7.3L Died while Driving. Start-No Start

11591 Views 11 Replies 3 Participants Last post by Greg03PSD, Oct 10, 2015

Boarder22

Discussion Starter · Oct 5, 2015

Ok I have a 08/99 F-350 Super duty with 7.3L it died when driving down the road pulled over hit the key and It fired up got it home and went to start next day will not start only crank over. Things that have been checked are as follows

No Codes at all have shown up in the computer.
HPOP is good on oil in the Res.
Motor oil is full.
WTS light is coming on.
Good hot batteries.

ICP sensor- Replaced
Cam Sensor - Replaced
IPR - Replaced / Scan tool showing 15% / 12V going to plug verified/ Brass nut is tight.
Lift Pump - Checked / good working order
HPOP - Snap on scan tool Ethos showing up to 2,250 psi on InjCtrlPr(PSI) when cranking over in live Data for 12 sec.
IDM- Put in one off another truck that is good and did not change anything.
Checked fuses and relays.

Hopefully someone can shed some light on something I have over looked or could check?

Thank You

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Greg03PSD

· #2 · Oct 5, 2015

Run an injector buzz test and see if you get anything. If you get no buzz, I would be looking at power to the PCM & IDM. You've already replaced the likely culprits. Double check your PCM fuse - the PCM & fuel bowl heater share the same fuse. The fuel bowl heaters are notorious for shorting out and blowing the fuse. When that happens, the PCM never gets power and the engine will obviously not start. If you find that the fuse is blown, unplug the fuel bowl heater, replace the fuse, and try to start it up.

Do you get any smoke or diesel smell at the tailpipe when you crank? If you are seeing smoke, then you know the engine is getting fuel.

Also check the wiring harness going to the 42 pin connector on top of the driver side valve cover. The harness is known to chafe on the valve cover. If the wires rub through, some important signal will short to ground and potentially cause a no-start.

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Greg03PSD

· #4 · Oct 6, 2015

roger.lees51 said:
Hi,
I have a similar problem I have been fighting for a number of years. My 2001 7.3L will occasionally stall when in traffic with no warning.
The bigger problem occurs when I have been on the road for 2-4 hours traveling with no stops. I get a very, very hard miss with black smoke out the tail pipe. It is very brief and I immediately back off the speed and it goes away. I have replaced both the ICP and CAM sensors. I never get a code. I'm at a loss. I'd take it to a shop but I just don't know how they could diagnose this when it only occurs on the road.
Thanks

Problems like this could be related to the IPR. Make sure the tin nut is present at the back of the IPR - it is what holds the little solenoid in place. An IPR solenoid sometimes will become weak with age, and it is aggravated by high temperatures. If the problem only occurs when the engine is hot, your IPR may be on its last leg.

You would need some hardware and software to do this, but if you could monitor your ICP and datalog it while driving, it might reveal something. A sudden drop in ICP followed by a return to normal could indicate a failing IPR. A new IPR is about $200.

If you don't know what you are looking for, look down the backside of the HPOP toward the driver's side. Here is a picture of an IPR. The tin nut is the gold nut at far right end of the picture:
IPR Injection Pressure Regulator 96-03 7.3L Ford

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Greg03PSD

· #7 · Oct 6, 2015

roger.lees51 said:
Greg,
Thanks a million for the info. I'll start on that tomorrow.
If I am ever in your neck of the woods I will certainly the bring beer!
Thanks again

Sounds like a deal. My neck of the woods is about to make a big move from Connecticut to San Diego. The government decided to move the submarine I am stationed on to the west coast. Never been out there, but I guarantee there are no New England winters in southern California. I was told the last time San Diego saw snow was in 1967. My vehicles will certainly appreciate not having to deal with road salt all winter.

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Greg03PSD

· #10 · Oct 8, 2015

Boarder22 said:
Ok so I went to do a buzz test (KOEO) self test on snap on scan tool ethos. I can hear the fuel pump kick on but that's it no buzzing from injectors.

If you know that the PCM & IDM are getting power, my guess would be a bad PCM or a bad IDM. There's not much else that will cause all 8 injectors to not work. You stated that you tried a known good IDM off of another truck. Try installing your IDM in the other truck and see if it works. If it does, put your PCM in the other truck and see if it works. Maybe you can borrow the PCM from the other truck and give it a try in your truck.

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Greg03PSD

· #12 · Oct 10, 2015

Correct - if the PCM has no power, there won't be any communication.

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