weephee Posted February 18, 2007 Report Share Posted February 18, 2007 Just recently I've notice my 02 STS has started pinging and slight acceleration. I always use 87 Octane. Could this possibly be the EGR valve or can you suggest what I might check for. Thanks Link to comment Share on other sites More sharing options...
Bruce Nunnally Posted February 18, 2007 Report Share Posted February 18, 2007 General engine sound diagnosis: http://www.gmgoodwrench.com/_res/pdf/Engin...ust%202004).pdf Noise Symptom Description Check or Test (pick one, then read diagnosis): Double knock Light crankshaft-speed knocking noise heard for the first few minutes after start-up. Check for a loose piston pin. Rattling − Light, irregular, "dieseling" or "marbley" rattle, ticking noise heard for first few minutes of start-up. − Light, regular, camshaft-speed ticking noise, heard best when the engine is increased to 2000 rpm, then released to idle − Check for several loose piston pins. − Check for defective/misaligned balance shaft bearing. Thumping Light, regular thumping noise heard best near accessory drive belt pulleys. Check drive belt pulley tensioner. Adjust to specified deflection. Check pulley alignment. Dull Knock Heavy, regular, dull metallic knock that occurs on acceleration, under load. Check for incorrect main bearing clearances. Chirping, Squealing Steady "chirping" at nominal speeds, loud squealing upon acceleration or tight turns. Check drive belts for looseness/glazing; check pulleys/tensioner; check for paint in grooves. General Knock Includes dull, regular and metallic knocking. Check for incorrect connecting rod bearing clearances, piston scuffing, tight piston pin, clogged anti-drainback filter. Sharp Knock Light, regular, sharp metallic rapping of clattering knock heard best at speeds between 25 and 35 mph. Check for loose flexplate bolts, cracked flexpate, incorrect connecting rod bearing clearances. Repair as required. Loud pop GM Northstar - Pop when key is released after extended crank and failure to start. May be a normal pressure release from the fuel induction system/intake manifold. Refer to GM Bulletin 57-60-02. Valve train noise − Worn or defective camshaft may be problem. − Loose rocker arm attachments − Worn rocker arm or pushrod − Broken valve springs − Sticking Valves − Worn, dirty, defective lifters − Defective fuel pump, pushrods − Low oil pressure − Worn valve guides − Collapsed Lifters − Check for popping noise through throttle body; perform visual inspection; check with dial indicator. − Visual inspection; service as required. − Diagnosis cause and repair. − Visual inspection; vacuum gauge test. − Visual inspection; vacuum gauge test. − Visual inspection. − Visual inspection. − Check oil pressure; repair as needed. − Perform vacuum test; use dial indicator to check wear. − Oil drained out of lifters, replace as indicated. Tick − GM C/K vehicles - On cold start at low temperatures during engine deceleration after idle flare. Not consistently repeatable. − Confirm proper VCM calibration. Refer to GM Bulletin 99-06-04-014 for details. Knock, engine cold. Continues for 2 to 3 minutes. Increases with torque. − Flywheel may be contacting splash shield. − Loose or broken torsional damper or drive pulleys. − Excessive piston-to-bore clearance (piston slap). − Bent connecting rod. − Perform visual inspection. − Remove accessory belts; perform visual inspection. − Check with bore gauge and T-gauge micrometer. − Perform visual inspection. Heavy knock, engine hot, torque applied. − Broken harmonic balancer or pulley hub. − Loose torque converter bolts. − Exhaust system grounding out. − Cracked flywheel, loose rivets. − Incorrect main bearing or rod bearing clearance. − Remove drive belts; perform visual inspection, service or replace as required. − Visual inspection. − Visual inspection; carbon knock possible. − Visual inspection. − Visual inspection. Light knock, engine hot, under light load conditions. − Pre-ignition; ignition control problems; detonation. − Poor fuel quality − Loose torque converter bolts. − Exhaust leak at manifold. − Excessive rod bearing clearance. − Check engine codes and ignition timing settings; reset to specifications; check EGR for blockage. − Owner input; use known good fuel. − Visual inspection. − Visual inspection. − Visual inspection Start-up knock, lasts a few seconds. − Timing chain tensioner not properly set. − Improper oil viscosity. − Bearing knock. − Hydraulic lifter bleed down. − Check filter with anti-drainback valve. − Change oil; check engine performance for knock. − Confirm that filter has anti-drainback valve. − Check requires special equipment. Knock at idle, engine hot. − Drive belts too tight; accessory belt pulley bearing loaded. − Improper oil viscosity. − Noisy piston pin (double knock). − Loose torsional damper. − Remove accessory belts; observe change, if any. − Change oil; check engine performance for knock. − Short out suspect cylinder; noise should disappear. − Perform visual inspection with engine under load Bruce 2023 Cadillac CT4-V Blackwing Follow me on: Twitter Instagram Youtube Link to comment Share on other sites More sharing options...
Ranger Posted February 19, 2007 Report Share Posted February 19, 2007 EGR would be the first suspect I would think. It should set a DTC if faulty. If that is OK, then perhaps a faulty knock sensor. I would think that too would set a DTC. Your car should run fine on 87. Link to comment Share on other sites More sharing options...
95SevilleSLS Posted February 19, 2007 Report Share Posted February 19, 2007 Just for kicks and giggles you should try 91 octane and see if it still does it. -Dusty- - 02 Seville STS, white diamond - 93 Sixty Special, Tan with vinyl top - 79 Coupe DeVille, Tan with Tan top - 06 GMC Sierra Z71, Black - 92 Silverado C1500, black and grey - 83 Chevy K10 Silverado, Black and Grey Link to comment Share on other sites More sharing options...
clarkz71 Posted February 19, 2007 Report Share Posted February 19, 2007 perhaps a faulty knock sensor. I would think that too would set a DTC. Your car should run fine on 87. I agree, somethings not working as designed with the knock sensor system, my 95 Eldo requires 93/premium, yet when I ran 87 it made no pinging or knocking noises at all. Link to comment Share on other sites More sharing options...
GreenMachine Posted February 19, 2007 Report Share Posted February 19, 2007 ^Manual says you may hear pinging or knocking not using 91 octane. Knock sensor can't retard timing until it hears it, might be some heavy detonation etc. I'd give the higher octane a try and see what happens. If it goes away you may want to go that route and see the fuel economy and acceleration increase and decide to stay that way The Green's Machines 1998 Deville - high mileage, keeps on going, custom cat-back exhaust 2003 Seville - stock low mileage goodness! 2004 Grand Prix GTP CompG - Smaller supercharger pulley, Ported Exhaust Manifolds, Dyno tune, etc 1998 Firebird Formula - 408 LQ9 Stroker motor swap and all sorts of go fast stuff Link to comment Share on other sites More sharing options...
Ranger Posted February 19, 2007 Report Share Posted February 19, 2007 The knock sensor will "hear" it and retard the timing long before you will ...... if it is working correctly. Link to comment Share on other sites More sharing options...
GreenMachine Posted February 20, 2007 Report Share Posted February 20, 2007 True, unless the first ones that occur are indeed loud It could happen sudden without "silent pings" first I'd imagine. The manual wouldn't mention the pings if there wasn't a chance you hearing them. Don't know. The Green's Machines 1998 Deville - high mileage, keeps on going, custom cat-back exhaust 2003 Seville - stock low mileage goodness! 2004 Grand Prix GTP CompG - Smaller supercharger pulley, Ported Exhaust Manifolds, Dyno tune, etc 1998 Firebird Formula - 408 LQ9 Stroker motor swap and all sorts of go fast stuff Link to comment Share on other sites More sharing options...
clarkz71 Posted February 20, 2007 Report Share Posted February 20, 2007 Just recently I've notice my 02 STS has started pinging and slight acceleration. I always use 87 Octane. Could this possibly be the EGR valve or can you suggest what I might check for. Thanks ^Manual says you may hear pinging or knocking not using 91 octane. Knock sensor can't retard timing until it hears it, might be some heavy detonation etc. I'd give the higher octane a try and see what happens. If it goes away you may want to go that route and see the fuel economy and acceleration increase and decide to stay that way The knock sensor will "hear" it and retard the timing long before you will ...... if it is working correctly. I agree with Ranger, the guy has always used 87 with no problems. Switching to 93 isn't fixing the problem, not to mention the fact that 2000 & up models don't require it.. He needs to get a Tech 2 on the car and test the knock sensor system. Also verify what timing the PCM is giving the engine. Link to comment Share on other sites More sharing options...
weephee Posted February 20, 2007 Author Report Share Posted February 20, 2007 Thanks guys for the input. I'm returning on a 1500 miles trip from home so on the next fill up I will try a higher octane. There are no codes so I will take it in to the dealer when I get back. I also agree that it shouldn't ping with 87 octane so something isn't right. Gas mileage is not as good as I'm used to with this car. Car has 50k miles on it. I'll report back when I have some new info. Link to comment Share on other sites More sharing options...
JimD Posted February 20, 2007 Report Share Posted February 20, 2007 Your first impression that EGR delivery is the problem is the first item I would attack. It is possible for the EGR valve to become sluggish or even held slightly open at the wrong time but not set a code. Too much EGR at the wrong time could result in the symptoms you have described so far. If you are the least bit inclined to DIY, removing and cleaning the EGR valve shaft is about as easy a job as you can hope to find. I would certainly do that before darkening the dealer's door. Without DTCs present, you would be granting the dealer's service department permission to empty your bank account while they "try" to isolate the problem. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
blue_eldo Posted February 23, 2007 Report Share Posted February 23, 2007 I have had an intermittent pinging issue with my 96 deville with 118K on in. I bought the car 20 months ago with 97K on it and it has been pinging since then. I run nothing but 91 or 93 octane, and I do many WOT's to keep the carbon down. There are no codes to reflect anything wrong. I pulled the EGR out and it looked perfect. I have been thinking that one of the crank position sensors is goofy since it will be stimulated by a bump in the road. You hit a bump with your foot into the throttle half or greater, and she will ping so hard your foot comes right off in an automatic reflex reaction. One in a while it will do it without the bump stimilus. Other than this issue the car has been perfect. The only thing besides plugs and a coolant change has been a blower motor and a couple hits of 134A. Link to comment Share on other sites More sharing options...
epricedright Posted February 24, 2007 Report Share Posted February 24, 2007 EGR would be the first suspect I would think. It should set a DTC if faulty. If that is OK, then perhaps a faulty knock sensor. I would think that too would set a DTC. Your car should run fine on 87. I had the pinging with slight acceleration and no codes were set. I replaced the EGR valve and all was well. Link to comment Share on other sites More sharing options...
blue_eldo Posted April 3, 2007 Report Share Posted April 3, 2007 I have had an intermittent pinging issue with my 96 deville with 118K on in. I bought the car 20 months ago with 97K on it and it has been pinging since then. I run nothing but 91 or 93 octane, and I do many WOT's to keep the carbon down. There are no codes to reflect anything wrong. I pulled the EGR out and it looked perfect. I have been thinking that one of the crank position sensors is goofy since it will be stimulated by a bump in the road. You hit a bump with your foot into the throttle half or greater, and she will ping so hard your foot comes right off in an automatic reflex reaction. One in a while it will do it without the bump stimilus. Other than this issue the car has been perfect. The only thing besides plugs and a coolant change has been a blower motor and a couple hits of 134A. As a follow up on the above, I replaced the EGR yesterday. Initial testing indicates that I am still pinging. I did a WOT from a slow roll. It downshifted in first pulled strong then upon shiftiing into second there was slight pinging. Not the heavy type that I sometimes experience. I will continue testing. I will most likly be replacing the Crank position sensors next. Link to comment Share on other sites More sharing options...
KHE Posted April 3, 2007 Report Share Posted April 3, 2007 I would not suspect the crank sensors based on your description of the symptom. Before you throw more parts at it, I would suggest troubleshooting the knock sensor and associated wiring. It may be possible that the knock sensor has failed and is not automatically retarding the timing to prevent the pinging. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
OynxSTS Posted April 3, 2007 Report Share Posted April 3, 2007 If it goes away you may want to go that route and see the fuel economy and acceleration increase and decide to stay that way If your lucky... In my 02 my mileage goes down and the performance stays about the same with the high test fuel. And I agree, while the orginal crank sensors on 00-03 cars are problematic and will all need to be replaced... they cause random stalls... not pinging... Maybe carbon buildup... piston slap? Easin' down the highway in a new Cadillac, I had a fine fox in front, I had three more in the back ZZTOP, I'm Bad I'm Nationwide Greg Link to comment Share on other sites More sharing options...
clarkz71 Posted April 4, 2007 Report Share Posted April 4, 2007 Maybe because your 02 doesn't require premium. I gain 2 to 3 mpg when I use premium in my 95. Link to comment Share on other sites More sharing options...
OynxSTS Posted April 4, 2007 Report Share Posted April 4, 2007 Maybe because your 02 doesn't require premium. I gain 2 to 3 mpg when I use premium in my 95. Exactly, thats what we are all saying, the person with the problem has an 02 and its pinging... the solution is not high test fuel. Easin' down the highway in a new Cadillac, I had a fine fox in front, I had three more in the back ZZTOP, I'm Bad I'm Nationwide Greg Link to comment Share on other sites More sharing options...
clarkz71 Posted April 4, 2007 Report Share Posted April 4, 2007 I agree, somethings not working as designed with the knock sensor system, my 95 Eldo requires 93/premium, yet when I ran 87 it made no pinging or knocking noises at all. Exactly, thats what we are all saying, the person with the problem has an 02 and its pinging... the solution is not high test fuel. I know, I'm one of those people. Link to comment Share on other sites More sharing options...
BodybyFisher Posted April 4, 2007 Report Share Posted April 4, 2007 You know, many say it doesn't but I really don't think many realize that using regular when the engine calls for premium causes a performance hit. I have been hurting financially since September and have been using 87. I can not use 87 in the summer when the engine is really hot as I ping, in the winter I don't hear ping. BUT, I will bet that if I were to get into heavy traffic and the engine got hot my engine would ping with 87. Recently I started using 91 again and I felt a big difference in performance. If you are using 87 when your engine takes 91, please try using 91 for a couple of tanks you might be surprised. The guru once said the $ you think you are saving using 87 you are loosing on degraded miles per gallon. You can do this test yourself. Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
OynxSTS Posted April 4, 2007 Report Share Posted April 4, 2007 Whoops, I think we have hijacked this thread and it has degraded into the old premium vs regular debate. I agree many pre 2000 northstars run better on 91 or 93. But the 2000-2004 N*s should be happy as pie on 87. If it's not, then there is something a miss. My 4.5L 1990 Allante required 90 Octane or better and GM was right... It would ping on 87 so it got mid-grade 91. I wish we still had the old guru posts... I could have sworn his point of view was that the 2000 and up N*s would get a little better performance on the high octane juice, but the mileage would be no better, which is pretty much my experience. Back to the problem: Is there a chance that the EGR passageway is plugged? I know on some GM motors the EGR "pipes" were particularly prone to carbon build up and blockages... When this happened these motors would ping like crazy too... IIRC GM improved the EGR passageways in the 2000 and newer N*s, but that doesn't mean that they couldn't be plugged. Easin' down the highway in a new Cadillac, I had a fine fox in front, I had three more in the back ZZTOP, I'm Bad I'm Nationwide Greg Link to comment Share on other sites More sharing options...
BodybyFisher Posted April 4, 2007 Report Share Posted April 4, 2007 Will a bad knock sensor set a code? I would think that your knock sensor is bad. Are you overheating at all? Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
Ranger Posted April 4, 2007 Report Share Posted April 4, 2007 Will a bad knock sensor set a code? Yup. # P0324 - Knock Sensor (KS) Module Performance # P0325 - PCM Knock Sensor Circuit # P0326 - Knock Sensor Circuit Excessive Spark Retard # P0327 - Knock Sensor Circuit Low Voltage # P0328 - Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor) # P0329 - Knock Sensor 1 Circuit Intermittent (Bank 1 or Single Sensor) # P0330 - Knock Sensor (KS) Circuit Bank 2 # P0331 - Knock Sensor 2 Circuit Range/Performance (Bank 2) # P0332 - Knock Sensor 2 Circuit Low Input (Bank 2) # P0333 - Knock Sensor 2 Circuit High Input (Bank 2) # P0334 - Knock Sensor 2 Circuit Intermittent (Bank 2) # P0335 - CKP Sensor A Circuit Performance Link to comment Share on other sites More sharing options...
blue_eldo Posted April 5, 2007 Report Share Posted April 5, 2007 Will a bad knock sensor set a code? Yup. # P0324 - Knock Sensor (KS) Module Performance # P0325 - PCM Knock Sensor Circuit # P0326 - Knock Sensor Circuit Excessive Spark Retard # P0327 - Knock Sensor Circuit Low Voltage # P0328 - Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor) # P0329 - Knock Sensor 1 Circuit Intermittent (Bank 1 or Single Sensor) # P0330 - Knock Sensor (KS) Circuit Bank 2 # P0331 - Knock Sensor 2 Circuit Range/Performance (Bank 2) # P0332 - Knock Sensor 2 Circuit Low Input (Bank 2) # P0333 - Knock Sensor 2 Circuit High Input (Bank 2) # P0334 - Knock Sensor 2 Circuit Intermittent (Bank 2) # P0335 - CKP Sensor A Circuit Performance I am the guy with the pinging 96 deville. Again I am not getting any codes for knock sensor or from crank position issues. I still can't figure out why the pinging is stimulated by bumps in the road. I believe my next step is to pull the intake and clean the carbon out of the EGR passages since replacing the EGR did nothing. It seems to run a little stronger with the new EGR however. Does anyone have any suggestions. Blue_Eldo Link to comment Share on other sites More sharing options...
Ranger Posted April 5, 2007 Report Share Posted April 5, 2007 My guess would be a loose electrical connection since it is induced by bumps. The million dollar question is which one. Link to comment Share on other sites More sharing options...
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