Running out of ideas here. Went to start this morning and it was like 5* and noticed immediately that the wait to start light wasn't on. Well needless to say it didn't start.

Tested the glow plug relay, didn't work so i replaced it. Still no start.

Tested the #30 relay and that seems to work (clicks when i jump it not when it's plugged in) also tried swapping one of the other relays with the same p/n to test and nothing. Think maybe blower motor?

Now I'm pretty irritated at this point having already looked at all the bus fuses under the hood and not finding any bad ones I pulled out the scan tool. Can not connect to pcm... *****, I think my pcm is kaput?


Any hints or tips guys before I go get another one? I need to find a diagram so I can test for power and make sure it's not a corroded wire somewhere, other then that I'm stuck for now.

 

Check your fuses under the hood and in the cab, including the maxi fuses. I think its fuse 19 or fuse 22 but not sure. If blown, unplug the fuel bowl heater on the back he fuel filter housing (only plug there).

 

What Carlton said, on my 99, its fuse 30 under the dash. Just remember to unplug the bowl heater, then change the fuse.

 

Don't jump to conclusions. It could be a myriad of other issues first.

Is it not even trying to crank? Meaning like a dead ignition response? Just curious. It does sound like the #30 fuse.

With the temperature that cold, your batteries might not be able to handle any load. I recently went through all sorts of crazy diagnostics (with numerous calls to Mueckster) in a similar situation. I would ohm my batteries and they were plenty strong. But when measuring them separately while cranking (one unplugged, then reversed) I noticed that the ohms were dropping WAAAY down and all over the place. To confirm my new suspicion, I finally went to the auto parts store and bought a gravity tester and found both batteries were bad. Holding charge, but no load capability. These were 850cc top-of-the-line Interstates (*ahem* *snort*) and one was only 2 years old.

On another truck, it was really cold and it wouldn't start. Embarrassingly, it was because I didn't have enough oil in the crankcase. As in VERY low.

Don't lose heart. Keep trying what is suggested, and eventually your diagnostic results will lead to someone knowing what the answer is...and hopefully for little to no extra money.

 

What year is your truck?
I think you need to check a fuse instead of relay.
Use a meter. I have had fuses that "looked" good but failed the ohm test.
I am thinking pcm, fuel pump, and fuel bowl heater are on the same fuse.
On my 2001 it is fuse #30 under the hood.

I think Blh4488 had the same failure today.
https://www.ford-trucks.com/forums/1...wts-light.html

Disconnect the bowl heater (and leave it disconnected), then replace fuse #30. Give your truck an overnight battery charge. Try starting the engine again and update us.

 

thanks guys, i just got back home from towing with somebody elses truck i had to borrow. i'll give that under dash fuse a shot in the morning.

the truck cranks, like a champ. has 2 new group 31 batteries with a new starter. And, my volt meter is missing... that was the first thing i looked for to start testing stuff and almost flipped ***** when i couldnt find it. tomorrow i'll grab one from my shop and bring it back so i can test, or just replace fuses with new ones...

i was worried about the pcm because when i hooked up my obd2 scanner it wouldnt connect to the pcm, and neither would my obd2 blue tooth reader... but, if the pcm fuse is blown i guess that would do that lol. my hands were so cold from messing with it last minute before i had to run out and tow i just tried swapping glow plug relays and the relay in the engine fuse box and gave up.

 

#30 fuse was fine, replaced it anyway and still now wait to start light AND it didnt start. even had the fuel heater unplugged

my truck just hit 80k i feel like it shouldnt have a problem like this...

anyone have a wireing diagram so i can start pulling things apart and checking them? i used to buy EVTM's but i dunno if they still exist even with all the computer stuff

edit*

a friend gave me his napafix password and i found this... might help me, or someone else with the same problem

Customer Concern:
The engine will not start. The Wait to Start light on the dash will not come on and the Powertrain Control Module (PCM) will not communicate with a scanner.
Average Reported Mileage:
184920
Tests/Procedures:
1. Access the Powertrain Control Module (PCM) and check for an aftermarket performance chip installed. If installed, remove and recheck operation. If the problem is solved, leave the chip removed or replace with a new part.

2. If no chip is installed, or removing it does not help, check fuse #22 20A in the Central Junction Box (CJB) (interior fuse panel) to make sure it shows full battery voltage on both sides from the PCM power relay. If OK, check pins 71 and 97 Red wires at the PCM connector to be sure they are both full battery voltage with key on from fuse #22.

3. If the powers are OK, check for 5 V reference voltage (vref) on the Brown/White (BR/WH) wire at pin 90 of the PCM or at any of the three wire sensors under the hood with key on and the PCM connected. If the voltage is low, disconnect the Injection Control Pressure (ICP) sensor, exhaust backpressure sensor, Manifold Absolute Pressure (MAP) sensor, Accelerator Pedal Position (APP) sensor, and camshaft position sensor one at a time to see if one is shorted and pulling the voltage down. If disconnecting any of the sensors causes the 5 V to return, replace the shorted sensor.

4. If disconnecting all sensors does not affect the vref, cut the wire near the PCM and recheck out of the PCM. If 5 V is now present, locate and repair the short to ground on the BR/WH wire.

5. If the powers to the PCM and the vref voltage is OK at 5 V, check all of the PCM grounds. These are pins 51, 77 and 103 Black/White (BK/W) wires and pin 25 Light Blue/Yellow (LB/Y) wire. Repair any circuit as needed and recheck operation.

 

Under dash or under hood? On my 2001, it is #30 under hood.
Good luck.

 

Yeah I don't have 30 fuses under the hood... that's what threw me off at first. #30 is a relay... Under the dash I have 31 fuses. My truck is option delete besides the diesel.

Anyway tho I found the problem. While pulling out the pcm I noticed the chip I have backed out half way, this caused my scan tool to not connect with the pcm but still powering the chip controller enough to light up the lcd display and let me change it to stock tune.

 

just had the same issue. truck died going down the road,#30 popped,replaced and off we went. two days later wouldn't start, same thing, replaced fuse and as soon as I turned the key it popped again so i came here and checked, then went out and pulled the plug on the bowl and it worked fine. NOW my question is, is the bowl heater fried ?

 

Yes, most likely it is.