[bukhntr]

I'm working on a no start situation and I believe I may have lost lube oil pressure. Does the ECM require an oil pressure signal to start or will the engine start with no pressure until the HPOP reservoir is empty?

Does anyone know how the ECM gets the oil pressure signal? I know the sending unit on top of the HPOP supplies the dash guage with information but does it also signal the ECM that there is adequate oil pressure to start?

The HPOP is full. Engine has plenty of oil. I have changed the CPS and IPR and have tried disconnecting the ICP, but still no start.

I have checked for codes and have none except for low ICP signal when I disconnected it and a TPS signal which I always have since I spliced the wire for my idle throttle control.

Am I missing something here? /ubbthreads/images/graemlins/shrug.gif /ubbthreads/images/graemlins/confused.gif

 

[centerline]

I think that would be the ICP sensor in the front of the drivers side head.. pointing toward the valley.

 

[bukhntr]

Centerline, thanks for your response but I don't think it could be the ICP because I have read on this forum the engine will run in the limp home mode without an ICP signal.

I have been told by a Ford diesel tech that this engine will not run without oil pressure. /ubbthreads/images/graemlins/confused.gif

 

[TimMiller]

Are you getting smoke out of the tail pipe?

 

[centerline]

have you checked maxi-fuse #22?

 

[bukhntr]

All the fuses are good. All the wiring looks OK. No smoke out the tail pipe that I can see from the drivers seat. Plenty of fuel in the filter bowl. Changed the fuel filter changed the air filter.

The engine doesn't try to start at all.

 

[Cratos]

Sounds more like a CPS death.

 

[trucktech]

The mechanic is correct in the fact that the engine will not run without oil pressure, but the oil will be depleted from the HPOP reservoir and prevent the injectors from working. If there is oil in the reservoir, then you have oil pressure. The only oil pressure signal that is fed to the PCM is from the ICP and that signal is used to control the IPR.
If you don't have smoke out the exhaust when cranking, then you aren't getting fuel into the cylinders. Use a guage to check your fuel pressure, then use a guage to check your oil pressure from the HPOP. If your pressures are correct, then you may have electrical problems. Have a Buzz test done, then get back to us and let us know what you have found so far.
Do your diagnostic step by step in a logical sequence and it will be a lot easier to locate the problem. Good luck.

 

[bukhntr]

Thanks for your response trucktech. The oil in the reservoir was poured in there by me. When the no start initially started the reservoir was dry and I added a quart. The reservoir however does not go down from cranking.

What should the fuel pressure and HPOP pressure be and where is the most convenient places to test.

Thanks,

 

[Partsman]

Did you check the whole harness going to the IPR when you replaced it? They are very prone to getting diesel in them and melting the insulation. That being said, you need about 40PSI at the FPR for fuel and 500PSI at the hose going into the head for the oil.

 

[bukhntr]

No I didn't check the whole harness when I changed the IPR because I didn't remove the fuel filter bowl. As a matter of fact I had the start of a mouse nest in the valley under the fuel filter bowl. I had to take the bolts out of the fuel bowl and push it to one side to get the IPR in and out and all of the harness I could see looked alright on the outside. I guess in order to check it I will have to completely remove the filter and bowl. That is another possibility if I have good fuel pressure readings.

I would have to get a 75 mile tow to get a buzz test. That's what I'm trying to do without.

Are those pressures you gave me attainable just cranking with the starter?

Thanks for all the info.

 

[Partsman]

[ QUOTE ]

Are those pressures you gave me attainable just cranking with the starter?



[/ QUOTE ]

Yes thats what you need to start it. Actully the FP could be a little lower and still start but the OP has to be there before the PCM will fire the injectors.

 

[bukhntr]

Thanks, I killed one of my batteries with all the cranking so I have to take a break and go buy another one.

 

[fastrepoman]

have you disabled the glow plugs and tried to start it up on ether??? ps little shot goes a long way!! sometimes the pick up tube will crack drawing air in system and will cause to not start but will run once primed. if it does start and run after prime recheck ipr and wiring then if still no problems found jack ass end of truck up about a foot and add 3 extra quarts of oil and see how it goes if all ok then its cracked pick up tube.

 

[bukhntr]

OK, here is the latest.

I took the fuel bowl out and examined the IPR - fuel heater wire loom and all checks out. Even did a continuity check.

Hooked up a guage to the HP Oil rail with the reservoir full and cranking with new batteries could only get 200# oil pressure. Checked the tail pipe while cranking and could not see any white smoke. Put a tire guage on the schrader valve while cranking and could not get any pressure reading on the fuel. Couldn't figure out a place to check the fuel pressure with a better guage. I need a 1/8" NPT and couldn't find one.

What do you guys think? /ubbthreads/images/graemlins/shrug.gif

 

[fastrepoman]

will it fire off of alternate fuel source and continue to run???

 

[bukhntr]

[ QUOTE ]
will it fire off of alternate fuel source and continue to run???

[/ QUOTE ]

I'm hesitant to try that because this truck had the lube oil pump go out at 70K miles under warranty and they replaced the oil pump. If that has happened again I would be running the engine with absolutely no oil pressure.

I had to take my grandson to a ball game tonight but tomorrow I'm going to check the oil pressure at the HPOP reservoir to see if I have lube oil pressure and then go from there.

I anyone has any other suggestions I'll try them.

Thanks,

 

[fastrepoman]

if your seeing 200# on scanner for hpop pressure at icp then you indead do have oil pump pressure just not the needed 500# to fire the injectors if you give it a small prime it should fire then if you hold throttle it should continue if it stalls at idle when let off afterwards bumm ipr VERY common. I do understand you say you have rebuilt or replaced. wiring can be bad you can do this to verify startup and ability to build 2400#

 

[bukhntr]

I went out this morning and dumped a little fuel to make sure the bowl had filled after I had emptied it to get to the wiring. I cycled the tank switch and hooked up my guages. I started cranking and she lit. SURPRISE ! the pressures are as follows:

HPOP idle 700#
1500 - 700
2000 - 800
2500 - 1000#
3000 RPM 1300#
fast accel to WOT 1800#

The HPOP pressures might be a little off because my hose sprung a leak and I had a big mess to clean up.

LUBE PUMP idle - 30#
WOT - 60#

FUEL idle 60 - 70#

I don't know what I did to get it to start since I had the fuel bowl apart and out and the wire loom out and apart. I did clean a lot of lint off the FPR screen while I had it out. The truck is running but still dies ever once in a while while it is idling. The fuel guage looks like the pressure drops after it dies, or tries to die, and the same with the oil pressures.

Any more ideas?

 

[bukhntr]

I've decided that the problem is a bad HPOP. I put another IPR valve and got it started with a guage on the HPOP rail. While she is running pressure is jumping all over the place and RPM's follow. The truck keeps trying to die but only when the pressure drops below 500#. Sometimes you can crank and crank and the HPOP will not build more than about 150# and she will not start.

I've started with starter fluid after disabling GP system and she will not stay running because the pressure will not get above 200#.

Thanks everyone for your help.