Good morning Iam new to this site and have been reading some old threads on my issue but can't find what I need or cant tell whenI find it (lol)
My 2002 f350 7.3 had a IDM failure I put one in from a salvage yard and it ran fine for a couple days not far only about 20 miles next morning it would not start just spin over like before. My ? is what will cause IDM failures I have done alot of checks and things are checking out ok. Thanks in advance for any advice/help

 

Let me add a little info to this back in june I had #4 injector go out, replaced it and the UVCWH truck had some idm errors also since then it ran fine until it sit for a few days (not my daily driver) then no start ( this is when I found the first idm bad)

 

What would really help you out is the ability to get codes from the PCM. Even though the check engine light may not be on, it doesn't mean there aren't stored or active codes in there. Search for Torque (for use on an Android device) or Forscan (Windows PC) in this forum. You'll also need an OBD-II adapter - BT for Torque, USB for Forscan. Our trucks aren't truly OBD-II complaint, so generic code readers don't work.

 

I don't have access to a scanner that will read the codes I have a programmer but it does not show any codes (not sure why it has in the past). I was looking for information on resistance readings and things to check that way.

 

SENSOR VOLTAGES, KNOWN GOOD:

Delta for comparison:

AP: 5 Volt Reference Circuit, 0.5-0.7 vdc at idle, 4.5 vdc at WOT.

BARO: 5 Volt Reference Circuit, @ 4.6 volts / 14.7 psig at sea level, decreasing as altitude increases.

CMP: high = 12 vdc, low = 1.5 volts.

EBP: 5.0 volts Reference Circuit, 0.8-1.0 vdc / 14.7 psig

EOT: 5 Volt Reference Circuit, 4.37 vdc @ 32°F, 1.37volts @ 176°F, 0.96volts @ 205°F.

IAT: 5 Volt Reference Circuit, 3.897 vdc @ 32°F, 3.09 @ 68°F, 1.72 @ 122°F.

ICP: 5 Volt Reference Circuit, 1.0 vdc @ 580 psig, and 3.22volts @ 2520 psig.

ICP Vdc
0 0.2
200 0.4
400 0.73
600 0.96
800 1.2
1000 1.4
1200 1.6
1400 1.9
1600 2.1
1800 2.3
2000 2.6
2200 2.8
2400 3.0
2600 3.3
2800 3.5
3000 3.8

EXBP 10-15 psig w/ EBPV closed and not exceed 45 psig at WOT

*Note: EXBP showing low (3-5psi) that barley rises with acceleration indicates bad sensor or plugged tube.

IDM: 110 volt signal to the injectors. Grounds each injector as fuel is required for that cylinder. Fuel Pulse width is increased to deliver more fuel. The IDM sends a feedback signal to the PCM for fault detection.

IVS: 0 vdc at idle, 12 volts off idle. (off/on)

MAP: Frequency output; 111Hz / 14.7 psi, 130Hz / 20psi, 167Hz / 30psi.

IPR: Idle Warm: 8% - 14%, Idle Cold 10% - 15%, Electromagnetic Coil Test: OHMS = 10.2 - 10.6, Range: 0% - 65% (Not more than 20% Starting).

EPR: Exhaust Back Pressure Regulator, also EBP regulator Output: For quicker engine warm-up at cold temperatures. If the IAT is below 37°F (50°F some models) and the EOT is below 140°F (168° some models) the PCM sends a duty cycle signal to a solenoid which controls oil flow from the turbo pedestal. This causes a servo to close a valve at the turbo exhaust outlet. The PCM monitors the EBP input to determine if the EPR needs to be disabled to provide power for increased load, then reapplies the EPR as load demand decreases until EOT or IAT rises.

The Exhaust Back-Pressure sensor is a variable capacitor sensor that is supplied a 5-volt reference signal by the PCM and returns a linear analog voltage signal that indicates pressure. The Exhaust Back-Pressure sensor measures the pressure in the RH exhaust manifold. This sensor is used in conjunction with the exhaust back-pressure regulator to form a closed loop exhaust back-pressure control system.

The exhaust back-pressure is controlled by the PCM to provide more heat to the coolant for cab heating when ambient air temperature is below 7°C (45°F) and engine oil temperature is below 75°C (167°F) during low load, low speed operating conditions.

An open or short in the Exhaust Back-Pressure sensor wiring will result in a low out of range voltage at the PCM, and the PCM will disable Exhaust Back-Pressure control.

** NOTE: The Exhaust Back-Pressure sensor is not present on F-650 and F-750 models. **

 

thanks that is awesome information it will be next week before I can check it out.