The roof is leaking and the heat is broke in my garage right now.95 ram 1500 360 4x4

Melted the egr transducer and has loud vacuum sound. The harder I step on the gas, the louder it is and the less power I have. Do you think the Cat could have plugged and caused this? I can't think of any reason why it would melt like that.

 

Replace the little vacuum pot, it shouldn't have exhaust gases anywhere near it, unless the egr valve itself has also failed....

 

That's what's confusing me. What melted it? Hopefully tomorrow I can get it inside and see if exhaust is actually coming out of that hole. I have a new EGR valve and transducer. I didn't think a bad valve would do that, so that's why I wondered about the clogged Cat causing more pressure. I don't want to wreck the new part, LOL.

 

Very good question.... and considering the way the system works, you wouldn't think it would be able to manage that...... Even a clogged cat shouldn't cause that...... If the valve was getting exhaust to it via the vacuum lines, (only connection to the egr valve) you would think the lines would melt first......

 

The bottom port is below the valve. It has exhaust pressure to it all the time. I believe if there is pressure, it over rides the vacuum and opens or closes the EGR valve. I'd have to read the repair manual to see for sure.
That port connects where my transducer is melted.
If I rev the engine, exhaust shoots out of the black hose like air out of a blow nozzle. That's the line from the base of the EGR.
I believe I'm really lucky it didn't melt other lines or wires once it melted the transducer. I have to inspect it closer yet, but haven't seen anything else melted yet.

I'm pretty sure the Cat is plugged. What else would cause this much pressure in the exhaust?

 

May just be a bad egr valve, that then took out the plasticy part.

 

that is wild!

 

The EGR valve control also contains an internal
pressure-type transducer (Fig. 18). This transducer
portion of the valve control is operated by exhaust
back-pressure from the EGR valve. Exhaust is delivered
to the EGR valve through the metal EGR tube
(Figs. 19 or 20). This connects it to the rear of the
right exhaust manifold. A rubber hose connects the
back-pressure fitting on the EGR valve to the backpressure
fitting on the valve control (Fig. 18).
When the ground signal is removed from the electric
portion of the valve control (solenoid is not energized),
and exhaust gas back-pressure entering the
EGR VALVE VACUUM INLET
CONTROL FITTING FROM
ASSEMBLY ENGINE
EGR VALVE
BACK-PRESSURE
FITTING J9525-8
Fig. 18 EGR Valve and EGR Valve Control—Typical
Fig. 19 EGR Tube-3.9U5.2U5.9L Engines
EGR valve inlet is high enough, back-pressure is supplied
to the valve control. It then holds the bleed
valve in the transducer closed. This allows engine
vacuum to flow through the EGR valve control to activate
and operate the EGR valve for exhaust gas recirculation.
If back-pressure is not strong enough to
close the bleed valve in the transducer, the valve control
will bleed off engine vacuum preventing EGR
valve operation.
The transducer measures and uses this exhaust
back-pressure signal from the EGR valve to regulate
and provide the correct amount of exhaust gas recirculation
under all conditions.
Exhaust gas recirculation will begin in this order
when:
• The powertrain control module (PCM) determines
that EGR system operation is necessary.
• The electrical portion of the EGR valve control is
not energized (grounded) by the PCM.
• Exhaust back-pressure entering the transducer in
the EGR valve control is strong enough to close its
bleed valve.
• Engine vacuum is passed through the EGR valve
control to the EGR valve.
• The inlet seat (poppet valve) at the bottom of the
EGR valve opens to dilute and recirculate exhaust
gas back into the intake manifold.
For more information, also refer to Open Loop/
Closed Loop Modes of Operation in the Multi-Port
Fuel Injection section of Group 14, Fuel Systems.

 

I don't believe the EGR valve failing would cause the problem. The transducer is designed to operate off normal exhaust back pressure. I removed my Cat and cut the end off. The internal honeycome had come loose and was tipped at almost a 45 degree angle. I should have a new Cat and Cat back exhaust system tomorrow. I installed the new EGR valve and transducer today. I'm going to get a new NTK O2 sensor also. I should be in good shape once the exhaust flows again. LOL

 

The piece in front of the old muffler with the hangers was supposed to be reused on the front of the new exhaust. Silly me assumed a cat back system would include everything behind the cat. So imI waiting for a new one because I cut long slots in it with a die grinder to make removal easy. LOL.