Alfredo Deville Posted December 2, 2012 Report Share Posted December 2, 2012 Hi Everyone I'm New to this Forum but not Cadillac. my De Ville showing code P-0507 just one code idle up and then down.i sprayed throttle body fluid around intake area when i got to the plenum it almost died out i waited then i shot it again did same thing it seems there's a vac leak on the side or bottom of plenum clamp.but i want to make sure its not the IAC Valve. what should I do try another can of spray and really see exactly where it changes the engine revs? Thanks in Advance ...... Alfredo DeVille Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 2, 2012 Report Share Posted December 2, 2012 Welcome aboard! Be very careful spraying anything into the throttle body, we have had a TECH hydrolock a Northstar by spraying a solvent into the throttle body which resulted in a rod blowing through the side of the engine. If you need to clean the throttle body it is best to clean it with GM upper engine cleaner and detail brushes and rags. Its a dirty and time consuming process. Pay particular attention to the REAR of the throttle plate, the edges and the throat where the plate contacts it. I refuse to spray anything into the intake since I saw a TECH catastophically destroy an engine doing the same. BUT, back to your problem, the rubber plenum develops cracks in it and it begins to leak, it must be replaced, it causes an erratic idle and will eventually cause lean conditions on both banks. It sounds like you have confirmed that you have a leak, good job diagnosing the problem 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...
KHE Posted December 3, 2012 Report Share Posted December 3, 2012 I believe the intake manifold needs to come off in order to replace the rubber plenum boot. It is not a difficult job. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
LINDAL Posted December 5, 2012 Report Share Posted December 5, 2012 Did this fix the problem? I have the dame year dame problem. Linda Link to comment Share on other sites More sharing options...
KHE Posted December 5, 2012 Report Share Posted December 5, 2012 Did this fix the problem? I have the dame year dame problem. Linda If you spray carb cleaner on the underside of the plenum boot and the engine about stalls, I would say the plenum is ripped. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
LINDAL Posted December 5, 2012 Report Share Posted December 5, 2012 Went to autozone at noon did dx test. Needx a sensoor on vac hose. Will put it on tonight. Link to comment Share on other sites More sharing options...
KHE Posted December 5, 2012 Report Share Posted December 5, 2012 Went to autozone at noon did dx test. Needx a sensoor on vac hose. Will put it on tonight. What is a "dx test"? What sensor are you referring to? Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
LINDAL Posted December 5, 2012 Report Share Posted December 5, 2012 Diagnostic test. Dx is equal to diagnosis in medical terminology. Sorry I was trying to abbreviate. Doing this on smart phone. The mass air flow sensor is what their test said is wrong. Will replace and let u know if it fixed it. Linda Link to comment Share on other sites More sharing options...
Logan Posted December 6, 2012 Report Share Posted December 6, 2012 What code are you getting? Mass air flow sensors are pretty robust and expensive. I don't put too much faith in free AutoZone Dx scans. Kinda a 'gee I dont know.....maybe you need a MAF.' Logan Diagnostic LLC www.airbagcrash.com www.logandieselusa.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
KHE Posted December 6, 2012 Report Share Posted December 6, 2012 To add to what Logan posted, AutoZone's Mass Airflow sensors are JUNK. Especially the rebuild ones. I went through two of their rebuilt units on a Buick Park Avenue I used to own.... I got my money back from them after the second one failed and purchased an OEM unit from the junkyard. Check the plenum boot! Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 6, 2012 Report Share Posted December 6, 2012 On the subject of Autozone, I just saw this http://www.theblaze.com/stories/autozone-employee-and-veteran-fired-for-using-his-gun-to-ward-off-armed-robber/ 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...
LINDAL Posted December 6, 2012 Report Share Posted December 6, 2012 The definite miss is gone. But the service Enginel lite on again It seems to ne surging. Going back at noon today. I cleared codes a few weeks ago. I need to pull them at noon. Autozone has hit the mark before. I will let u know Link to comment Share on other sites More sharing options...
Logan Posted December 6, 2012 Report Share Posted December 6, 2012 My guess is you are getting a 171 and 174 which are lean bank codes. At first glance, with these codes one would suspect a bad MAF. It sure sounds like a failed plenum boot. Every boot will fail sooner or later. Will cause surging, lean bank codes, SES light, etc. I bet the old MAF was fine. I attached a picture of the rubber plenum boot that fails. The intake has to come off to replace. Pretty sure it is a dealer-only part. Logan Diagnostic LLC www.airbagcrash.com www.logandieselusa.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 6, 2012 Report Share Posted December 6, 2012 I recently had an MAF code on a 95 that had a bad coil causing a bad miss, when I replaced the coil the MAF code went away, not sure why, but it was interesting to see that We have seen these boots go bad and affect the idle without setting the lean codes, I mentioned the lean codes above in my first post. I CAN NOT believe that you let autozone read ANY codes given that you can read them yourself, they may have ignored the lean codes altogether and went DIRECTLY for something they could SELL YOU. CHECK YOUR OWN CODES, if you do not know how see the bottom of MY POST my signiture I said in my FIRST post, the plenum sounds causes this, check your codes like I said in my first post above it will cause both bank lean codes, as logan said, you NEED to check your own codes and post them all, do not rely upon clowns 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...
airmike Posted December 6, 2012 Report Share Posted December 6, 2012 The definite miss is gone. But the service Enginel lite on again It seems to ne surging. Going back at noon today. I cleared codes a few weeks ago. I need to pull them at noon. Autozone has hit the mark before. I will let u know You really should listen to the guys on here and deal with that boot. Surging is a definite result of lean. If Auto Zone was right two times and then wrong the next 8, how many times would you be willing to replace parts they suggest before you realized they got lucky, on the first two? p.s. you can effect a vacuum leak ( which then could effect miss/idle quality) just from wiggling/moving parts around. Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 6, 2012 Report Share Posted December 6, 2012 I revised my post above airmikes post above please read it and check your own codes if you dont know how, let us know but read my signiture 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...
LINDAL Posted December 6, 2012 Report Share Posted December 6, 2012 Don't get excited guys. LOL! I know how to pull the codes. I just thought I could get it taken care of at lunch yesterday without too much trouble. My mistake! I pulled the codes before lunch and cleared. Then pulled again after lunch. The PCM P0174 Current is the one. Do I need someone to look at the part first before I buy one or just get one and have my husband replace it? Linda Link to comment Share on other sites More sharing options...
airmike Posted December 6, 2012 Report Share Posted December 6, 2012 Linda if you have not already had the boot checked per KHE post, then have that done and plan on ordering the boot then. I would definitely check as described, a vacuum line off or broken can cause the same result, and you should be sure before wasting money on part. Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 6, 2012 Report Share Posted December 6, 2012 P0174 - Fuel Trim System Lean Bank 2 which is the front bank. This would tend to eliminate the intake plenum, since its not both banks showing lean codes, drive the car a little more and check the codes again and see if P0171 comes up for the rear bank also, that would indicate the plenum. But with only one bank lean, its probably not the plenum You need to find out what is causing the front bank lean condition. Keep in mind that a lean condition can be caused by too much air OR too little fuel. Look your front bank over, I dont know the 2002 (assuming this is your 2002), but you are looking for something that affects only the front bank while you only have the P0174 code. Did you have any other codes? 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...
LINDAL Posted December 6, 2012 Report Share Posted December 6, 2012 I had some ABS codes. I will check them again. Yes, this is my 2002. I am trying to hang on to it for a little longer. The service engine soon light went out when I cleared the codes and has not come back on again. I drove around at noon just to see if it would come on. No luck. But, it was surging the whole time. The only code that came up in the PCM was the 174. I will check again later when I get home. I cleared the codes again after lunch. So, it will only be from the 18 mile drive home if it throws a code. Thank You, Linda Link to comment Share on other sites More sharing options...
LINDAL Posted December 7, 2012 Report Share Posted December 7, 2012 NO codes on the drive home. It did still surge. What next guys? My next idea is take it to the mechanic. But, I am afraid he won't find it until the light comes on again. Or it shows another code. Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 7, 2012 Report Share Posted December 7, 2012 how bad is it surging? explain in detail. Have the fuel pressure tested, very important now to know what is going on, test it with the key on engine not running and with the engine idling and post results here. Keep looking for codes and check engine lights. I would not take it to a mechanic unless the surging becomes a big problem, until we can narrow it down. Do you have someone who can do a little work on the car? 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...
KHE Posted December 7, 2012 Report Share Posted December 7, 2012 I would still spray some carb cleaner around the intake plenum - just to rule out a ripped boot. The next thing I'd try is to torque the intake manifold bolts to specification and see if that makes the 174 code go away. If that did not correct the problem, it may be a lazy oxygen sensor on the front bank. A shop with a Tech-2 should be able to identify the source of the problem. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
airmike Posted December 8, 2012 Report Share Posted December 8, 2012 I also would spray some carb cleaner, and wiggle things (hoses, plenum boot, any possible vacuum source) while spraying. I think the size of a leak may determine if it will set a code or not. Link to comment Share on other sites More sharing options...
LINDAL Posted December 8, 2012 Report Share Posted December 8, 2012 Surging pretty bad today. I feel like it is going die on me. Pulled codes at gas station. It is showing a upcoming u1000 history, and u 1000 history. Sdm u 1000. Silly phone keeps changing what I type in. Abs 1214,1232,1248 current. I have to figure this out before I am stranded. Link to comment Share on other sites More sharing options...
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