EGR Valve Troubles

I don't have a 1995 Riviera FSM here at the shop. We weren't a Buick dealer in '95. I'm trying to find answers for you. I swear a code "41", in OBD1, is a Cam Sensor code. I'm not clear on what it is for OBD1.5. I thought that the OBD1.5 codes were 4 digit like OBD2 (PXXXX).
Not all shops have the ability to read OBD1.5, as it was a GM specific set-up. I'll try and have some sort of answer by the end of the day. \

Check your EGR wiring in the meantime, or take a stroll back to the shop that diagnosed it for you and start asking questions. They would've (apparently) thrown an EGR valve on there as well.....

Much appreciated Scott. The shop just diagnosed me and they said: Code 41 EGR Valve malfunction. According to google code 41 is related to the cam shaft. So either they are pulling my leg or got their codes and diagnosis mixed up. Everything on the EGR valve looks fine (wiring, piping, valve). I think I'm barking up the wrong tree. Would the cam sensor cause my rough running problem? (sputtering, feeling like it's going to stall out?).

Absolutely. The Cam and Crank Sensors work together so that they know where each other are respectively. The Ignition Module uses both of those signals to supply spark and advance/retard timing. IF one of those signals gets messed up, the car will run like balls. Usually, with a faulty Cam sensor, the car can still run. If the Crank sensor goes bad, it won't run at all.

Again, let me keep looking. Our OBD1.5 compatible scan tool is missing the GM code information for some reason. I have to see what I can dig up on it to be sure.

If it helps at all, Code 41 is definitely a cam sensor malfunction in OBD1...Scott, you are correct in that OBD 1.5 uses Pxxxx codes like OBD2.

Sound like cam sensor to me. Went through the same issues with our Reatta (though it is OBD1).

Ok guys, much appreciated. Either the shop was pulling my leg or they mixed up their codes. Car is running like balls and I smell a hint of gas/exhaust in the engine bay when trouble shooting. Still sound like symptoms of a bad CAM sensor? I'm going to get in there and take a look.

Ok so I called the shop to see if they could confirm the code and they reported it was P0401 EGR Malfunction. So sorry fellas, it was a complete mis communication on there part as they wrote down 41 on my invoice. With this knowledge I am going to get into the throttle body and see if I can clean out any carbon where the exhaust gas shoots back into the intake.

That makes sense. It's a very uncommon occurrence for a 3800 to get carbon buildup in that EGR hole, but certainly possible. The 3400's were EXTREMELY common for that problem.

Just a recap on anyone following this. So the dealer read me the wrong code. I took it back to them and they reshot and gave me the right one (Still an EGR fault code). I told them I replaced the EGR valve and nothing changed in the rough running. They dug deeper at no charge and traced it back to a dead ignition coil. I changed them all out my self at ~$40 a pop at AZ and the car runs smooth now. A couple of hickups here and there but I'm hoping those smooth out. Thanks for the help guys.

I just installed the torque app on my phone and ran the test and got two errors for my car.

One was TID:$07 CID:$0c minimum sensor voltage for test Max: 0 Current 65,491.
The second was TID:$07 CID:$0d minimum sensor voltage for test Max:1 Current 65,532.

There is no service engine light and the car seems to be running fine except for a little lower gas mileage than it used to get. Any ideas?

I did some searching and found the following.  

07 0C No EGR off-idle test, MAF Out of range high
07 0D EGR decel test

What should I look for on my car to fix this or is it something to keep an eye on?

Try a bottle of techron in teh gas (pure techron not the FI cleaner) and after running that tank remove and clean your MAF and the EGR passages where it mounts. Your issue sounds like air flow's not what it could be.

Albertj

albertj wrote:

Try a bottle of techron in teh gas (pure techron not the FI cleaner) and after running that tank remove and clean your MAF and the EGR passages where it mounts.  Your issue sounds like air flow's not what it could be.

Albertj

I ordered the techron and will buy the maf cleaner and give it a shot once it gets here.  What is the proper way to clean the EGR passages?  Spray brake cleaner in it?

If you delete the codes and they do not come back, it could have been a fluke. No SES light indicates less important issues. First time I scanned my car, there were two transmission codes that never came back.

If they do come back, I'd replace the EGR sensor (buy a used one), or just put up with resetting the codes if they do not cause other issues. Best of luck.