Cranks but wont start

[thedodgeguy69]

Hello, New here. I have a problem with my wife's 08 expedition, she drove it to the resturant, everything working fine. Parked, locked with remote, got food, unlocked with remote, went to start but only cranked. My friend was close by and towed her home. Keep in mind, she drove about 2.5 miles and outside temp has about 25*. Next morning i checked fuses, plugged in code scanner and got P1288 code. Picked up new cht sensor and installed. Cranked and no start. I did check the fuel shut off switch first, before doing anything. Tried disconnecting battery, same results. It does however run with starting fluid. Not sure what to do next. I really need to get this pile going, my wife just just gave birth to our 3rd child and the extra room would be really nice. Also all fluids are topped off. The theft light flashed until the key is in rum position. Goes out after about 3sec. Any advice would be greatly appreciated.

 

[k9education]

If it starts with starter fluid, then it sounds like a fuel-related problem.

 

[Bedrck47]

See if you can check the fuel pressure at the fuel rail. Agree with the above if its starts with starting fluid I would suspect a problem with fuel pump or clogged fuel filter. Or if you can get under the vehicle and disconnect the fuel line at the filter then turn the key on to see if its pumping fuel. Just be careful. Check to see if you are getting voltage at and thru the fuel shut off switch.

 

[Bedrck47]

Which fuse (how Many) did you check and how did you check them

 

[thedodgeguy69]

I will check voltage at fuel shut off and the fuel filter/pressure. I checked the fuses in the fuse block under the hood. I checked all the fuses with a multimeter and the relays i switched with ones that are working. I be leave their are 6 fuses/relay that deal with the fuel system?

 

[Bedrck47]

Please refer to fuses with the fuse # example #55 0r #3 etc. so I can look on my prints. Same for relays

 

[Truck3]

I'm going with either fuel pump relay or the fuel pump itself. Past experience with fuel pumps tells me they go without warning, at the least convenient time, in the worst weather and when you are in a hurry or depend on the vehicle the most.
Does not matter what vehicle, or manufacturer, fuel pumps suck.

With the key in the ignition position, you should be able to hear the "hum" of the fuel pump or with an ear at the relay center, the click of the relay.

 

[MarkJ]

Same problem I had earlier this year with my '07. I checked the fuel pressure rail with key on, no pressure. Took it to a shop and they discovered it was the fuel pump. Good luck.

 

[Bedrck47]

Some times it is just the pump but there are other components in the wiring that could also cause no pressure at the rail. Taking it to a shop and they most likely will check to see which component failed. But if you are doing it yourself then you want to check everything in the circuit.

There is a proper way to troubleshoot a problem or the other way is to throw parts into the expy and hope you get lucky.

I would hate to replace a fuel pump and then find out it was just a blown fuse or bad wire that was the cause of the problem

 

[thedodgeguy69]

I do hear the relay clicking when key is in the run position. But no hum of fuel pump. The check engine light is on all the time with P1288 code. I cannot erase the code either. My understanding of the cht is, it shuts the fuel off if critical temp (358*) is sensed in the engine. Could all my problems be cht related? I will definatly check power for pump and shut off switch.
I checked all fuses and relays. The first fuses I checked for the fuel system or related are: #18-relay,#32-mini fuse, #46-cartridge fuse, #60-looks like mini fuse, #62-" ", #69-mini fuse.

 

[Bedrck47]

Check fuse #32 and #71 in the battery junction box under the hood key should be in the run position

P1288 - Cylinder Head Temperature (CHT) Sensor Out of Self-Test Range
Description: Indicates the CHT sensor is out of self-test range. The engine is not at a normal operating temperature.
Possible Causes: Cold engine
Engine overheating
Damaged harness connector
Low engine coolant level
Damaged CHT sensor

Diagnostic Aids: Bring the engine to operating temperature. If cold, repeat the self-test. If the engine overheats, check the cooling system. Refer to the Workshop Manual Section 303-03, Engine Cooling for cooling system diagnosis.
Application Key On Engine Off Key On Engine Running Continuous Memory
All GO to Pinpoint Test DL .

 

[Bedrck47]

At the shut off switch You should see two wires a Vt/gn wire and a Bn/wh wire Place one lead of your meter on the brown/white wire and the other lead on a good ground point. You need to be watching the meter while someone tries to start the expy You should see 12 volts as the engine is being started if it doesn't start the voltage will drop off which shuts down the fuel pump That is normal if the engine does start the voltage will remain at 12 volts

 

[thedodgeguy69]

So I checked fuse 32 and 71 with ignition on. 12.5v. I checked for power at fuel shut off. 11.9v before cranking. 9.4v while cranking. Im the process of lifting vehicle so I can get under it to check voltage at fuel pump.

 

[Bedrck47]

Take a rubber mallet and hit the side of the tank while someone is trying to start the expy Sounds stupid but it has worked for some if it does start then replace the pump

 

[thedodgeguy69]

Smacking the tank did not do anything. I think I am going to bite the bullet and take it to a shop to at least have them diagnose it. I'm thinking you are right and the fuel pump drive module or the pump its self is gone south.

 

[Bedrck47]

lets us know what you find out

 

[Truck3]

Take a rubber mallet and hit the side of the tank while someone is trying to start the expy Sounds stupid but it has worked for some if it does start then replace the pump

As unconventional as this sounds, it is true. I was told to do the same thing by a mechanic when faced with the same thing on a mustang. Sure enough, it was the fuel pump. Based on what you described at the beginning of this thread, I was leaning toward the fuel pump. I hope you are able to replace it without a whole bunch of cash and down time.
I also agree, let us all know what the end-all is on this one.

 

[thedodgeguy69]

Where is the fuel pump driver module located?

 

[Bedrck47]

There is no fuel pump driver module on the 08 expy

Check back in a few minutes and I will post the wiring diagram for a 07 expy which is the same as the 08

 

[thedodgeguy69]

So the culprit was the fuel pump. Shop put in a new one, runs like a champ. Wife is very happy. Thank you for everyone's advice/help.