What am I missing?

[Purv-Dawg]

I've been trying to figure out what I'm overlooking silently now for a couple of weeks. While I tuned my vehicle myself using EBL block learn multiplier, I can't figure out why my tables are not even remotely close to the tables on the bins that are commonly listed for my vehicle.

Can someone direct me to the info?

If it helps, I'm tuning a 1989 C1500 5.7l 2.73 rear gear

[dave w]

I've had similar experiences when I've AFR tuned EBL.

I use an excel spreadsheet to help me "see" what's happening with the EBL VE Table.

The documentation with EBL is better than factory tuning documentation.

17985

17986

[Purv-Dawg]

The bins that meet the description for my vehicle won't even crank on mine. The spark tables are so high I have to wonder if the descriptions are missing information on modification. I've read people say that you can run the spark tables higher on these old heads but I can't imagine spark advances of 60-80 when I'm getting a high of about 28-32.

[dave w]

Excel with EBL SA Tables

17987

17988

[Purv-Dawg]

Those are much closer figures to what I would expect. I'm just not understanding how or why the other bins are so different

[Purv-Dawg]

Those spark tables make it run great. Thank you. I've read three different opinions on how much I can advance the timing on the stock 193 heads. One person throws them together with several other heads and says 36-38 degrees is acceptable, another person says 25-29 degrees for these heads, and the most conservative I've read says that 24-25 degrees is best for them. I'm unsure which is correct but even if I set all my timing tables to zero degrees within cruising range I still max out my knock count st 255 within five miles. What do you make of that?

[1project2many]

What are the conditions when the counter is increasing? Acceleration? Cruise? Is the AFR lean or rich when the counter is increasing? Is timing increasing when the counter is increasing? Is the engine or drivetrain noisy? There's a lot of reading available to help you learn to recognize detonation and to separate it from noise, which is what the knock sensor detects.

[Purv-Dawg]

What's happening is that once I get up to cruising speed, just above 40mph, the torque converter locks and overdrive kick in and there is a clatter that sounds like valves clicking or the transmission. This is the exact time it pegs the 255 count mark on EBL what's up display.

I can go back and recheck my valve clearance this evening. I may have tightened them a bit too much when I swapped to an edl 3702 cam this spring.

Keep in mind I have a 2.73 rear end. I'm not a mechanic I'm a former welder who assembled busses for blue bird. However this truck has been in my family for thirty-three years now and I've owned it for over twenty years and I've done almost all of the physical work on it, including remanufacturing the transmission. So Ii know the truck reasonably well but I don't claim to be an expert mechanic. And since buying the EBL I'm new to the settings and I still don't understand many of the terms.

I increased my tcc lock up speed to 50 to see if that helps.

[Purv-Dawg]

Increasing the torque converter lockup speed eliminated the problem. Thanks for the help.

[1project2many]

I apologize for not getting back to this quickly.

Changing the lockup speed changes the load on the engine. If this eliminates the knock sensor issue that's a good immediate fix. You might want to look into the underlying cause though. If there's a mechanical issue it will likely get worse. If it's a tuning issue the problem may rear it's head when you least expect it to.

"I'm not a mechanic I'm a former welder who assembled busses for blue bird." Kind of funny... I'm a bus mechanic but not a welder.

[LeMarky Dissod]

Keep in mind I have a 2.73 rear end.
Increasing the torque converter lockup speed to 50MpH eliminated the problem.
Changing the lockup speed changes the load on the engine. If this eliminates the knock sensor issue that's a good immediate fix. You might want to look into the underlying cause though. If there's a mechanical issue it will likely get worse. If it's a tuning issue the problem may rear it's head when you least expect it to.The 2.73 axle ain't helping, and locking up the TCC at too slow a road speed was likely lugging it enough to set off the knock sensor.

As 1project2many suggests, keep your ears on for knock, and keep your eyes on the knock count.