EGR valve/code

[jd87sep]

I know I've posted something along these lines before, but i doubt anyone will read the old topics. I have a '92 RS. A while back I couldn't pass emissions because of EGR problems. Well I did the first time I went, but my car overheated on the dyno because my fan went out. Ever since then I've had an EGR code annoyance. The egr valve is good, because the diaphram holds and doesn't go back to place. When doing a test once, I got someone to rev the engine and I felt the vacuum line leading to the EGR. When the car was under high load(when i was accelerating) the line had suction, but as soon as I held the throttle at a contstant rpm, there was no longer suction. I have yet to test voltages, because im just hoping its not ecm related. If anyone has any suggestions or ideas, it would be great.


P.S.- I know I often ask for help, but fail to return any. I am new to cars and actually working on them. But after enough fixing I might have my two cents worth of knowledge to give.

[Morley]

T in a vacuum gauge in the line from the EGR solenoid to the valve, tape the gauge to the windshield and take it out for a drive. When you get to a steady cruise speed, keep an eye on the vacuum gauge and note what it does when the check engine light comes on.
If it gets vacuum and keeps it, you will probably have to remove the intake manifold and throughly clean out the EGR passages.
If it gets vacuum and looses it immediatly, the next step is to put a small digital volt meter on the 2 wires going to the EGR solenoid. Tape the meter to the windshield next to the vacuum gauge. Take someone along with you and repeat the drive. Have them note the voltage when the gauge shows vacuum, and see if it goes to 0 when you loose vacuum.
If you keep the voltage but loose vacuum, your solenoid is bad and not holding open. If you loose voltage and vacuum, there is a problem with either the power wire to the solenoid or the ground. The ground wire should be going to the ECM, this is how the ECM turns things on and off (supply ground and remove it). Figure which wire has the problem and fix it.