Well, guy's I'm back...
Here's a link to my first post...
Truck ran fine after replacing IDM
https://www.ford-trucks.com/forums/7...-no-start.html
In case you don't want to look...
Early 99 PSD "No Start" - Ford Truck Enthusiasts Forums
7.3 PSD

Here's the latest,,,
Truck was running like a champ for about a month or so after replacing IDM.
Comming back home one day, floating down off the mountain and it started stumbling,,,
Managed to limp on home and was feeling kind of low, I figured it was the IDM again, (rebuild). I have to get a plug in here for the people that I got the thing from tho,,, I called them and before I could ask them if they would send another one it was on the way here!
AutoComputerExchange.com (you can find them on e-bay... Great guys there...

Well I patiently waited for the replacement IDM to show up and when it did I ran right out and changed it out and guess what? It didn't fix the problem...

On to what it's doing now and what I've done...
I can start the truck and it will run fine for a few seconds (up to 20-30) then it drops the left side completely!

If I unhook one injector and restart, it will run fine on 7 holes, any injector unplugged...

I have ohmed each injector on that bank (at the injector) and get, consistently, 3.2 ohms. If you read my previous post, I've changed both UVCH's, valve cover gaskets, new glow plugs and the IDM (and again).

One more thing about the ohm test,,,
When the solenoids are cold (ambient 55 F they test at 2.7 ohms
I brought them in the house and warmed them all up to about 120 F and they show 3.2 ohms, I don't know if that means anything but I like to do the variable thing. I also tested them from the IDM connector and they show about 1.8 ohms across the entire bank. I can't find any shorts or open circuits anywhere either???

I only have access to a Auto-Tap scanner and can't pull the IDM codes (yes it's giving me the P1316 IDM codes detected). When it first starts the SES light is out, then it comes on when it starts missing.

The thing that's getting me is the fact that I can unhook any of the injectors on that bank and it levels out and runs on 7 cylinders, yep, any injector on that bank...

I have some old solenoids that seem to ohm fine 3.2 but they are from a 1995 PSD and the part number is different???

My question here is will these solenoids interchange with the ones in my 1999??? The part number on the '99 starts with AB and the number on the '95 starts with AO...

I will await your responce before continuing this post...

BTW Happy Holidays to all...

Catchup


PS: What's a track back? It's at the bottom of the posting page...

Thanks for all your help...

 

You'll need someone smarter than me to figure this out, but I'll throw out what I have experienced.

I've seen the IDM shut down an entire bank from one bad injector solenoid. That injector ohmed 2.6 while the other 3 ohmed 3.2. Unplugging that injector made the truck run on 7 cylinders. I never thought to try unplugging any other injector. I'm not sure how the IDM detects one bad solenoid, but it must be some sort of resistance through an electronic feedback, which I would guess would be the center common pin.

Have you tried testing the right side injectors while cold to see if they ohm at 2.7, or are they up around 3.2? The only things I can think of are to wiggle the wiring while you check for continuity to make sure you don't have an intermittent short, or if the right side injectors ohm better than the left, swap the injectors around. I wouldn't swap the solenoids from the older injectors, but don't have enough knowledge to tell you exactly why.

 

Thanks for te reply Chris,,,
It's a little strange isn't it?

Something is obviously making the IDM go into safe mode, (or so I've read) I did try the older solenoids (no change) I haven't ohmed the drivers side, yet, probably should tho...

I did check them the last time trouble showed up.
This time I felt the manifolds when it was running and the passenger side was cold so I assumed that the problem was on that side, which seems logical to me.

I'm wondering if a solenoid can show good when not charged but fail under load???
If I had a good scan tool, it would tell me just what's up...
The AutoTap is OK but lacks the ability to read just what IDM codes are stored,
I wish I could find someone around here with a AutoEnginuity tool, I can't afford to pay attention right now let alone spend $400.00 for a scantool...

Catchup

 

I found this on AllData concerning the IDM functions and just what it does:

Output Functions

High Side Drive Outputs (Right and Left Bank) - The high side driver output function is to distribute energy to the proper bank based on Cylinder Identification (CID) and provide regulated current to the unit injectors, based on Fuel Delivery Command Signal (FDCS) from the Injector Driver Module (IDM) internal 115V supply. The injection timing and duration is commanded by the Powertrain Control Module (PCM) in the FDCS.

Low Side Drive Outputs - The low side drive outputs control the sequencing (firing order) of the engine based on the CID and FDOS inputs.

WARNING: RED-STRIPED WIRES CARRY 115 V DC. SEVERE ELECTRICAL SHOCK MAY BE RECEIVED. DO NOT PIERCE.

CAUTION: Do not pierce engine electrical wires or damage to the harness may occur.

Detection/Management
The IDM is capable of detecting individual injector open and shorts to either ground or battery while the engine is running. It is also capable of detecting right or left bank high side opens or shorts to ground. A special on-demand buzz electrical self test will also allow the operator to enable all injector solenoids while the engine is off to verify circuit operation. IDM detected trouble codes will not be transmitted if the EF line is not functioning; however, the engine will not shut down due to a non-functional EF line.

If a low side short to ground condition is determined by the IDM, this condition will be transmitted to the PCM via the EF signal. The PCM will enable the CHECK ENGINE light and command minimum fuel to the affected bank.

I thought this was pertinent...

Catchup

 

That kind of matches what I was thinking earlier. There might be a problem with the electronic feedback (EF line). If there was a problem with one particular injector or solenoid, then unplugging that injector should make it run on 7 cylinders. Unplugging the other injectors in that bank should have no affect.

I know you've got some new parts in there, but I'd start checking the common wire. Wiggle the wiring harness as you check it. Also check the center pin on the pass through connector on the valve cover gasket (try and wiggle that also).

Since you said the truck starts and runs fine for a short time before it acts up again, what happens if you shut the truck off after the left bank falls out, then start it up again? Does it start back up on all 8, or are you still missing the left side? Maybe shutting the truck down after it starts acting up, then running a buzz test will tell you if there is any communication between the IDM and the left bank.

 

Hi All;
Well, here's an update on what's going on with our 7.3 PSD...

We've replaced the PCM, IDM, UVC harness' (both sides), new valve cover gaskets,
Glow plugs x8, new alternator including new wire plug, 2 new batteries and I have inspected
all the wiring harnesses from and between everything without finding any problem with the wiring.

Here's the latest results...

The truck sat for about 3 weeks without being started while we waited for new PCM.

After installing the new PCM and starting the truck, it ran like a top for about 90 seconds (longest ever).
After which time it dropped the right bank (Passenger side) like before.
When I disconnected one of the injector leads, it ran on 7 cylinders just like before...

My thoughts...

Beings how we have pretty much eliminated anything electrical, the only thing left is
1) Fuel
2) Oil Pressure

As far as fuel, it's getting plenty of supply pressure to the left bank (60 PSI)
As for High Pressure Oil, without a gauge, I can only feel the pressure build up in the high pressure lines.
It seems that there is pressure building and both lines indicate about the same
pulse pressure by feeling the lines with fingers... If that makes any sense to you...

Observations...
When the truck was started after sitting for that length of time, it seemed to run longer than before.
It would only run for a few seconds before dropping the left bank.

Is it possible for some kind of obstruction to be present in the left head oil galley or in the
injectors themselves that is causing some kind of loss in oil pressure that actuates the
injector?

I am concerned about some filings in the oil pan (magnetic plug) and the fact that the
oil from the high pressure oil pump to the injectors is not filtered.
Could this contamination be from the HPOP and could this contamination be causing this
kind of problem?

I ask this because of the fact that it ran for the longest time after it sat for so long.
Could it have settled the contamination enough to allow it to run for this time
before it stirred up the contamination and restricted the flow of oil???

Would the restriction be in the injectors themselves, OR could the oil galley in the head be plugged?

I have asked several people and I only get a blank kind of stare from them and a
"Huh, never heard of that one"...

By disconnecting one of the injectors, any injector on the left bank, it would seem to me that
the amount of available high pressure oil would be sufficient to operate the remaining 3 injectors.
Is that even a possibility?

Anyway, I sure would be appreciative of any insight or ideas you might have about this problem.

Thanks for your help

 

The only time I ever heard of this ,,it was a bad soloniod causing the problem...

 

I still think your problem is electrical You can get a 0 - 100 gauge to check fuel, and a 0 - 3000 psi gauge to check the oil in each rail, but I'd be surprised if that has anything to do with this. We've seen far too many cases of fuel restriction and shutting down one bank unless an injector was unplugged never came up. If the issue were high pressure oil, you could get around this by just installing a crossover connect line between the 2 oil rails.

Did you ever look into the GEM? Your other thread also mentioned a large discrepancy in the ohm readings between the right and left bank. Did you ever check the wires for continuity, or ohm each end of each wire between the IDM & 42 pin connector, the 42 pin connector to the valve covers, as well as the pins in the connector itself? The EF line is the only one I can think of that would allow 3 cylinders to pick back up after any injector is unplugged. You can still unplug any of the injectors and the others pick up again, right? If it only happens with one injector, then that solenoid is bad.

The other thing to try is find someone else with a 7.3 and stick your IDM in their truck to see how it acts. There's a chance the new IDM is bad, or a wiring issue has damaged it.

I'm with you Rick, but the problem is (or at least was) he could unplug ANY solenoid on that bank and the other 3 injectors would start to fire. Plug it back in and drop the bank. Unplug the next one, back to 7 cylinders.

 

Pipe plugs leaking on the left side in the oil rail ?

 

I have tried other solenoids with out any improvement of the situation...

I'm not sure what is meant by "Pipe plugs"???

Have checked wires for continuity, shook, wriggled and inspected...

Is there anything in the GEM that would cause this problem?

Oh, and yes, I can disconnect any of the injectors on the left bank and the other three will run but,,, I have to shut down the engine and restart before the IDM resets to get them to fire. If I re-connect the fourth injector while the truck is running it will fire 3-4 times and then the bank drops out again...

 

If the external high oil pressure plugs were leaking you should see it.You talked about high pressure leakage test to each cylinder head.Ford has a wired tee you can buy or make one yourself if no lap top available. Remove high pressure hose from the right cylinder head and plug the hose.Measure the ICP during cranking 1-4 volts is spec.If the engine starts leak is in the right head.If unable to maintain pressure with both heads blocked change IPR valve and retest. Sensor cable part number i think is t94-50-a. Then move on to check high pressure oil pump test or drive gear. IPR are touchy its easy to distort the head of it when installing making the poppet valve stick causing some real headache.

 

Well,,,
1) there are no external oil leaks, There are no HPOP leaks under the valve covers.

2) This morning I went out to start it, just because, and it ran like a top for what I would guess was approaching two minutes, I was nearly ready to cheer... Then it went and done it again, dropped the left bank...

3) I pulled the harness gasket plug and stuck a wire in the middle terminal and restarted. Checked voltage at that point and found only 20 volts, what's up with that? I don't have any kind of breakout box so the left bank was completely disconnected at time of test.

4) Re connected the harness plug and disconnected one injector lead, re started and checked voltage, it was the same 20 volts. Don't know what the voltage is on the other head, I guess I don't know what it should be either...

5) After it started and ran for those couple minutes, when I start it after that, it will only run for a few seconds before dropping left bank.

6) Still, I can disconnect any injector on the left bank and it will run on 7...
7) HELP!!!!!!!!

 

Is it possible you are not getting correct voltage to the pcm? I guess you checked the 104 pin connector at the pcm check for bent pins? I assumed you removed the chip too and retried it?Grounds to the PCM? Looks like your back to square one at least this is where I would start.Scan for codes, buzz test injectors ,check for rpms while cranking.Never heard of this but was wondering if the injector solenoids got shorted when you were having IDM problems?Thus back to the injector buzz test one at a time. The only other thing i can suspect is leakage in the path of the High pressure oil pump.I know this is old news recheck the oil reservoir.I know its not what you wanted to hear we need to recheck things again.

 

With the key on you should measure around 4.5vdc on the common pin (female side of the plug) with it unplugged. You can test this by testing at the 9 pin plug at the valve cover. Have you swapped the idm relay and checked all your fuses. I would also make sure the wires that lay on the drivers side valve cover are not rubbing. This is the bundle that goes to the 42 pin connector.

 

This is borrowed from your other thread. Have you done this check again with the new IDM? If you're still getting these readings, you've either got a wiring issue or another bad IDM the way I see it.