Help! after cam timing
11-02-2018, 04:15 PM
#1
Rennlist Member
Thread Starter
Help! after cam timing
My 02 Boxster had the scavenge pump on bank 1 sieze and cause the camshafts to jump time. I replaced the pump and gear and re-timed the cams. All looked good putting it back together. It started up fine and sounded fine then the cel came on. I get codes P0300, 301,202, 303. (All misfires on cyl 1-3) I can let it idle and the cel will come on flashing for maybe 15 seconds and it sounds like there is a misfire. The light will go off by itself and the idle smoothes out. This repeats every 15-30 seconds. If I rev up to 2-3000 rpm the light usually comes on and then will go off again by itself after several seconds. I have a Durametric but i’m not sure what to check. The variocam system seems to be working fine on both banks. Anybody have any ideas? Thanks!
11-02-2018, 04:30 PM
#2
Connect the Durametric, under the Engine Module section, go to "actual values". Then check boxes for "Camshaft position 1 and Camshaft position 2". Report back the camshaft deviations for bank 1 and 2. Then, check boxes for "rough running cylinder" for all 6 cylinders and then report back their values.
11-02-2018, 05:00 PM
#3
Race Director
You can do as NuttyProfessor advises.
However, I suspect the problem is valves are bent from contacting piston tops from the timing jump.
If you find the camshaft position readings within spec, a compression test/leak down test is probably called for.
In the meantime, I'd be leery of running the engine too much. If I'm right, if valves are bent, a valve head could separate from its stem and that ain't good.
However, I suspect the problem is valves are bent from contacting piston tops from the timing jump.
If you find the camshaft position readings within spec, a compression test/leak down test is probably called for.
In the meantime, I'd be leery of running the engine too much. If I'm right, if valves are bent, a valve head could separate from its stem and that ain't good.
11-02-2018, 05:04 PM
#4
Rennlist Member
Thread Starter
Camshaft position 1 = -3.4
camshaft position 2 = -11.3
I think the difference there is I changed the somewhat worn chain pads on bank 1. This engine has 234,000 miles on it.
rough running cylinders -this is an average as numbers jumped around somewhat.
1= 7.2
2= 7.5
3= 6.5
4= -6
5= -6.2
6= -6.9
camshaft position 2 = -11.3
I think the difference there is I changed the somewhat worn chain pads on bank 1. This engine has 234,000 miles on it.
rough running cylinders -this is an average as numbers jumped around somewhat.
1= 7.2
2= 7.5
3= 6.5
4= -6
5= -6.2
6= -6.9
11-02-2018, 05:07 PM
#5
Rennlist Member
Thread Starter
If valves were bent would it still run as good as it does? When the cel light is off it runs about as smooth as it ever did. It does smell like it might be running a little rich.
11-02-2018, 05:23 PM
#6
Fred, I'm going to be straight with you. Not trying to add insult to injury, but in my opinion, your engine is experiencing serious issues. This is not a slight mistiming/misalignment issue. The camshaft deviation can not be more than 6 degrees apart per Porsche directives. Bank 1 should be a positive number and bank 2 should be a negative with -6 degrees deviation. The rough running indexes for all cylinders should read around 0 (less than 1). Your engine is way off. I agree with Macster. Don't run the engine until this motor is closely examined by a trained Porsche mechanic.
Last edited by NuttyProfessor; 11-05-2018 at 10:08 AM. Reason: Corrected a mistake
11-03-2018, 01:37 PM
#7
Race Director
A cold engine at start up and for a time after is going to smell rich even if it is healthy. The converters are cold and not able to process exhaust gases properly. It doesn't take much un-burned gasoline to make that rich smell.
Once the engine RPMs drop to near normal hot idle speed and the secondary air injection system shuts down the engine is running in closed loop mode because the converters/O2 sensors are all up to operating temperature. At this point then the rich smell should go away.
I can't see how replacing a worn chain rail pad can affect timing. There is some travel to compensate for the wear the pads experience which then helps ensure the chain is kept properly tensioned.
NuttyProfesser is worried about the cam timing. I think his worry is properly placed. That cam timing needs to be addressed for sure. Bent valves may still be possible but deal with what is obvious first.
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11-03-2018, 06:26 PM
#8
Rennlist Member
Thread Starter
I’ll get under it tomorrow and double-check all of the wiring, but i’ll probably check into getting the dealer to take a look and see what they think. I appreciate all of the input.
11-04-2018, 03:38 PM
#9
Rennlist Member
Camshaft position 1 = -3.4
camshaft position 2 = -11.3
I think the difference there is I changed the somewhat worn chain pads on bank 1. This engine has 234,000 miles on it.
rough running cylinders -this is an average as numbers jumped around somewhat.
1= 7.2
2= 7.5
3= 6.5
4= -6
5= -6.2
6= -6.9
camshaft position 2 = -11.3
I think the difference there is I changed the somewhat worn chain pads on bank 1. This engine has 234,000 miles on it.
rough running cylinders -this is an average as numbers jumped around somewhat.
1= 7.2
2= 7.5
3= 6.5
4= -6
5= -6.2
6= -6.9