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7.3 driving me crazy

6774 Views 19 Replies 6 Participants Last post by  Mazlin
Where do i start.
Bought a f250 2004 7.3 4x4 extra truck with 170000 miles having just sold a 2006 crew with 20000 miles.
Buying price is cheap(well cheap in Australia,sold my 2006 with 40000km's for $88000)
As i'm due to pick up the 04 the seller tells me there is a problem with it and he has it booked into Ford.he tells me the fault is running on 1 bank occassionally)I do some research and figure i can fix this(UVCH's,IDM??)
Buy the truck even cheaper.
2000 mile from home,no parts available without a weeks wait.
Could not get the truck to fault when i test drove it 20 miles.
The truck is now mine.Driving real well,then rough for 5 seconds,check engine light,then clears and continues to drive well.
Pulled and checked UVCH's plugs and connections all seemed good.Ohmed wiring harness from IDM.All readings within spec.After 20 mile on highway down to 1 bank.Drivers side exhaust cold.
Ordered UVCH's,IDM and the oil sender that fits to the Passenger side(remember we sit on the other side)head front area.Is it the ICP?
After sitting for a while it will start and drive well then the 1 bank running starts.Normally once it starts it continues.
Replaced UVCH,s no success,IDM no success,ICP sensor no success.
Replaced oil,oil filter and fuel filter,no success.
Mechanic's recommendation was HPOP so replaced with very low K's HPOP.Still the same fault.Connected fuel pressure gauge at filter and had constant 60 PSI.Fuel pump looks new.
No oil from injector drains drivers side when running,occasionally injector cylinder 3 had oil.
Finally found that when the wiring harness in the valley was pulled a certain way engine increased decreased.Has to be the problem.replaced entire harness from large plug on top of passenger rocker cover.Engine runs smooth and all drivers injectors have oil.I'm thinking we have won.
Now to the current fault and i'm thinking it maybe something i've created.
It is now very hard to start,cranking 6-7 seconds,sometimes longer,seems to start easier the longer it is left sit.It then idles and it varies between 10 to 1 minute,then a detectable miss that progressively gets worse until stalling.
Fuel pressure at filter is good.Air has been purged from fuel,return at filter disconnected and run into a bucket.Pulled oil feed to drivers injectors and got about 100 ml's of oil with 2 cranks.
Crank sensor has also been changed.Pulled the HPOP out again and refitted the original.4 people have spent 3 solid days under the bonnet.
There are probably things we have done but forgotten to mention.
Sorry for the huge post but i'm at a complete loss.
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Dang, looks like you already have a good grasp on a lot of this.
I wonder if you have leaking injector orings and you're losing your high pressure oil. What is the ICP reading as it starts to die vs. just cranked up?
Quick question.. You say it's a 2004 with a 7.3?!?!?!? Correct me if im wrong but Did ford not end production of the 7.3 in mid 2003 and change to the 6.0L... Leaving the question- what motor is actually in the 2004 you got??

Sent from my iPhone using Autoguide
They produced 7.3s for later models out of the US till 06 I think.
Could that yr truck still have the leaky windshield problem?
Maybe the pcm is doing some funky chit.

I agree to get an icp reading during cranking and when it starts acting up.
We got the f250 7.3 from 99 to 06.
I do not know the ICP readings.I was not there when they were done.I think that might be the issue however.
There was a time when we had all passenger side injectors oiling and only cylinder 3.We swapped injectors 1 and 3 with each other so maybe when they were reinstalled could be the issue.
We did not have access to a pressure gauge to read oil pressure at each side.I did however read this morning about reading the voltage at the sensor wires to determine pressure.
Thanks for all the replies.
If i'm loosing oil pressure due to the injectors not being seated properly what would the symptoms be?
Do you know how the HEUI works?
Loss of high pressure oil will cause incomplete injection or lack of injection

I made my Samsung SGH-I997 send this.
Is there any sign though?
Does the lost oil just go into the pan?
No leaking orings will leak oil into the exhaust. Well, into the cylinder.
Okay thats not happening.No unusual smoke.
The HPOP driven pulley,how does it drive the pump?
The pulley fits on easy then large washer and bolt.I saw no key way or shoulder for that pulley to actually drive the pump.I think by looking at the driven pulley that it could go on both ways.
The HPOP driven pulley,how does it drive the pump?
The pulley fits on easy then large washer and bolt.I saw no key way or shoulder for that pulley to actually drive the pump.I think by looking at the driven pulley that it could go on both ways.
Idk, I just know it's gear driven

I made my Samsung SGH-I997 send this.
Does the HPOP pump pulley slide on and be held in place with the single middle bolt?
Is there no keyway or should for the pulley to lock into?
Yeah I think that's right there's no key way. It's been a while since I took one apart. Ill ask my brother today about it. He's done it recently.

Sent from my Autoguide iPhone app
Need some help.
Replaced motor wiring loom.Now have no Check engine light.It starts hard with quite a bit of cranking,idles well then stumbles and eventually stalls.
What do i need to check?
Icp for sure. Run buzz and contribution tests

I made my Samsung SGH-I997 send this.
I have had 2 different ICP's on there though.I changed my HPOP with a known good one and after it didn't make a diference swapped it back.
Could i have done something when reassembling?
Is the hpo reservoir full when you try to start it? Could be the lpop isn't supplying enough oil for the hpop to fire all the injectors
Yes reservior is always full.
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