Pinging and rotten eggs

[epricedright]

Whenever the engine is warmed up I get a pinging noise when I accelerate. I believe its called light acceleration detonation? Sounds like my valves clattering...metal pinging noise. It's been doing this for awhile, but has gotten worse here lately. It's more pronounced when lightly accelerating, whereas if I accelerate hard, it's not as noticeable. I cleaned out my throttle body and EGR tubes really well about a month ago and that took care of the slight hesition from a standstill I was having, and took care of (mostly) the rough idle I was having, but I still have the pinging. The noise is similiar to the noise you get when you burn cheap gas. I am also getting that rotten egg smell from the exhaust occasionally. I believe I was told here replacing my EGR might take care of the pinging...is that true? What else could it be? Could the EGR valve also cause the rotten egg smell, or is my CAT conv. going bad? I use premium everytime usually from Murphy's (wal-mart) or Costco. Going on a road trip to Gatlinburg (mountains) 800 miles roundtrip in a couple of weeks, could that create major problems for the engine if not fixed beforehand?

[adallak]

Whenever the engine is warmed up I get a pinging noise when I accelerate. I believe its called light acceleration detonation? Sounds like my valves clattering...metal pinging noise. It's been doing this for awhile, but has gotten worse here lately. It's more pronounced when lightly accelerating, whereas if I accelerate hard, it's not as noticeable. I cleaned out my throttle body and EGR tubes really well about a month ago and that took care of the slight hesition from a standstill I was having, and took care of (mostly) the rough idle I was having, but I still have the pinging. The noise is similiar to the noise you get when you burn cheap gas. I am also getting that rotten egg smell from the exhaust occasionally. I believe I was told here replacing my EGR might take care of the pinging...is that true? What else could it be? Could the EGR valve also cause the rotten egg smell, or is my CAT conv. going bad? I use premium everytime usually from Murphy's (wal-mart) or Costco. Going on a road trip to Gatlinburg (mountains) 800 miles roundtrip in a couple of weeks, could that create major problems for the engine if not fixed beforehand?

Yes, it definitely sounds like spark knock caused by the lack of EGR. The EGR valve is about $50. Removing the valve without a custom made wrench is next to impossible. Same relates to the cleaning. Do not waste your time, buy a new one (with gasket) and replace. Another possibility is a bad EGR solenoid. It is cheaper and takes 2 minutes to replace. You might want to start there. The plastic vacuum tubes could be bad as well. I replaced nearly all of them with pieces cut off a vacuum tube a bought at Advance (I bought some 10'). A lot of 4.9s have that knock.

[TDK]

epricedright,

The rotten egg smell might be some excessive sulfur compounds in the fuel.

I would try a couple tankfulls of some premium at Chevron or another high-dollar brand in your area.

I realize this might start another round of: "all gas is the same etc", but I think some distributers have some quality control problems now and then with the various additives.

Good luck

[epricedright]

Whenever the engine is warmed up I get a pinging noise when I accelerate. I believe its called light acceleration detonation? Sounds like my valves clattering...metal pinging noise. It's been doing this for awhile, but has gotten worse here lately. It's more pronounced when lightly accelerating, whereas if I accelerate hard, it's not as noticeable. I cleaned out my throttle body and EGR tubes really well about a month ago and that took care of the slight hesition from a standstill I was having, and took care of (mostly) the rough idle I was having, but I still have the pinging. The noise is similiar to the noise you get when you burn cheap gas. I am also getting that rotten egg smell from the exhaust occasionally. I believe I was told here replacing my EGR might take care of the pinging...is that true? What else could it be? Could the EGR valve also cause the rotten egg smell, or is my CAT conv. going bad? I use premium everytime usually from Murphy's (wal-mart) or Costco. Going on a road trip to Gatlinburg (mountains) 800 miles roundtrip in a couple of weeks, could that create major problems for the engine if not fixed beforehand?

Yes, it definitely sounds like spark knock caused by the lack of EGR. The EGR valve is about $50. Removing the valve without a custom made wrench is next to impossible. Same relates to the cleaning. Do not waste your time, buy a new one (with gasket) and replace. Another possibility is a bad EGR solenoid. It is cheaper and takes 2 minutes to replace. You might want to start there. The plastic vacuum tubes could be bad as well. I replaced nearly all of them with pieces cut off a vacuum tube a bought at Advance (I bought some 10'). A lot of 4.9s have that knock.

Thanks Adallak! What does that custom made wrench look like? Do I need that to take off the EGR valve? Can one be bought somewhere? I will look into the EGR solenoid as well. Where is that located? And where are all the plastic vacuum tubes? I only cleaned out the metal EGR tubes in the throttle body.

epricedright,

The rotten egg smell might be some excessive sulfur compounds in the fuel.

I would try a couple tankfulls of some premium at Chevron or another high-dollar brand in your area.

I realize this might start another round of: "all gas is the same etc", but I think some distributers have some quality control problems now and then with the various additives.

Good luck

Thanks TDK! I will try some Shell gas as there are no Chevrons in the area I'm aware of. I was hoping the pinging (EGR) and sulfur smell was related.

[Ranger]

You need to diagnose this as Adallak said, it might be the control solenoid OR the EGR.

Another thought on the sulfer smell. I believe I recall the old guru once mention that rotten egg small is a sign of a rich fuel mixture. Check the FPR.

[adallak]

The solenoid (see the picture) i s between TB and EGR valve, connected to the both with vacuum tubes. Just follow the vacuum tubes from TB. Hint: you can buy a solenoid and test it first. If nothing changes, next will be EGR valve. Some say you can remove the EGR valve with a 13mm distributor wrench. But I still believe it's not going to be fun either.

Check this out, it might work:

http://cgi.ebay.com/ebaymotors/2-piece-dis...623277213QQrdZ1

[epricedright]

You need to diagnose this as Adallak said, it might be the control solenoid OR the EGR.

Another thought on the sulfer smell. I believe I recall the old guru once mention that rotten egg small is a sign of a rich fuel mixture. Check the FPR.

Thanks Larry! I'll check the FPR as well. So what's that procedure again, do I take the vacuum hose lose from it and while running, if its leaking there, then I need to replace?

The solenoid (see the picture) i s between TB and EGR valve, connected to the both with vacuum tubes. Just follow the vacuum tubes from TB. Hint: you can buy a solenoid and test it first. If nothing changes, next will be EGR valve. Some say you can remove the EGR valve with a 13mm distributor wrench. But I still believe it's not going to be fun either.

Thanks for the pics Adallak! So are there 2 bolts holding the EGR valve on? Did you make a special wrench to fit in there?

[adallak]

You need to diagnose this as Adallak said, it might be the control solenoid OR the EGR.

Another thought on the sulfer smell. I believe I recall the old guru once mention that rotten egg small is a sign of a rich fuel mixture. Check the FPR.

Thanks Larry! I'll check the FPR as well. So what's that procedure again, do I take the vacuum hose lose from it and while running, if its leaking there, then I need to replace?

The solenoid (see the picture) i s between TB and EGR valve, connected to the both with vacuum tubes. Just follow the vacuum tubes from TB. Hint: you can buy a solenoid and test it first. If nothing changes, next will be EGR valve. Some say you can remove the EGR valve with a 13mm distributor wrench. But I still believe it's not going to be fun either.

Thanks for the pics Adallak! So are there 2 bolts holding the EGR valve on? Did you make a special wrench to fit in there?

When I was trying to clean my EGR valve I did not have any special wrench and had to remove TB. Cleaning did not work. I wull replace it in a month or so. Yes there are just two bolts, but they are not easily accessable. Check my post with pictures i added some info for you.

[epricedright]

You need to diagnose this as Adallak said, it might be the control solenoid OR the EGR.

Another thought on the sulfer smell. I believe I recall the old guru once mention that rotten egg small is a sign of a rich fuel mixture. Check the FPR.

Thanks Larry! I'll check the FPR as well. So what's that procedure again, do I take the vacuum hose lose from it and while running, if its leaking there, then I need to replace?

The solenoid (see the picture) i s between TB and EGR valve, connected to the both with vacuum tubes. Just follow the vacuum tubes from TB. Hint: you can buy a solenoid and test it first. If nothing changes, next will be EGR valve. Some say you can remove the EGR valve with a 13mm distributor wrench. But I still believe it's not going to be fun either.

Thanks for the pics Adallak! So are there 2 bolts holding the EGR valve on? Did you make a special wrench to fit in there?

When I was trying to clean my EGR valve I did not have any special wrench and had to remove TB. Cleaning did not work. I wull replace it in a month or so. Yes there are just two bolts, but they are not easily accessable. Check my post with pictures i added some info for you.

Thanks for that ebay link! Do you think those wrenches will work? It says they are 1/2" and 9/16". Every wrench I've used on the caddy has been metric.

[adallak]

You need to diagnose this as Adallak said, it might be the control solenoid OR the EGR.

Another thought on the sulfer smell. I believe I recall the old guru once mention that rotten egg small is a sign of a rich fuel mixture. Check the FPR.

Thanks Larry! I'll check the FPR as well. So what's that procedure again, do I take the vacuum hose lose from it and while running, if its leaking there, then I need to replace?

The solenoid (see the picture) i s between TB and EGR valve, connected to the both with vacuum tubes. Just follow the vacuum tubes from TB. Hint: you can buy a solenoid and test it first. If nothing changes, next will be EGR valve. Some say you can remove the EGR valve with a 13mm distributor wrench. But I still believe it's not going to be fun either.

Thanks for the pics Adallak! So are there 2 bolts holding the EGR valve on? Did you make a special wrench to fit in there?

When I was trying to clean my EGR valve I did not have any special wrench and had to remove TB. Cleaning did not work. I wull replace it in a month or so. Yes there are just two bolts, but they are not easily accessable. Check my post with pictures i added some info for you.

Thanks for that ebay link! Do you think those wrenches will work? It says they are 1/2" and 9/16". Every wrench I've used on the caddy has been metric.

Yes, the bolts seem to be 13 mm. Please check it out. As far as these wrenches... they are 12.7 mm and 14.28 mm. Pretty close. LOL you can also search for metric distributor wrenches on ebay.

[epricedright]

You need to diagnose this as Adallak said, it might be the control solenoid OR the EGR.

Another thought on the sulfer smell. I believe I recall the old guru once mention that rotten egg small is a sign of a rich fuel mixture. Check the FPR.

Thanks Larry! I'll check the FPR as well. So what's that procedure again, do I take the vacuum hose lose from it and while running, if its leaking there, then I need to replace?

The solenoid (see the picture) i s between TB and EGR valve, connected to the both with vacuum tubes. Just follow the vacuum tubes from TB. Hint: you can buy a solenoid and test it first. If nothing changes, next will be EGR valve. Some say you can remove the EGR valve with a 13mm distributor wrench. But I still believe it's not going to be fun either.

Thanks for the pics Adallak! So are there 2 bolts holding the EGR valve on? Did you make a special wrench to fit in there?

When I was trying to clean my EGR valve I did not have any special wrench and had to remove TB. Cleaning did not work. I wull replace it in a month or so. Yes there are just two bolts, but they are not easily accessable. Check my post with pictures i added some info for you.

Thanks for that ebay link! Do you think those wrenches will work? It says they are 1/2" and 9/16". Every wrench I've used on the caddy has been metric.

Yes, the bolts seem to be 13 mm. Please check it out. As far as these wrenches... they are 12.7 mm and 14.28 mm. Pretty close. LOL you can also search for metric distributor wrenches on ebay.

Pretty close....you're funny! I found a metric set here: http://cgi.ebay.com/ebaymotors/ws/eBayISAP...mMakeTrack=true

More expensive though. I'll check my EGR solenoid 1st and if that doesn't fix it, I'll call around and try to find that wrench locally. I'm try to find that solenoid at rockauto now.

[Ranger]

"Thanks Larry! I'll check the FPR as well. So what's that procedure again, do I take the vacuum hose lose from it and while running, if its leaking there, then I need to replace?

"

Correct.

[adallak]

You need to diagnose this as Adallak said, it might be the control solenoid OR the EGR.

Another thought on the sulfer smell. I believe I recall the old guru once mention that rotten egg small is a sign of a rich fuel mixture. Check the FPR.

Thanks Larry! I'll check the FPR as well. So what's that procedure again, do I take the vacuum hose lose from it and while running, if its leaking there, then I need to replace?

The solenoid (see the picture) i s between TB and EGR valve, connected to the both with vacuum tubes. Just follow the vacuum tubes from TB. Hint: you can buy a solenoid and test it first. If nothing changes, next will be EGR valve. Some say you can remove the EGR valve with a 13mm distributor wrench. But I still believe it's not going to be fun either.

Thanks for the pics Adallak! So are there 2 bolts holding the EGR valve on? Did you make a special wrench to fit in there?

When I was trying to clean my EGR valve I did not have any special wrench and had to remove TB. Cleaning did not work. I wull replace it in a month or so. Yes there are just two bolts, but they are not easily accessable. Check my post with pictures i added some info for you.

Thanks for that ebay link! Do you think those wrenches will work? It says they are 1/2" and 9/16". Every wrench I've used on the caddy has been metric.

Yes, the bolts seem to be 13 mm. Please check it out. As far as these wrenches... they are 12.7 mm and 14.28 mm. Pretty close. LOL you can also search for metric distributor wrenches on ebay.

Pretty close....you're funny! I found a metric set here: http://cgi.ebay.com/ebaymotors/ws/eBayISAP...mMakeTrack=true

More expensive though. I'll check my EGR solenoid 1st and if that doesn't fix it, I'll call around and try to find that wrench locally. I'm try to find that solenoid at rockauto now.

Okay The wrench the guy used was a 13mm distributer wrench from Sears, it was $9.99 and was for AMC and Ford V8's. Hope this will help, and let us know how it works out.

[epricedright]

More expensive though. I'll check my EGR solenoid 1st and if that doesn't fix it, I'll call around and try to find that wrench locally. I'm try to find that solenoid at rockauto now.

I just ordered a Standard Motor Products EGR vacuum solenoid from Rockauto...the only one they they had. Around $27.00 w/ shipping with my discount. I ordered brakes pads for the minivan as well. I will check out my EGR vacuum tubes while I'm replacing the solenoid. I will check my FPR as well.

Thank you Adallak, TDK, and Larry for all your help! Thanks for the wrench info Adallak. Hopefully I won't need it, but if I do, now I know what I need and where to get it. I will be sure to post back with the outcome.

[KHE]

Have you checked the EGR tubes for carbon? They might be clogged and could be the reason for the pinging.

[epricedright]

Have you checked the EGR tubes for carbon? They might be clogged and could be the reason for the pinging.

I cleaned the 2 metal EGR tubes inside the throttle body. Are those the ones you're referring to?

[KHE]

Yes - those are the ones. Is there any possibility that the timing could have been changed? It might not hurt to put it in set timing mode and verify the base timing with a timing light.

[epricedright]

Yes - those are the ones. Is there any possibility that the timing could have been changed? It might not hurt to put it in set timing mode and verify the base timing with a timing light.

I was wondering that as well, as that's what it sounds like...the timing is off. I haven't done anything to affect the timing that I know of. I was under the impression that the timing was computer controlled on these cars? I will put in the EGR vacuum solenoid being I already ordered it and check my vacuum tubes 1st. I don't have a timing light. Do you recommend I get my timing checked before I replace my EGR valve?

[BodybyFisher]

I doubt its timing. We have had this discussion over and over regarding light pedal detonation on the 4.9, its imfamous for that light pedal detonation, imfamaous. I myself thought it was related to timing but the guru set me straight and said its detonation and explained exactly the differences between detonation and pre-ignition, something that I WAS NOT aware of previously. He explained that lack of EGR flow can cause this light pedal detonation. I tried unsuccessfully for about a year to get rid of the light pedal pre-ignition, I did this:

1) pulled my EGR and cleaned the H out if it, replaced the gasket

2) while the EGR was off, I cleaned the tubes down the throat of the TB with solvent, 22 caliber gun cleaning round wire brushes (Hoppes), put a rag over the open EGR ports and shot compressed air into the TB EGR ports to BLOW OUT the ports

3) I replaced ALL EGR vacuum hoses

4) I checked that the EGR solenoid was functional

5) I flushed my cooling system thinking she was running hot (which she was not)

6) I even used Sunoco 93 as a shot in the dark thinking as you did it was timing in the beginning... NO CHANGE

I could not get rid of it, UNTIL, I met a mechanic in my local CADDY dealer, he said, those EGRs are nearly impossible to clean, just replace it with an OEM EGR..... If you have gone through what I went through above, replace it with OEM

PROBLEM GONE NO MORE E046 either, I will send you a case of beer if its timing

Here is a the BEST article I have ever seen on PREIGNITION and DETONATION, save it to your harddrive it's a CLASSIC, Mike

http://www.streetrodstuff.com/Articles/Engine/Detonation/

[epricedright]

I doubt its timing. We have had this discussion over and over regarding light pedal detonation on the 4.9, its imfamous for that light pedal detonation, imfamaous. I myself thought it was related to timing but the guru set me straight and said its detonation and explained exactly the differences between detonation and pre-ignition, something that I WAS NOT aware of previously. He explained that lack of EGR flow can cause this light pedal detonation. I tried unsuccessfully for about a year to get rid of the light pedal pre-ignition, I did this:

1) pulled my EGR and cleaned the H out if it, replaced the gasket

2) while the EGR was off, I cleaned the tubes down the throat of the TB with solvent, 22 caliber gun cleaning round wire brushes (Hoppes), put a rag over the open EGR ports and shot compressed air into the TB EGR ports to BLOW OUT the ports

3) I replaced ALL EGR vacuum hoses

4) I checked that the EGR solenoid was functional

5) I flushed my cooling system thinking she was running hot (which she was not)

6) I even used Sunoco 93 as a shot in the dark thinking as you did it was timing in the beginning... NO CHANGE

I could not get rid of it, UNTIL, I met a mechanic in my local CADDY dealer, he said, those EGRs are nearly impossible to clean, just replace it with an OEM EGR..... If you have gone through what I went through above, replace it with OEM

PROBLEM GONE NO MORE E046 either, I will send you a case of beer if its timing

Here is a the BEST article I have ever seen on PREIGNITION and DETONATION, save it to your harddrive it's a CLASSIC, Mike

http://www.streetrodstuff.com/Articles/Engine/Detonation/

Thanks Mike! That's a great article! I only wish it explained how the EGR affects detonation. It stated: "Detonation is influenced by chamber design (shape, size, geometry, plug location), compression ratio, engine timing, mixture temperature, cylinder pressure and fuel octane rating." I don't doubt the EGR affects detonation, I just wish I knew why exactly. Of course I know nothing about about EGR, so maybe that's why. Always more to learn...

[BodybyFisher]

Pay attention to BILLK here

http://www.chevelles.com/forums/showthread.php?t=86407

I believe that combustion chamber temperatures are HIGHER without EGR flow, EGR cools the chamber

[adallak]

I doubt its timing. We have had this discussion over and over regarding light pedal detonation on the 4.9, its imfamous for that light pedal detonation, imfamaous. I myself thought it was related to timing but the guru set me straight and said its detonation and explained exactly the differences between detonation and pre-ignition, something that I WAS NOT aware of previously. He explained that lack of EGR flow can cause this light pedal detonation. I tried unsuccessfully for about a year to get rid of the light pedal pre-ignition, I did this:

1) pulled my EGR and cleaned the H out if it, replaced the gasket

2) while the EGR was off, I cleaned the tubes down the throat of the TB with solvent, 22 caliber gun cleaning round wire brushes (Hoppes), put a rag over the open EGR ports and shot compressed air into the TB EGR ports to BLOW OUT the ports

3) I replaced ALL EGR vacuum hoses

4) I checked that the EGR solenoid was functional

5) I flushed my cooling system thinking she was running hot (which she was not)

6) I even used Sunoco 93 as a shot in the dark thinking as you did it was timing in the beginning... NO CHANGE

I could not get rid of it, UNTIL, I met a mechanic in my local CADDY dealer, he said, those EGRs are nearly impossible to clean, just replace it with an OEM EGR..... If you have gone through what I went through above, replace it with OEM

PROBLEM GONE NO MORE E046 either, I will send you a case of beer if its timing

Here is a the BEST article I have ever seen on PREIGNITION and DETONATION, save it to your harddrive it's a CLASSIC, Mike

http://www.streetrodstuff.com/Articles/Engine/Detonation/

Thanks Mike! That's a great article! I only wish it explained how the EGR affects detonation. It stated: "Detonation is influenced by chamber design (shape, size, geometry, plug location), compression ratio, engine timing, mixture temperature, cylinder pressure and fuel octane rating." I don't doubt the EGR affects detonation, I just wish I knew why exactly. Of course I know nothing about about EGR, so maybe that's why. Always more to learn...

First, EGR is there to cool down mixture in cylinders and hence reduce NOx. At slight throttle PCM changes ignition timing assuming the mixture in cylinders is sufficiently cooled down by the flow of exhaust gases. But if EGR system mulfunctios (say, EGR valve does not open as much as it is supposed to do at slight throttle) the cylinders are too hot, and that causes spark knock.

There are much more owners of 4.9 on the other board and virtually there is no week someone would not come up with the "light throttle engine hot knock". Most of the cases were successfully solved by replacing the EGR valve among with other components. But in most cases nothing helped unless the EGR valve was replaced as well.

[BodybyFisher]

This is from the GURU, I found this on my hard drive:

Have you checked the ignition timing?? If you just got the car I might suspect that someone has retarded the ignition timing so as to run regular fuel. That will kill the mileage also.

Open the throttle bores and look down into the intake manifold. See the two tubes sticking up at you from the floor of the intake?? Those are the EGR delivery tubes and they are NOT supposed to be full of carbon and plugged up. Rod them out with a piece of stiff wire and clean them with carb cleaner. If the tubes are plugged (and they probably are) the EGR cannot flow and the engine will have a tendency to spark knock. Many times mechanics or owners will then retard the distributor setting to stop the detonation thus hurting the mileage.

See this EGR THEORY of OPERATION

http://www.autoshop101.com/forms/h61.pdf

[epricedright]

Ahhh! This all makes sense to me now. Thanks again Mike and Adallak!

[adallak]

Here is more EGR related info from the GURU. BodyByFisher, thank you for your question. I believe you would post the answers here anyway, so I did it myself.

"The EGR is an inert gas (already burned) that is introduced into the combustion chamber to dilute the charge and slow the burn rate and maximum temperatures. This is done to reduce the formation of oxides of Nitrogen which are considered a pollutant.

One nice thing about EGR is that the more EGR that is introduced the more the spark timing can be advanced and the better the fuel economy the engine gets. It gets into the pumping losses the engine deals with while running part throttle and reducing the pumping losses by throttling the engine with EGR and thus reducing the intake vacuum at cruise conditions which reduces the pumping losses. In short, while most people vilify EGR, it actually IMPROVES the engine's efficiency and fuel economy with the modern control systems used today.

The control system automatically increases the spark advance considerably when the EGR is scheduled. This ensures maximum economy and efficiency. If the EGR is not present (due to clogged EGR tubes or inoperative EGR valve, etc.) then the extra spark advance that is being scheduled anticipating the presence of EGR is what causes the detonation.

All engines that employ EGR will act this way, not just the 4.9. It is a bit more obvious on the 4.1/4.5/4.9 engines due to the fact that those engines do not have a knock control system. Engines like the Northstar will partially correct the spark for the lack of EGR in the event of an EGR failure using the knock controller."

I recently changed my EGR valve on my 4.9, and the increase in fuel economy was one of the things I noticed immediately! That and the no more knocking on part throttle acceleration!

"Yep, EGR is good. A lot of the work on current engines involves combustion chamber work to allow the engine to be more and more tolerant of high levels of EGR. The more EGR that the engine can tolerate the better the efficiency will be. That is one of the reasons current engines get such good fuel economy. They can run very high levels of EGR (up to 20 percent of the charge is EGR under some load conditions) and still have stable combustion due to the advances in the combustion chamber technology. You do NOT want to disconnect the EGR. It turns off at full throttle for max power anyway so there is absolutely no reason to disable it."

When exactly is EGR turned off in 4.9? What throttle angle in percents? Thank you.

"It depends on the model and year but roughly 50 percent throttle. It is off well before full throttle. EGR will be present during most "throttled" driving conditions that the car spends 99 percent of its life at but will turn off in any performance situation and at heavy throttle crowds beyond about 50 percent for maximum torque."