Engine/Transmission (1998.5 - 2002) Engine static timing -also how much timing does a smarty or edge box add (in degrees)

[GOT-Torque]

Anyone know what the static timing of our diesel engines should be? Is this something that can be read out by a piece of equipment? For example, 10 degrees BTDC.



What amount of timing (in degrees) is the ECM capable of adjusting? I've read that the VP44 can adjust 2 to 3 degrees max.



Also, how much timing do the different boxes add (Edge or Smarty for example). 1 degree of timing? 3 degrees of timing?





My truck has too much timing in stock form. If it's cold outside (less than 50 or so) and I run my comp box, it fires too soon when under a load I can however fool the ECM into thinking the IAT temp is 200 degrees which causes it to pull out some timing (how much?). I can then turn on my edge box (which adds how much timing?) and run it with no problems All I know at this point is that the ECM is pulling out more total timing than the edge box is adding. So performance wise, how much timing could I still add before I have the same problem? Does this amount to 10 hp on a dyno or 80 hp on a dyno? Or maybe it makes no difference at all related to hp and only effects EGT's

 

[ERuhl]

how much timing could I still add before I have the same problem? Does this amount to 10 hp on a dyno or 80 hp on a dyno? Or maybe it makes no difference at all related to hp and only effects EGT's

As you know I'm in the same boat along with several others on here. I don't know the answer to any of your specific timing questions, however if you use a potentiometer you can adjust the resistance on the fly and run at the maximum allowable timing before the miss sets in. The 1k ohm resister has been working flawlessly for me so far (nice and smooth and sounds much better), but I'm planning to swap it out for a potentiometer so I can have the intake heater on longer on chilly startups. IMO if you/we pull out enough timing so that it runs smooth then we're finally running at the same net timing as all of the others who have reported no issues at all.



Meanwhile I've been trying to find a replacement IAT sensor that is less sensitive than the Cummins sensor. So far a late 80's GM sensor is looking pretty good. Does anyone know the thread size for the stock/Cummins IAT sensor? Ideally I'd like to find a drop-in replacement and I'd prefer not to pull mine or visit a parts store just to find the stock thread size.



Also does anyone have a more complete resistance table for the Cummins IAT sensor? The only info I've been able to find is on dodgeram.org which doesn't go very cold and if you plot the numbers it isn't very smooth. Here's the Cummins and GM sensor data:

Cummins IAT Sensor

-------------------

Deg F	ohms

30	40k

32	30-36k

76	13k

77	9-11k

81	6. 87k

122	3-4k

130	4k

167	600-675

212	600-675



GM IAT Sensor

--------------

Deg F	ohms

-40	100700

0	25000

20	13500

40	7500

70	3400

100	1800

160	450

210	185

Hopefully someone else will know the answers to your (our) specific timing questions.