EGR valve problem

[Chevys_n_Hawgs]

Good evening, gentlemen.

I have a 93 Chevy Silverado. 5.7 engine. I've been getting a check engine light for some time. It doesn't come on all the time, and when it does, it usually goes out after a while. So, I wheeled into Autozone to let them check it out for me. The came back with a code, that said the EGR valve is bad. Anyways, I took the EGR valve off the engine, scraped the carbon out from inside it, and douched it out with carb cleaner. I also cleaned the vacuum lines out good. I put the valve back on, and now the truck REALLY acts up. The light comes on immediately. The idle jumps up and down, and it just has a different "feel" when I drive it. So, what happened? Did I plug up the EGR valve even more? Did I give it the knock-out punch by cleaning it? Thanks

Larry

 

[jetmech1]

Sounds like it's either stuck open or drawing air and leaning out to me. Also, double check your vacuum. EGR should only be open at cruising speeds. If your getting vacuum at the EGR where it's opening the valve at idle, you've got a problem in the vacuum control.

Oreilly's sells an EGR block off plate. It's a Mr. Gasket Part# 7631. $10.00. Put that on with new gaskets and you'll completely eliminate any further EGR issues or at least eliminate that issue for diagnostic purposes.

 

[brelandt]

When I was having issues on my 91 Sidekick I tried cleaning that hard carbon out. I was never successful at it. There is just too much of it to get out. The intake was baked in that stuff.
My guess is that you really didn't get "everything" out. I ended up buying a new EGR and spent 2 days removing the carbon on the intake side and resetting the idle and timing afterwards.

 

[cchase]

Can you move the EGR valve manually? That's usually the test on these trucks? You should be able to (while it's installed) stick a hand there and push it, then it should return back on its own.