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Discussion Starter #1
A few months ago, I replaced the IDM, and the truck had been running perfectly. Last week I replaced both batteries because they were getting old and slow to crank and finally just wouldn’t crank. I drove just one day after replacing them and it ran perfect. Parked it on level ground and the next morning, dead.
I immediately suspected the IDM because it is not fuel, as there is 25 psi like always at the bowl (I replaced the Schrader valve with a fuel gauge). Had another IDM sent to me, replaced it and much to my surprise it’s still dead, with not even a hint of firing.
I’ve done the usual: checked all fuses, unplugged ICP, tach reads about 200 while cranking, has a new Ford CPS, WTS comes on and goes off as usual, it’s still dead. Only thing I haven’t done is checked oil at HPOP, because the Allen head bolt stripped for the right size wrench, so I’m going to try tapping a Torx male socket and see if it comes out, and replace it with new one. I doubt that it’ is that, because oil has always been full, and with all the cranking I have done, it would’ve filled back up, and this happened after a full day of driving, and last week, it sat for over a week, and after I replaced the batteries, it started in les than 3 seconds of cranking, like it always does.
I’m going to try swapping around the IDM relay, but I can’t remember which one it is, because it still sounds electric to me. I know there is fuel in the bowl and fuel pressure, and mechanical problems don’t show up like that, from 100 to 0 in one day.
The truck is 100% stock and other than these episodes, always reliable.
What else am I missing. Any help will be appreciated.
 

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Is the tach reading while you are cranking and does it sound like it is cranking over at a good speed?

Have you checked the battery voltage?

I agree it sounds electrical, perhaps check the cps connection.

On the HPOP reservoir, if you have a Harbor freight close by pick up some left handed drill bits and then use a reversible drill. A large bit will bite into the plug and spin it right out.
 

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Discussion Starter #3
Thanks Bugman, I posted you a PM.
I hope this can help others with the sane problem.
The problem was the IDM relay. It is the number 2 in the fuse box. I replaced it with the one that was in the number 4 socket, which I believe is for a trailer tow package, and the engine fired right up, as if nothing had happened.
It feels good when it goes from 0 to 100% by just replacing a relay.
I don’t know if a scan with AE or any of the other code readers would detect a faulty relay, but when the symptoms sound electrical rather than mechanical, that relay has to be kept in mind.
Thanks
 

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I've attached the Power distribution diagram pages that might help you. Cheers!
 

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Discussion Starter #5
Thanks Patrick.
I am going to try to figure this thing out.
I just checked the voltage at the IDM relay socket, and there is always 12 volts at contact 30 even with the key Off, and when the key is On, there is also 12 volts at contact 86, which is the way it should be for the IDM should be energized. But it’s not starting.
So I have to discard the relay issue and try to find the problem elsewhere. All the signals are ok, like fuel pressure, ICP, CPS , WTS, RPM, so what else could be causing what appears to be, the injectors not firing. The IDM is also new.
What else could I check?
 

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Discussion Starter #6
Hey guys, if the CPS were bad or erratic, would it show the tach moving while cranking.
Do the Apps such as Torque tell you if the CPS is bad?
Since what I have sounds electrical because it either runs perfect or doesn’t run at all, no in between, and I have discarded the IDM relay, the IDM itself, fuse 22 and all the rest, ICP off and on, good fuel pressure, oil in HPOP, I have a fairly new OEM CPS, could it be erratic and work off and on?
What else am I missing?
 

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Here are some more diagrams. IDM will have power at IDM connector pin 14 when the PCM Power relay shuts and then pulls the IDM relay shut. The power out of the IDM is high voltage DC, so don't go probing those wires! Cheers!
 

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Discussion Starter #8
Sometimes I read posts that have no conclusion, so I thought I’d post this in case anybody was wondering how this problem got resolved.
I had tried all the usual but nothing worked, so I ordered an OBDII diagnostic scanner and downloaded the Forscan App to see if I could monitor any of the parameters while the engine was cranking, as it was deader than dead. Particularly, I wanted to see the HPOP pressure, to make sure that the engine could start, as unplugging the ICP will make the ECM go to default pressure, but what if there is actually no oil and no pressure at all?
So when I got it from Amazon, I went to the truck and plugged it into the OBDII port, and got the software ready, and as soon as I cranked it, the engine started in less than two seconds like it always did. So I drove it home immediately because it was in a different location, and when I got home, I looked at the gauges and ran the cylinder balance test, and everything was good, no codes accumulated or while running, and it has not failed to start again since that day.
So I don’t know what actually caused the truck to not start at all for a period of about a month, and then all of a sudden start running again as smoothly as ever like if nothing had happened. I always thought that it was an electrical problem, but now I have no way of knowing what actually caused it because it starts immediately when I turn the key. Thanks to all specially to Patrick and Bugman for their input.
 

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Discussion Starter #9
Well, I’d like to revive this thread because I still don’t feel that I am in the clear. The truck had been running fine from the time in May or early June when I got the OBDII scanner, and then I left for a long vacation. Came back and the truck started right up like always, in less in two seconds of cranking. Drove about 20 miles in city traffic that day, with several stops along the way, and at the end of the day, I parked it in the same spot. The following day it was dead again. So it starts right up after 20 days of inactivity, and then the following day it won’t start. What the heck is going on?. I checked the oil levels, and they were both fine, if maybe a little dirty.
So I hooked up the OBDII scanner to see if I could read the data stream while cranking the engine, and I don’t think it’s very accurate or stable but the HPOP pressure only read about 200 while cranking. I have over 30 pounds of fuel pressure, and it does the buzz test without fault. So I decided to change the oil in the pan and in the HPOP, to see if it made any difference. It did not start right away but it started the following day, and between yesterday and today, I drove it about 30 miles in city traffic, and it ran perfect, but I really don’t know if it will start tomorrow. I’m going to try to upload a couple of pictures that I took of the data stream at idle and at about 2000 RPM to see if any of you can spot anything that is not right.
I can’t find a way to load up the pictures from my iPad, so I will load them from my computer a bit later. Thanks in advance for your comments.
 

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Discussion Starter #12
Patrick, I hope you can see these pictures and tell me if you see something suspicious.
Also, since the HPOP pressure at idle is about 580 psi, I am assuming that at during cranking at around 200 RPM or less, it would be well below the 500 minimum that it needs to run.
Question: is there a function of the ECM that operates the IPR at a much higher duty cycle to allow more pressure to develop while cranking?
If not, how does the engine start with lower HPOP pressure?
 

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What was the IPR% during the runs? You should be able to monitor the ICP and IPR% during cranking as well. I'd have to go look, but it seems like the reference voltage should be closer to 5V. The IPR% should be around the following:

KOEO: 14%
Crank to Start: Less than 30% typically with no leaks and engine starts
Idle: 8%-16% @ NOT
Full Load: Less than 50%with no ICP system leaks
No Start (max command): 54%

So the ECM will increase the IPR% to raise the system pressure to start, but only to 54%.

Cheers!
 

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Discussion Starter #14
Patrick, here are a few more images of my truck running perfect, and then what happens when I crank it and it won't start.
You remember that I have had this problem off and on without any obvious pattern for some time, and it's driving me crazy, because while it would run perfect one day, I did not know if the next day it would start.
From seeing how it runs normal, with good HPOP pressure under all conditions, and then how it is not registering hardly any pressure 274.8 psi while cranking, with the IPR at maximum duty cycle of about 54%, my conclusion is that my IPR valve is sticking, and even though it is commanded to open by the PCM, sometimes it will open and let pressure into the cylinder heads and start perfectly, and sometimes it won't. That is what makes it start and run perfect sometimes, and not at all other times.
What do you think?
In the first picture you see what happens when it starts normally in less than two seconds. The IPR barely moves to maybe at about 20% and it settles back down to 15% and the ICP goes from 0 psi and it spikes up to close to 1400 psi and it settles back down to 671.
Second picture is idling steady at 629 RPM,
Third is accelerating shifting gears as can be seen by the RPM's
Fourth is golding steady at about 60 mph and 2000 RPM
Fifth is hard acceleration from 60-75 mph and then letting go of the throttle.
I will pst one more for the next time I tried to start it that it would not start, and just cranked with IPR at maximum and ICP at only 274 psi
 

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Discussion Starter #15
This is cranking but no start. ICP sensor is new and I have tried unplugging it, but it won't start because even though it reads enough pressure, there is actually no pressurized oil in the rails.
The graphs are not in the same position as before because I removed some of them, so ICP and IPR are side by side, and RPM is right below.
 

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At this point, if there are no codes present, I would probably try a new OEM IPR. I'll assume that the IPR solenoid is snug and not able to move around. Cheers!
 

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Discussion Starter #17
Is it possible to remove and replace the IPR without removing the fuel filter bowl? I have only found videos for 98 and later.
When I replaced the ICP sensor, the oil that dripped out was ver dirty,. Is there a procedure for flushing out the rails and the lines from the HPOP? Particularly while I have the IPR out.
 

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IIRC, guys have done it without removing the bowl, but they usually involve making a tool to enable it (think 1-1/8" deepwell socket probably cut down with a handle welded on). You could drain the rails if you wanted to remove the end plugs or suck them out via the rear rail port plugs on each side. Hoses can be removed and flushed. Personally if I was going to do that, I would just go ahead and remove the bowl and clean up the valley and top of the engine (after doing the IPR removal of course). Cheers!
 

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Discussion Starter #20
I wanted the update this post to show the conclusion.
I replaced the IPR with new Motorcraft unit,
Changed the HPOP oil and also flushed out both oil rails in the heads, to have all new oil at the top.
Replaced all glow plugs with new OEM units
Replaced valve cover gaskets and the UVC harnesses,
New ICP
Removed and clean out fuel bowl replaced all hoses and filter. Found a lot of powder fine dust which I also found in the front tank when I siphoned out the fuel. Will remove and clean later, for now, I am not using it.
The truck has been running perfect just like it did between the times when it just wouldn’t start. But it’s been only three weeks and I haven’t had any tantrums yet. I have to drive it some more and not have any issues, before I can say that the problem is gone.
So, what appeared to be an electrical issue, because it would run perfect some times, and be totally dead other times, and made me think it was a bad relay or a bad IDM, could just have been a sticky IPR, that would not open to let high pressure oil into the heads, and when the ECM didn’t register enough pressure, it would not command the IDM to fire the injectors. I do think that is the case, because even when it would not start, it would do a perfect buzz test, but while cranking, the IPR would show a high duty cycle steadily, but the ICP would only show about 200 Lb of pressure in the rails. As opposed to when it does start well, the IPR only spikes up to a high duty cycle for a fraction of a second during cranking, and as soon as the ECM detects high pressure at the ICP, it fires the injectors, the RPM goes up, and the IPR duty cycle goes back down to around 14%.
Another reason why I think this is the case, is because of all the parameters that the ECM monitors, ONLY the ICP pressure can cause the ECM to not fire the injectors. All the other six or seven variables, (oil and coolant temperatures, MAP pressure, TPS, RPM, etc), only tell the ECM HOW to modify the firing, how long the pulse width, and how quickly to do it. But only the reading from the ICP can cause it to fire, or not to fire.
Thanks to all for your comments.
I have an injector question that I will post in a new thread
 
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