Help me figure this out....

BigRedDiesel · Mar 3, 2012

This started on Saturday night on my way home from a 7.3 get together. I pulled into a rest area to re-attach an intercooler pipe that popped out of the boot. When I went to start the truck up this is exactly what it was doing. It has been doing it ever since. It is like this when the truck is up to operating tempature. After it starts and you shut it down it can sit for less than a minute and the symptoms are the same. It seems to be getting worse by the day. I'm leaning toward IPR is bad or HPOP is going south.

What has been done:
Melling LPOP installed July of 2011
ICP Sensor Replaced July of 2011
Oil Changed last Friday
International CPS swapped for a Grey one and then back to black one.
Replaced the orings on the IPR and filled the HPOP with fresh oil.

What I'm seeing with AE:
ICP during cranking 2100 psi
Once started during the Romping period ICP varies 400 to 2800 psi
ICP Duty Cycle up to 44%
Fuel pressure is steady at 68 PSI

What am I missing?

Click the picture it should take you to the video...

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Data log also attached

BigRedDiesel · Mar 5, 2012

Anybody?

golfer · Mar 5, 2012

extended crank screams for a low pressure (oil) problem..

did you inspect the front cover for scoring/scratches when you installed the Melling last summer?

have you taken any LPOil pressure readings?...

the LPOil gauge on the dash doesn't come up until after the engine has started...which is another indication of a LP problem...and the romping is directly related to this...aerated oil in the reservoir is causing the PCM to bounce the IPR% since the 'quality' of oil is so poor (aerated)...

//I will say that some "LPOil" issues can actually be attributed to HPOil problems as well...ie...if something in your HPOil system was bleeding off soooo much ICP...then the LPOP wouldn't be able to keep up...

JLDickmon · Mar 5, 2012

subscribing

BigRedDiesel · Mar 5, 2012

I have not taken any LP oil readings. There was no scoring/scratching on the cover. Starting to believe this is a fuel pressure issue. As in too much. We installed the check valves in fuel ports and hooked up the fuel lines for the vegi conversion. The added fuel lines connect the two rails together causing excessive fuel pressure until it starts and the check valves don't allow it to go anywhere.
I'll keep this updated as we rule stuff out.

golfer · Mar 6, 2012

LOL...fuel pressure

Hotrodtractor · Mar 6, 2012

I'm backing Dave on this one.... you have an oil pressure issue - either a low pressure, high pressure, or both. I'll watch the video when I get home - but longer and longer starts scream oil problem. Its not your fuel pressure as long as you have some fuel in the rail it will start.