hard to start again

[cain6.0]

03 6.0 cc truck started great again this morning came back from dinner shut it off went to restart 5 min. later would not start. all it would do is start & die. finally i just held the key over & it started real slow. just changed all filters about a week ago. no dtc. pulled it into garage where i work it did it again about 5 more times.our mechanics talk to dealer they said hpop?? oh yeah i also have access to a good scanner

[cain6.0]

oh and dealer said hpop was leaking off causing my problem .hoping some of you tech guys can tell me more

[m-chan68]

If the diagnosing tech monitored your ICP (volts & psi), ICP (desired psi), and IPR duty cycle when the condition is present, he shouldn't have too hard a time diagnosing this. Being a 2003 model year (assuming mileage is pretty high), I would be inclined to agree with the diagnosis.

[cain6.0]

ok heres what i got icp cranking 287@hot idle icp desire 637.77,icp was 634-640,icp. volts .93 icp volts@2500rpm1.16v. ipr duty cycle koeo15%-cranking65%-@idle24% would i be able to tell more whats going on when it has one of its spells? also what kind of pressure do i need to make it start?

[m-chan68]

Originally Posted by cain6.0

ok heres what i got icp cranking 287@hot idle icp desire 637.77,icp was 634-640,icp. volts .93 icp volts@2500rpm1.16v. ipr duty cycle koeo15%-cranking65%-@idle24% would i be able to tell more whats going on when it has one of its spells? also what kind of pressure do i need to make it start?

The numbers highlighted in red represent numbers that are not acceptable.

The numbers highlighted in green are considered normal.

The last number I highlighted in yellow only because it wasn't that far out of range. I would prefer to see between 21 to 23% at HOT idle. Anything higher indicates a high pressure oil system leak, necessitating the elevated IPR duty cycle.

What I don't fully understand from your post is your ICP volts reading.

At key-on/engine-off, you should see a reading between 0.14 to 0.24 volts. This will confirm your ICP sensor is reading correctly.

To enable the engine to fire up, the PCM needs to see MINIMUM (0.8 volts) 500 psi.

[cain6.0]

sorry man i didn`t check the icp volts @koeo i`ll get back with you on that

[cain6.0]

ok i got more info koeo icp voltage is .14 & this time ipr duty cycle cranking got to 28% i also started it 3 different times & all 3 times while cranking icp read a little over 600 i think this thing has a mind of its own

[m-chan68]

Originally Posted by cain6.0

ok i got more info koeo icp voltage is .14 & this time ipr duty cycle cranking got to 28% i also started it 3 different times & all 3 times while cranking icp read a little over 600 i think this thing has a mind of its own

Those look like absolutely normal numbers to me. You're not going to like this, but you need to get those readings when the engine DOESN'T start (preferably when the engine is HOT, if it is low ICP issues).

[cain6.0]

i`ll keep computer in the truck when it acts up again i`ll get some more info. it looks like it has to be something with oil pump though as it got worse after changing over to the 10w30. i also really appreciate you taking the time to help thanks alot!!