EGR Valve Diagnosis

[markpelly1]

Hello,

I got a code the other day for the EGR valve being faulty, but I want to make sure it is this and not a vacuum line leak.

I removed it the other day and checked out the valve. It moves freely and didnt look terribly dirty. I believe that I can hear the valve opening and closing in 2 second intervals when in the cabin, this is usually when I start the car (50% of the time).

Is it a good or bad thing that it is making a noise? Is there a specific vacuum line I should be checking?


Thanks guys!

[MKMike]

There are a few different EGR codes. Some are triggered by the egr passageways getting clogged inside the manifold or a problem with the metal tubing, etc.
The 200+ code list is here http://www.pontiacbonnevilleclub.com/fo ... c8893.html
The metal tubing that's by the EGR can develop a vacuum leak--often underneath where you can't see it.
Not sure that you could hear the EGR open or close.
If the EGR opened at idle, the engine would run rough.
What is often heard in the car is the air pump for the rear shocks, which should run at startup but not at other times, unless a heavy load is added to the car.

Be sure to also read the Common Problems sticky, here:
http://www.pontiacbonnevilleclub.com/fo ... 25362.html

[markpelly1]

Thanks for the information. I did indeed read through some of those.

The sound is definitely coming from near the firewall. It sounds like a small pneumatic nail gun, not the motor running to get the compressor up to pressure but it sounds like the nail gun itself putting the nail into the material. From right behind the radio section. Maybe it is something else back there or in the engine bay but like you said it might not be the EGR.

Is there something I can do to get the passageways unclogged?

BTW I am getting these two:

P0141 O2 Sensor Heater Circuit Malfunction (Sensor 2)
P0442 Evaporative Emission Control System Leak Detected (small leak)

and on the other end I have one for

P0118 Engine Coolant Temperature Circuit High Input
Which this one we were able to fix for a few weeks, the wiring had corroded or melted in the front part of the engine. But now it is back..

[MKMike]

I'm guessing you're getting a total of 4 codes since none of the codes you listed is for the EGR.
AFAIK, the only way to clean the egr passages is to do so with throttle body cleaner and/or manually.

P0141 O2 Sensor Heater Circuit Malfunction (Sensor 2) usually means that the downstream O2 sensor has gone bad. This is the one located under the car in the exhaust just past the catalytic converter.
Of course it could be corrosion on the connectors or a wire issue.

P0442 Evaporative Emission Control System Leak Detected (small leak)
This one could be anything from a loose or poorly sealed gas cap to a wiring issue
Some troubleshooting details found here http://www.obd-codes.com/p0442

P0118 Engine Coolant Temperature Circuit High Input
If the coolant level is low, this can set.
A bad sensor will also set the code, and you know wiring issues will, too.
Some troubleshooting here: http://www.obd-codes.com/p0118

One extremely important thing to know about the 3.8 liter engines is that the intake manifold gaskets WILL leak at some point, causing problems --even leading to engine failure if uncorrected.
It's not a matter of if they'll go bad, just a matter of when.
The only solution is to immediately replace the gaskets when they go bad or to replace them as a preventative measure.
Sometimes the only symptom is that you notice the level of coolant has dropped in the overflow tank.
On the supercharged engine, you may see some pooling of coolant when you look below the supercharger.

[markpelly1]

Thanks again for the tips. Is there a how-to out there for the intake manifold replacement?

Also, any good sources for a downstream oxygen sensor? Less than 40 dollars?

Why are there two different downstream Denso's on this page?
http://www.partsgeek.com/catalog/2001/p ... ensor.html

[MKMike]

You're welcome.
I like to get parts from Rockauto (and sometimes Amazon or GMpartsdirect).
Rockauto is a forum sponsor, which adds to their appeal, in my book.
They also give forum members a 5% discount when you use the code they post in the vendor's forum http://www.pontiacbonnevilleclub.com/fo ... 47829.html
Whenever I have doubts about a part being right, I search online for the manufacturer's catalog site. http://densoautoparts.com/find-my-part/ ... -selection
2 different part numbers are listed for the Denso at that site because 1 is OE style and the other is a "Universal" fit .
You will like the price at Rockauto for the DENSO 2344087 much better than at the site you linked--much less than 40. http://www.rockauto.com/

Typically ACDelco OE parts are my preferred choice but Denso have been reported as good by many here.
It has been often reported that there are problems when using any other brands than those.

There's at least 1 excellent how-to for the LIM gaskets on this forum http://www.pontiacbonnevilleclub.com/fo ... c3591.html
It is a long job, so expect it to take up much of the day.
Here's a site which condemns DexCool antifreeze as a causative factor in the gaskets deteriorating http://www.dex-cool.net/
They are not alone in that belief , as many here (and elsewhere) also believe the DexCool is responsible.
It also shows pictures of what the gaskets will look like when they're leaking.
I've done 2 Bonnevilles, so far, and that's also the way mine looked.

[markpelly1]

Wow that is what heck of a process. I am going to look for signs of leaks and evaluate what I want to do here. I am using 2001 as a commuter currently and I am going to run it until it dies (while doing regular maintenance). I am not sure I want to put this much effort into the engine right now.

I am definitely going to grab that sensor from AC Delco though!!

[MKMike]

It's the type of job that you really have to be in the mood to do.
My incentive is to think of the savings and to then reallocate those saved funds for other hobbies.
Sort of like winning twice

[markpelly1]

It's the type of job that you really have to be in the mood to do.
My incentive is to think of the savings and to then reallocate those saved funds for other hobbies.
Sort of like winning twice

Totally agree on the money savings, I just know that I will be interested in a new car a couple years down the road when this one decides to take a turn for the worse. Believe me I wouldnt be doing any of these small repairs if I didnt like saving the money for other things. But like buying an older house, gotta pick your battles and fix what will be worth it to you.

[MKMike]

Totally agree on the money savings, I just know that I will be interested in a new car a couple years down the road when this one decides to take a turn for the worse. Believe me I wouldnt be doing any of these small repairs if I didnt like saving the money for other things. But like buying an older house, gotta pick your battles and fix what will be worth it to you.[/quote]

Absolutely.
You've got to do what works best for you.

[markpelly1]

Hey guys, I went to change the downstream sensor the other day and ran into a problem. I cannot get to the connector for the sensor. There seems to be a metal panel covering it that is riveted in. Does everyone else have this same panel there? How are we supposed to remove the sensor without being able to get to the connector?

Thanks guys.

[96 SSEi]

hi, your metal panel is a heat shield and we all have it..............you have to drill the heads of the rivets and then use metal screws to fasten when you are done

also, add this sit to favorites........lots of great diagnostics that we all use at times..........

http://easyautodiagnostics.com/gm/4.3L- ... ve-tests-1

you can test the o2 sensor before you drop money to replace here at the same site!!......its gold!!!

http://easyautodiagnostics.com/gm/3.8L/ ... ic-tests-1

[markpelly1]

Thank you very much, that is pretty crazy. Gotta do it though. I already bought the o2 sensor though, maybe i will test just in case.

[96 SSEi]

hi, you can always return it if its unused..... they may refund or give credit on future stuff...they aint cheap

[markpelly1]

hi, you can always return it if its unused..... they may refund or give credit on future stuff...they aint cheap

Well it wasn't the most expensive part I bought for this car so far haha. But yes I would like to save anything I can.