Here's the story. Truck has showed no signs of rough running. Wife drives truck around town. Truck up to temperature and doing fine on a 90 degree day. Stops at red light. Makes left turn engine light comes on truck seems to be running on 4 cylinders. Pulls over light goes off engine idles perfect. Pulls back on road light on no power. Gets truck to a local friends house lets it sit til I get off work. I check for codes get p1316. Drive truck toward my house no problems for 4-5 miles then does the above with me. Limp it home. I know it is pointing at a wire problem to injectors and or IDM. Did a buzz test passed fine. Plan on pulling valve covers and looking for the usuall things. Any thing I am missing? What will a kOEO test tell me? Should I run one? How common is IDM to go out? One last thing just put a rebuilt transmission in it 3 days ago may be unrelated it seems to be doing fine.

2003 f-350 cc 7.3.

 

Click that UVCH link in my signature. The answer may be lurking there.

 

Tugly's post may be the issue. An open somewhere. You'll need a code reader that will read the IDM.

DIAGNOSTIC TROUBLE CODE (DTC) P1316 INDICATES THAT CODES ARE STORED IN THE IDM

Possible causes:

a. Injector(s) or circuit(s)

b. Open or shorted IDM enable circuit

c. Open/short in EF circuit

d. Open/short in FDCS circuit

e. IDM relay

f. IDM powering circuits

g. IDM

h. PCM

Check for other codes.

Key on, engine off. (KOEO)

Perform KOEO On-Demand Self Test.

P1316 OR P1670, CHECK FOR AN INTERMITTENT OPEN CIRCUIT Key off.

If you can locate a 104 Class V Breakout Box, If not, use a quality DVM and Back Probes which will not spread the terminals on the wire.

Install breakout box, leave PCM disconnected.

Disconnect IDM.

Check for intermittent open in the following circuits:

Measure resistance on (FDCS) Circuit 821 (BR/O) between IDM connector Pin 17 and PCM Test Pin 95.

Measure resistance on (EF) Circuit 818 (GY/W) between IDM connector Pin 4 and PCM Test Pin 48.

Grasp the harness close to the IDM connector. Wiggle, shake the harness while working your way back to the PCM, while looking for a spike on the DVOM.

Description The IDM provides the EF output signal to the PCM to confirm that proper timing/duration of fuel delivery command signal (FDCS) was received. Additionally, the EF signal is used to send diagnostics of the IDM and injectors (electrical) to the PCM.

DTC Description

P1668 = PCM-IDM diagnostic communication error

P1670 = Electronic feedback signal not detected

P1316 = Indicates that IDM DTCs are stored within the IDM

DTC P1668 and P1670 indicates that a communication error has occurred between the PCM and the IDM.

Possible causes:

a. Open fuse

b. IDM relay

c. Open or shorted IDM enable circuit

d. Open/short in EF circuit

e. Open/short in FDCS circuit

f. IDM powering circuits

g. PCM

h. Check for other codes.

Key on, engine off.

Perform KOEO On-Demand Self Test and retrieve Continuous DTCs.

CHECK CIRCUIT 818 (GY/W) FOR OPEN

Install breakout box; leave PCM disconnected.

Disconnect the IDM harness connector.

Measure resistance on Circuit 818 (GY/W) between PCM Test Pin 48 and IDM harness connector Pin 4.

Key on, engine off. Measure for voltage on Circuit 818 (GY/W) between PCM Test Pin 48 and battery ground.

Turn ignition switch to OFF. Measure resistance on Circuit 359 (GY/R) between PCM Test Pin 91 and IDM connector Pin 2.

CHECK IDM POWER

PCM connected, IDM disconnected.

Key on, engine off. Measure voltage between IDM connector Pin 14 and battery ground.

CHECK IDM GROUND

Key off. Measure resistance between IDM connector Pin 26 and battery ground.

NGS Tools are hard to come by. An IDS which is about $8k so that's probable out of the question as well. I know of no other tool which will do the test without a Break Out Box, and Ribbon Cable. So, If you call a shop, at a minimum ask if the have an NGS or IDM with a Break Out Box.

** MEASURE FREQUENCY ON THE EF LINE - NGS Tools ONLY **
Connect PCM to breakout box.

IDM connected to harness.

If you know of, or can locate a NGS Tester:

Set up NGS Scan tool as follows:

Connect NGS Tester to the DLC

Connect test probe between NGS common and breakout box Pin 77 (ground).

Connect second test probe between NGS signal and breakout box Pin 48 (EF line).

Select VEHICLE and ENGINE

Select DIGITAL MEASUREMENT SYSTEM

Change level to 4 VOLT DC

Press the link button to choose a PID

Select PID/DATA MONITOR

Select RPM PID

Press START

Key on, engine running.

Measure frequency at 3 different RPMs.

rpm Frequency (Hz)

1000 66

2000 133

3000 200

Hope this helps.

 

I am oficially overwhelmed. I have AE. I will need to run a KOEO test to receive the stored codes in the IDM correct? And this can be done with AE correct? I am at best a shade tree mechanic. I was hoping for some loose connections or rubbing wires.

 

If you pull codes and there's a P1316, you need to run a KOEO or injector electrical self test (buzz test) before clearing DTCs. If you clear codes, then run buzz or KOEO, the IDM codes will no longer be there to retrieve.

 

The fog is lifting. I will run the KOEO test and see what the codes are stored in IDM.

 

I vote UVCH as well but we will see.

A loose harness could be barely plugged in enough to work so driving could cause enough vibration for the harness to bounce and loose contact. In turn leaving you with 4 cylinders running but when pulling over the vibrations calm down and the pins start making contact again.

Staying tuned to this.

 

If indeed it is a loose UVCH, be sure to look closely for any burnt pins in the connectors, they have been known to cause issues following a harness flapping in the wind.......

 

Pulled the codes from the IDM. Got p0276. I have a place to start looking. #6 injector.

 

That's a UVCH code.

 

Not necessarily. It could be a short anywhere between the IDM and the injector. One of the likely spots is the underside of the main engine harness where it crosses over the left valve cover. The fact it happens in a left turn makes that spot even more suspect.

 

Truck fixed. Turned out to be the harness rubbing on the valve cover. The #6 injector wire was the one rubbing and shorting out. Taped up wrapped with a pieces of heater hose. Got to start on those preventive maintance threads I collected. This was on the list. Thanks for all the help guys.