I believe that when people ask questions, especially ones that requires some thought, that they should put in at least as much effort as those who my be offering some help or advice. Half of this thread has been spent trying to get all the details out of this guy. If he had just put some effort into his initial post, it would have helped everyone out, including himself. Something like this:
Hello, I'm looking for some tuning advice. I have a 4.0 Jeep with a FAST engine management system. The specs of the motor are :
camshaft: 214 degrees of duration @ .050, I don't have any other specs on the cam.
32 degrees of timing total advance from 2800 rpm up, I found that the power drops off above 32 degrees
air fuel ratio is 13:1, if I tune it any richer I find that the plugs foul out
I'm just looking to see if anyone would share their tuning experience with a similar setup to what I'm running. I do understand that it would be best if I tuned this on a dyno, but unfortunately I don't have access to one.
Your plugs should not be fouling out if you run a little richer than 13:1 at full load. The stock Jeep was tuned to run as rich as 11:1 (.75 lambda) in order to protect the catalytic converter. I have found that there is almost immeasurable differences in power between 12.8 - 13.2 afr (.87 - .90) lambda on these motors, however I tend to stay towards the rich side, and it depends on the build, if it's a race engine running one pump 91, for example, I would run it even richer, just depends on the setup.
These motors will knock, if you are running that much timing, and assuming you are nowhere near sea level, I say that timing curve, from my experience, is too aggressive. Along the lines of what sidewaystarion said, verify the cam timing by putting a degree wheel on the engine, and checking the cam manufacture to see what the ICL should be. You should also do a cranking compression test if you have not already. Seems like a lot of Jeep people have been trouble with the cam timing. If the cylinder pressure is low / cam timing is off, the Jeep will run poorly.
STOCK 1999 XJ WOT TIMING 500 FEET ABOVE SEA LEVEL (APROX)
512 3.3
704 3.3
800 4.3
896 4.3
992 5.5
1120 8.8
1248 9.3
1504 14.8
1760 16.3
1984 17.3
2240 21.0
2496 22.0
3008 22.3
3488 20.5
4000 18.3
4480 18.3
4992 25.0