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IDM or IPR? Please help.

8K views 13 replies 4 participants last post by  79jasper 
#1 ·
Been working on this for a while. Appreciate any ides or advice. Read through all the similiar posts but still unsure of what all the tests results mean. Am hoping the more experienced and knowledgable can shed some light.

Engine stopped midway through a few hundred mi trip. Towed home and now no start and no smoke. Am a weekend mechanic. More of a electronics guy and have the tools and experience to repair circuit boards.

Single owner. 2002 7.3 Powerstroke. 36K miles. No problems before this one.

Strong Engine cranking.
HPOP has oil within 1" of top. No HPOP leaks.
No oil on ICP connector and engine still does not start with ICP unplugged.
Fuel pump runs and fills fuel filter bowl.
Fuel filter is new. Changed filter when checking to see bowl fill by pump.
Batteries are charged and less than 1 yr old
GPR test good
Tach does not move when cranking. WTS DOES light every time.
CPS was replaced by Ford on recall 6 months ago. I replaced with a new Ford part CPS anyway.
No smoke but fuel filter bowl fills and fuel pump whirls.
Fuel gage will not go above empty even though the fuel tank is completely full.

Ran ForScan and CarGuage Pro buzz test. Buzz tests results in only a single audible click. Engine is cold since it will not start. At the end of tests get codes:
Always get code P0460. This is most likely due to the fuel sense circuit but would this cause a NO START?
Clear codes and rerun buzz rest then get P0460, P1283, and P1667. Have run apx 20-30 buzz tests. P0460 is after every test. P0460, P1283, and P1667 is registered after about 80% of the tests and once the result was P0460 and P0231. Nevewr hear more that the one very short click under the hood on all tests. Same results either running buzz test with ForScan or CarGuage. Never hear any of the clicking seen from the numerous Youtube buzz tests videos.

Ran GB Remanufacturing - Tech Bulletin #103 test on IDM connector. All tests results well within specs. Ohmed tested valve cover connectors (glow plug test). Test results all good with no shorts. IDM connectors are clean and shinny. No corrosion on IDM or 9 pin injector connectors. Have not opened yet since I am unsure weather the issue is IPR or other. If it is the IDM I can repair but did not want to break the IDM water seal unless all of the tests point to the IDM.

When cranking both Cargauge and ForScan provide these measurements:
EOT=59F
IAT=56F
IMAT=106F
EBP=14PSI
TFT=57F
ICP=2000-2600PSI while cranking and 222PSI with key in ignition after cranking stops.
GPR=98.83 (not sure what this number represents but the GP side of the GPR terminal reads ~.75 volts less than the hot side of the GPR.
MAP=99 kPa
IPR Duty = 30.8% KOEO, Cranking 51%
IPR Pressure = .21V KOEO, Cranking 2.62V
RPM = 178
Electronic Pressure = 34.3 KpA KOEO
Fuel Pump Duty Cycle Cranking = 101.6%
Glow Plug Left and Right (cranking) = 0Amps

All fuses test OK. Swapped out IDM relay and still no start.

So all the wiring is verified from IDM to injectors. Injector resistance at valve cover 9 pin connector is good. Do these results mean that the IPR is bad or IDM? If the IPR is bad would it stop the buzz test from stepping through all 8 injectors or ???????.

Do I need to run other tests or is there something here that those with experience and knowledge would suggest?

Appreciate any suggestions on where to look next.

Thank you so much.
 
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#2 ·
The IPR wouldn't affect whether the buzz test would run. But your IPR duty cycle looks high. KOEO should be ~14%, and normally shouldn't get over 35% while cranking before starting.

If you only got a click when trying the buzz test, it might indicate that the PCM isn't communicating with the IDM, which would cause a no-start.

Your P1283 means the IPR circuit has failed. It might be that the IPR coil has failed. You can check that with an ohmmeter. You should get about 10 ohms across the terminals of the coil.

Your P1667 is CID circuit failure. CID = Cylinder IDentification. One of the tests is to check for continuity on circuit 817 (YE/LB) between PCM test pin 96 and pin 16 on the IDM harness connector. A good test would be 5 ohms or less. If the circuit is good, it's possible that either the PCM or IDM is bad.
 
#3 ·
So you don't hear all 8 injectors buzzing during the test? I would suspect the UVCH (under valve cover harnesses)... they have been known to come unplugged. But geeze, only 36K miles on a 2002, wow! My next suspect would be the IDM, but usually that is a progressive issue, as it gets harder and harder to start until it dies. Check for chafed wires at the connection to the UVCH's. Last suspect would be the IPR, but again, only 36K? Good luck.
 
#4 ·
Wait, you also said the tach does not move when cranking... that is a text book sign your CPS is bad or at least not giving a signal. You said you replaced it, but check the wires.
 
#5 · (Edited)
The tach only moves when cranking on pre'02 7.3L's. That changed with the complete electrical system change in '02 models. No tach movement doesn't mean anything on an '02 model.

Also, even if the UVCH's are disconnected, there will be a light buzz from the IDM during a buzz test. He's just getting a click, possibly indicating that the IDM isn't getting the signal to run the buzz test.

If it's been sitting in a barn (with such low mileage), maybe the rodents have set up housekeeping and have been chewing on wires. :icon_mad:
 
#6 ·
Thank you guys for all your comments and suggestions. Decided to go ahead and pull the IDM since I had made access to it when I checked the connector and wiring harness. Two bolts, pulled it out and sloshing with water inside. Not sure that is za board I wan to repair since it most likely needs a new boards and the majority of the components. A few of the ford components are proprietary. Can anyone recommend a reputable rebuild house other than Swamps? Swamps has a great reputation but very pricy.

Funny, this was my diagnosis last year before I had buzz tools. Kind of makes since that if the IDM cannot send the 110V to the injector solenoids than No buzz.

Thanks much again.
 
#7 ·
#9 ·
Oh yes....36K and I am the original owner. Did not drive it that much but trying to change that. Great truck but IDM is really strange. Can't figures out how it got so full of water. Sounds like shaking a 3/4 carton of milk. Have seen many posts about this. But one guy says he has 1.5M miles and never lost an IDM! Mine is well maintained, driven lightly, but still IDM filled with water.
 
#10 ·
Seems hit and miss far as taking on water.
I guess you could say "a factory defect."
My 94 idm is factory, of course I don't single it out to aim at it, but do hit it with the pressure washer occasionally.

Sent from my SAMSUNG-SM-G935A using Tapatalk
 
#11 ·
IDM's are all over fleabay for $180. Most don't seem to ask for a core charge or return.

I've had a couple repaired by a guy in Florida, who I think was working out of his house. Don't recall his contact info, though.
 
#12 · (Edited by Moderator)
Thanks guys. Ordered one from LEMKE's guy. They sell fleabay as well and have 100% positive feedback.

Real question is how are these things filling up with water? There is only one tiny weephole near the bottom which is in the vertical position when mounted. The rest of the box is sealed with non corrosive silicone (most grey RTV is non corrosive). Is it condensation? The large diodes and power transistor inside have get very hot (~70C+) converting from 12V to 110V but that is a lot of condensation. When mine went out my son was driving for 3 hours in non stop torrential rain but with just the tiny weep hole doesn't add up. In electronics we call this PFM (Pure ****** Magic).

Seriously any one figured out how the water gets in? Knowing that we should be able to figure out how to keep it out.
 
#13 ·
The IDM has a breather port on the backside of it. If it didn't have that it would blow up like a balloon (mild exaggeration) when it got warm. So any moisture in the vicinity will be sucked in as the IDM cools down. It would eventually build up if conditions were right. Ford didn't pick a real good location for it behind the wheel in the path of spray, etc. The spot under the hood on the OBS trucks wasn't all that much better, but at least it was accessible for R&R if needed. Not sure why they didn't mount it like the PCM is inside the cab, but it's probably a matter of space, as the PCM is there in the gasser trucks and they have no need for an IDM. So the IDM got stuck where there was space. International uses a combination PCM/IDM for their DT444E (basically the same as a 7.3L Powerstroke) applications, and probably mount it somewhere drier.
 
#14 ·
Some reason I think it's mounted to the engine on T444E, but thats probably incorrect. Lol

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