4544x4 Posted October 29, 2008 Report Share Posted October 29, 2008 I removed the engine to reseal it and no for the past 2 months these code keep reseeting. I've cleaned the injectoers replace the fuel pump and filter. today I noticed the valve cover seals were not in the grooves all the way around the covers so I took some gms and filled the voids for now.not leaking oil but could this cause unmetered air to enter? Link to comment Share on other sites More sharing options...
Ranger Posted October 29, 2008 Report Share Posted October 29, 2008 I don't think the cam covers would cause unmetered air to get into the intake. Check the intake mount, PCV grommet, vacuum lines etc. Link to comment Share on other sites More sharing options...
Ranger Posted October 29, 2008 Report Share Posted October 29, 2008 Deleted duplicate post Link to comment Share on other sites More sharing options...
4544x4 Posted October 29, 2008 Author Report Share Posted October 29, 2008 ok thanks Link to comment Share on other sites More sharing options...
Cadillac Jim Posted October 31, 2008 Report Share Posted October 31, 2008 Valve cover leaks will allow excess air to enter through the PCV valve. It can cause the lean mixture codes. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
Ranger Posted November 1, 2008 Report Share Posted November 1, 2008 That makes sense. I stand corrected. Link to comment Share on other sites More sharing options...
growe3 Posted November 1, 2008 Report Share Posted November 1, 2008 Valve cover leaks will allow excess air to enter through the PCV valve. It can cause the lean mixture codes. How can a valve cover leak allow more air to enter the PVC? The PVC is a metered flow valve, only so much air is allowed to pass, by design. The only effect loose or leaky valve covers would have, is to allow dirty air in to the engine (or of course oil leaks). Normally the air necessary to ventilate the engine is passed through the air cleaner, then into a valve cover, to be pulled across the engine through the PVC, to be burned during the combustion process. -George Drive'em like you own 'em. - ....................04 DTS............................ Link to comment Share on other sites More sharing options...
growe3 Posted November 1, 2008 Report Share Posted November 1, 2008 I removed the engine to reseal it and no for the past 2 months these code keep reseeting. I've cleaned the injectoers replace the fuel pump and filter. today I noticed the valve cover seals were not in the grooves all the way around the covers so I took some gms and filled the voids for now.not leaking oil but could this cause unmetered air to enter? The most likely source of a lean mix would be a poorly sealed intake. If the 02 sensor detects a rich mix (bad or weak ignition, partially plugged catalytic converter), the PCM will reduce the pulses to the injectors, to try and correct the fuel imbalance. This could also cause a lean condition. As for cleaning the injectors, without special tools you cannot really clean the injectors. You can clean off the outside and the tip, but this has very little effect on their flow, as they may be partially clogged internally, and/or not functioning electrically. The link below is to a test that I had done by Cruzin Performance, to the injectors from my 93 STS. This is a very dependable and honest shop. My injectors turned out to be OK, and I was only charged for testing, not any unnecessary work. In my case it turned out to be an intermittent fault with the PCM that was causing the lean out condition. Cadillac Info Look for "Injector Test Results". Sometime Yahoo has problems, so it may be best to just download the PDF file, rather then try to stream it. -George Drive'em like you own 'em. - ....................04 DTS............................ Link to comment Share on other sites More sharing options...
Cadillac Jim Posted November 1, 2008 Report Share Posted November 1, 2008 A cam cover gasket leak can kill the vacuum in the crankcase. If the PCV valve is stuck open, it can cause a lean condition and throw codes. Yes, if the PCV valve is operating properly, it will restrict air flow and prevent a lean condition except possibly at idle. If there is a cam cover leak, including gasket or oil cap, it should be sealed. Likewise the dip stick should be present, the correct one for the car, and pushed all the way down so that it seals. The normal crankcase ventilation path is air from the intake path before the throttle body (i.e. air filtered by the air cleaner) through a hose to one cam cover, down through the front head, across through the crankcase, up through the rear head, then through the PCV valve into the intake behind the throttle valve. Although PCV was first used as an emissions control device, keeping blow-by from being simply vented, its immediate effect on automobile engines was that blow-by products were not dumped into the oil, either. The difference between a 1,000 to 2,000 mile oil change and a 3,000 to 6,000 mile oil change is PCV. If your PCV system has any problem at all, watch your oil (color, smell, and texture) and be prepared for early oil changes to protect your engine from sludge and corrosion. Back to the codes, yes, when you get lean condition codes from both banks, it's usually an intake manifold leak. These are simple to fix -- Check all the hoses, and if they are good, just pop the intake and check or replace the intake manifold gasket as necessary. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
growe3 Posted November 1, 2008 Report Share Posted November 1, 2008 A PCV stuck wide open may cause a very minor lean out at part throttle, but the PCM should be able to compensate to a great extent. A cam cover would need to have a substantial leak, to not be able to apply some vacuum. At idle the PCV is open quite a bit, the only time it is open more is under deceleration; where the low pressure is greater. Under acceleration it does almost nothing. Simple to check the PCV, with engine off it will rattle when you shake it. With the engine running, slip your thumb over the opening and remove your thumb. You should hear the valve shuttle back and forth. This does not mean it is working perfectly, but well enough to not cause a problem. -George Drive'em like you own 'em. - ....................04 DTS............................ Link to comment Share on other sites More sharing options...
Ranger Posted November 2, 2008 Report Share Posted November 2, 2008 Sometime around 2000, GM changed from the old rattle can PCV to a metered orifice (no moving parts to rattle). No point to this. Just thought it was worth an honorable mention. Link to comment Share on other sites More sharing options...
growe3 Posted November 2, 2008 Report Share Posted November 2, 2008 Sometime around 2000, GM changed from the old rattle can PCV to a metered orifice (no moving parts to rattle). No point to this. Just thought it was worth an honorable mention. Interesting, I had not noticed this change. After reviewing my 04 manual it appears that they have gone to a 3 mm hole, with no backfire valve prevention. Apparently the new smaller opening makes the valve unnecessary. Again it is easy to see if this metered orifice is working right, and then clean with spray Throttle Body Cleaner if needed. Thanks for the update Ranger. -George Drive'em like you own 'em. - ....................04 DTS............................ Link to comment Share on other sites More sharing options...
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