Basically a blast from the past. Remember the issues we had with getting the correct timing values with LS1 edit? We never had any good explanation on why you could input a value of X all across the table, and end up with Y.

I spent the afternoon today with a tuner working on the Escalade. This guy had tuned lots of Fbod and C5s. We had a wideband and a Tech2 to tune with. He removed TM and cut down KR, and set timing at 26* for every cell on the bottom half of the tables. I told him to check timing, and it showed 21-22 degrees. This had him a little stumped. He thought it was in the low oct table or it was previously learned KR. We reset the PCM, gave the low oct table higher values and still ended up with the same result. Now he was a litte more than stumped. He said when he puts in 26 degrees on an LS1 car, 26 degrees comes out (disregarding KR). He checked everything he could think of for KR, TM, abuse, whatever, with no real explanation. We finally set the PCM tables at 31 degrees timing, and would see 25-26 degrees come out. For the most part we had no KR, with the occasional 1 or 2 degrees.

I have no answer for the problem, but it appears that its not isolated to our old 99 trucks. Needless to say, the tuner was a little suprised to see the issue, and had no answer for it.

 

I just use the cells that the HPP3 uses and adjust them for how much timing I want to add or subtract. Putting in a specific value doesn't work for whatever reason like you mentioned. If I want to lose 5* I just subtract 5* from the specific cells. I don't even know what my timing table looks like because it's basically useless.

There has to be an adjustment table that EDIT doesn't show but, why is what I'm wondering.

Maybe Harlan would know.

 

I'm sure Ken Kelly at Carputing knows too.

I agree, there is something else on the trucks PCM that factors into the timing, and either we are missing it, or don't have the tables available in LS1 edit yet.

 

so is it a true 5deg all the time? that is good info to have, i wan't even sure if my adjustments were having any effect. i can do the 5deg adjustment noproblem.

 

Jim - You can make the adjustments in any increment you want, it doesn't have to be a 5* adjustment.

I'll write down the cells the HPP3 adjust and post it up. It's basically every cell from .32gms/cyl down for all rpms except some of the lower rpm columns. That works for me. Thanks Hypertech.

 

My buddies and i also ran into this problem i dont know if you guys read the end of the last post you put up. I posted on there what several of the cars and trucks i have edited have done. The conclusion that we had come up with is the tables are directly tied into the timing how ever insead of being used individually i found that many cells are combined and averaged to create a base timing curve. It seemed that even when we would advance only the low end RPM the top end seemed to change as well.

 

I would understand an average, but when every cell is set to 26*s and we se 21-22-21-22-21 and no KR at all, where is the average?

I cant say that a solid 5 degrees across the board is the correct formula, but that seemed to be the number that worked.

One other thing to throw back into this equation - Jim, remember when you finally did the resistor mod in the knock sensors, you gained lots of power. When I did the knock-out-box, I did too. On the same tune, before the KOB, I saw low 20s timing, with the KOB installed, I instantly had mid/upper 20s timing, even higher than my set values.

 

I didnt realize you guys were changing every cell. That is weird. What size resistor did you guys use in the knock sensors. I can remember.

 

BigTex I maybe sounding dumb here but did you check the IAT-MAP timing tab? I have the whipple and whenever it was hot outside the computer will automatically pull timing according to the temp. I zeroed that out and I see to get pretty much what I put into it.

 

i had my IAT zeroed as well as my knock learn disabled but still didn't see the timing numbers i expected.

doesn't really matter i guess as long as the numbers change when you change them with edit.