My 2001 Ram 2500 5.9 auto trans wont fire number 4 injector.I did all my checks(OHMs and voltage drops).I need a PCM.Can I use a PCM out of a 2000 Ram 1500 with a 5.9 auto trans.Do I have to get the VIN number programmed at the dealer or just plug it in and go.

 

Why do you think it is the PCM because one injector will not fire? Not enough information to really make that determination.

Regarding the programming, once again, not enough info, but probably. Some discussionn here realted to some states that check PCM during inspections, and that could create a problem. More info about where you live would help others provide a good answer for your state.

 

Does the plug get a spark on number four? And please share with us the basics of what readings you got on what.

I have my doubts about a PCM being at fault when just one particular cylnder is involved; sounds more like a sensor problem.

I don't want to sound like a broken record, but I just fixed a problem where, maybe coincidentally, #4 wasn't firing, and it turned out to be a bad crank sensor. The procedure for finding, removing, and (crudely) testing it can be found in these three threads:

01 5.9 no signals to coil Help
Interesting spark problem
Really rough at cold idle

Dodge ignitions seem to me to have a reputation for being well-designed and very reliable, and as with all electronic ignitions, really pretty simple. Crank sensor, cam sensor, temp, O2, manifold pressure, throttle position sensors, coil, distributor, computer/PCM. Lots of relay, fuses, links, and a few other goodies, but still pretty simple.

I'm far from the most experienced guy here, but it seems to me that PCM's are probably replaced far more often than they are actually bad. (Code 53 is "An internal PCM failure or PCM communications failure has been detected." Have you ever gotten that?)

Just do you best to rule out the basics first before you plunk down the big $$$ for a new computer; especially the crank sensor.

 

Maybe the cap and rotor not making a good contact on that number ?

 

Wouldn't explain the injector not firing.

 

Is it clogged ?

 

Assuming tested with noid tester.....but assuming usually gets me in trouble.....

 

I know our injectors are not the best only having 1 hole. I see a lot of guys replacing them . May wanna change the sensor and the injector . I know I broke a couple sensors installing my airgap . Check it out

 

Move the injector to a different cylinder and see if the misfire follows it.

 

I put a niode light at number four injector, no pulse.I have power to the injector,power out of injector.I did a voltage drop from injector to PCM,thats ok.The PCM is not grounding the injector.If I supply a ground to the injector it fires.Is it possible the crank sensor is faulty and for some reason it wont fire number four injector.Thank so far for the help.Im new to this forum,and always had a dodge truck.