Road tripped to the Dells this past weekend in the Formula (2.8) for the show. After arrival it was found that the EGR vacuum line was disconnected from the EGR. So I hooked it back up. A couple strange things:

There were not really noticable symptoms when the EGR was disconnected, perhaps 100-200 rpm or so higher idle? If anything startups were slightly sluggish after hooking up the vacuum line, when not connected they were perfect.

Freeway mpg was 30.5 on teh way down(disconnected). Mpgs were 27 on the way back (connected) but conditions were rainy and not freeway and AC was on some. So I consider that pretty much equal.

With disconnected vac line on the trip down, a service engine light came on maybe 3 times for about 15 seconds each time, probly 30 minutes between times, always while cruising at speed with cruise on. BUT on the way home when it was hooked up.. the light did the same thing.

When looking at other 2.8s at the Dells show I found that my EGR vacuum nipple is facing the opposite direction than everyone elses. Mine pints at the cruise cannister, as opposed to everyone elses pointing towards the throttle body. Perhaps that put a strain on the line and connector which allowed it to unplug. Strange, but my main wondering is if its normal for the EGR to seem to do almost no effect.

Your problem is probably with the EGR solenoid. If the EGR valve was connected, the EGR tube isn't leaking, the vacuum line from the solenoid to the EGR isn't cracked, and the light still came on with everything connected, take a look at the solenoid. A common failure is the little hose that loops from the vacuum to the electro part of the solenoid. The rubber sleeve tends to rot and leak. Replace the line with a small vinyl hose.

Your EGR valve is an aftermarket valve. The nipples are oriented to mount to later model vehicles that used the same base. Some EGR tops can be rotated to make a better OEM style connection for the vacuum line. EGR will set a code 32 and cause the light to come on then go out, but only at highway speeds. Be sure to check all trouble codes, then clear them by disconnecting the small barrel connector near the battery for about 30 seconds. This will save radio presets but clear the ECM.

A slight loose fit on that vac line will create a code 32. New rubber elbows are probably needed...

quote Originally posted by fierofool: Your problem is probably with the EGR solenoid. If the EGR valve was connected, the EGR tube isn't leaking, the vacuum line from the solenoid to the EGR isn't cracked, and the light still came on with everything connected, take a look at the solenoid. A common failure is the little hose that loops from the vacuum to the electro part of the solenoid. The rubber sleeve tends to rot and leak. Replace the line with a small vinyl hose. Your EGR valve is an aftermarket valve. The nipples are oriented to mount to later model vehicles that used the same base. Some EGR tops can be rotated to make a better OEM style connection for the vacuum line. EGR will set a code 32 and cause the light to come on then go out, but only at highway speeds. Be sure to check all trouble codes, then clear them by disconnecting the small barrel connector near the battery for about 30 seconds. This will save radio presets but clear the ECM.

Thanks, so you would mean that there must be a vacuum leak elseware ("little hose that loops") and that is why there is little difference hooked up vs. not?
What difference should be expected if there were no leaks?

[This message has been edited by 2.5 (edited 06-02-2014).]

Yes, that little loop on the solenoid has a rubber 90 degree end piece which usually holds up pretty well. The other end had a little thin rubber sleeve that doesn't fare well under engine heat and oils. I've used aquarium aerator vinyl hose as a replacement, with good success and life.

It should correct idle speed and no SES light at road speeds. It may improve mpg, but probably not by much. If you have a hand vacuum pump, pull about 5 inches on the hard line from the end of the solenoid that leads to the EGR valve. If you have no leak down, the hardline is good where it runs underneath the manifold.