New Member: 996 GT3 timing/knock issues
#18
Update... yes.
Solution... no.
I ran some higher octane fuel through the car a mix of 110 leaded and 93 unleaded the ratio made it close to 104 mix.
I only had one knock to where she pulled timing at 7800 rpms. Ideas? Ill post the chart below.
Solution... no.
I ran some higher octane fuel through the car a mix of 110 leaded and 93 unleaded the ratio made it close to 104 mix.
I only had one knock to where she pulled timing at 7800 rpms. Ideas? Ill post the chart below.
#21
75 degree weather
Motor is in timing as far *porsche spec*
Compression is a lil low but uniform across the board, no more than 8 psi between highest and lowest cylinders.
Leak down are all under 10% leak down
Motor is in timing as far *porsche spec*
Compression is a lil low but uniform across the board, no more than 8 psi between highest and lowest cylinders.
Leak down are all under 10% leak down
#24
#26
In your initial log posted the A/F lambda trims are off bank to bank about 5%. B1 is removing fuel while b2 is adding fuel. This may be the place to check first. I would also compare maf sensor readings with another GT3 known to be good and running correct.
It is possible it is pulling timing for safety if the fuel trims are not within spec and or if the MAF measured vs spec are not within a certain range of each other.
Fueling off bank to bank could be
-air leak in the rxhaust
-plugged cat
-damaged exhaust or failing muffler
-cam timing is out of spec. One bank retarded more than the other.
-injectors plugged slightly on one bank.
It is possible it is pulling timing for safety if the fuel trims are not within spec and or if the MAF measured vs spec are not within a certain range of each other.
Fueling off bank to bank could be
-air leak in the rxhaust
-plugged cat
-damaged exhaust or failing muffler
-cam timing is out of spec. One bank retarded more than the other.
-injectors plugged slightly on one bank.
#27
In your initial log posted the A/F lambda trims are off bank to bank about 5%. B1 is removing fuel while b2 is adding fuel. This may be the place to check first. I would also compare maf sensor readings with another GT3 known to be good and running correct.
It is possible it is pulling timing for safety if the fuel trims are not within spec and or if the MAF measured vs spec are not within a certain range of each other.
Fueling off bank to bank could be
-air leak in the rxhaust
-plugged cat
-damaged exhaust or failing muffler
-cam timing is out of spec. One bank retarded more than the other.
-injectors plugged slightly on one bank.
It is possible it is pulling timing for safety if the fuel trims are not within spec and or if the MAF measured vs spec are not within a certain range of each other.
Fueling off bank to bank could be
-air leak in the rxhaust
-plugged cat
-damaged exhaust or failing muffler
-cam timing is out of spec. One bank retarded more than the other.
-injectors plugged slightly on one bank.
No exhaust leaks
No cats anymore
No injector issues (all 6 have been removed and flow tested)
Damage to exhaust or failing muffler *maybe*
Cam timing out of spec, I have suspected this for a while, is this possible to be checked via durametric?
#28
Ok this is the type of diagnosis I needed to hear.
No exhaust leaks
No cats anymore
No injector issues (all 6 have been removed and flow tested)
Damage to exhaust or failing muffler *maybe*
Cam timing out of spec, I have suspected this for a while, is this possible to be checked via durametric?
No exhaust leaks
No cats anymore
No injector issues (all 6 have been removed and flow tested)
Damage to exhaust or failing muffler *maybe*
Cam timing out of spec, I have suspected this for a while, is this possible to be checked via durametric?
I would also also recommend swapping pre cat o2 sensors bank to bank and recheck your logs
#29
Its not the mufflers.... I had some old 996 pipes, I put them on with no change.
I am left with Cam timing... will check that shortly.
#30
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Cam timing:
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bank 1: BBC
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Cam timing:
CJv mmbcbc CNBcbmcbm bmw C
bank 1: BBC