[russ93spirit]

I'm getting an egr fault code on 93 2.5L tbi. Idle is somewhat rough, as usual with this code. However, while idling, if I disconnect either the vacuum line to the egr or the electrical connector to it, the idle gets much worse. This seems to indicate that the egr valve is functioning. I have removed it, cleaned it with carb cleaner and reinstalled with a new gasket, making sure to clean the mating surfaces. There was no buildup of carbon at all, and the car has only been on the road with this setup for a few months anyway.

Any thoughts?
Thanks

 

[Bob Lincoln]

If I remember right, disconnecting the solenoid applies vacuum and opens the valve. Likewise, depending on which hose you unplug (supply or feedback from the diaphragm), it can open further. I suspect it's stuck open and your test made it open further.

Another failure mechanism is that the diaphragm can rupture or tear, causing a vacuum leak, and unplugging the hose causes a bigger vacuum leak. You can pry the black diaphragm disk apart with a screwdriver (the tabs may break) to inspect the diaphragm.

 

[russ93spirit]

Thanks for the reply. I didn't open the diaphragm and risk breaking the tabs at this point, since I don't have a spare.

Today, I had a helper idle the engine for about 70 seconds as per the FSM, then punch the throttle, and I am not seeing movement of the rod in the valve. I do see slight "vibration" type movment, but that's it. I can lift up on the rod with a screwdriver, and idle quality suffers quite a bit.

Is this an indicator of a stuck valve in your opinion? Based on the FSM, I'm thinking it is. I was going to swap out the transducer from my 90 Daytona, but it doesn't have the electrical connector on it, as the 93 does.

 

[Bob Lincoln]

If the transducer diaphragm is torn, the valve stem won't move when it's prompted to. That's probably what happened. And if the diaphragm is ripped, it will create a vacuum leak with the rough idle you're getting.

 

[russ93spirit]

I think it's time to buy a new one...thanks, and I'll update once I get one installed.

 

[chuzz]

Just keep in mind that you can't buy the transducer alone, Russ. The whole thing comes as an assembly at your local auto parts store. Junk yard one may have the same problem. Last one I bought on the 94 Spirit came from Advance Auto Parts and IIRC, was around sixty bucks.

 

[russ93spirit]

Got the entire assembly from Rock Auto for around 20.00 bucks. Installed it earlier this evening, but haven't tested the car yet. Will do a cold startup in the a.m.

I'll update.

 

[chuzz]

Twenty bucks? Wow! I feel violated now. :excited:

 

[Bob Lincoln]

Must have been a closeout. That part was $98 many years ago.

 

[russ93spirit]

Yes, Rock Auto has been running quite a few manufacturer closeouts for our cars. Lots of brake stuff, in particular.

I installed the complete new assembly. Did one startup in 50 degree temps in the morning, and idle seems better, but there is an intermittent stall after startup. I hear the IAC flareup, but the amount of flare seems to be less than normal.