I've got some general questions for you all.
1. what is the base timing on my truck and by how many degrees does an ez, advance time over stock.
2. What are the operating values of the intake air temp sensor, in ohms I mean like x ohms@30* and x ohms @90*
3.what are the operating values of mass air pressure sensor, in ohms, x ohms@0psi,x ohms@20psi
4. at what psi does the ecm start defueling
I'm asking about iat sensor because my truck idles @1000rpms when air temps are cold and the engine is fully warmed I'm thinking I have a bad sensor causing this.
The other 3 ? are just wanting some general info to think about.
Any thing you guys could fill in for me would be helpfull.

Jed

 

I don't have all your answers but I have some:

1) I don't think there is one explicit base timing setting with the 24v......the ECM has many timing maps that it selects from depending on what fueling map is being used.......remember that on a 24v motor static and dynamic timing can almost be considered one in the same because the computer adjusts the peak and the curve on the fly depending on the conditions that the motor is in so, to suggest that there is 1 specific # for base timing, I think may be inaccurate........someone else might be able to chime in and let you know how much an EZ advances the timing or you could try the Edge products website for any insight....

2) Don't know

3) Don't know

4) peak boost defueling depends on the year but it should be around 21-23 psi and starts to defuel at 2700 rpm

5)Diesels are unthrottled motors........they take in a full intake air charge regardless of fuel or rpm.......the only thing that will alter the power or rpm is fuel.......these motors have nothing that meters idle air levels because they are unthottled........there is no IAC motor........I would suggest it could be an ECM problem or another sensor.......get it on a scanner.........the air charge temp sensors have been known to get a layer of grime built up on them that causes them to become de-sensitized..........may be a problem....

 

CTD nut thanks for the reply, I have cleaned the air charge sensor, same thing that I call IAT sensor with no change to the idle problem.
I know there is no thottle body, I suspect ecm is getting wrong signal from IAT or maybe another sensor and adding extra fuel causing the fast idle. I,m hoping somebody else has had a similar problem and can steer me in the right direction.
I have had it scanned and only get an over boost code which puzzles me because as far as I know it is completely stockand I canmove the wastegate lever with some moderate resistance.
I did get some codes for injector pump on its way out but, none since I installed a fuel cooler in sept. It also did this last winter before the lift pump went south and caused IP problems.
Just read a thread with a 3rd gen having close to the same problem.


JED

 

linetrash75,
Check out this link, it has some of the info yuo`re asking for.

http://www.dodgeram.org/tech/dsl/sensors/IAT/clean.htm

 

Davemac, thanks that helps. Now if I can just find the reading for the MAP sensor, I looked around on that site and found nothing about it.

Jed

 

Check out Cummins dealer and ask for The wiring diagram for that year for the 99 should be the same it is Bulletin No. 3666480 (for ECM Part No. 3942336)