My problems: bad mileage, irratic idle, and worst of all shotty performance. These symptoms have plagued my roc for some time now and cost me lots of money. Well, after running around the block a few times, I am starting to question the condition of my egr system again. A while back I did get an egr code form the computer, but nothing recently. I figure the valve might not be closeing all the way(?) and introducing eg when it shouldn't. Does anyone know how to check this systems operation? I read a post a while back that had a long list of things to check for proper egr function, but of course I can't find it again by searchingwhen I need it. Does anyone remember this post and know where it is ??? I would also love some other ideas you guys come up with on what else could be making my car drive like poop . Skip the thougths of dirty injectors, malfunctioning sensors, clogged IAC passages, and every thing you could think to replace and/or check on a tune-up(these are things I have already checked or replaced).

Thanks for any posts gentlemen!

:hail:

 

Dustin,

An inoperative EGR may cause poorer fuel mileage, but shouldn't cause poor idle or performance.

If the EGR valve happens to be stuck OPEN, however, you could have all those issues. Unfortunately, with the TPI system layout the EGR valve is inconveniently located directly beneath the plenum, making access difficult.



If you can somehow access the valve diaphragm through the underside of the valve, you could try to manually actuate it open and closed to see if it moves smoothly or "hangs" when it returns. This could indicate carbon buildup in the valve pintle or base, holding the valve open slightly and creating an internal vacuum leak. If this is the case, you'll be removing the plenum to repair it.

Another thing to check is the vacuum source to the EGR valve. There should be no vacuum at the valve in the idle position. You can check with a vacuum tester or unplug the EGR valve line from the EGR solenoid and cap the fitting and test drive it.

If you do have a vacuum gauge, what is the vacuum at idle?

 

A bad MAF sensor can cause poor driveability. If you haven't seen already, here's a post over on the Tech board with lots of good info from Vader and friend and others.

 

It just so happens my tpi is dismantled right now anyways on account of some spring cleaning and porting. I'll go ahead feel up the egr valve while it's apart. Do you guys really think I'll be able to tell if it isn't completly shuting just by feeling it's action? After I have it back together I am planning on a full vaccum test as described in the formentioned post, thanks kev. Then, if nothing is found, I'm gonna have to break down and do the unthinkable; a leakdown compresion test. Considering how much of a pain in the A it is to do my plugs, I was intentionally saving this test for last. My new engine doesn't seem to burn any oil, so I am not expecting to find any inconsistant readings. Are there any other systems capable of giving me these syptoms? I do have a scan tool and other than a slightly skewed Integrator, all my sensors seem regular. Thanks for the posts fellas, any more thoughts are appreciated.
:hail:

 

Dustin,

As long as the plenum is off, remove the EGR valve and inspect the pintle and seat. You might as well clean out the passages in the intake manifold while you're at it. You can use anything you want to clean the intake but avoid solvents on the EGR valve. You should be able to see if the pintle is sealing against the valve seat just by looking, and can watch the valve action as you manually actuate the valve diaphragm.

 

Thanks for all the help Vader, it's really appreciated! Can you expand a little more on your last post. I am a little confused on how to clean these things. My manifold base is still on the engine, do you still recomend cleaning the egr passages? How would I do this, and what do you recomend for the valve itself?

 

You should be able to close the egr by pushing up on the bottom of it. It will cause your car to choke if you had it running. Mine went bad one time and it idled like crap. Because it wasn't doing what it is suppose to. I replaced the egr and the problem went away.
---Justin Myers
Houston. tx.