Engine/Transmission (1998.5 - 2002) Understanding timing

[Jdonoghue]

Hopefully there's someone out there that can help answer this question. The following image is the timing map from my '01 HO ECU. If I'm right, the numbers in the cells are the base timing values in degrees. The left scale is an internal torque number, and it never goes above 2208, so the bottom half of the table can be ignored. But, does it seem normal that the full load timing range would go from 12. 73* at idle up to 25. 87* at 3500 RPM? 25. 87 doesn't sound right to me, so I'm thinking I've got some numbers wrong. Perhaps someone more familiar with diesel timing could shed some light on this...

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[Vaughn MacKenzie]

I have always wondered what a 24-valve timing table would look like, pretty cool. It would make sense the higher the RPM the more advanced the injection timing would be, and even though 25 degrees seems like quite a bit of advance it's probably ideal for high RPM.

When it comes to diesel injection timing, the numbers shown in the chart is where the crank is before TDC when the injector begins to fire. There is an ignition delay, then injection (and combustion) continues for several degrees until well past TDC at full throttle.

 

[timbo]

The timing sounds about right at little to no load. Boost and IAT maps need to be looked because they will change the end timing number.

 

[Jdonoghue]

The timing sounds about right at little to no load. Boost and IAT maps need to be looked because they will change the end timing number.

At operating temperature and boost above 11psi, there is no timing added to the value from that map. 2psi or less appears to add about 4 degrees.



Jim

 

[timbo]

At operating temperature and boost above 11psi, there is no timing added to the value from that map. 2psi or less appears to add about 4 degrees.



Jim

Do you have an IAT correction table? I started this thread year or so ago https://www.turbodieselregister.com...-1998-5-2002/174551-miss-only-edge-fixed.html The IAT definitly changes timing. I have the IAT on a potentiometer to adjust for max timing benefit without a bucking or missing feeling.

 

[Jdonoghue]

Do you have an IAT correction table? I started this thread year or so ago https://www.turbodieselregister.com...-1998-5-2002/174551-miss-only-edge-fixed.html The IAT definitly changes timing. I have the IAT on a potentiometer to adjust for max timing benefit without a bucking or missing feeling.

I do, but I have to figure out the scale on the temperature numbers. It takes a voltage reading and scales it to some internal value. The internal value is applied to one side of the map, the other side is barometric pressure in kPa.

 

[timbo]

I do, but I have to figure out the scale on the temperature numbers. It takes a voltage reading and scales it to some internal value. The internal value is applied to one side of the map, the other side is barometric pressure in kPa.

EXCELLENT WORK !!!!!!

 

[Vaughn MacKenzie]

Just checked back to this thread to see the timing map but it's gone