454 TBI lack of power

[legopnuematic]

I'm reasonably sure it its that rear cat causing most of the issues. I've been having a **** drive today where it seems to block up (can hear a lot of exhust trying to escape from a pin hole leak) and then I loose a heap of power and then she overheats. Dosent help when the weather has been hot either. I'm going to cut the cat off when I get home and see how it goes.
On a side note, I cannot figure out how the "egr" does anything as its not hooked up to the exhaust in anyway that I can see

The egr is connected via the intake manifold. In the cylinder heads there are cross over ports that run through the intake, so on a carbureted non egr engine the butterfly valve on the passenger manifold would be closed when cold and idling sending exhaust gasses under the carb to warm it up. So when egr's started to be put on engines they used that cross over in the manifold, so the egr gets exhaust gasses from the intake itself. Lots of times they get plugged up with carbon and other deposits and will stick open or closed and fail to function correctly.

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[Rusty Nail]

Oh overheats too? You didn't mention that previously... sounds like you nay be barking up the right tree, now.

 

[4WDKC]

I'm reasonably sure it its that rear cat causing most of the issues. I've been having a **** drive today where it seems to block up (can hear a lot of exhust trying to escape from a pin hole leak) and then I loose a heap of power and then she overheats. Dosent help when the weather has been hot either. I'm going to cut the cat off when I get home and see how it goes.
On a side note, I cannot figure out how the "egr" does anything as its not hooked up to the exhaust in anyway that I can see

plugged exhaust can cause a gasket leak, an exhaust leak with the egr disconnected can cause the ecm to try to reduce the amount of fuel when it is expecting to see the exhaust gasses. When its not getting the exhaust from egr and a leak allowing fresh air in makes the ecm dump more fuel creating a rich condition that is bad for your already plugged cats.

 

[shanegtr]

Oh overheats too? You didn't mention that previously... sounds like you nay be barking up the right tree, now.

It's not always overheating - it was ok for temps during my run last night when the ambient temps where down. It's mainly during the middle of the day when it's hottest (it is summer here after all)

 

[bucket]

I'm reasonably sure it its that rear cat causing most of the issues. I've been having a **** drive today where it seems to block up (can hear a lot of exhust trying to escape from a pin hole leak) and then I loose a heap of power and then she overheats. Dosent help when the weather has been hot either. I'm going to cut the cat off when I get home and see how it goes.
On a side note, I cannot figure out how the "egr" does anything as its not hooked up to the exhaust in anyway that I can see

Yep, symptoms of a plugged exhaust.

As for the egr, I don't remember the specific codes, but if that one is for "lack of flow", it won't cause any issues with the driveability of a healthy engine.

 

[Snoots]

Yep, symptoms of a plugged exhaust.

X2

 

[shanegtr]

Well got a little a pissed off with the power levels dropping (I've been on a 1500km drive) and stopped at a hardware store in a country town (not many towns to drive through on this trip either) and picked up a new hacksaw:

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Wow, what a difference, the burb is working again, no issues holding speed uphills now . Besides some of the cat internals falling apart the front face is covered in what looks like rust particles. So I've defiantly found the issue. I'll be putting in a straight bit of pipe and turfing the cat completely

 

[carfanatic63]

No cats is the way to go on these old trucks if you can where you live anyways. Nothing like the smell of fresh hydrocarbons in the morning.

 

[Rusty Nail]