restriction. 2" or more and you might as well have the exhaust welded shut. Keep in mind that a rich exhaust will clog up cats in a hurry.

Take care,
-Chris

 

Here's what my 1994 ford f150 4x4 5.0 302 did. The engine all of a sudden didn't rev up past 2500 rpm in any gear, neutral, reverse, park. The way that a previous tread said to check is to see if someone can feel for a difference in pressure at the exhaust tip(s). What i did to check because mine wasso bad was to take the O2 sensor out and started the truck. The exhaust gas came out of the O2 sensor hole fine, so i figured the exhaust must be clogged after the O2 sensor. Plus I was in nneed of changing the O2 sensor anyway(30,000)miles.

 

What's is the manifold vacuum source?