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6.0 low high pressure oil problem after oil cooler replacement. no start cold

8K views 6 replies 5 participants last post by  Devon2576 
#1 ·
Okay so I had replaced my oil cooler on my 05 6.0 recently due to high deltas after switching to ford gold coolant. After the replacement it ran for about 15 seconds then died and would not start. low high pressure. icp was around 100psi. instantly suspected clogged IPR. pulled the ipr, found that the screen actually broke and caved in. small bit of it seems to be missing. i cleaned ipr and didnt work so i replaced ipr with oem ford ipr valve, now im seeing 300psi fluctuating sometimes peaking at 400. Pulled dummy plugs and stand pipes, which i updated before all are good. (when i updated however i only updated the top portion of the passenger side stand pipe because it was stuck down there, i also coukd not get it out when diagnosing the recent no start) next thing i did was pull the hpop to check o rings and stc. which i had updated before and all checked out fine. i did an air test after reinstalling the hpop with cover off and both valve covers and ipr in with a pig tail to wire to the battery. i charged 100psi through the icp port and closed ipr in 15-20 second intervals. could not hear anything or see anything through any of the covers. I am not sure what to expect. Im not one to throw parts at a problem without knowing for sure. my only suspect is the hpop. is there any way to diagnose this part as failed other than process of elimination? if so, which parts should i suspect first? im getting base oil pressure on the idiot gauge and watched the oil filter housing fill. which filled a little slow but it went to the top. i have good ficm voltage and sync, icp seems to be valid, and ipr is commanded at 85% with the low 300psi ICP. Anything i should suspect before hpop or a way to surely test it. All input is appreciated.
Thanks
 
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#2 ·
Certainly could be an HPOP issue. ...but, if you instead have a wiring problem between the PCM and the IPR valve, you won't know it without investigating in some specific way, though.

I'd check to make sure that the IPR valve is getting a signal from the PCM. If you have an oscilloscope handy, look for a crappy square wave whose duty cycle matches the IPR% shown on your monitor. That or force the IPR valve closed with 12V while trying to start the truck.
 
#4 ·
You can try to unplug the ICP, and if it starts, the ICP valve is bad.

For wiring problems, if you have a way of seeing the ICP voltage and IPR voltage, not fluctuating at start up indicates bad wiring or bad sensor.

Also, the low pressure could be an indicator of the screen under the oil cooler clogged. If you do go that deep into it, may be worth checking the tube from the reservoir to the pump.

Personally, before changing the HPOP, I'd think seriously about towing it to a shop for a diagnostic. AAA gives me three tows a year.

Also, the readings for the air test, was that with this oil cooler swap, or previously when you updated the STC fittings?
 
#5 ·
Yes, the air test was after all the updates and oil cooler swap. Also, I have an edge cts 2 which should be able to give me those readings. ill check today. i hope its not the reservoir screen. i already have it tore down for a quick hpop replacement but the oil cooler is a PITA to get to lol
 
#6 ·
Have you checked the IPR valve screen?
 
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