Ok, I have been working on this issue with this truck for the last couple years. It really has not gotten worse or better.

Background: I live in the California Bay Area. The truck is a 2000 F350 7.3, 4x4, 6 speed. It does not get very cold here. Most of the time when I am trying to start this truck its between 50 and 80 degrees.

Symptoms:
-Anytime the truck has not been run at least 24 hours and I go start it up it takes an many cranks to finally start. Sometimes if I stop cranking and start again it fires right up.
-If I drive the truck around the block and turn it off it will still hard start.
-If I drive the truck and get it up to temperature it will fire right up like it is suppose to.
-If I try starting it 4 times in a row without warming it up it will usually throw trouble code P1670.
-This symptom is the same if I have recently done an oil change or in need of an oil change.
-It also does not change if I have just changed the fuel filter.
-I checked the HPOP oil level and it does not drain after sitting.
-I checked the GPR. It is working. The voltages are approximately 12.4V on the battery side and 10.5V on the glow plug side.
-I swapped out the IDM relay with no change.

(This is the one that really confused me today)
-I unplugged the ICP today and tried starting the truck. The truck would not start. It cranked and sounded like a couple of cylinders were firing but it never started. I got a smell of something like an electrical resistor burning but never figured out where the smell was coming from. I plugged the ICP back in and it started right up, no hesitation.

I just ordered a HPOP test gauge so I can see what the pressure is doing over night and at start up.

Until I get the test gauge can anyone give me any thing else to test or any insight into why the truck would not start after unplugging the ICP but will when it is plugged in.

Thanks
SES50

 

My 95 F350 would sometimes start like it was only runing on a few cylinders. Other tims it would start fine and othertimes it didn't want to start at all.
The Ford dealer changed the engine harness because the pin connections were burning up. This fixed my problem.
My truck had around 200,000 miles on it when this happened and Ford told me that was about the life expectancy, their story, but it fixed mine.

 

I just went through this. I first thought idm relay and the new one seemed to help but ultimately did nothing. Kept on the idm track through and discovered that water would condense and travel down wire harness and collect at idm connector. Once I blew out the water and prevented any future water from puddling there, it started as it should and has not thrown a p1670code since. I don't have an answer as to why it won't start with icp unplugged.

 

Shanejet,

Yeah, I was initially thinking it had something to do with the IDM but was told by a couple sources I should check some other things. I will check out the cables and connector for the IDM and see if that helps. I will let you know.

Thanks
SES50

 

kstones,

Thanks for the imput but I have never had a no start until I unplugged the ICP. that is interesting that the harness has a life expectancy.

Thanks
ses50

 

Bring your truck to my house a few days in advance of the wrenchin day and we'll let the guys all watch and guess...

 

I think the life expectancy thing is just a way of the stealership to get more of your hard earned cash. How many miles on the truck currently? Do you have a way of getting live data like AE? I can only assume that you have done the 50 cent mod. Hard start cold since how many miles on the vehicle? This is stuff others are going to bring up eventually. Have you changed out your batteries since this has been a problem? Have you ever done a buzz test on your injectors? Have you done the hutch mod? What is your fuel pressure while you are cranking and while running?

 

Current Miles: ~185k
Problem Started: ~160k about 4 years ago

Parts Changed since problem started:
-Both Batteries
-Positive Battery Cable (Then battery clamps were getting pretty trashed so I figured it could not hurt and may help, it did not)
-Fuel Filter
-Regular Oil and Filter Changes

I do not currently have a way to pull live data off the truck. I have been debating on buying a computer based scanner/diagnostic program. No, I have never done a buzz test and can not tell you currently what the fuel pressure is. Do not know what the hutch mod is.

Got access to the IDM last night. Plug looks very clean. Need to test the cable tonight with an ohm meter to per the P1670 trouble shooting tests. Anyone know what break out box they are refering to in the following text:

FJ10 DTC P1316 OR P1670, CHECK FOR AN INTERMITTENT OPEN CIRCUIT
Key off.
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.
Do all readings remain below 5 ohms throughout procedure?

Thanks
SES50

 

Yeah, I just want to get as much information as possible before all the guys are standing around so that I have some answers and can maybe rule out some issue so we do not waste our time there.

 

Ok, I got through FJ10, FJ11 and FJ12 (see below). I guess I need to buy a scanner to run FJ13 and FJ14. After putting everything back together it started fine and did not throw a check engine light, but it has only been sitting for two days. I will try starting again in the morning when it is cold and then not touch it until after the long weekend.



FJ10 DTC P1316 OR P1670, CHECK FOR AN INTERMITTENT OPEN CIRCUIT
Key off.
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.
Do all readings remain below 5 ohms throughout procedure?
Yes-GO to FJ11 . No- REPAIR open in the suspect circuit. RESTORE vehicle. CLEAR DTCs and RETEST.

FJ11 CHECK FOR AN INTERMITTENT SHORT TO GROUND
Check for intermittent short to ground on the following circuits:
Measure resistance on (FDCS) Circuit 821 (BR/O) between battery ground and PCM Test Pin 95.
Measure resistance on (EF) Circuit 818 (GY/W) between battery ground 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.
Do all readings remain above 10,000 ohms throughout procedure?
Yes-GO to FJ12 . No- REPAIR short to ground on the suspect circuit. RESTORE vehicle. CLEAR DTCs and RETEST.

FJ12 CHECK FOR AN INTERMITTENT SHORT TO POWER
Key on, engine off.
Check for intermittent short to power on the following circuits:
measure voltage on (FDCS) Circuit 821 (BR/O) between battery ground and PCM Test Pin 95.
measure voltage on (EF) Circuit 818 (GY/W) between battery ground 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.
Did voltage ever appear on any circuit throughout procedure?
Yes-REPAIR short to ground on the suspect circuit. RESTORE vehicle. CLEAR DTCs and RETEST. No-GO to FJ13 .

FJ13 VERIFY DTC P1316 AND/OR P1670
Restore vehicle.
Clear DTCs.
Cycle key off, than start engine.
Road test vehicle.
Perform KOEO On-Demand Self Test and retrieve Continuous DTCs.
Was DTC P1316 and/or P1670 set in Continuous without any codes in KOEO On-Demand?
Yes-GO to FJ14 . No- REPAIR KOEO On-Demand DTCs. RESTORE vehicle. CLEAR DTCs and RETEST.

FJ14 ATTEMPT TO GENERATE IDM DTCS
Key off.
Disconnect one valve cover connector.
Start engine to generate IDM codes.
Perform KOEO Injector Electrical Self Test and KOEO On-Demand Self Test.
Are IDM codes retrieved?
Yes-REPLACE PCM, RESTORE vehicle. CLEAR DTCs and RETEST. No- REPLACE IDM. RESTORE vehicle. CLEAR DTCs and RETEST.

 

The "Breakout Box" is a series of individual switches designed to go between the Valve Cover gasket harnesses to shut off or turn on individual circuits(injectors)

Are you getting any DTC's or is your concern just for the "long" starts?

 

I am trying to figure out why I am getting long starts after sitting for a while and a P1670 on occation because of the long starts.