'92 Code 71 ?? EGR.? (1 Viewer)

[Scota4570]

How do I troubleshoot the individual parts? The repair manual gives possibilities but I do not see information on how to test the possible malfunctioning components. I do not want to throw random parts at it. I would think there might be a diagnostics and trouble shooting flow chart out there.

I have tested the EGR gas temp sensor. It measures 0.28 megs cold and drops when warmed.
The EGR vacuum modulator checked out previously with a hand vacuum pump.
The VSV for ERG was previously replaced
The hoses are all good or have been replaced
? The EGR valve has some rust visible in the tubes. How do I properly test the EGR valve? When I put a hose on it and suck the engine stumbles. Engine off, if I suck, put my tongue over the hose, it holds vacuum. I can hear parts move inside.

My local dealer had made it plain that they do not want to work on this truck. My local private shops are not interested and/or not competent.

Any ideas?

Thanks,
Scot

 

[Malleus]

The inspection procedures are in the FSM:

The entire Emissions Control section is attached.

 

[Scota4570]

I went through that chart. Page EC-17, the VSV for all does not work as described.

Eureka, the VSV for ALL valve is bad. That was too easy. Many thanks.

The problem now is where to get one. The part is discontinued. 25860-61020
Is there a substitute?