Service engine soon light

[mountie]

If you have an OBD 1 , The codes work sorta like a house.... Imagine a code, and it shows you a room in the house.... The OBD 1 code tells you what, room in the house, has an issue, but it does not tell you WHAT IN THAT ROOM IS BAD. OBD 1 only shows the area, not the item. ( un like an OBD 2 that is more exact)

My oil pressure gauge jumps a bit.... sets off the CES light...then it turns off. It took me a while to notice that.

 

[DerekTheGreat]

What some other guy said. Unless the diaphragm is leaking on your EGR valve just clean it out. If the plunger is stiff try and massage it. Aftermarket stuff is typically junk so whenever possible I try to recondition OEM parts.

My firebird once set code 32. EGR valve was fine, however the passages inside the intake were all gooed up so be sure to have a peek-a-loo at the intake once/if it ends up being EGR related and the valve comes off.

 

[someotherguy]

I did a write-up years ago on troubleshooting negative backpressure EGR's on these trucks which is what a lot of the TBI V8 trucks came with, the article also helps determine if that's what you have. It's not 100% but it will get you most of the way down the road on this issue. Again IF what you have is a code 32: http://www.chevytalk.org/fusionbb/showtopic.php?tid/258416

Richard

 

[Eveready]

Great article. I tried to upload a file version but I think it was too large. That one should be a sticky somewhere on here. Kudos to @someotherguy for that one.

 

[94burbk1500]

I said I was going to check this weeks ago, but I got distracted with bigger problems. It was throwing a code 32, which is either egr or map. I took a look at the egr and found that someone had disconnected the vaccuum line from the valve and plugged it with a screw. I pulled the valve, the diapragm seems to be ok. It compresses fine, returns fine and holds vaccuum, so I cleaned it out and put it back in with a new gasket. Then I replaced the vaccuum lines from the valve to the solenoid and from the solenoid to the tb, went for a test drive and got the same code. Just replaced the solenoid, will update once I take her for a beat down, uh, I mean road test.

 

[90halfton]

That bulb will burn out eventually, don't worry about it.

 

[94burbk1500]

That bulb will burn out eventually, don't worry about it.

Hahaha, if I didn't live in an inspection state I wouldn't. Truck seemed to be running perfectly fine even when the light came on, no signs of pinging

 

[randomguy]

First while the truck is running try compressing the diaphragm by hand. If it stumbles or almost stalls that’s a good thing as it means the passages are not clogged. If the idle doesn’t change then more likely than not the passages are clogged with carbon.

Throw a vacuum gauge between the solenoid and the egr. Drive around with the gauge on the windshield and you should see whether or not the solenoid is activating.

 

[94burbk1500]

First while the truck is running try compressing the diaphragm by hand. If it stumbles or almost stalls that’s a good thing as it means the passages are not clogged. If the idle doesn’t change then more likely than not the passages are clogged with carbon.

Throw a vacuum gauge between the solenoid and the egr. Drive around with the gauge on the windshield and you should see whether or not the solenoid is activating.

I'm about to hit the road to see if the code comes back, it was coming on pretty reliably after a few minutes at highway speeds. If it does, I'll give that a try. Thanks!

 

[94burbk1500]

The egr valve is definitely bad, I didn't even make it half a block before I turned around. It runs ok at idle or even revved up a little while in park, drive is a totally different story. It stumbles and wants to die, almost like it is missing. I played around with the throttle a bit for the hell of it and it seemed to run better if I revved the **** out of it. That explains why the line was capped.