7.3 workhorse not so happy
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Junior User
Joined: Mar 2010
Posts: 94
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7.3 workhorse not so happy
My 450 dump now has 170k on her and would only start when plugged in. We have replaced stock turbo injectors glow plugs along with harness and high pressure oil pump. So here's my problem when we crank over no oil pressure then a turn or two it goes up. My mechanic has a movie what was happening before oil pressures up. It does start and blows white smoke on start then stops. No mods but fuel tank harp conversion. Not a mechanic but can understand what's going on and can turn a wrench but need help here. Thanks in advance guys just looking to get her back n the road so I can make some money
Laughing Gas
Joined: Nov 2010
Posts: 1,193
Likes: 2
From: D.C. but heart's in TEXAS
Maybe your low pressure oil pump? If you crank it over and the pressure builds then fires right up...sounds like it's leaking down while sitting. For instance, if you've been driving it during the day and let it sit only a few hours, does it still fire up easily?
I'm no expert, but if you've replaced injectors, wiring harnesses, glow plugs...I would SUGGEST your Glow Plug Relay ($30), but I don't know what having the truck plugged in would have to do with the GPR. I think you're close with the oil pressure problem.
I'm going to throw my bet on the LPOP, but I will let the experts give you better diagnosis...
I'm no expert, but if you've replaced injectors, wiring harnesses, glow plugs...I would SUGGEST your Glow Plug Relay ($30), but I don't know what having the truck plugged in would have to do with the GPR. I think you're close with the oil pressure problem.
I'm going to throw my bet on the LPOP, but I will let the experts give you better diagnosis...
9 ECHO 1
Joined: Aug 2009
Posts: 12,467
Likes: 58
From: Missouri
I agree, sounds oil related to me. The LPOP provides the HPOP with its oil, so that could be it. Check your IPR, just make sure its cycling. I am mostly typing this for a sub and a bump, but we will see what happens.
Hotshot
Joined: Jan 2011
Posts: 18,849
Likes: 179
From: Puget Sound
Unplug your ICP before your first start in the morning.
If the truck fires right up without the long crank, ICP sensor is your culprit.
If you still have a long crank, it could be an IPR or a bad check valve in the HPOP reservoir.
Is your mechanic watching your high oil pressure with his scan tool, or do you have one?
If the truck fires right up without the long crank, ICP sensor is your culprit.
If you still have a long crank, it could be an IPR or a bad check valve in the HPOP reservoir.
Is your mechanic watching your high oil pressure with his scan tool, or do you have one?
Elder User
Joined: Feb 2006
Posts: 765
Likes: 1
From: Eastern Ohio
Sounds like a lot of parts are being thrown it this thing.
Are the new GP's working? Are they motorcraft Gp's?
Is the starter fast? These things need to cranks fast to start, especially cold. A weak starter with start a warm or plugged in truck but not a cold one. I made it though all winter this way be cause I didn't want to swap the starter in the snow.
Are the new GP's working? Are they motorcraft Gp's?
Is the starter fast? These things need to cranks fast to start, especially cold. A weak starter with start a warm or plugged in truck but not a cold one. I made it though all winter this way be cause I didn't want to swap the starter in the snow.
More Turbo
Joined: Mar 2011
Posts: 683
Likes: 1
From: cincinnati, oh.
x 2 , i would be testing this if it starts up fine when plugged in.
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Postmaster
Joined: Apr 2012
Posts: 2,613
Likes: 8
From: North Georgia
How about a few probing questions...
Behind your turbo... there are those up pipe things... check for soot... is there black soot around where the pipes y off from the turbo? Look over the top of the drivers side fender and back in behind and down below the turbo... where the pipe part meets the collector is there soot?
Do you have gauges?
If so... max boost?
Max egt's at max boost?
Do you work it hard and hot?
Flip the oil cap over on its back on the filler tube it unscrewed from with the engine running at idle... does the smokey puffs blow it up off the tube any?
Check the oil level... and the condition of the oil on the dipstick... feel of it... is it gritty? Still nice and slippery... how long can you easily slide your thumb/index finger together with it? Does it smell burnt? Like diesel?
If your mechanic has the capacity/capabilities... have him compression test all 8...it should have been part of the diagnostic before injectors were replaced anyway.
Behind your turbo... there are those up pipe things... check for soot... is there black soot around where the pipes y off from the turbo? Look over the top of the drivers side fender and back in behind and down below the turbo... where the pipe part meets the collector is there soot?
Do you have gauges?
If so... max boost?
Max egt's at max boost?
Do you work it hard and hot?
Flip the oil cap over on its back on the filler tube it unscrewed from with the engine running at idle... does the smokey puffs blow it up off the tube any?
Check the oil level... and the condition of the oil on the dipstick... feel of it... is it gritty? Still nice and slippery... how long can you easily slide your thumb/index finger together with it? Does it smell burnt? Like diesel?
If your mechanic has the capacity/capabilities... have him compression test all 8...it should have been part of the diagnostic before injectors were replaced anyway.
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Junior User
Joined: Mar 2010
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These parts have been thrown in during the last year. I run a construction company so this truck is worked but always oil changes at 3000 miles. Let turbo cool before shut down. All the parts we swapped out were originals. Today the oil pressure completely dropped at idle at any rpms it picked up when hot. At initial start up no pressure either. Shut off let sit start back up ad oil pressure is back up and running. This truck starts no problem now with injectors. Starter spins this baby over well. My mechanic said when I dropped off truck and said compression was good.
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