Pulling timing '98 350

[heavychevy98]

Two questions. one, where is the knock sensor circuit on the computer plugs. Two, assuming we rule out the knock sensor, what else can pull timing?
Problem: At WOT i have 20 degrees timing. If i floor it, it goes from around 30 to 20 the moment i floor it. if you ease into it, only using a 1/4 of the throttle, it will run up to redline @ 45 degrees or so. Im stumped. Had a freind set my cam offset and do a crank relearn with his snap-on scan tool and still not right.

 

[1997chevydriver]

Torque management.

 

[heavychevy98]

Oh yea i forgot bout that. Can the versus scan tool max out the torque management specs?

 

[bluex]

Nope contact black bear performance for a custom tune. It is not recommended to completely remove it unless your ready for a transmission rebuild....

 

[1997chevydriver]

I have no idea sorry

 

[heavychevy98]

even with a 5 speed?

 

[Aloicious]

many things can affect timing, the whole timing table is variable based on RPM and MAP input in a '98, and the stock commanded value at higher rpm and higher load IS right around 20* on the tune I'm looking at, where lower load at higher RPM is around 40* which sounds exactly like what you describe...then there are a number of other things that can affect the advance such as burst knock retard, knock retard, IAT modifiers, fuel mixture spark correction, torque management, abuse mode, ECT modifiers....I don't see anything problematic with the scenario you're describing, it sounds like the spark is acting just like it should, I doubt torque management, or knock or anything else is affecting it, its most likely just what the spark map is commanding for various loads and engine speeds...perhaps it would be better to ask what you were expecting to see?

 

[heavychevy98]

Lack of power. It runs great down low but dies off when you gun it? Everything im used to gains timing under load. . . . I was looking for 50* to 60* at WOT.

 

[Aloicious]

I've never seen ANY tune for ANY vehicle reach 50-60* advance in any real life situation, most every vehicle tune I've ever seen has the spark at it's highest in low load, tapering off in higher load...you can get a tune to increase the spark some, a mail order won't be a huge increase or anything though, a dyno tune would be ideal.

however, understand that more spark advance doesn't always mean more power, its a balance of creating the most efficient combustion, setting the spark at the appropreate time to create the highest cylinder pressures without introducing pre-detonation, and proper fueling plays just as much of a role, if not moreso than the spark advance...in fact giving too much advance will cause more problems than gain....