adallak Posted April 27, 2006 Report Share Posted April 27, 2006 Today I replaced (finally!) the EGR valve, but nothing changed... The spark knock is still there. I am sure it is EGR related (hot engine-slight throttle), but cannot figure out what is wrong. No vacuum leaks, solenoid works properly as well. The only modification done by me is vacuum tubing instead of some cracked plastic lines. Could larger cross-section of vacuum tubes play role? The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
epricedright Posted April 27, 2006 Author Report Share Posted April 27, 2006 Today I replaced (finally!) the EGR valve, but nothing changed... The spark knock is still there. I am sure it is EGR related (hot engine-slight throttle), but cannot figure out what is wrong. No vacuum leaks, solenoid works properly as well. The only modification done by me is vacuum tubing instead of some cracked plastic lines. Could larger cross-section of vacuum tubes play role? Did you by chance check to see if your EGR tubes between the TB and the EGR valve were clear? I blew air through mine to make sure they weren't clogged with carbon. Link to comment Share on other sites More sharing options...
adallak Posted April 27, 2006 Report Share Posted April 27, 2006 Today I replaced (finally!) the EGR valve, but nothing changed... The spark knock is still there. I am sure it is EGR related (hot engine-slight throttle), but cannot figure out what is wrong. No vacuum leaks, solenoid works properly as well. The only modification done by me is vacuum tubing instead of some cracked plastic lines. Could larger cross-section of vacuum tubes play role? Did you by chance check to see if your EGR tubes between the TB and the EGR valve were clear? I blew air through mine to make sure they weren't clogged with carbon. Epricedright, I would love to blew air through the passages, but I do not have any source of compressed air. I even wanted to clean them up mechanically by means of a cord, but something stopped me from getting into holes with unknown anatomy. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
epricedright Posted April 27, 2006 Author Report Share Posted April 27, 2006 Adallak, I imagine a can of compressed air would work, the kind for PC's and what not. Not sure if that little nozzle extension would be long enough, but I'm guessing it would be. I wouldn't be afraid of holes of unknown anatomy, as long as your nozzle is long enough. Link to comment Share on other sites More sharing options...
KHE Posted April 27, 2006 Report Share Posted April 27, 2006 Adallak, Rod out the EGR tubes with a piece of coathanger wire. They are staked into the manifold and you won't hurt anything. I bet there clogged with carbon and the engine is not getting EGR flow which will result in pinging. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
epricedright Posted April 27, 2006 Author Report Share Posted April 27, 2006 Adallak, Rod out the EGR tubes with a piece of coathanger wire. They are staked into the manifold and you won't hurt anything. I bet there clogged with carbon and the engine is not getting EGR flow which will result in pinging. I used a coat hanger, then a wire brush from my gun cleaning kit to clean my tubes. I assumed Adallak cleaned his as well. But the tubes curve around and up to the EGR valve, hence why I blew air through mine to confirm they were clear where a wire wouldn't reach. I figured mine were clean after I was done, but I had to check with air for peace of mind. Now that I think about it, maybe the tubes themselves don't curve, but there is a void in the manifold that you cannot see if it's clear, hence why I blew with air. The holes in the EGR tubes and EGR valve are offset, hence why I said the tubes curve and go up. Link to comment Share on other sites More sharing options...
epricedright Posted April 27, 2006 Author Report Share Posted April 27, 2006 Tip: When rodding out your EGR tubes, put a small rag or paper towels down into the bottom of your TB to catch all the crud (carbon) that will collect there. When spraying intake cleaner through your tubes, it will make a mess, and the paper towels will catch all the flying crud. Link to comment Share on other sites More sharing options...
adallak Posted April 27, 2006 Report Share Posted April 27, 2006 Adallak, Rod out the EGR tubes with a piece of coathanger wire. They are staked into the manifold and you won't hurt anything. I bet there clogged with carbon and the engine is not getting EGR flow which will result in pinging. KHE, The EGR tubes have been perfectly clean for years. I check them out from time to time. My concern is the EGR passages BETWEEN the throttle body and the ports of EGR valve. the ping is not as loud as before, but it is still there! Looks like the EGR valve just does not get enough vacuum or backpressure to open up a little bit more and cool down the mix. Well, let me find/borrow a compressor and see if it helps. If it does not make difference I will have to live with that slight ping. Epricedright, The Guru told us to not worry about chunks of carbon falling down. You seem to be a perfectionist just like myself. But I learned perfectionists and Cadillacs do not mix well. lol The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
adallak Posted April 27, 2006 Report Share Posted April 27, 2006 Adallak, I imagine a can of compressed air would work, the kind for PC's and what not. Not sure if that little nozzle extension would be long enough, but I'm guessing it would be. I wouldn't be afraid of holes of unknown anatomy, as long as your nozzle is long enough. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
epricedright Posted April 27, 2006 Author Report Share Posted April 27, 2006 Adallak, Rod out the EGR tubes with a piece of coathanger wire. They are staked into the manifold and you won't hurt anything. I bet there clogged with carbon and the engine is not getting EGR flow which will result in pinging. KHE, The EGR tubes have been perfectly clean for years. I check them out from time to time. My concern is the EGR passages BETWEEN the throttle body and the ports of EGR valve. the ping is not as loud as before, but it is still there! Looks like the EGR valve just does not get enough vacuum or backpressure to open up a little bit more and cool down the mix. Well, let me find/borrow a compressor and see if it helps. If it does not make difference I will have to live with that slight ping. Epricedright, The Guru tout us to not worry about chunks of carbon falling down. You seem to be a perfectionist just like myself. But I learned perfectionists and Cadillacs do not mix well. lol LOL! Yes, to my detriment, I am a perfectionists. Perfectionists or not though, I don't see how anybody could leave all that crud in their throttle body, especially being it cleans up so nice and shiny. When I was done cleaning mine, you could have eaten out of it. If you use a compressor to check your passages, have some small flexible rubber hose on hand to put in the TB EGR tubes. The butterfly gets in the way of one of the tubes, so you won't have a straight shot with a ridgid blow nozzle. I guess you could blow through the EGR valve holes and see if you get air out the TB EGR tubes...didn't try that, not sure that would work. What tool did you use to remove your EGR valve? You didn't take out your whole throttle body again did you? If your passage is clear, maybe you got a defective EGR valve??? Don't tell Mike I said this , but have you checked your timing? Link to comment Share on other sites More sharing options...
adallak Posted April 27, 2006 Report Share Posted April 27, 2006 Adallak, Rod out the EGR tubes with a piece of coathanger wire. They are staked into the manifold and you won't hurt anything. I bet there clogged with carbon and the engine is not getting EGR flow which will result in pinging. KHE, The EGR tubes have been perfectly clean for years. I check them out from time to time. My concern is the EGR passages BETWEEN the throttle body and the ports of EGR valve. the ping is not as loud as before, but it is still there! Looks like the EGR valve just does not get enough vacuum or backpressure to open up a little bit more and cool down the mix. Well, let me find/borrow a compressor and see if it helps. If it does not make difference I will have to live with that slight ping. Epricedright, The Guru tout us to not worry about chunks of carbon falling down. You seem to be a perfectionist just like myself. But I learned perfectionists and Cadillacs do not mix well. lol LOL! Yes, to my detriment, I am a perfectionists. Perfectionists or not though, I don't see how anybody could leave all that crud in their throttle body, especially being it cleans up so nice and shiny. When I was done cleaning mine, you could have eaten out of it. If you use a compressor to check your passages, have some small flexible rubber hose on hand to put in the TB EGR tubes. The butterfly gets in the way of one of the tubes, so you won't have a straight shot with a ridgid blow nozzle. I guess you could blow through the EGR valve holes and see if you get air out the TB EGR tubes...didn't try that, not sure that would work. What tool did you use to remove your EGR valve? You didn't take out your whole throttle body again did you? If your passage is clear, maybe you got a defective EGR valve??? Don't tell Mike I said this , but have you checked your timing? Timing is fine. Eight degrees and a half with 89 octane. Getting into the smaller EGR tube is gonna be a problem. My nozzle do flex but not that much. I think one should blow air throught the EGR tubes not through the ports of EGR valve. I shaved a 13 mm six-point socket to be able to reach for the bolts holding the EGR valve. But I ended up removing the throttle body since one of the bolts holding ISC motor bracket had stripped and you could move the ISC motor with a finger... After all was put back, I had to go through Minimum Air, TPS, ISC adjustments. You know that's the best part! The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
adallak Posted April 27, 2006 Report Share Posted April 27, 2006 Will GM engine top cleaner clean the EGR passages? If so, what exactly and HOW should I apply? Thank you. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
epricedright Posted April 27, 2006 Author Report Share Posted April 27, 2006 Will GM engine top cleaner clean the EGR passages? If so, what exactly and HOW should I apply? Thank you. Lay off that Viagra, and maybe your nozzle will flex more. I've never used the GM stuff, the label should say if it's ok to use. I used CRC fuel injection intake cleaner. I once used the gumout carb cleaner to clean my TB till I read it wasn't safe for fuel injected cars, something about teflon and sensors...oops! What I did was: -Clean my TB and butterfly first with the intake cleaner and a tooth brush (my wife's ), paying attention to to the underside of the butterfly...a pain. -Put a rag in the TB to prop open the butterfly. -Put paper towels in the bottom of the TB to catch the crud. -Ran a hanger in and out the tubes. -Then I used a brass/and copper cleaning brushes (22 cal or 9mm, can't remember which worked best), spayed down the tube with the cleaner, worked the brush in and out. I had to bend the brush where it screws into the brush holder to fit down in one of the tubes. -Put the brush over a rag and sprayed the brush with the cleaner till the brush was clean. -Repeated till the brush came out clean. -Carefully removed all the paper towels-had to use needle nose to get it all out. -Cleaned up the TB some more (because I'm a perfectionists ). -Once I was done, I shot air through the tubes to confirm they were clear, and that's it. Link to comment Share on other sites More sharing options...
adallak Posted April 27, 2006 Report Share Posted April 27, 2006 Epricedright, Thanks for sharing your experience. An update: It knocks in gear but does not in P or N. Which is understandable. The ECM changes ignition timing at slight throttle when engine is hot and in gear, but does nothing when in P and N. At the same time it opens the EGR solenoid to open up the EGR valve and let the exhaust gases into the chumbers. Now the wiered part... I bypassed the solenoid to supply a healthy dose of vacuum to the EGR valve. It used to do th etrick - the spark knock would disappear...but with this new OEM EGR valve nothing changed! Knocks like crazy. WTH is going on? The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
epricedright Posted April 27, 2006 Author Report Share Posted April 27, 2006 Epricedright, Thanks for sharing your experience. An update: It knocks in gear but does not in P or N. Which is understandable. The ECM changes ignition timing at slight throttle when engine is hot and in gear, but does nothing when in P and N. At the same time it opens the EGR solenoid to open up the EGR valve and let the exhaust gases into the chumbers. Now the wiered part... I bypassed the solenoid to supply a healthy dose of vacuum to the EGR valve. It used to do th etrick - the spark knock would disappear...but with this new OEM EGR valve nothing changed! Knocks like crazy. WTH is going on? I dunna. If your EGR tubes are clean & clear, I'd maybe swap your new EGR valve for another new one, maybe you got a dud! If that doesn't work, get you vacuum lines back to OEM, and replace your vacuum solenoid. After doing that, and it's not your timing, what else could it be? Link to comment Share on other sites More sharing options...
Ranger Posted April 28, 2006 Report Share Posted April 28, 2006 Today I replaced (finally!) the EGR valve, but nothing changed... The spark knock is still there. I am sure it is EGR related (hot engine-slight throttle), but cannot figure out what is wrong. No vacuum leaks, solenoid works properly as well. The only modification done by me is vacuum tubing instead of some cracked plastic lines. Could larger cross-section of vacuum tubes play role? How much larger? Link to comment Share on other sites More sharing options...
adallak Posted April 28, 2006 Report Share Posted April 28, 2006 Today I replaced (finally!) the EGR valve, but nothing changed... The spark knock is still there. I am sure it is EGR related (hot engine-slight throttle), but cannot figure out what is wrong. No vacuum leaks, solenoid works properly as well. The only modification done by me is vacuum tubing instead of some cracked plastic lines. Could larger cross-section of vacuum tubes play role? How much larger? I just looked at... only rubber elbows were replaced with tubing. Should not really make a difference. There is a pretty good vacuum by the EGR valve input. I'll get a timing light and check the timing one more time. Thanks for all replies. The idle speed is another pain. No matter what I do (exactly per FSM or by bbobynski) the result is the same. At start up it jumps to some 2500 and drops to some 1000in a few seconds. At operational temperature in P it is 600-650. Just one example from FSM: 18. While still in diagnostics turn ignition off. Allow approximately 20 seconds for the ISC motor to retract and perform TPS 'learn". 19. Leave the ignition key off for a minimum of 10 seconds to allow the PCM to complete a "TPS Learning" routine. Repeat step 18 after entering diagnostics. WTF is 19 for? Could not they just say intelligibly: 18. While still in diagnostics turn ignition off. Wait for 60 seconds. Turn ignition on. Enter diagnostics. Turn ignition off for 60 seconds. Remove the key. Done. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
epricedright Posted April 28, 2006 Author Report Share Posted April 28, 2006 I just looked at... only rubber elbows were replaced with tubing. Should not really make a difference. I had to replace a rubber vacuum elbow that went from my FPR to my TB...it was maybe 2" long and cost $7.50 at the stealership. It was larger on one end, hence why I didn't use a piece of vacuum line. So did you clean your tubes and check to see if they were clear yet? Link to comment Share on other sites More sharing options...
adallak Posted April 28, 2006 Report Share Posted April 28, 2006 I just looked at... only rubber elbows were replaced with tubing. Should not really make a difference. I had to replace a rubber vacuum elbow that went from my FPR to my TB...it was maybe 2" long and cost $7.50 at the stealership. It was larger on one end, hence why I didn't use a piece of vacuum line. So did you clean your tubes and check to see if they were clear yet? Two EGR tubes inside TB? They have been clean all the time. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
epricedright Posted April 28, 2006 Author Report Share Posted April 28, 2006 Mine were pretty cruddy, after about 8k miles. Are you saying they have always been clean and you've never had to clean them? If so, there must be some blockage in there somewhere between the TB and the EGR valve, hence why they're not getting dirty, and why you have detonation. Link to comment Share on other sites More sharing options...
adallak Posted April 28, 2006 Report Share Posted April 28, 2006 Mine were pretty cruddy, after about 8k miles. Are you saying they have always been clean and you've never had to clean them? If so, there must be some blockage in there somewhere between the TB and the EGR valve, hence why they're not getting dirty, and why you have detonation. They were partially (some 30%) restricted some 5 years ago. Code 048 showed up. I cleaned them up and just watched and cleaned from time to time. They probably did not have a chance to get clogged. But your idea may be correct after all. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
epricedright Posted April 28, 2006 Author Report Share Posted April 28, 2006 Mine were pretty cruddy, after about 8k miles. Are you saying they have always been clean and you've never had to clean them? If so, there must be some blockage in there somewhere between the TB and the EGR valve, hence why they're not getting dirty, and why you have detonation. They were partially (some 30%) restricted some 5 years ago. Code 048 showed up. I cleaned them up and just watched and cleaned from time to time. They probably did not have a chance to get clogged. But your idea may be correct after all. Hmmm...I'd check to make sure they're clear. Good Luck! Link to comment Share on other sites More sharing options...
adallak Posted April 28, 2006 Report Share Posted April 28, 2006 This set of wrenches bought at Advance Autoparts works very well both on TPS and Minimum Air screws. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
adallak Posted April 28, 2006 Report Share Posted April 28, 2006 Verdict: the knock is not spark knock, it is mechanical and more pronounced at 1300-1400 RPM at light load when engine is hot. I cannot hear it in N or P. The EGR system works properly. It does not sound like main bearing. Well... whatever I am done. Will live with it. lol The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
epricedright Posted April 28, 2006 Author Report Share Posted April 28, 2006 I have the #1 main bearing knock. It sounds like what you describe...can't hear it in P or N. Have you tried power braking it in the driveway, and have someone loosen your belt tensioner? When I do that, the noise goes away. The Rotella 15W40 helps my knock somewhat. It sure is annoying though. Sounds more serious than it supposedly is. I thought you had that main bearing knock in the past? Is this a new noise? Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.