Hi all,

I TOTALLY new to the diesel world, but for background, I do all my own work on my gas vehicles so I do know a little bit about cars, but I must confess searching around this forum - I'm totally lost about what is going on with my truck.

I have a 2005 F350 6.0 diesel. What happened to me was this: I drove about twenty minutes, left the truck idling while I ran a building (this took about 30 seconds) and when I came out it was not running. I tried cranking it several times and it wouldn't start. Eventually it started sounding like the batteries were getting a little worn down so I called a buddy of mine and he had me look at the oil pressure gauge while I cranked it. It didn't register anything. I eventually noticed that when I turned the key to the on position, I didn't hear the normal whirring sound I usually hear when I start it up. I sat there about 10 minutes praying and the next time I tried it I DID hear that noise (which I assumed to be a fuel pump) and it started right up. The only other clue I can add is for the last week or so, when I would start it - especially in the mornings, it seemed to me that it was cranking a tad bit longer before it started. But it was subtle- to the point that I wondered if I was imagining it.

If this was my car, I would change the fuel pump. But after watching some vids on YouTube, DieselTech Ron said it's hardly ever the fuel pump and went on about all these parts that look like alphabet soup to me...IPM, ICP, HPOP, FICM, etc.

I made it home and parked the truck, then a couple days later tried it out. Started up just fine. We are in the middle of a move, and now I'm afraid to drive it. The fuel pump is about $200 bucks and while it doesn't look like too bad of a job, $200 bucks is a lot to pay if the problem is a sensor or relay. I appreciate any guidance that may be offered.

 

High pressure oil leak most likely. You can try dummy plugs and stand pipes.

Richard

 

This is where you get asked what codes are present - you need a reader.

Where is the whirring coming from (or not):under the cab or under the hood?

 

Thanks for the replies. Euroman, I have another post out requesting info on code readers too because reading this forum I quickly realized I am going to need one of those.
Not knowing at the time where the fuel pump was, it sounded like the whirring was under the cab somewhere behind the front seats.

 

I would doubt its the fuel pump.....

Was the noise more of a clatter of the injectors?

Definitely need to start by getting a scan gauge, or an app for your phone, truck could of cooled down enough to thicken up the oil resulting in it starting after many failed attempts.

More than likely being an 05+ its a HPO issue-failed(failing) STC fitting-bad o ring on a stand pipe or dummy plug.

 

The noise was more of a whir or hum, like something electrical. I had just been driving it for about 20 minutes in 90 degree+ weather and parked it, leaving it running for about 30 seconds to a minute. My daughter left her scriptures at church and we ran back to get em. We ran in and got em and back out. By then the truck had died. I ended up sitting there cranking it from time to time for a total of about 10-15 minutes before it started again. It's been parked since then til yesterday when I moved it so I could get my Trailblazer in the garage because it's AC went out (when it rains it pours). It started right up and I moved it and then went back a little while later to see if it would start and it did.

 

I would let it get up to operating temp, stay close around the area, and once its fully warmed up...shut it down and try restarting it-and I don't mean warm going off the gauge on the dash....thats worthless

 

Ok I started it up like 2006powerstroke90 said to do and I let it run for a bit and get up to temp while I set up Torque Pro. It was definitely up to temp- about 194 degrees. So I shut it off and when I tried to start it again, it was dead. I jumped it and the battery voltage was only 9.6- 10.8 volts while running. The batteries are only about 2 months old so I immediately thought it must be the alternator.

As to my problem of not starting then starting, I was thinking if the alternator was bad and the batteries weren't getting charged, then I would have noticed the gradual lengthening in time it took to get the engine started. Also probably the voltage just wasn't there to keep the fuel pump running at idle after having driven that long and it stopped. After the motor was off a while there was a little more voltage available and the pump kicked in, and it started.

I ran out and got an alternator and in a little bit I started it again and didn't have great voltage so I charged it most of the day and when ran it again the battery voltage is only showing up about 11.0 -11.4 volts. I'm new to diesels but am at a total loss why it would be doing this. I could understand if the battery was 11.1 with the key off but with the alternator running full speed, shouldn't it be in the upper thirteens/lower fourteens? Obviously it isn't going to keep running if I'm only getting 11 volts out of the alternator. Is there ANYTHING I am missing here? My pitiful differential diagnosis is
1. The new alternator is bad
2. Batteries are worn out and need replaced again
3. There's some kind of short somewhere (please Lord not that!)

 

Have you checked all your battery terminals and connections ? Just a fyi if you run to long with low voltage you could damage your ficm.

 

Anything under 12.2-12.4 with the key off is a low or dead battery. Check at the lead terminals and at the cable. If they are different you have a connection issue. Also check from ground to the alternator terminal (there is a fuseable link there).

After a minute or so the alternator should be putting out at least 12.8 volts.

Again be sure that with the key off you have battery voltage at the alternator lug.

Richard

 

Does raising the RPM of the vehicle bring up voltage

IV had a bad alternator pass a bench test but fail in vehicle

There's a pinpoint test I can post tomorrow for alt

​​​​​​​Load test battery's and check FICM voltage

 

Where are you reading the voltage? If your batteries were on a charger all day, and then you checked them, only saw 11.4 volts, your batteries are bad.

 

Ok, here's the update. It WAS the alternator. Old one tested bad and once I juiced up the worn down batteries, I'm getting 13.6v while it's running. So that part is good. I picked up an ELM327 Mini and Torque Pro so was able to now see the voltages. I started driving it and the same quitting while idling thing happened again. Now I had the TP app and was able to see that the delta T between the ECT and EOT was super high! ECT was running on a 100 degree day around 210 and the EOT was 235!! I let it all cool off and drove it again watching the temps rise and now I'm looking at a new oil cooler
I appreciate all the help and info I got on here.

My next question I will be posting is about doing an oil cooler backflush and whether one should do a Restore flush before or after the oil cooler back flush

 

The oil cooler is probably clogged or close to it but that is not causing your truck to die. It sounds like a high pressure oil leak, you need to see what ICP volts and IPR reading is when/after it dies and won't restart.