I'm finally done swaping out my 4.6 for a 5.4l Now she won't start up. I know I have to tune the ECC for the 5.4 but everyone I have talked to on the forum and else were said the engine should at least start. I have narrowed it down the the fuel injectors. They are not firing. I hit the engine with either and she fired up. That comfirmed it. I have fuel going to the rails but don't know the pressure yet. I also confirmed no fuel is getting in the cylinder by pulling a plug. Should I just wait until I tune my ECC to see if that will fix it or is there another problem with the system? I plan the test the electrical connections tommorrow with a "noid" light to actually comfirm an electrical problem. Any other suggestions? Thanks, Chris

 

Does your fuel pressure regulator have a electrical plug on top? Is the tach moving when you crank the engine.

 

It should still run. You are missing a signal fom somewhere. Cam sensor, crank sensor?

 

My pressure regulator has a vacuum hose connected to it. And the tach does not move when cranking. All the gauges are zeroed out except the fuel gauge while cranking. After I release the key the oil pressure gauge jumps up for a couple of seconds then drops down. So I have oil pressure also.

 

I double checked all my connections. All plugged in correctly. Just for location purpose, is the crank sensor under the a/c compressor?

 

Yep, to the left of the balancer. Cam sensor is in the timing cover usually behing the PS fluid tank.

 

Alright, heres an update. I checked the 42 pin connector and 16 pin connector between the 4.6 harness and 5.4 harness. I found the 5.4 harness is not using 3 pin locations that the 4.6 is using. On the 5.4 42 pin connector pin 17 is not used. All other locations and wire colors match on that connector. For the 16 pin connector pins 9 and 10 are not used. Can anyone that has a good wiring diagram tell me what these pins are for. To clarify, my truck has a 4.6 connector that has three pins that the 5.4 engine harness does not have. These are the connectors that are on the firewall below the soleniod toward the passenger side. I wonder if I switch the harness will that fix the problem. Thank you for any help.

 

Ok, I had time to think. Everything the engine needs is on the wire harness so changing the harness won't change anything. The only thing I'm worried about is one of those pins might be a feedback to the PCM. Like LxMan1 said I'm missing a signal somewhere. I'll keep working on it

 

Well I found out my 4.6 engine had a IMTV (Intake Manifold Tuning Valve) that my new 5.4 does not have. That accounts for two wires that are now not used. I can't find it on any of my crappy wiring diagrams of course. Do you think this could cause the problem. I appericate any help please.

 

It's possible, I would think that it would show a code for it missing.

 

For once my truck doesn't show a code. I have to correct my last statement. I traced the 2 IMTV sensor wires out. One goes to pin 42 (which seems to be a constant hot wire when the key is on). And the other wire goes to pin 17 ( one of the pins the 4.6 used but 5.4 doesn't). So I found out about just one pin so far. I think pin 17 is a input signal to the PMC from the sensor valve. I also removed the valve from the 4.6 intake and tested continunity on the pins. At the normal/starting position, the continunity is very low. Around 40- 50 ohms. As I rotate the valve the continunity goes up to open. So, I'm thinking that with this signal not getting back to the PMC it may be causing my fuel delivery problem. If thats the case and the 4.6 PCM program is looking for the input so It can start, then a flash of the PCM to the 5.4 program should fix the problem since that program doesn't look for that input. I just may be blowing smoke right now but that's all I have. I though of jumping those 2 wire together and see what happens but I have a chip coming so I might just wait. Anyone have anymore ideas? I know the fuel injectors are getting constant voltage when the key is on. The PCM is not firing them.
Thanks, Chris

 

Can you remove just the actuator and plug it in just to see if it will start?

 

I actually thought about that for a second. But realized the 5.4 harness doesn't have a plug for that sensor.

 

Oh, I thought that you still had the 4.6 harness.
No chance of getting the donor truck PCM?

 

No chance of getting it. Besides the donor had a 4R100 tranny, it wouldn't work with my 4R70w tranny. I'm getting the chip monday. Lets see what happens.