When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hello gentlemen, long time reader and follower of many post on here. Ive stalked many many threads on here and your info has helped tremendously. Now for once, i am finally stumped and have no direction to go on. I am lost.
2000 F450 7.3 PS 76k miles
Crank No Start.
truck has been to previous shops for extensive work. Our shop(ME being our resident diesel tech) has solved all of their other ******* child 6.0s that this company has brought to us.
New Parts From Other Shops,
Fuel bowl and Filter
Junk ICP Sensor
Junk CPS sensor
Junk IPR Valve
Ford REMAN HPOP
Reman ECU
IDM
Everything I have done and replaced.
Ford New IPR
Ford New CPS
Ford New ICP
I have confirmed SES and WTS light do come on KOEO, Confirmed 12V to IPR Valve, Confirmed 5VREF and Sig Return to all 5Vref sensors.
Did the GB Service Bulletin Check for shorted or grounded injector power circuits, passed. Resistance check on injector circuits to IDM, slightly high on some injectors but should still start.
Confirmed HPOP Reservoir is full and stays full, confirmed with gauge LPO is adequate.
When cranking and watching pid information, IPR duty cycle goes too high 35-53% almost fully closing IPR to build pressure. self testing(power & ground) to IPR to try and start does not change starting condition.
ICP Pressure reads gradually all the way to 3000 psi after installing new ford ICP Sensor. I do believe this is pcm default due to not making actual HPO.
I do have RPM on my scanner, tach does "bounce" when cranking. so definitely not a CPS ISSUE being its from ford and im seeing the correct information.
Also confirmed power and ground to PCM and IDM.
I built a custom tool to go from the STC fitting lines to the oil rails to connect to shop air and pressure check injectors, heard no air hissing out(had valve covers off and oil filter out, no bubbles)
If anyone has any insight as to what is going on would be FAN****INGTASTIC, thank you geniuses' TIA.
Oil level correct?
fuel pressure?
fuel tank k above 1/4 tank?
engine spinning fast enough?
voltage not dropping below 10.5v while cranking?
Engine does not drop below 12v when cranking
Fuel Level reads full, emptied fuel bowl and turned key on and it does refill.
Have not verified "pressure yet.
Engine spinning at 300 RPM. Removed belt to PTO pump since it has a dump bed and salt spreader on it. To increase chances of starting. Did not effect rpm increase. Will verify fuel pressure, and hpop pressure with mechanical guages tomorrow at work
I’d probably start by checking fuel pressure and HPOP pressure.
I think it’s Kintla that recommends testing with various sensors on the 5v reference circuit disconnected. He had a sensor shorting out and causing the system to do nutty things. (My memory of the condition anyhow)
that era of F450's had steel fuel tanks that were painted inside, paint will flake off and cover the fuel pickup shower head inside the tank.
have you tried plugging the block heater in? if the injector armatures are worn out they won't open the injectors with cold oil, (ie) 15w40, with that low of mileage that shouldn't be a problem but they could have had a bad life.
when you do the shop air into the oil rails on a cold engine it can take several hours to hear an air leak.
I’d probably start by checking fuel pressure and HPOP pressure.
I think it’s Kintla that recommends testing with various sensors on the 5v reference circuit disconnected. He had a sensor shorting out and causing the system to do nutty things. (My memory of the condition anyhow)
I tested all 5VREF plugged and unplugged, both test had the same result. good continuity on all 5vref wires, definitely had that kept in mind. I'll be checking pressures tomorrow when my guages get here.
that era of F450's had steel fuel tanks that were painted inside, paint will flake off and cover the fuel pickup shower head inside the tank.
have you tried plugging the block heater in? if the injector armatures are worn out they won't open the injectors with cold oil, (ie) 15w40, with that low of mileage that shouldn't be a problem but they could have had a bad life.
when you do the shop air into the oil rails on a cold engine it can take several hours to hear an air leak.
It did try to start one time when I sucked all the oil oil out of the reservoir and added fresh 15w40. I'm going to change the oil on it tomorrow aswell. Are there multiple fuel filters on the truck or just the one in the fuel bowl after the pump?
What is your ICP voltage reading key on, engine off, and again while cranking? PSI is pretty meaningless when diagnosing a no start due to the way the PCM uses and reports an inferred pressure under certain circumstances.
What is your ICP voltage reading key on, engine off, and again while cranking? PSI is pretty meaningless when diagnosing a no start due to the way the PCM uses and reports an inferred pressure under certain circumstances.
It starts at .2v KOEO then while cranking ramps all the way up to 3-3.3v
If I understand correctly you haven't actually verified the presence or absence of high pressure oil? Is it possible there is a leak resulting in zero pressure and you are only seeing the default pressure through the scan tool? If so, do you have a way to dead head each side of the hpop one at a time to see if it then starts and runs on one side, thus indicating a leak on the opposite side?
I see you used shop air to check for leaks, not sure if that can be 100% conclusive though I could be wrong on that. I do know that in the service manual Ford indicates to use dead heading to check for a leak. I brazed some parts together and bought some parts to make a dead head set and gauge attachment.
I have only checked individual sides for leaks. Next step was checking pressure mechanically and dead heading sides. Brand new 1000cca battery's and new glow plug relay as well. Verified glow plugs are lit
