sameerg

Awesome... Thanks.

beden1

The dealer installed a new HPFP and it did not solve the problem. They said the car started throwing codes they didn't understand.

They called Porsche techs and determined it was the HPFP sensor on the intake side. They ordered the part this morning and hopefully, the problem is solved by tomorrow. The car has been at the dealer since last Wednesday.

The dealer said this is the first time they have seen this problem. Just my luck.

beden1

The dealer called today to say that the HPFP sensor also did not solve the problem, Now, the car won't start at all and is sending the same codes.

I am more than frustrated, now, having been without my car for a week, and counting.

Petza914

Old thread, but I'm having what might be a similar issue with my C2S and was wondering what the final solution to your issue was determined to be. Thanks.

Comanche_699

Intrigued. Today (very rainy) she ran a little choppy at first but idle stayed down around 700 RPM's which felt very low to me. She wasn't choking but just low idle. Never happened before. Drove up the freeway and back, got the temps to about 210° and got off the freeway. Stopped at a light by my house and she just died.

Very slow to start again.

It threw some sort of PCM diagnostic warning in the tach, and then started. Drove home and idle was still very low. I let her sleep, we'll see how it feels in the morning...

Comanche_699

Today we had more rain, some really good down pours which we desperately need here, and the driving today the car seemed fine, although I was a little anxious about it. The idle was still a click low, but not a cliff hanger- well when I got out of work I drove home and the car was fine.

Cleaned up to go out for the night, drove 3 blocks and the car died at the first light I came to. And here's what I noticed... When I let off the gas and coast in to the stop, the RPM's just drop, like right down to zero, and the motor just shuts off.

Happened twice on my trip. I kept having to stab the gas to keep her running.

Then, whenever I reached a destination and pulled in to park, it was totally fine, except the idle was about 1 click low. So my issue seems completely different than those described above.

Will check it out with some pros tomorrow -

Petza914

Was your climate control system on normal or in Economy mode. I'm not sure about the 997, but many cars have a switch or circuit that boost the idle when the A/C compressor is running to compensate for its additional load on the engine. Maybe do a little research into that.

Macster

That behavior strongly suggests a bad fuel pump. Remember there are two in the cars with DFI engines and both pumps have to work. If the low pressure pump is not working correctly the HPFP won't work right either and could possibly be damaged as these generally require a good supply of fuel to act as a lubricant and to cool the pump.

The informal word I get is an early batch of the HPFP was found to be bad -- not 100% but enough -- and were replaced. However, it appears that some of the replacement pumps appear to be prone to early/premature failure and techs at the various dealers I visit report a number of cars are coming back for another fuel pump R&R. Not all of the replacement pumps are failing, just a few.

Comanche_699

I still haven't been able to get into the shop. All the last minute pre thanksgiving hustle at work is biting into my "sneak off to the indie shop" time. The issue is still present, but more manageable. Cold starts are rough. Fires right up but has trouble finding its momentum and leveling off but after a few seconds he gets there.

Then it is almost trustworthy but when you pull the car out of gear and let off the throttle it looks as though the RPMs will go all the way to the floor and then catches itself and hover's around 800 or so but usually needs a quick stab of the throttle to keep the revs up. Once warmed up its still a little petulant.

I made a video today that shows first checking the oil level and then cold start / you'll hear the revs and then I backout shut the car off go to work all day and when I come out it's another cold start and I watch the tachometer, The EOD cold start is less rambunctious then the SOD cold start which was unusual.

http://s1101.photobucket.com/user/da...atljw.mp4.html

Petza914

That's certainly not normal behavior. You need to get it checked out. I'd say you have a vacuum leak somewhere other maybe a bad temperature sensor or MAF.

Comanche_699

Oooh vacuum leak. Good one. When I swapped out my airbox for the EVOMS v-flow my mechanic and I had a debate about which end of the vacuum hose I had plugged, I can certainly look at that this morning.

The only thing about it is, I can remember the exact moment that this issue presented itself. I was leaving work on a particularly rainy day. I got on the throttle a little bit, to "wave goodbye" to a coworker with a C4s, and when I was reaching for third gear the car kind of choked and lost power & wanted to cut out between gears almost like hitting the rev limiter, (but I was well under the limiter because I had only just started the car so revs may be tapped 4K, tops alright maybe 4300 ...) and after that it's behaved like this ever since.

Let's see what I can find out today.

Comanche_699

So an update - brought it in to the Indie shop on Wednesday just to have a quick peek and see if it was something simple. The code it had thrown pointed to the MAF sensor, so we pulled the CAI, cleaned the throttle body, pulled out the MAF sensor to clean it and (SHUCKS) no MAF sensor cleaner in house.... swapped in a drone sensor, and the issue was notably worse.

The car was definitely having an issue with simply wanting to die at an idle. - being so close to Thanksgiving, I didn't want to get the techs too caught up in trying to find the gremlin, but also with no MAF sensor cleaner on hand, we were just going to have to wait. - So, I drove off with a plan to reconnect after the weekend.

Immediately there-after the car was just a little fuss-budget. I found myself heal & toeing up to the stop lights, just to keep the car running. It was a real treat.

I found that the issue was always compounded when there was another car behind me, or as fate would have it, 'only in worst case scenarios' - example: I pull up to a light, no one behind me, the car idles perfectly fine.

I pull up to the next light, and highway patrol pulls up behind me? Raa! Raaa! RAAA! i have to rev the snot out of it just to keep it from dying. And of course the high-flow cats, x-pipe, and fister sport mufflers aren't as discrete - so... I'm suddenly THAT guy at the light.

Anyway, I nursed it along and figured i'd just take it easy through the weekend, but jaunts over the mountain would have to wait.

Coming down the freeway today, there was a wreck in the number 2 lane. As I approached, all traffic in all lanes came to a stand still.

I couldn't keep the car alive. She just died, and of course has the old starter cable deal, so it was painfully slow to start up again. hahahah

Well. That was the last straw. I got her started up and looped back around to the nearest auto parts store, and got a can of MAF sensor cleaner. Drove straight to work where I have a set of security torx drivers and took that MAF sensor out right there in the parking lot. Sprayed the hell out of it, sprayed it some more, and then sprayed it again.

Put it back in, tightened everything up, and she's been running like a champ ever since. I'm still skeptical, but she never stalled or even hinted at a stall since the CRC bath this afternoon, and the idle is definitely back up to normal.

Pleased.

Wayne Smith

Congrats on what is hopefully a final fix. A guy I hired on 30 some years ago had your symptoms for a month until he swapped out his MAF ... One problem since ... a second MAF further down line. He told me that car has 5 MAFs. He did not try the cleaner.