my 01 2500 is giving me problems. For the last few months its been runnin wiered. it started with everytime i tried to mash the gas pedal to th floor or even give it gas it would try and stall out,i replaced the old plugs with new ones and that didnt even help it. I have been driving it here and there and it works fine but it wont start now. When i try to start it all it does is crank over, I had it hooke dup to a computer last week and it said the iac sensor had a short in it and that it was reading a different temperature.sometimes it will start with no problems at all and sometimes she doesnt start at all. I need help because this is my primary truck for plowing this winter and its starting to **** me off.

 

Check the wiring for shorts for the IAC motor.

When it cranks, but won't start, find out what you are missing. Does the fuel pump prime? Do you get spark? Injector pulse?

The temp reading differently than it should needs to be addressed. Check the connectors first. You only have one sensor, so, should be easy to find.

 

i hear the fuel pump working when i turn the truck on.but when i try and turn the truck over it floods itself out. and what is injector pulse

 

I suspect that right there is your problem, and is DIRECTLY related to the engine coolant temp sensor. If the PCM thinks it's -40*C outside (which is what it thinks when the sensor fails.) It will DUMP gas into the cylinders, in hopes that enough will atomize in the severely cold temps, to actually be able to burn. Replacing the temp sensor, or, fixing whatever it's problem might currently be, may just solve all of your issues. (not to mention better gas mileage. )

The PCM meters gas by pulsing the injectors. We have a sequential injection system, so, the PCM is only firing one injector at a time. (as opposed to a batch fire system, in which it would fire all four on one bank, or all four on the other bank, at a time.) So, the pulse is when the PCM is allowing current flow thru the injector, thus, opening it up, so fuel can flow. There is a neat little tool that plugs into the injector connector that blinks with injector pulse. Nice to have for troubleshooting.

According to theory, stomping the gas pedal to the floor, and HOLDING IT THERE while cranking, will put the PCM into "Clear Flood" mode, and it RADICALLY dials back the amount of fuel being added. Of course, as soon as you let off the pedal, if the temp sensor is toast, it will immediately begin dumping inordinate amounts of fuel again, causing at best, CRAPPY fuel economy/power, and, at worst, a stall. (not to mention washing down the cylinder walls, so you start getting metal to metal contact, then grooves.... and loss of ring seal.)

 

sorry for the delay but i ended up replacin the iac valve/sensor yesterday.
when i went to start it up this morning all the truck did was just turn over it took it like a minute or two of me just cranking the key to get it started.im gonna try and hook it up 2 a scan tool sometime this weekend. but what else could this be.I replaced all the plugs with bosch platinum4 and i put new ntk o2 sesnors in this spring. i also checked the intake and it was clean the only other thing i noticed was that my oil pressure is way up.

 

Did you do anything with the temp sensor as HeyYou suggested?

 

no i didnt i dont know where it is located. i just changed the iac sensor.How hard is this sensor to replace

 

That'll happen if you don't reset the PCM, and also if the reset PCM hasn't had a chance to recalibrate for the new part. Try this: Unhook the battery negative cable, let it rest ten minutes, then put it back. Then start the truck -- you'll probably have to use the throttle to get it started and keep it running because the IAC will be out of position -- and go for a ride. As quick as you can, find a stretch where you can hit exactly 40MPH and just cruise at that speed for a bit without adjusting the throttle to maintain speed. After a bit of cruise at 40, coast down to a stop. That's when the PCM calibrates the IAC.

If it's just lack of calibration, that'll fix it right up. I wouldn't do anything else until after doing that -- though it might not be your problem, you won't know for sure until you've given the PCM a chance to catch up to the new reality.

 

A little update, I did what unregistereduser told me about unhookin the battery and then drivin for a bit,Well the other nite i was bring my truck over to my bosses shop so i can work on it. on my way there as soon as i let off the gas the truck stalled right out and i couldnt get it started again all it did was just turn over. so i had it towed the last mile to the shop. well we did a fuel pressure test and its reading 44 psi, we looked in the haynes manual and it said the fuel pressure is supposed to be between 35-45psi and he called napa and they said between 50 and 65 psi.Does anybody know what it could be,Also does anybody have a diagram or a step by step of the engine coolant sensor i cant find it i want to replace that. And does this type of truck have a fuel filter i have been told it is part of the fuelpump assembly and i have been told that t should be under either the drivers side or passenger side hooked up to the fuel line.

 

There is no in-line fuel filter on these trucks. Have a look at this thread for filter info.

https://dodgeforum.com/forum/2nd-gen...he-tank-3.html

And for the location of the coolant temp sensor these pix should help you out.