Ok well i honestly haven't had much time to sit down and figure this out but I figured I'd let you guys all take a stab and help me out Here's the deal... The car is currently on pump and running about 16 degrees of advance timing at WOT, zero to .5 knock under those conditions. The funny thing is, which I need your help with is the car pulls out tons of timing when I am ripping through the gears. When I will say shift from 3rd into 4th the car will drop about to 0-5 degrees of total timing and bog the engine terrible, then build that timing back up to the 15+ advance before redline, any ideas why ? Like I said there are no signs of knock at all and the timing tables are all set up to run 15+ advance. This is weirdddddd, help



"Horsepower is the Ultimate Accessory"

mm... that is weird. I can't think of anything off the top of my head. Ur sure u didn't change the timing tables at all? lol.. just a thought. Do u have any Misfire problems? I use to get it once in awhile...now more often while dragging/practicing. i log the misfires, but nothing seems irregular other then total # of misfires go up.

Nate



Evolution of Cavyboy-->C22t--> C24na--->c24s/c
1995 Cavalier W/2k1 Engine
GM S/C 13.940@99.78pmh w/2.068 60ft

no engine misfires here. AFR are dead on at 12.0-12.2 on pump and the timing tables are all in check, this is just really weird. I'm going to try setting my pe delay to 0 and seeing how things work tuning that way.



"Horsepower is the Ultimate Accessory"

How do you shift? Do you let off the gas and shift, or stay on the gas? Just trying to get a feel for how your driving is while thinking about this. From datalogs I have on my N/A 2.4 the timing does change between shifts, and I would expect it to.



FU Tuning

I always let off the gas between shifts. I just shift fast... The car should pull a tad bit but i mean its dropping from like +15 or so down to +2 and that's definately not right. I have heard from some fellow GM guys who have been tuning longer than us that although the manual tranny's dont use the torque management the way the auto's do that unless you zero out all of those tables it will affect timing at certain rpms and loads. I am going to look at this and zero out these tables and log some runs. The car just seems to bog after a quick shift and then you can feel the timing kick back in, very weird. Like I said before no knock or misfires either.



"Horsepower is the Ultimate Accessory"

5spd or auto? thats just the engine torque managment. just play around with it abit in hpt.


_______________________
** Flat Broke Racing Inc.**

Is the knock sensor reading something else that's being interpreted as knock?

I was reading up on KR prevention on the GTP's today... and some of them use Dynamat around the transmission and the knock sensors (they have two on a V6), to help prevent false knock...

I've heard of guys sealing the sensors up with some sort of sylicone or using a rubber bushing on the knock sensor as well. I'm not getting any KR on the logs im pulling at the points where it is pulling timing though. I know some guys who know their cars are tuned exact will actually just turn the knock retard off completely. I might give this a try for a log and see if it makes any difference.



"Horsepower is the Ultimate Accessory"

well I do know that the car with the SC flash will pull timing before shifts. its a precatuion to help save the tranny.


the Q is how much sounds like yours is off.


"boobs now with Riboflabin"

whenever you let off the gas the engine will pull timing to.. uh.. you know... slow the engine down?
if it didn't, it would hang at whatever RPM you left it at.

I'll run a log today and see how far my timing drops or check previous runs but I'm pretty sure this is normal.

the surefire way to eliminate false knock is just turn the KR off

haha.. jk.. i wouldn't recommend that even tho I've done it.


I have to relocate my knock sensor...