Hello everyone,

My name Arty Arocha.

I have a Ford Expedition 2003 Eddie Bauer (4.6). One of sparks plug decided to leave the cylinder head for a better life and it took the threads with it. Long story short, I have to replace the cylinder head. I just assembled everything yesterday and this is what happened when I tried to start the engine.
1. First try: Engine started spluttering. Check the code and find out I forgot to plug the MAF.
2. Second try (and following tries). Once the MAF sensor is plugged the car make an attempt to start and just die. I have no code (well I have one code I'll explain below).
Our first assumption was to check the MAF and it is OK. It have the 12V and we checked the signal in it and is working.
Then we check the TPS sensor, it has the 5v and the voltage change when you move a accelerator.
The only thing changed was the DPFE. When I was taking apart the engine, I broke the connector to the hose, now the sensor is useless. And that's the only code I have in the computer, the P0402.

Any idea will be appreciate.

Thanks

If you want to hear how it sounds here is without the MAF connected: http://www.iniciado.com/MAF-No.wav and here is when the MAF is connected: http://www.iniciado.com/MAF.wav

 

If the DPFE sensor is no longer working then disconnect the vacuum line from the EGR valve and plug the vacuum line with a golf tee.

The defective DPFE may be sending vacuum to the EGR valve during cranking, start up, and idle.

 

I did it. I plug them with a screw and no change at all.

 

Clean the MAF sensor.

 

I did that too.

 

With the MAF unplugged, and the truck is barely running, what is the fuel pressure at the rail? Make sure the fuel pressure regulator is plugged into its vacuum hose, and there is no fuel present at that hose.

 

Oh, and double check that there is no vacuum leaks in the DPFE, EGR system. Esp. since that one part is broken you may need to fix that inorder to be sure that's not the problem.

 

The fuel pressure is 45 psi, 5 psi less than what the manual says.

 

5 psi low would not make the truck run like that at idle. It would only be perhaps a problem under load and/or at wot.

I'm also inclined to think the MAF sensor is defective. Even tho' you wrote that the checks you made were good, and cleaning a MAF doesn't always help.

Is that '03 a coil on plug ignition system?

 

is there any gas in the vacuum hose going to the regulator ? there should be no gas in the vacuum hose ! did you take the EGR valve off and clean under it ? the code that was coming up did you try clearing it ?