CEL - P0446, P1124, P1126; Starting problems

[gavinmead]

Hello everyone. I have a '99 C2 with 79k miles. For the last few months, I've had intermittent problems with starting (takes a long time, seemingly at random; other times, starts fine) and with a hunting idle below 1k RPM. I haven't been able to correlate the failure to any specific variable (ambient temperature, engine temperature, amount of fuel, etc). Additionally, I can often smell fuel after cranking.

Initially, I thought it may be tied to the ignition switch issue, but I replaced the electronic backing of the switch and have had no further problems there but my starting and idle problems persist.

As the CEL as been illuminated for some time, I finally broke down today and went to AutoZone for a code pull. Turns out, I've got P0446 (EVAP Canister), P1124, and P1126. I tried searching the forums for these codes, but I haven't found any definitive answers. My initial thoughts were fuel delivery. Does this make even vague sense? If so, where is the valve to check pump pressure? What else should I be considering?

[Loren]

P1124 and P1126 (opposite sides of the engine) both show an air leak that the DME can not adjust for. The evap canister fault (P0446) could be a loose gas gap (or bad seal) or could be a bad purge valve. I would check all the vacuum lines on the engine. I would also take the air cleaner off and see if the idle valve and throttle butterfly are gummed up with carbon.

Yet another possibility could be a cracked or leaking oil filler hose or even oil seperator. Any smoke from the engine? Also, where are you located?

[gavinmead]

Yet another possibility could be a cracked or leaking oil filler hose or even oil seperator. Any smoke from the engine? Also, where are you located?

I haven't noticed any smoke. I'm in Atlanta, where we've had fairly moderate temperatures for the last few months.

[gavinmead]

I cleaned the ICV and so far haven't had any of the same symptoms, but the failure has always been intermittent. It still has what almost sounds like a soft skip at idle (not on the same cylinder every time and not serious enough to pop a code).

When I was cleaning the ICV, I noticed that below the valve, on the sensor/motor portion of the ICV, there were cracks that the carb cleaner ran out when I was drying it with an air compressor. Could this be a sign that I need to replace the entire unit?

[Loren]

Yeah, I think sometimes the solenoid gets weak or the buildup is just too much. I'm about 50-50 cleaning and replacing these - sometimes cleaning works and sometimes you just need to replace it.

996.606.160.01 Idle Speed Adjuster -- retail $366.28 (as of February 2006)

I'm sure the folks at Sunset Imports (Porsche parts at Dealer Cost) can get you a better price.

[bar10dah]

Gavinmead, as this post is nearly six years old, and you only have 12 total posts, are you still around?

[Niceguyeddie]

On 3/2/2006 at 11:02 AM, gavinmead said:

Hello everyone. I have a '99 C2 with 79k miles. For the last few months, I've had intermittent problems with starting (takes a long time, seemingly at random; other times, starts fine) and with a hunting idle below 1k RPM. I haven't been able to correlate the failure to any specific variable (ambient temperature, engine temperature, amount of fuel, etc). Additionally, I can often smell fuel after cranking.

Initially, I thought it may be tied to the ignition switch issue, but I replaced the electronic backing of the switch and have had no further problems there but my starting and idle problems persist.

As the CEL as been illuminated for some time, I finally broke down today and went to AutoZone for a code pull. Turns out, I've got P0446 (EVAP Canister), P1124, and P1126. I tried searching the forums for these codes, but I haven't found any definitive answers. My initial thoughts were fuel delivery. Does this make even vague sense? If so, where is the valve to check pump pressure? What else should I be considering?

I was getting similar symptoms: hard starting when the engine is warm/hot. It would crank and crank. Only by pumping the gas pedal vigorously could i get it to start, which seemed to produce a lot of gas smell and rough idle. 

Was getting
P1124
P1126
P0455

400 miles after replacing part 996.110.129.53 (which is referred to as a Vent line)
And clearing the codes. No codes have reocurred and the hot start problem has not occurred. Hope this helps others. There is a ton of info about the Boxster problem but very little about the 996. The vent line was very easy to replace but it was expensive.