No start but cranks and has fuel

2007 2.4L Manual trans
Well its been a wonderful 12 years with this truck but for the first time it's given up and won't start. Two days ago the 'ECU-B' 7.5 amp fuse blew and it wouldn't start, new fuse and it worked like new for another day and a half. Today it wouldn't start again, won't fire even once, but I checked every single fuse with the ohm-meter and all are good. I thought the fuel pump went out so I popped the fuel line off the fuel rail and jumpered the 'EFI' relay and 'C/OPN' relay and I got a jet of fuel about 2 feet high. Popped the fuel line back on and with the relays still jumpered I tried starting again but still nothing. I played musical chairs with a few other relays and double checked all the fuses again but no luck. The truck is parked at work so I'm going in early with some tools to see if I'm getting spark but since I'm not getting a single fire I'm betting there won't be any spark.

ECU-B fuse blew, won't start, replaced fuse and works fine
2 day later won't start again.
Verified all fuses good, and fuel pressure to fuel rail, swapped relays around, still no fire.

Does anyone have any suggestions on what me be causing this? I thought there may be a part that controls all the ignition coils but they're wired directly to the ECU. Granted the ECU-B fuse blew but they're two separate 'ECU's, right? Also I read that a crank sensor or cam sensor could cause this same issue? Any ideas on that?I read elsewhere you can pull the MAF plug, crank sensor plug, and temp sensor plug, and you can sort of force the ECU into 'limp home' mode, I'll give that a try just so I can get it home.

Any and all help is greatly appreciated, I feel pretty dumb asking to bum a ride at 30 years old.

 

Does the Stereo, Dome light work?

This is why I ask:

 

Hmm, I swapped the dome fuse for the ECU-b fuse so I dont have some lights right now, but the short pin still reads good.

 

The short pin is just a conductive bridge ( not a fuse ) that is removed during vehicle shipping to remove battery drain while the vehicle is in transit and storage. It is installed as part of vehicle prep by the dealer.

 

long time listener. first time caller. this is for a 2.7 litter. 2007. all the things that fuse works. hope this helps some

 

If the fuse blew, I would check all the wiring back to where ever that ECU lives. If the wiring is good, you probably have a bad ECU. One way to check the wiring is to find the ECU and the fused wire which terminates to the plug in connector. Put a good load on it (say a 50W-75W load). If it works without blowing the fuse the wiring is likely good.

 

You need to ensure that there is not an excessive amperage draw from the radio or there is nothing defective about the dome assemblies. If that can be ruled out then you have a defective PCM which is causing too much resistance.

You will also have to check wiring to make sure that you don't have an intermittent short circuit either, which is always a possibility on a truck that old.

There is no easy way to check this. If it is out of your league I would take it to a shop to get professionally inspected.

 

So after a few hours of shooting wires I pulled out the ECU-b and found the problem, somehow plug 1I on the back of the ECU-B worked it's way loose and just fell out as I pulled it back. The plug has some sore of molding deformation as the clip has some extra mangled plastic where it should depress and snap into its slot. I cut out enough of it to get the plug to seat properly but will have to take a closer look tomorrow with some daylight. Either way it was a weird situation, I've never had the ECU-b out before or had that plug out so it's a surprise it's held on for this long, and I've never seen a plug with this manufacturing fault before. But thank you all for the good info and insight, and I'm really glad I saved the wiring diagrams I found here a few years ago, they were a Godsend.

 

Thanks for the reply on this thread OP!!! I have an 06 2.7L manual myself, so considering that we likely have the same qiring harness and ECU setup this info might help me some day.

Glad you found what appears to be the issue!