2003 Boxster S skips at 4500 RPM

[ctimgo]

I am hope someone here can help with my issue and thanks.  03 Boxster S. I noticed that the car had to be turned over longer than usual to start a couple days ago and I didn't think anything of it. I did notice a new sound coming from what seemed like the right side of the car in front of the dash. It sounded like something trying to adjust itself over and over. It kind of sounded like the flaps in the air vents adjusting and not finding a stopping point and then re-adjusting. Yesterday went out and car cranked fine and drove to the gas station about 5 miles with no problems. After leaving station I got about 3 miles down the road and there was a hesitation like I took my foot off the gas then put it right back on. After about another mile it started to fumble and loosing power to a point that I pulled over. After pulling over it was idling rough and wouldn't take any gas but didn't shut off. I turned the car off then restarted the car and now it will run fine until you hit 4500 RPM then it starts to fumble again until you lower the RPM then fine again. From where the sound was coming from it seems like it could be the fuel pump or relay. Maybe it is getting enough fuel for the lower RPM range but at higher RPM it isn't getting enough. It threw codes P0335, P0336, and P1266. Anybody have this before or have any ideas where to start looking. Seems odd that it happened right after getting fuel.  Thanks again Tim

[JFP in PA]

3 hours ago, ctimgo said:

I am hope someone here can help with my issue and thanks.  03 Boxster S. I noticed that the car had to be turned over longer than usual to start a couple days ago and I didn't think anything of it. I did notice a new sound coming from what seemed like the right side of the car in front of the dash. It sounded like something trying to adjust itself over and over. It kind of sounded like the flaps in the air vents adjusting and not finding a stopping point and then re-adjusting. Yesterday went out and car cranked fine and drove to the gas station about 5 miles with no problems. After leaving station I got about 3 miles down the road and there was a hesitation like I took my foot off the gas then put it right back on. After about another mile it started to fumble and loosing power to a point that I pulled over. After pulling over it was idling rough and wouldn't take any gas but didn't shut off. I turned the car off then restarted the car and now it will run fine until you hit 4500 RPM then it starts to fumble again until you lower the RPM then fine again. From where the sound was coming from it seems like it could be the fuel pump or relay. Maybe it is getting enough fuel for the lower RPM range but at higher RPM it isn't getting enough. It threw codes P0335, P0336, and P1266. Anybody have this before or have any ideas where to start looking. Seems odd that it happened right after getting fuel.  Thanks again Tim

3

 

Welcome to RennTech

 

P0335 and 0336 are cam and crankshaft position sensor issues, sensors are either out or wiring to them is questionable.  P1266 is for your "drive by wire" system, which is also reading out of range, which can also be related to the sensor issues.

[ctimgo]

Thanks for the quick reply JFP.  So if it is a crankshaft sensor that is bad or the wiring could that also cause the cam sensor and "drive by wire" system to throw codes?  I would think that it has to be one or the other as it would be quite the coincidence for multiple systems to fail at the same time.      I have heard that the p1266 could be caused by a bad DME or a bug in the programming in the DME.    Is that true and what years was it a problem?    

[ctimgo]

 

One other thing.  Why would the cam or crank sensor only be a problem at 4500 rpm.  The car runs perfect till 4500rpm.

[JFP in PA]

1 hour ago, ctimgo said:

   I have heard that the p1266 could be caused by a bad DME or a bug in the programming in the DME.    Is that true and what years was it a problem?    

 

I am not aware of that happening.

[JFP in PA]

1 hour ago, ctimgo said:

 

One other thing.  Why would the cam or crank sensor only be a problem at 4500 rpm.  The car runs perfect till 4500rpm.

 

Only way to know that is to connect a Porsche specific scan tool to the car and collect real time data.

[ctimgo]

That makes sense about a bug in the programming.  If there was one, there is no reason I can think of that it wouldn't have caused problems right after leaving the assembly line.  I have a Duramertic so what data should I look at.  I will connect it over the weekend and take the car out and get some data.  Is it possible that after throwing the codes the DME won't let the engine go past 4500 RPM till the codes are cleared?    Just curious as the symptoms that I am having aren't the same as the original symptoms.  After the first initial problem it all changed after shutting off the car and restarting.  Now the only problem is the 4500RPM ceiling.Thanks again.  

[JFP in PA]

I would try and grab as much data as possible, as at this juncture you don't really know what you are looking for.  I would, however, pay particular attention to the fuel data.

[ctimgo]

Ok so took the car out this weekend to run some tests.  First I let the car warm up to operating temps before driving.  The car drove fine for the first 5 miles then the tach fluctuated down to 1000 rpm even though I was still going down the road at speed.  Didn't notice any thing  in the running of the car after that except that the idle was up from 700RPM to 1000RPM and again at 4500 it starts to jerk like you are getting on the gas then off but really fast till you drop below 4500 then its fine.  

 

Here is some info I got from Durametric after the car started acting up

 

These are all at idle.

Camshaft position 1 deviation 0.25

Camshaft position 2 deviation 2.63

Actual angle for inlet camshaft bank 1 0.09

Actual angle for inlet camshaft bank 2 128.00 < THAT CAN'T BE RIGHT!!

Spec angle for inlet camshaft bank 1 0.00

Spec angle for inlet camshaft bank 2 0.00

Tank pressure difference -20.4

 

One difference this time is that it didn't throw any codes.

 

Edited May 7, 2018 by ctimgo

[joe hurst]

I would be looking at variocam solenoids... with most VVT systems issues will appear higher up the rev range as lower down the crank sensor will establish TDC, cam one and crank are key for idle,

 

then higer up cam 2 is for when the vvt engages to the point where the exact injection point for bank 2 cannot be calculated from crank and cam one position, this is the case unless the car is very early and is variocam rather than variocam plus, then you only have ONE cam sensor.

 

my point is the chances of crank, and both cams going bad simultaneously is ''slim''  so something else is affecting timing and the sensors are actually ok.

 

my first guess would be lazy variocam solenoids...crank would just not start or cut out when hot as they go ''open circuit'' and then when cool again all is fine.

 

you ''could'' have one bad cam,sensor ( I would say bank 2 most likely due to issue being higher up the range) and that would be my 2nd guess after confirming variocam solenoids are ok.

 

worth also swapping the fuel pump relay as the noise you say you heard is coming from exactly where the pump is, ( on UK spec cars at least)

 

good luck, live date may well be key on this one.