sarakw806 Posted March 30, 2011 Report Share Posted March 30, 2011 So that's why I'm taking to get it done. lol Or is there something else I can do? The something else I would do is: Get on a stretch of Interstate highway Run the vehicle at the speed limit in 3rd gear (even better would be 2nd gear) for 30 minutes Your P0420 is set by the PCM based on the activity of your O2 sensors. And if your O2 sensors have been subjected to urban short trip stop and go driving, they "might" benefit from a thorough heat-soak and high velocity exhaust gas experience. And the above procedure will certainly do that. Plus - If the above did not resolve the code, I would do some serious diagnosis of the O2 sensors before I butchered the exhaust system to replace a catalytic converter. I am wondering if I should go the speed limit on 2nd or 3rd or will it matter? Thanks If you have freeways around you .. I would probably use 3rd... Speed limit around here on a lot of the freeways is 70MPH. In my car...2nd gear at 70 MPH is over 5000RPM... In my opinion...that is too much RPM for running it 30 minutes. For a long 30 minutes run... I would use 3rd gear... If you are running at 50 MPH or so... use 2nd... Link to comment Share on other sites More sharing options...
sarakw806 Posted March 30, 2011 Report Share Posted March 30, 2011 Well, I did the test drive and did the 3rd gear the RPMs' was at 39000, , the only problem was that the gas pedal at my foot was shaking so much that it was kinda hard to drive and your foot shaking so bad. lol The car was not shaking just the pedal and the mph was at 20. Link to comment Share on other sites More sharing options...
Texas Jim Posted March 30, 2011 Report Share Posted March 30, 2011 Well, I did the test drive and did the 3rd gear the RPMs' was at 39000, , the only problem was that the gas pedal at my foot was shaking so much that it was kinda hard to drive and your foot shaking so bad. lol The car was not shaking just the pedal and the mph was at 20. Please elaborate... What exactly was shaking...and at what speed? Did the engine stay at proper temperature? Is the car driving OK? Any unusual noises? Do you know how to pull the codes on your car and write them down? If so ..please do that and post them here. Link to comment Share on other sites More sharing options...
JimD Posted March 30, 2011 Report Share Posted March 30, 2011 http://www.caddyinfo.com/readingcodes.html Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
Ranger Posted March 31, 2011 Report Share Posted March 31, 2011 i wonder how fast i can go in second? if i'm on the highway would it be better to be in third gear? When I do a WOT I can reach 80 MPH in 2nd and still not shift into 3rd. Link to comment Share on other sites More sharing options...
sarakw806 Posted March 31, 2011 Report Share Posted March 31, 2011 Well, I did the test drive and did the 3rd gear the RPMs' was at 39000, , the only problem was that the gas pedal at my foot was shaking so much that it was kinda hard to drive and your foot shaking so bad. lol The car was not shaking just the pedal and the mph was at 20. Please elaborate... What exactly was shaking...and at what speed? Did the engine stay at proper temperature? Is the car driving OK? Any unusual noises? Do you know how to pull the codes on your car and write them down? If so ..please do that and post them here. Well, at 50 mph or 70 mph, there was vibration under my foot from the gas pedal shaking, while I was driving, the temps were normal. And no unusual noises or tugs or pulling. The car drove fine. Although the gas pedal does seem kinda stiff when pressing on it, even while its shaking. P. S. The codes pulled are the same ones prior: PCM 0420-C I did look under the car where the muffler belly and exhaust pipes are, I did notice some soot on the underside of the tank (2) leading to the exhausts, not much kinda like soot is hitting the ground and back up to make contact with that underside. Link to comment Share on other sites More sharing options...
Texas Jim Posted March 31, 2011 Report Share Posted March 31, 2011 I don't know what the vibration in the gas pedal may be.. If it drove fine and ran fine..that is a good sign. Does it still have the noise when you start it... and does the noise stop after it runs for a minute or so? If the converter code is still there after the drive...it is either the converter O2 sensor... or it really does need a converter. Hopefully someone else will jump in here and give their opinion also... You said you were in Texas.. I am in the DFW area... If you are close I might be able to run by and take a look at it.. Link to comment Share on other sites More sharing options...
sarakw806 Posted March 31, 2011 Report Share Posted March 31, 2011 I don't know what the vibration in the gas pedal may be.. If it drove fine and ran fine..that is a good sign. Does it still have the noise when you start it... and does the noise stop after it runs for a minute or so? If the converter code is still there after the drive...it is either the converter O2 sensor... or it really does need a converter. Hopefully someone else will jump in here and give their opinion also... You said you were in Texas.. I am in the DFW area... If you are close I might be able to run by and take a look at it.. Thanks, that is kind of you but, I have it scheduled to be in the shop tomorrow. I guess I will find out what is wrong then, thanks for your help. Link to comment Share on other sites More sharing options...
Texas Jim Posted March 31, 2011 Report Share Posted March 31, 2011 I don't know what the vibration in the gas pedal may be.. If it drove fine and ran fine..that is a good sign. Does it still have the noise when you start it... and does the noise stop after it runs for a minute or so? If the converter code is still there after the drive...it is either the converter O2 sensor... or it really does need a converter. Hopefully someone else will jump in here and give their opinion also... You said you were in Texas.. I am in the DFW area... If you are close I might be able to run by and take a look at it.. Thanks, that is kind of you but, I have it scheduled to be in the shop tomorrow. I guess I will find out what is wrong then, thanks for your help. No problem... Please keep us informed as to what is wrong and what you did to fix it. Good luck... Link to comment Share on other sites More sharing options...
relaxitsonlyagame Posted April 23, 2011 Author Report Share Posted April 23, 2011 Sorry to leave this thread high and dry for a bit but I haven't been home much with work and the general obligations of life. I had a chance to take a look at this but I am kind of lost. My Helms is for a 95' model year and I have two 94's! The intake is completely different on mine. I pulled the magnesium cover off but I have no clue of where to find this relief valve or what it looks like. I did notice that when putting the cover back on, the female threads for one bolt on the far bottom RH side are stripped and possibly is not allowing the intake cover to seal properly. Mufflers, cats, and 02 sensors are all new as of November 2010 and the car has no codes besides a bummed hub sensor. The car runs tops! But the noise is annoying when the stereo isn't being used and people look at it as if I have a supercharger the size of a D cell battery One thing I notice, is that when parking and shutting the car off, the wheezing/whistling sound dies off after a second or two with depressurization. Link to comment Share on other sites More sharing options...
Ranger Posted April 24, 2011 Report Share Posted April 24, 2011 The cover on the '93/'94 is the relief valve. It sits on rubber grommets and in the event of a backfire, it lifts enough to vent the manifold. Be sure to use the proper torque when you put the manifold back on. If you torque down the bolts tight, you defeat it's ability to relieve pressure. One thing I notice, is that when parking and shutting the car off, the wheezing/whistling sound dies off after a second or two with depressurization. Definite sign of a vacuum leak. Link to comment Share on other sites More sharing options...
scott y Posted April 24, 2011 Report Share Posted April 24, 2011 The cover on my '94 sits on a very thin gasket and the torx head bolts must be torqued at around 10 inch pounds if I remember correctly. That doesn't feel loose but I notice that when it is properly torqued and using the cruise servo to work the revs up and down the cover looks as tho it is "breathing". Look at your belly as you breathe in and out and that's what it looks like. Link to comment Share on other sites More sharing options...
sarakw806 Posted April 26, 2011 Report Share Posted April 26, 2011 . Link to comment Share on other sites More sharing options...
sarakw806 Posted April 26, 2011 Report Share Posted April 26, 2011 Well, I took my car to the muffler shop and they said it was an air line pin hole in the air suspension ride that is causing the whistling noise. It will cost 450.00 to replace the air line. Wow, I hope they are being honest. It does sound like it would be the problem. Link to comment Share on other sites More sharing options...
sarakw806 Posted April 26, 2011 Report Share Posted April 26, 2011 The cover on the '93/'94 is the relief valve. It sits on rubber grommets and in the event of a backfire, it lifts enough to vent the manifold. Be sure to use the proper torque when you put the manifold back on. If you torque down the bolts tight, you defeat it's ability to relieve pressure. One thing I notice, is that when parking and shutting the car off, the wheezing/whistling sound dies off after a second or two with depressurization. Definite sign of a vacuum leak. Link to comment Share on other sites More sharing options...
sarakw806 Posted April 26, 2011 Report Share Posted April 26, 2011 I got mine checked out and they said it was an suspension ride air line, it has a pin hole from a clip holding it on. Link to comment Share on other sites More sharing options...
Ranger Posted April 27, 2011 Report Share Posted April 27, 2011 I just reread your symptoms in post #31. They are not related to a pin hole in the rear level control air line. Link to comment Share on other sites More sharing options...
sarakw806 Posted April 28, 2011 Report Share Posted April 28, 2011 I just reread your symptoms in post #31. They are not related to a pin hole in the rear level control air line. Link to comment Share on other sites More sharing options...
sarakw806 Posted April 28, 2011 Report Share Posted April 28, 2011 Well, I feel like I am just running around in circles now, I re-read the diagnostic codes and now I am getting the code of PCM 0410C and still the code of PCM 0429C. I still heat a air loading sound in the control panel. UGRRRRR!!! It is driving fairly well,but the mpg is only 19 when in the past it was 20.7 same routine of driving. Link to comment Share on other sites More sharing options...
BodybyFisher Posted April 28, 2011 Report Share Posted April 28, 2011 Well, I feel like I am just running around in circles now, I re-read the diagnostic codes and now I am getting the code of PCM 0410C and still the code of PCM 0429C. I still heat a air loading sound in the control panel. UGRRRRR!!! It is driving fairly well,but the mpg is only 19 when in the past it was 20.7 same routine of driving. WAIT, you hear AIR in the CONTROL PANEL???, what control panel? Why are you posting here, is THIS related to your REAR SUSPENSION??? 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...
sarakw806 Posted April 28, 2011 Report Share Posted April 28, 2011 Well the relief valve issue would make sense. I listened around the other night and it is a deafening sound that makes you want to rip your hair out when leaning over the P/S pump. This relief valve; is it under the pretty magnesium manifold cover? Do the gaskets on these tend to dry out or break? Just wondering if I should pick up a new one before I start working on this pig. Thanks for all the responses! I was leaning more to the TC before, because I've heard noises similar to this being created from other cars' TC's but this car is in pretty rock solid condition and the sound is most definitely coming from the top of the motor and not underneath. Link to comment Share on other sites More sharing options...
sarakw806 Posted April 28, 2011 Report Share Posted April 28, 2011 Did you find out what the sound was caused by, sure could use your help in resolving mine. Link to comment Share on other sites More sharing options...
Ranger Posted April 29, 2011 Report Share Posted April 29, 2011 Well, I feel like I am just running around in circles now, I re-read the diagnostic codes and now I am getting the code of PCM 0410C and still the code of PCM 0429C. I still heat a air loading sound in the control panel. UGRRRRR!!! It is driving fairly well,but the mpg is only 19 when in the past it was 20.7 same routine of driving. P0410 is an AIR pump code. The pump should only run for about 40 seconds after a cold start. If it's working properly you should not hear it. There is no P0429. I suspect you mean B0429. That's the rear temp control actuator. Neither would affect your fuel mileage. Link to comment Share on other sites More sharing options...
sarakw806 Posted April 29, 2011 Report Share Posted April 29, 2011 Well, I feel like I am just running around in circles now, I re-read the diagnostic codes and now I am getting the code of PCM 0410C and still the code of PCM 0429C. I still heat a air loading sound in the control panel. UGRRRRR!!! It is driving fairly well,but the mpg is only 19 when in the past it was 20.7 same routine of driving. P0410 is an AIR pump code. The pump should only run for about 40 seconds after a cold start. If it's working properly you should not hear it. There is no P0429. I suspect you mean B0429. That's the rear temp control actuator. Neither would affect your fuel mileage. Link to comment Share on other sites More sharing options...
sarakw806 Posted April 29, 2011 Report Share Posted April 29, 2011 How about worn out tires, I think I need to get a new set, my car is kinda vibrating when I get to 66 mph. Link to comment Share on other sites More sharing options...
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