Bob Lemay Posted July 23, 2023 Report Share Posted July 23, 2023 Hello All, My 05 Boxster S has been giving me a CEL every 150 miles or so, and the OBD is saying insufficient flow to bank 1. Today, I removed the air pump and the check valve. Air pump running strong,, with direct 12 v to it, and the check valve seems to be working properly, despite being able to blow back in the opposite direction very slightly. if I manually blow into the tube that supplies bank 2, there is no resistance. When I manually try the same on bank 1, there's some resistance, it's not as free flowing as bank 2. If there's a clog within the cylinder head, how would a person clean it? Thank You in advance with any help, Robert Lemay, Sherman Ct. Quote Link to comment Share on other sites More sharing options...
Paul P Posted July 23, 2023 Report Share Posted July 23, 2023 Hi. depends on the actual code you got but some of this info might be relevant. Quote Link to comment Share on other sites More sharing options...
Bob Lemay Posted July 23, 2023 Author Report Share Posted July 23, 2023 The code is a p 0491, the icarsoft also clearly says it’s insufficient flow to bank one Quote Link to comment Share on other sites More sharing options...
Paul P Posted July 23, 2023 Report Share Posted July 23, 2023 55 minutes ago, Bob Lemay said: The code is a p 0491, the icarsoft also clearly says it’s insufficient flow to bank one The write up from one of the responders on that thread suggests the method he used (as an Porsche specialist) to resolve the issue. Seems like you are already in the “right pace” and his method involves some chemical assistance. Quote Link to comment Share on other sites More sharing options...
Bob Lemay Posted July 25, 2023 Author Report Share Posted July 25, 2023 Hi! I've since cleaned the passageways in the engine's head, using chemicals to do the work.. there was definitely a clog here. Started with a bunch of carb cleaner down the injection hole in a few applications, then, compressed air in the hole, very well sealed at this opening for a few seconds, then a strong vacuum following. a few times of this and no success. I kept on trying to get the same flow of air as the second bank had, manually, with just my lungs, that had no resistance. I saw an old friend of mine today at the parts store and talked about the problem with him, and he suggested to try some oven cleaner to break up the deposits. Arriving home with some ez off, I shot a bit down the hole. Pushed air, pulled air. Many times. Tried the lung test again, pushing, and it got way worse!!.. No movement of air at all! Panic attack! Shot more carb cleaner, and just left it for an hour. I came back and started to try to pull air through, and instantly heard the vac make a relieved sound, like it wasn't begging for forgiveness anymore. Put the lung powered hose back on for the test... and.. SUCCESS!! Got it! Pushing air as easy as breathing.n There was a comment on the article I read, that was praising the author's help there through this forum, and I just wanted to say the same. Thank you again, Bob Lemay, Sherman Ct. 5 Quote Link to comment Share on other sites More sharing options...
Ninesomething Posted August 5, 2023 Report Share Posted August 5, 2023 Sure I remember reading somewhere that some people remove the pump entirely and plug the tube. Something to do with the weight of it or something. Must admit IDK what it does or why.... Quote Link to comment Share on other sites More sharing options...
Paul P Posted August 5, 2023 Report Share Posted August 5, 2023 I think it's an emissions device, if so then in theory could be bypassed. You would would probably need a custom ecu map to remove the checks/errors associated with it working "properly" 1 Quote Link to comment Share on other sites More sharing options...
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