No Start After IPR Replacement

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Jul 5, 2019 | 11:02 PM

#16

sunogbahay

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From: Baltimore

I found this checklist for the P1668 DTC Code:
FJ1 DIAGNOSTIC TROUBLE CODE (DTC) P1670 and P1668

DTC P1668 and P1670 indicates that a communication error has occurred between the PCM and the IDM.
Possible causes:
- Open fuse -- the 30A IDM fuse checks out okay.
- IDM relay -- I am planning to swap around some relays to see if I can get the buzz test to work. This is kind of my last option at this point for a quick and easy solution.
- Open or shorted IDM enable circuit -- Is this the fuse 22 circuit do you suppose?
- Open/short in EF circuit -- What is the EF circuit?
- Open/short in FDCS circuit -- What is the FDCS circuit?
- IDM powering circuits -- same as above, no?
- PCM -- the PCM appears to be working since I am able to retrieve codes, etc.

If it turns out that I DO need a new IDM, does anyone have any recommendations on what to buy?

It sounds like the Ford part from the dealer is around $900!!
I see a Sinister Diesel remanufactured unit for $269+125 core
Riffraff also has a remanufactured Alliant unit for $389+150 core
I could probably pick up a local Napa Remanufactured Computer unit for $349+130 core.
Napa also has a Napa Echlin Diesel unit for a bit more. From what I've read about Napa sensors in the powerstroke, I'm a bit wary of their offerings.

Does anyone have any experience replacing their IDM with one of these options?

Jul 6, 2019 | 12:02 AM

#17

Sous

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From: Lake Hartwell, GA

Jonathan at DTC does great work.

https://www.dieseltechchatt.com/pages/about-d-t-c

Jul 6, 2019 | 01:55 AM

#18

aawlberninf350

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From: Elk Grove, CA

Not sure if new IDM is the answer, but RAE hi voltage is what I would do if needed.

Jul 6, 2019 | 05:35 AM

#19

FordTruckNoob

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From: Henderson, NV

I went with the one from RiffRaff. A short in the engine harness took out my original. It's been in there for slightly over a year and is working well.

Jul 6, 2019 | 12:51 PM

#20

aawlberninf350

It's a Van Gogh

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From: Elk Grove, CA

Quote:

Originally Posted by sunogbahay

I do see the injector pressure numbers changing while cranking: 2212.81, 2200.37, etc.

That's not any real change tho, should range like 500 to 2800 psi depending on load. So although you have a new ICP the PCM is not getting the signal and is using the default value. Eyeball the harness closely at the ICP where it gets worn. Or check connectivity from the ICP wire to pin 87 on the PCM connector.

Jul 6, 2019 | 01:28 PM

#21

BBslider001

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Joined: Mar 2012

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From: Texas

And I guess the first question is are you getting a wait to start light? There's a possibility you may have blown fuse number 30 in the dash fuse panel, not under the hood panel. It may have happened in your messing with the fuel bowl. Ask me how I know. LOL

Jul 6, 2019 | 02:36 PM

#22

slowsure

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From: Southern Middle TN

Quote:

Originally Posted by Sous

Jonathan at DTC does great work.

https://www.dieseltechchatt.com/pages/about-d-t-c

I second the above. Jonathan rebuilt my OEM IDM. I’m lucky in that he is local to me. Fast turnaround time and was out the door for about $480.00ish.

My idm IDM went bad driving down the road. Here is my thread on my experience. LINK

Jul 6, 2019 | 06:07 PM

#23

sunogbahay

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From: Baltimore

I have good news to report.

I fully charged both batteries overnight and tried swapping out the IDM relay with the PCM relay this morning. Still no sound when running the buzz test and I continued to get the P1668 DTC. I was pretty sure that it was the IDM at this point. I don't think that a bad ICP would cause the buzz test to fail.

I picked up a Napa Echlin IDM (because it was local and I was able to get it today). Once it was installed, I first tried the buzz test again and finally heard happy injectors!

Next, I tried starting it and it fired right up. I ran it through the KOER test with AE and everything came back clean.

I drove it around for a while this afternoon and so far so good.

I'm a little nervous about the Napa IDM. It has a 3-year warranty, so hopefully that is good for something. We'll see.

Thank you all for your help and interest in helping me solve this latest puzzle!