I have an 02, f250 7.3 diesel, I’ve replaced all the injectors, fuel regulator, fuel pump, oil pressure sensor, oil pressure regulator valve, and the cam sensor... ( prolly more stuff but that’s the bulk of it. I have minimal blow by, 187k miles, and the #4&#8 injectors are showing 3.5 to 4.5 over at idle, and I’m getting fuel into the oil, ( about 2 quarts for every 75 miles) The mechanic I just paid 550 bucks to is stumped, called another mechanic and he said it sounds like the injector cup or a cracked head. Thought I’d check here and get some ideas. If it truly is a cracked head I’ll be posting parts soon.honestly I don’t see how it could be a cracked head considering I’ve only gotten it hot once a very long time ago... any thoughts are appreciated!

 

3.5 to 4.5 over what ?


in order to get fuel into the oil the only place they can come unto contact with each other is a failed o ring around the injector. if you had a cracked cut you would be getting fuel into the coolant.

or

if a piston was cracked or had a hole in it, then the fuel that gets shot into the cylinder that should be combusting is flowing straight into the oil pan.
you would have bad blow by if this was the case.

 

oh, and yes you should scap your mechanic and find one that knows the 7.3.

 

Jason,

Do you have a garage and how handy are you or a buddy on a wrench? It's not that tough to figure this out.

Denny

 

By 3.5 to 4.5 do you mean perdels?

 

That can be an internal injector problem. Rare for fuel contamination from external o-ring failure.

Replace ‘mechanic’ and swap in a set of injectors.

 

loosing that much oil your most likely buring it, which i would think you have pinched an injector oring , i woud think getting a new set of orings would not coast alot, while your in there keep an eye on your cups see if you see seeping. just my .02
btw are the new injectors or remans?
Maybe there is a not fully rebuilt on in the mix ? It may have passed their tests , but has now failed ??
I don't know anything , just thinking out loud

 

It’s what the diagnostic said #4 was at during idle

 

its good to know the number came from a diagnostic and not just a random number the tech made up.

but our question is WHAT diagnostic was he doing ?
without know that we can not know what the 3.5 over number means or how it is related to the condition of #4 cylinder.

xx over could mean anything but without a reference it means nothing.

 

I agree. It is DEFINITELY time for a new mechanic. Trust the guys on FTE. They will take care of you.

 

Yep, scrap him, then find a new mechanic. Where do you live? We might have suggestions for a good shop or an FTE'er that'll check it out. A cup can't cause it and a cracked head is unlikely. Cracked cups lead to fuel in the coolant. If it wasn't doing this before and started right after the work was done that pretty much guarantees it's not a cracked head. If it was already doing it then maybe a cracked head. Injector O-rings or maybe a problem in an injector could do it, and I would expect oil in the fuel as well. Pull the fuel filter cap and see if it's darkened or totally clean fuel. If your oil was changed when the job was done it might not be obvious, but with blackened oil it's pretty obvious.

I think the only time fuel could go to the oil is during startup waiting for the glow plugs. There's fuel pressure and no oil pressure so the fuel can go to the oil. Once it starts the flow should reverse with the higher pressure oil going to the fuel. I assume your 75 miles was several short trips.(?) If the oil level went up two quarts it's probably a lot more diluted than that since it's probably been pumping oil to the fuel so there is an unknown amount of fuel in the oil. I would do an oil change before running it again. If it's found that it was an o-ring the first mechanic should pay the bill of the new mechanic that fixes it. Since the bill was $550 I assume you supplied the injectors so if it's a bad injector it's on you to resolve that with whoever you got them from. This is all assuming that the first mechanic did the injector swap, if he's just coming in afterwords to diagnose the problem then he doesn't know this engine and shouldn't be changing for the diagnostic.

 

A cracked head wouldn’t do it?

 

"If it was already doing it then maybe a cracked head. Injector O-rings or maybe a problem in an injector could do it, and I would expect oil in the fuel as well."

 

The mechanic I use deals only with diesel motors, he specializes in 7.3’s... he’s got 30 years under his belt... I’ve checked the compression on the passenger side and they’re all around 400, today I’m checking the drivers side and we’ll go from there... I didn’t buy all the injectors as a set however they’ve all been swapped out ( rebuilt or reman. ) within a month of each other, I don’t think any of them have over 500 miles on them. When the mechanic did the original work he said that number seven had burnt up all of the seals in the copper washer at the bottom of the cup was gone. The number one cylinder was stuck open and grossly over fueling. That being said I went in to the passenger side bank And replaced the seals and copper washers It’s hard to believe after swapping out all of these injectors twice that is still a bad injector whether it be the seals or the Mechanical workings of the injector. Particularly when it’s the number four cylinder that shows up over fueling time after time. ( According to the diagnostic computer my mechanic is using, I watched him put two different diagnostic computers on my truck and they both showed the exact same thing)

 

Balance test at idle, The only injector that’s not showing zero is the number four cylinder, it’s showing 3.5 to 4.5. And I’ll be honest I really don’t know what that means but my mechanic said it’s supposed to be at zero with the rest of them