2006 Ford Expedition Crank, no start with a lot of diagnostics...

[GEONV]

Ok, I bought a 2006 Ford Expedition from a lady whose mechanic was throwing parts at it trying to fix a crank but no start issue.

I've been going through things one at a time to verify various things.

Her mechanic had put this laundry list on- 2 new camshaft position sensors, O2 sensor right upstream, mass airflow sensor, fuel pump driver module, fuel pump, battery, fuel filter, air filter, fuel rail pressure sensor, spark plugs.

When I first started diagnosing it- I found no fuel pressure. I tried starting it with starting fluid and it didn't even sputter- which made me think ignition was the problem. Clearly needed to get the fuel pump working too, but important that it wouldn't start with starting fluid.

I checked the various fuel pump systems and found them all to be functional- but the ground on the frame was bad so i fixed that as well as the other ground wire nearby. Fuel pump now turns on but only has 7 volts at module output- pull codes- high fuel rail pressure (they just put a new sensor on it). I removed connector and jumpered source 5v to pressure sensor- ECU reads 5V, jumpered it to ground- reads 0v. same with fuel temp sensor. Plug in sensor and data log it- it occasionally spikes to 5v and then back to 4.3 and then sits at 5v. get a p0193 code. replace the sensor- now it behaves properly and shows the cranking desired pressure is 57 psi- measured pressure is 54.7 while cranking. no more code. Can smell fuel in exhaust as it cranks but no trying to start up.

Check coil connectors- 12v to connector and grounds intermittently as ecu fires coil. same thing for injectors. Pull a coil off and hook up a spark plug and ground it- really weak spark but it does fire. check other side also really weak spark. Won't start with starting fluid.

check several more grounds- nothing terrible. by the fuse box there is zero rust which was surprising. pulled all of the grounds I found off and sanded to sheet metal. one to left of ECU, on behind the ECU one to right of ECU and the two next to the fuse box. add another ground cable from battery to engine and from engine to body just to be sure.

Check ECU ground pinouts to battery negative 0.8 ohms resistance, same to engine block.

test the coil capacitors- one has continuity with ground the other doesn't. Order a new one. I don't think this would prevent it from starting though right?

I removed cam sensor plugs and still no start. plugged them back in

I had replaced crank sensor as it was still stock and thought it could be providing an odd signal. no start.

MAF sensor responds while cranking, cam sensors and crank sensors show synch, ignition timing while cranking shows 10.3 degrees advance.

I hate to just throw parts at it, especially since all of the coils I tested showed weak spark- that just felt like it would be the ignition coil ground. but the wiring diagram I found shows the coils ground through the capacitors and the ECU. And checking the ECU it has good grounds. It seems unlikely for multiple coils to fail at once.

I also jumpered a hot wire to the fuel pump to bypass the fuel pump relay to see if that made a difference- no difference- has the 12 volts coming out of the fuse box, but just wanted to test it.

Any ideas? I'm running out of things to check. Though I do suspect there to be an extra ground I haven't yet found. As a test I checked resistance between the fuel rail pressure sensor connector and battery negative and it read 0.8 ohms the same as the pcm pinout did.

 

[purevw]

Does it have a transponder key? Is it correctly matched to the vehicle?

 

[GEONV]

I have been wondering about that as well. the security light doesn't flash during cranking at all. I used forscan and it says the primary key is inserted so I think that part is working. I also replaced the fuse box with no change.

 

[GEONV]

Well after checking every electrical connection and ground I could find in the wiring diagrams that touched the ecu I did a compression check. Drivers side cylinders are all almost zero compression. I’ll do a leak down and figure out if it’s skipped timing or if it’s bent valves.

 

[Vincent Vega]

Well after checking every electrical connection and ground I could find in the wiring diagrams that touched the ecu I did a compression check. Drivers side cylinders are all almost zero compression. I’ll do a leak down and figure out if it’s skipped timing or if it’s bent valves.

Good find. Situations like that can be hard because you don't know if the new parts were bad right out of the box (like Amazon parts) or if they were installed properly. I would be interested in hearing about what you find, so please keep us updated.

 

[Hamfisted]

Probably quicker to just pop the valve cover off and inspect the timing chain. You didn't say how many miles were on the Expy. Did you get any maintenance records or history with it?





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[GEONV]

No maintenance history unfortunately. I did pop off the cover hoping for something obvious like a sheared pin in the phaser. I’m going to do a leak down test and see if it bent the valves. Hoping not as then I can potentially just do a timing kit and a high volume oil pump.

142,510 miles.

I’m doubting what I heard of the history of the vehicle as well as it had 2 year expired plates on it and the lady I bought it from said it died at the smog test shop. When I started working on it for sure the fuel pump wasn’t working. But now that’s working and spark plugs are indeed working. I suppose it could have suddenly died if the cam skipped timing as she was there but seems odd the fuel system would die at the same time.

 

[Hamfisted]

Did it look like someone's been in there before? This is almost worth pulling the passenger side valve cover to solve this mystery ! But if you see piston top damage, the motor is toast.
If you have a borescope camera take a peak at the top of the pistons and see if there's been any contact damage.





Mechanics Borescope on Amazon






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[GEONV]

yeah someone's definitely had the valve cover off before. I heard the phasers had both an R and an L on them, but haven't checked. I did a leak down test and all the air was going into the crankcase. Seems hard to have that happen all at once for multiple cylinders on the same bank unless the head was cracked.

Also as an interesting note- a ton of oil squirts out from right behind the cam sprocket as i'm cranking it over.

 

[Hamfisted]

yeah someone's definitely had the valve cover off before. I heard the phasers had both an R and an L on them, but haven't checked. I did a leak down test and all the air was going into the crankcase. Seems hard to have that happen all at once for multiple cylinders on the same bank unless the head was cracked.

Also as an interesting note- a ton of oil squirts out from right behind the cam sprocket as i'm cranking it over

Yeah. I would stick a borescope camera into the sparkplug holes and inspect the piston tops. If no piston top damage, pull the other valve cover and timing cover and recheck the timing marks and the condition of all the timing gear.






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