7.3 no start
Lead Driver
Joined: Jun 2004
Posts: 6,321
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From: Amarillo, TEXAS!
Unplug the wiring harnesses from the valve covers to be sure none of the injectors try to fire and see what you get for an ICP reading. If it's still low, you likely still have an HPO leak in one or both of the heads. If it's normal, connect the harnesses again and watch the pressure and injector pulse width. The PW should come up to about 4(?) milliseconds or so when the IDM starts commanding the injectors to fire. If that's when the ICP suddenly tanks, my *guess* would be HPOP.
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Tuned
Joined: Oct 2012
Posts: 409
Likes: 4
From: oregon
Yes I did it was plumb full of oil less than a quarter inch from the top.
Were would I be leaking in the head? I did air test in the heads with a blow gun, with valve covers off and I don't hear and air anywhere.. is there any other things I could do to find a leak. I also just re o-ringed the injectors.
Were would I be leaking in the head? I did air test in the heads with a blow gun, with valve covers off and I don't hear and air anywhere.. is there any other things I could do to find a leak. I also just re o-ringed the injectors.
Lead Driver
Joined: Jun 2004
Posts: 6,321
Likes: 584
From: Amarillo, TEXAS!
If you're getting up to 380 psi or high pressure oil before it levels off, you may not hear a leak with only 120 psi of air. It's always possible an o-ring was defective or got nicked inadvertently.
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Tuned
Joined: Oct 2012
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Likes: 4
From: oregon
I was only building 500 from the get go (no air in the system)... And none of the oil orings were bad. And wouldn't you think if I had a leak small enough that I couldn't hear it with air the truck would start? And both heads reach the same max psi with the other capped? I'm just dumb founded that the truck could build that kinda pressure capped off but not when there in the heads and can't hear it with air?
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Tuned
Joined: Oct 2012
Posts: 409
Likes: 4
From: oregon
Also it takes forever to get pressure after it starts building which takes about a full minute of cranking it takes another 30sec to get to 380psi then flattens out it jumps to about 450ish then the injectors start firing and it drops to 380 and stays there
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Tuned
Joined: Oct 2012
Posts: 409
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From: oregon
so i have an idea, i have an argon tank over 1000psi of gas and a guage that goes to 500psi. i could hook the argon tank up and put 300 to 500 psi into the heads and then turn the tank off to see it it leaks down? and this would allow me to not have to put the truck back together. theoretically it should not leak down at all correct? that is if everything is ok. i have the fuel lines off the fuel bowl to so if i have an injector seal leak between the oil and fuel i could tell what head it is from? does this sound like i may be able to get some were with this or any way this could not be good?
Lead Driver
Joined: Jun 2007
Posts: 7,760
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From: Hampton, Maryland.
Don't hook it to the truck with the HPOP hooked up, it will leak down almost instantly back through the IPR and into the oil pan. That amount of pressure back through the oil pan might do some damage to the gaskets or something on the low side.
I am wondering if maybe the LPOP is bad on this truck, not keeping up with the requirements of the HPOP could cause it to initially start to build pressure, but not able to supply enough oil to get it over the hump, so-to-speak. That crank time just to get up to 380 is way too long, and I know I am not telling you something you do't already know.
I am wondering if maybe the LPOP is bad on this truck, not keeping up with the requirements of the HPOP could cause it to initially start to build pressure, but not able to supply enough oil to get it over the hump, so-to-speak. That crank time just to get up to 380 is way too long, and I know I am not telling you something you do't already know.
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Lead Driver
Joined: Jun 2004
Posts: 6,321
Likes: 584
From: Amarillo, TEXAS!
Let's think about this for a second. To recap, you said the pump would build 3200 psi with both lines capped, but only 380 with the heads connected. You also said there is no air in the heads. How did you bleed them?
Oil is (for our purposes, at least) an incompressible fluid. If the pump builds 3200 without the heads in the circuit, and there is no air in the heads, the pump should have no problem quickly building 3200 psi with the heads unless there is something relieving the pressure. It could be a leak at an o-ring, it could be a bad injector (far less likely). If an o-ring is the problem it could very well hold back 380 psi then start leaking, much like a pressure relief valve.
When you tested the pressure output of the pump with both lines capped, did it come up quickly, or did it take a long time? I agree that the porta-power approach might be a good way to continue, if you have access to one. I'd want to rule out any possibility of a leak before throwing $500 at an HPOP.
Oil is (for our purposes, at least) an incompressible fluid. If the pump builds 3200 without the heads in the circuit, and there is no air in the heads, the pump should have no problem quickly building 3200 psi with the heads unless there is something relieving the pressure. It could be a leak at an o-ring, it could be a bad injector (far less likely). If an o-ring is the problem it could very well hold back 380 psi then start leaking, much like a pressure relief valve.
When you tested the pressure output of the pump with both lines capped, did it come up quickly, or did it take a long time? I agree that the porta-power approach might be a good way to continue, if you have access to one. I'd want to rule out any possibility of a leak before throwing $500 at an HPOP.
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Tuned
Joined: Oct 2012
Posts: 409
Likes: 4
From: oregon
Thank you for the idea... I will try that. I have a porta power at work I can grab to use. So the heads should not bleed off at all right? And if I find nothing wrong its probably the hpop.
