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Jerry
Jerry, Master Mechanic
Category: Dodge
Satisfied Customers: 1754
Experience:  ASE Master tech, 30 years exp. troubleshooter, driveability tech
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My 2003 3.9L Dodge Dakota stopped running back in August.

Customer Question

My 2003 3.9L Dodge Dakota stopped running back in August. The fuel pump was not working. I installed a new pump. the truck would not start. but I could hear the new pump prime up when the key was turned on. I checked all the grounds on the truck and tightened them I also pulled on and wiggled all the wires going into the fuse box. The fog lights worked so I pulled the relay for the fuel pump and installed the one from the fog lights. I hit the top of the relays with my hand. When I tried to start the truck it started right up and ran good. It sat in the drive way for two weeks. I tried to start it and the battery was dead, I charged the battery over night. I tried to start the truck and it would just turn over but not start. I wiggled the fuel pump wires and the front and rear oxygen sensor wires. the truck started and ran good that day and the next. Last sunday I was driving down the road and the engine just died. It will start and run for one second then it shuts itself off. I can hear the fuel pump prime up when I turn on the key and I know it has spark because it will run for one second. There are no codes displayed on the Odometer and the check engine light is not on. Could this be a bad PCM.
Submitted: 1 year ago.
Category: Dodge
Expert:  -Brad- replied 1 year ago.

When it will not start have you checked for spark and fuel psi? Will it start with starting fluid?

Customer: replied 1 year ago.
When I try to start it it starts and runs smooth for about 1 second and the dies.
Customer: replied 1 year ago.
I have not hooked up a gage to the Schrader valve but I have opened the valve and fuel sprays out.
Expert:  -Brad- replied 1 year ago.

Ok if fuel comes out then it's likely no spark, and the #1 issue we see for no spark is a bad crankshaft sensor which is in the bellhousing... Have you replaced it yet?

Customer: replied 1 year ago.
If the truck starts and runs for a second there is spark. If there is spark then the crankshaft sensor is good.
Customer: replied 1 year ago.
Is there a way to test the PCM without having to buy a new one.
Customer: replied 1 year ago.
What other symptoms or cues would be showing up if the PCM was bad.
Customer: replied 1 year ago.
I don't know if it is related or not , but recently all the windows stopped working with the buttons on the individual doors. I can still roll the windows up and down with the controls on the drivers door.
Customer: replied 1 year ago.
You still there?
Customer: replied 1 year ago.
I have unplugged the crankshaft sensor and checked for corrosion in the plug , it was clean and looked good. Same for all the plugs on the PCM.
Expert:  -Brad- replied 1 year ago.

When it will not start you need to see if you have 12v on the green wire at coil, then see if you have a ground pulse on the other wire when cranking.

Customer: replied 1 year ago.
The truck starts and runs every time I turn the key on that is how I know all the plugs and injectors and coil is working. It dies after one second of running. It runs real good and smooth for that one second. Then it dies. Like the PCM is not telling the fuel pump to keep running.
Customer: replied 1 year ago.
I need to know how to test the PCM. It is not grounding the fuel pump to keep the fuel pump running. Or the auto shut down mode is not working right.
Expert:  -Brad- replied 1 year ago.

Do you have a scantool like the DRBIII I use at the dealership to monitor the PCM?

Customer: replied 1 year ago.
No I do not have on of those.
Customer: replied 1 year ago.
Well this has been a total waist of time. I know nothing more now than when I asked the question. I will not be paying the other money.
Expert:  -Brad- replied 1 year ago.

You will need a scantool to monitor the PCM

Customer: replied 1 year ago.
Ok never mind im gonna just go buy a new pcm. Like i was before asking the question.
Expert:  -Brad- replied 1 year ago.

Sounds like a plan..