I fixed some screw ups a hand held did to a kids shift points and he was able to start breaking the tires loose on take off. After tuning his VE we put down 331hp and 354ftlbs at the flywheel according to EFI Live but from 1000-3000 it just bogs now.
Getting 12.7 AFR right there according to my wideband but it's only putting 10degrees of timing and then slowly advancing until it finally gets power. The only changes to VE I did down low was add 15% per the VE tutorial and then monitored with my wideband when finished.

I assume the timing is causing the problem and seemingly flooding it. Should I advance the timing in that area or pull back the AFR some until 3k? At 1538 RPM at WOT he's at 92hp 326ftlbs at the flywheel with 7.5 degrees timing and no KR. At 2017rpm he's at 13.5 degrees 129hp 336ftlbs. AFR staying 12.7-13.0

All helpful suggestions appreciated. and for nay sayers i did not charge the guy for the tune, just the license.


Stock 4.8 engine


Oops. Meant to type LOSS not lose

 

If the spark is that low,that is why it is lagging,get more spark in there.
Are you using EFI or HPT?
Feel free to email me the tune file and log file and I will have a look at it for you if you like!!!!
charlie@gowheatley.com

 

EFI Live as mentioned in the post

I'm contemplating putting my spark table in his and pulling it back some. He has a cam, headers, and stall on order so I don't need to do a whole lot just now, just get him back to where he was down low so that I have a starting point after the upgrades.

 

I missed the EFI part.LOL sorry
Do you have a log available?

 

Spark 3 shows AFR
Spark 1 has Dyn Cyl Air
Wasn't logging both on both for some reason.

Also included log for when I was VE tuning.

 

I noticed that when its commanding 21 degrees of timing at 2000rpm it's actually getting 13.5 so It's pulling timing somewhere. I can't see anything pulling timing other than maybe B1901 set at 300ftlbs but I thought that would only matter if he has Traction Control.

Perhaps we need more VE tuning?

 

Have you been logging Burst Knock? That very well could be stealing your timing away.


Burst Knock doesnt show up as KR so make sure you are actually logging Burst Knock and see what you get.

 

Could be pulling timing from the IAT table, AFR table, or ECT table in the Spark Tab.....or at least thats were they are in HPT.

 

Yea i had read a few threads on the EFI forum that was talking about Burst knock but it was also saying that it's predictive from spikes and didn't really see any spikes.
Will give it a try, Should I just zero out B6212 Burst Knock Retard?
Obviously I would still need to make sure no KR occurs.

Edit. Looking at B6205 "Knock Retard Limit in PE Mode" It is set to a MAX of 8 degrees of timing at 2k rpm to be pulled which is how much timing I'm seeing pulled.

 

B6205 is the MAXIMUM spark retard limit allowed while in PE mode.Meaning KR will not go over this value in PE.Zero'ing that will not fix it.
Now like you said if you zero B6212,that will take burst knock out of the loop.