Replaced EGR valve and engine light still comes on

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95 chev Lumina w/170k. Took it to my mechanic and he put it on the computer and it indicated the EGR valve is bad. My check engine light would come on like once every few weeks and stay on for a couple minutes. So, I purchased the 160.00 EGR valvge and installed it, but my check engine light is still acting the same. Engine is running smooth and quiet. Idle is smooth as well. Any other ideas what it could be? Could it still be exhaust related but something else? O2 sensor? I will have it diagnosed, but wondered if any of you experienced this same issue. Thank you all. Really value any insight here.
 
I cant be sure than a GM is the same, but on my 96 Sebring and 07 Caravan I had to actually reset the error code with the scan tool before the light would go off. the instructions with the valve also confirmed that. normally you swap the part and everything is cool..... It's also possible that on an OBD I system it will evenutally clear itself.
 
I had a check engine light on my '99 Buick Century. It said low flow on EGR valve. I decided to just leave it alone until I had to take my car in for state inspections. When I was replacing my head gaskets, I discovered that the EGR passage way was clogged. My advice to you is to remove the EGR valve and spray some carburetor cleaner in the holes. Get some good carburetor cleaner too. That SuperTech stuff sucks.
 
You overpaid for the EGR valve. And just because the code your mechanic pulled out says "Exhaust Gas Recirculation Flow Malfunction" or something of that sort does not = bad egr valve. Read up and educate yourself http://www.obd-codes.com/faq/egr-explained.php Click on the 401/402/403 links as well to see what triggers those codes to be set in the computer.
 
Ok, so when I remove the EGR valve I see the port which is what it sits on top of correct? I should just spray the cleaner right inside those ports? Its not like I can stick a brush in there to clean it. Sorry if I sound ignorant. I've never gotten into this sort of thing with my car before, or any car for that matter.
 
I have faced this problem before. About 10 years ago, I had a 1994 Oldsmobile 3.1 that had a persistent EGR code. Be warned that you may need to buy a new gasket each time you R&R the valve.

1. Clean the EGR passageway. Use a stiff wire and rod out the plenum passageway and the supply tube.

2. Check that the new EGR valve works correctly. I bought two AC Delco units that were both defective. I finally went with a NAPA unit.

3. Check your exhaust backpressure upstream of the catalytic converter. If the cat is partially clogged, the EGR system fails its tests in these cars. I think what happens is that more exhaust than desired gets diverted back to the engine, and the PCM observes a larger-than-expected decrease in engine speed.

In my case, I needed to replace both the valve and the catalytic converter. Diagnosis is a real challenge when two factors contribute to the fault.
 
Just spray some cleaner in the port. If the cleaner doesn't drain, its pretty clogged and you might have to remove the intake manifold to thoroughly clean it out. I'll attach a photo to show you what I'm talking about. I used a clothes hanger to poke that gunk out.

I even found a video about EGR valves. http://youtu.be/XgfT3kuY8lc

My manifold was off because I'm replacing the head gaskets.



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Ok, I'm going remove the EGR valve again and spray some cleaner in there...Is it ok to reinstall the EGR valve and run the motor if the port is stll damp from the cleaner? Just wanted to be sure the EGR valve wont suck up any of that moisture and damage it. SIDE NOTE:: I installed the the valve when the engine was not completely cooled down, so this morning I torked the bolts down just a little bit tighter...I could barely turn them as I had it pretty tight to begin with, but could it not being on tight enough cause it to throw an error code as well?

And thank you all, I'm learning a lot here.
 
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If the port is clogged, just spraying cleaner in there and putting the valve back on probably won't make a difference. As others have mentioned, use something like a piece of coat hanger or heavy wire to make sure your passage is actually clean. I went through this with a Saturn, and had to remove the new valve to clean the intake passage again. I let it soak overnight with a couple ounces of LC20, which doesn't evaporate like throttle body spray.

To verify that your intake passage is plugged, try starting the car with the valve removed. If there is no blockage, it probably won't run because the open port acts like a huge vacuum leak. That will also blow any loose carbon out of the exhaust side. It will be loud.
 
I'll give that a shot..I have a wire coat hanger..that should do it. After I scrape it out, should I take my shop vack to suck on any loose stuff?
 
It's a good idea to use a shop vac if you have one. I used the house vacuum, and it has smelled bad ever since.

I don't know how your intake is set up, but on my Saturn the port was 10 or 12 inches long had a bend between the valve and the opening in the plenum. I didn't realize that at first, so it didn't get cleaned out right.
 
Man...I am scratching my head. So my mechanic looked at my car..hooked up the computer and got the error code that the 3rd bank of the EGR valve is bad. This is with the new EGR on there. So he cleared the computer and told me to come get it, get it out on the road and see if the engine light comes on again. It's only been coming on when I'm giong 60-70mph on the open road so it's not like the engine light goes on and stays on. Do you think that by clearing the computer after I've already installed the new EGR that the light will not come on again once I get up to cruising speed? He said if it does, then it could be a bad circuit and not necesarily the EGR valve. Also, if so, where would the circuit be? can I replace that msyelf?
 
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He's yanking your chain. Clearing the code accomplishes nothing.

He's right that it COULD be a wiring problem. But more likely it's a clogged passage or maybe a cracked tube.
 
WhatEVER!!! I've know this guy for 20 years, and he is also my friend. He would not lie to me and has no reason to. I trust him. He told me what code popped up after I replaced the valve and he told me to take it out tonight and bring it back in the morning if it is still doing it.
 
If your mechanic actually said "3rd bank of the EGR valve", he really meant that you need to change your blinker fluid and align the muffler bearings.

- Vikas
 
The port is not open enough to flow the amount it needs when all three sections of the valve are open a highway cruise. When the EGR valve opens it looks at manifold vacume/pressure change and as the valve opens more it wants to see change and if not flags a code because it doesn't know if the ports clogged or the valve didn't open. If he would look through the Tbody at the EGR port openning he will see a bunch of carbon at the openning. Clean it up with cleaners and wires, pics screwdrivers or what ever till it's clean and the problem will go away. This is fairly common on high mileage engines.
 
Originally Posted By: Vikas
If your mechanic actually said "3rd bank of the EGR valve", he really meant that you need to change your blinker fluid and align the muffler bearings.

- Vikas


I know it sounds odd, but lots of these GM 3100 engines came with a 3-solenoid EGR valve. The ECM opens one, two, or three little valves depending on what kind of flow it wants. That's what he's talking about.
 
Yes, this is in fact a 3-bank EGR valve.

The defective AC Delco units that I bought were both missing the threadlocking adhesive on one adjustment screw. They quickly adjusted themselves to an extreme (open or closed, I don't know) and set the code.

Double-check that this hasn't happened on your new replacement. The adjusting screws are on the top of each "tower"; if one appears to turn freely, the unit was assembled incorrectly.
 
DPFE ?? Differential Pressure Fuel EGR. This checks the exhaust pressure change. I replaced it on my 2000 Taurus and it cleared the codes. EGR valve and DPFE cost me about $45 each. The code doesn't mean it's that part. You need to do further diagnostics. Look up DPFE for your care at Advance Auto or Rock Auto. It was easy to replace for my car. Good luck.
 
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