Why is my CTT so hard to start?

[ALEV8]

Man I'm starting to wince every time I start the car. I do know my starter is going out because it's squealing, and I can easily replace it. What still concerns me is the drop in RPMs when the car first starts.....it's like the car is going to shake apart for a few seconds then smooths out. Drives me insane. Idle has been on and off slightly rough at the end of 2012. I've replaced all the coils with latest and greatest. Apart from the starter slowly dying am I looking at fuel filter/pump here? Anybody know an awesome indy mech in Dallas? Autoscope, RUF, etc......I want a Porsche only guy/gal.

[hahnmgh63]

Sounds like it could be a fuel pump or filter/check valve.

[deilenberger]

Ummm... the starter squealing can also be a sign of a slow start, and the automatic start circuit not detecting the engine running (the low RPM condition you mention) and not un-powering the starter. This symptom was what clued me into the starting problem (caused by loss of residual fuel pressure) in my '06. There is a thread going on about the same sort of thing right at the moment - and yes - you may be looking at a fuel system problem, NOT a starter problem.

FWIW - I have never experienced a squeal from the starter once the fuel pressure problem was fixed. It's worked flawlessly.

BTW - be helpful to know what year/model we're looking at.. perhaps adding it to your SIG might make that a bunch easier.

Edited January 8, 2013 by deilenberger

[ALEV8]

Sorry Don 'tis an 04 CTT. My mech tested pressure and it was fine. I'm wondering if it is the fuel filter or check valve or pump itself. Not sure how to diagnose without getting bent the hell over at Porsche. I'm keeping his car so I want it fixed. My first son is due to arrive 1-19 so I'm a little gun shy about the dealer.

Edited January 9, 2013 by ALEV8

[deilenberger]

Sorry Don 'tis an 04 CTT. My mech tested pressure and it was fine. I'm wondering if it is the fuel filter or check valve or pump itself. Not sure how to diagnose without getting bent the hell over at Porsche. I'm keeping his car so I want it fixed. My first son is due to arrive 1-19 so I'm a little gun shy about the dealer.

Did the mechanic do a retained pressure test? IE - when the engine is shut off the fuel rail should maintain some minimum pressure for XX minutes minimum. I could look those up for you, but I believe it was 2-Bar (about 30PSI) and running pressure is 3-Bar (~45 PSI). I also seem to recall the specification was 10 or 20 minutes. Usually when a check valve fails it will immediately depressurize when the engine is shut off, and eventually the fuel drains back to the tank from the fuel rail. That means the pumps have to re-pressurize and fill the fuel rail before it will kick off at normal idle RPM.

[ALEV8]

We did but I don't recall how high pressure was or leak down.