[fiater]

Is there a way to test the EGR system (besides pulling the valve)? My 85 Omni turbo keeps pinging, and I am missing a vacuum hose on the transducer(maybe there normally isn't one there?)

I've read of people just removing the system, but doesn't that raise you EGTs and NO2 (don't care about emissions, but EGR systems are supposed to cool the intake charge - possibly why mine is pinging). For those that removed it, how'd it turn out.

thanks

 

[tryingbe]

Are you using 91 octane gas?

 

[dirtyglhturbo]

you will need a vacuum pump/guage to test it. connect the vacuum pump to the egr valve, and while running apply vacuum to it. the engine should stumble and run kinda rough. that will tell you that the valve works, and the internal passages are not clogged. the valve should also hold vacuum and not leak. from there i would verify if the egr is being commanded under load. to do this connect the vacuum guage to the vacuum line side of the egr valve. tape the guage to yer windshield and go for a ride. under load you should see vacuum guage show vacuum. if there is no vacuum being commanded, you will need to verify you vacuum source at the egr sol. really check the connections and condition of every inch of those vacuum lines. mine liked to leak at that joint where they all come together over by the belt side of the engine. you should have found your problem by now, and if not the next step is verifying that the computer is actually commanding the egr sol. to come on. see if this helps ... its basic stuff lemme know if you need more info i can help. dont remove it. you are right by saying that the egr helps lower combustion chamber temps, and that cant be a bad thing

 

[dirtyglhturbo]

oh yea. there should be connection from the transducer to the valve. how else is the egr gonna see vacuum?

 

[fiater]

currently running 91, but it's a few years old. Drained most of it and refilled with fresh, but still a few pings.

I'm pretty sure there is a vacuum line from the transducer to the egr valve, but there is still a nib on the top of the transducer that has nothing on it, but I don't see a loose line that looks like it belongs there. I thought on the vacuum diagram I remember nothing going to it, but not sure. I'll take dirty's advice and just test the whole thing.

 

[dirtyglhturbo]

look at your vacuum diagram. there has to be a egr solonoid if you have a egr.its prolly on the pass shock tower. (i dont have one so i'm not a 100% but i can check for you). it should have a constant vacuum source one one side, and the other side will switch to vacuum when commanded, and that one will connect to the nub on the transducer.

 

[fiater]

Went out today and checked. The line off the bottom of the transducer was disconnected, but I think that happened recently (this line comes from a metal tube connected to the egr's flange). According to the diagram under the hood, two lines (one on the transducer, one on the EGR, combine and goes to a check valve, and nothing is connected to the other side of this check valve). That leaves one nib left on the transducer, which is supposed to go to the solenoid on the pass shock tower. Weird thing is, my check valve seems to be connected to the source, and nothing is connected to that transducer nib. It's almost like someone mixed the two up and connected them wrong. I just wanna make sure I get it right. I hate pinging in any engine, but especially this one.