maxy Posted 20July, 2013 Report Share Posted 20July, 2013 My car has had a problem of rough running when cold for years. Ive mucked around with it over the years but I just learned to live with the problem. The last couple of days ive been thinking about it and Googleing. My car today is running the best it has in 10 years. The problem was, and im sure some of you have the same problem, when I went to start my car when dead cold it would run rough as guts, for a few seconds and stall. On the second or third try it would run rough then catch on and idle at high revs. After a couple of mins it would idle normally. When hot, after sitting for 10 or 15 mins it would start first go but idle at around 500rpm but rough as guts for a few minutes then catch on and idle normally. I thought I might have a vacuum leak that I couldn't find so I hooked up my compressor to the intake of my air filter, taped up the gaps, stuck a tennis ball up the exhaust pipe and pressurised the motor to about 200 kpa. I then sprayed soapy water all around the intake area and low and behold, two significant vacuum leaks. After fixing the two leaks I did the cold start. There was a significant improvement but still not right. I went for a test drive and it defiantly felt better but still didn't feel right. After scratching my head for a few days I got to thinking about the pop off valve in the air box. It was the only place I couldn't check with soapy water test. I opened the airbox and wriggled the pop off valve and it seemed a little loose. I then pulled it and it pulled right out. After years of use the glue has deteriorated to the point I had a large vacuum leak where the pop off valve was glued in. After gluing the pop off valve back in properly, the car is running almost perfectly. I went for a drive today and I cant believe how much better my car is starting and driving. Its now time for a tune up to get it perfect I get so much satisfaction out of finding, diagnosing and repairing my car. These cars are so well engineered and so easy to work on. So if your having cold or hot start problems with your CSI equipped Porsche your car may be running lean due to vacuum leaks and if you have the after market pop off valve fitted, pull it out, if it will come out easy, and reglue it with a two part epoxy. Its made a wold of difference to how my car is running now. Link to comment Share on other sites More sharing options...
Ben C3.o Posted 20July, 2013 Report Share Posted 20July, 2013 Good on you mate. Link to comment Share on other sites More sharing options...
wasserkuhl Posted 20July, 2013 Report Share Posted 20July, 2013 Well Done. I hope you did the "I Fixed Something Dance" I do around my back yard when I have triumph'd! Now, just as a side note. It is C I S Injection ; Continuous Injection System. Not CSI, which is Crime Scene Investigation. Good stuff!! Link to comment Share on other sites More sharing options...
maxy Posted 20July, 2013 Author Report Share Posted 20July, 2013 Yep I danced a little and had a beer. The more beers I have the more I dance. And yes I approached it like a crime scene . Forgive me for the odd tipo, tyierpo, typo Link to comment Share on other sites More sharing options...
Harvs11 Posted 20July, 2013 Report Share Posted 20July, 2013 Well Done. I hope you did the "I Fixed Something Dance" I do around my back yard when I have triumph'd! Now, just as a side note. It is C I S Injection ; Continuous Injection System. Not CSI, which is Crime Scene Investigation. Good stuff!! Well done Maxy. CSI is what you'll need if CIS is mucked about with by untrained tuners. Going back to basics is usually the best way sort a problem. Link to comment Share on other sites More sharing options...
wasserkuhl Posted 21July, 2013 Report Share Posted 21July, 2013 I actually think CSI is more appropriate as sometimes repairing Porsches is like assessing a crime scene! Link to comment Share on other sites More sharing options...
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