cylinder contribution test

[Connor M]

So my truck is making a lot of oil, I haven't drained it to measure yet but it's 6-8 inches up the dipstick. It's not throwing a code, but I did a cylinder contribution test and it shows -2 for one injector and -1 for two injectors.
Problem is I have no frame of reference, how bad is a -2? The snap-on scanner I have access to doesn't have an option for percentage, as far as I can tell.

I'm thinking an injector stuck open, because there's minimal blowby and it sounds perfect, it just smokes and feels sluggish, it's burning oil out the tailpipe. I'm just looking for help diagnosing it before I go two far down the wrong path.

 

[Powerstroke Cowboy]

I have no idea about the contribution test. I do not think a injector stuck open would full the crank case like that. Most of the fuel would get pushed right out the exhaust and be a smokey mess in the process.

A injector could be leaking under the Valve cover. Also a line feeding a injector could be leaking.

Another thing that can cause fuel in the oil is the HPFP leaking out the front seal.

 

[6.0 Tech]

-2 isn’t bad. Ford would never give us a “spec”, but had an engineer tell me once if you’re seeing in the +/- 10 range that ain’t good. I’d be leaning more towards the hi pressure pump seal having gone out as the fella above me said. But this being a 6.4 anything else is possible as well.

Are you losing coolant at all? Front cover could be cavitated.

Best way to check is to drain the oil, put dye in the fuel filter housing. I’d typically put 3 bottles in. Then command the fuel pump on with the drain plug out. See if you have dye dripping out. If you do, it’s the hi pressure pump seal. If not, pressurize the cooling system and see if you’ve got drips. If not, fill the oil, and run the hi pressure fuel pump test 5 times in a row. Then pull the valve covers and use a Uv light and check all the injectors for dye on the bodies or the line connection points.


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[Connor M]

I have no idea about the contribution test. I do not think a injector stuck open would full the crank case like that. Most of the fuel would get pushed right out the exhaust and be a smokey mess in the process.

A injector could be leaking under the Valve cover. Also a line feeding a injector could be leaking.

Another thing that can cause fuel in the oil is the HPFP leaking out the front seal.

-2 isn’t bad. Ford would never give us a “spec”, but had an engineer tell me once if you’re seeing in the +/- 10 range that ain’t good. I’d be leaning more towards the hi pressure pump seal having gone out as the fella above me said. But this being a 6.4 anything else is possible as well.

Are you losing coolant at all? Front cover could be cavitated.

Best way to check is to drain the oil, put dye in the fuel filter housing. I’d typically put 3 bottles in. Then command the fuel pump on with the drain plug out. See if you have dye dripping out. If you do, it’s the hi pressure pump seal. If not, pressurize the cooling system and see if you’ve got drips. If not, fill the oil, and run the hi pressure fuel pump test 5 times in a row. Then pull the valve covers and use a Uv light and check all the injectors for dye on the bodies or the line connection points.


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I had an injector leaking air into the system ~5-10k miles ago. I’m hoping it’s a leaking injector. I’ll try that dye test. Here’s to hoping it’s something stupid and not a hpfp.

 

[Connor M]

Are you losing coolant at all? Front cover could be cavitated.

Only reason i think it’s not that is the oil has a fuel smell to it. Now that you mention it, the coolant is real low.

I have another front cover i can throw on if that’s the issue.

 

[Connor M]

I do not think a injector stuck open would full the crank case like that. Most of the fuel would get pushed right out the exhaust and be a smokey mess in the process.

it is pretty smokey. All blue grey and white smoke.

 

[Powerstroke Cowboy]

it is pretty smokey. All blue grey and white smoke.

Gotcha. That does happen when the crank fills up with fuel. Most times when the oil gets changed and it at a "normal" level the smoke stops till the crank case fills back up.

 

[DEEZUZ]

Have you drained the crankcase and refilled to the proper level yet?

You need to do that first.

Take it to 14 quarts even

 

[DEEZUZ]

If it is fuel 9/10 it's the pump seal.

 

[Connor M]

-2 isn’t bad. Ford would never give us a “spec”, but had an engineer tell me once if you’re seeing in the +/- 10 range that ain’t good. I’d be leaning more towards the hi pressure pump seal having gone out as the fella above me said. But this being a 6.4 anything else is possible as well.

Are you losing coolant at all? Front cover could be cavitated.

Best way to check is to drain the oil, put dye in the fuel filter housing. I’d typically put 3 bottles in. Then command the fuel pump on with the drain plug out. See if you have dye dripping out. If you do, it’s the hi pressure pump seal. If not, pressurize the cooling system and see if you’ve got drips. If not, fill the oil, and run the hi pressure fuel pump test 5 times in a row. Then pull the valve covers and use a Uv light and check all the injectors for dye on the bodies or the line connection points.


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Is there a way to command the fuel pump besides cycling the key? I cycled the key about 10 times till the pump kicked off and had no dye coming out of the oil pan. I’m gonna pull the valve covers tomorrow and check all the injector bodies and lines. I’m borrowing a tool to pressurize the cooling system as well.

I’ve been pulling like 10-12 hour days all summer and just driving my work truck and finally have some time to get into it.

 

[DEEZUZ]

Back probe the power wire into pump and toss it to 12v.

 

[6.0 Tech]

Is there a way to command the fuel pump besides cycling the key? I cycled the key about 10 times till the pump kicked off and had no dye coming out of the oil pan. I’m gonna pull the valve covers tomorrow and check all the injector bodies and lines. I’m borrowing a tool to pressurize the cooling system as well.

I’ve been pulling like 10-12 hour days all summer and just driving my work truck and finally have some time to get into it.

You can command it on with ids or as deezuz said, just power it with a power probe or something. The injector bodies or lines won’t leak unless it’s running, so running a hi pressure fuel system test 5-10 times in a row with the valve covers off will show you a leak, granted that means putting oil back in it, but it’ll help diagnose it.


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[Connor M]

I replaced the hpfp and it doesn’t seem to be making oil but it has a misfire and it’s pouring unburnt diesel out of the exhaust. Sounded like the miss was coming the worst from #8 but after pulling it apart, I don’t see any damage to the rocker arm assembly and the pushrods don’t have an obvious bow to them at all. I’m gonna get a big set of calipers to get a measurement on them. No weird wear on the tips or the bridges.

I only got a code for p0300.
Injectors all passed the cylinder contribution test.
All cylinders had good compression, ranging from 350psi to 375psi. I don’t think I have a cracked piston for this reason.
No coolant in the oil or vise versa.
No metal in the oil.

I’m thinking if I can’t find something else obvious I’m going to pull the heads to check lifters and cam lobes.

It will take some time to get my spare engine back from the machine shop and assembled, I think pulling these heads in the frame will be my fastest and cheapest option to see what’s wrong. Even if it turns out that something else is wrong i’m only out the cost of parts for a stud job which isn’t as much as say, buying new injectors.

 

[6.0 Tech]

I replaced the hpfp and it doesn’t seem to be making oil but it has a misfire and it’s pouring unburnt diesel out of the exhaust. Sounded like the miss was coming the worst from #8 but after pulling it apart, I don’t see any damage to the rocker arm assembly and the pushrods don’t have an obvious bow to them at all. I’m gonna get a big set of calipers to get a measurement on them. No weird wear on the tips or the bridges.

I only got a code for p0300.
Injectors all passed the cylinder contribution test.
All cylinders had good compression, ranging from 350psi to 375psi. I don’t think I have a cracked piston for this reason.
No coolant in the oil or vise versa.
No metal in the oil.

I’m thinking if I can’t find something else obvious I’m going to pull the heads to check lifters and cam lobes.

It will take some time to get my spare engine back from the machine shop and assembled, I think pulling these heads in the frame will be my fastest and cheapest option to see what’s wrong. Even if it turns out that something else is wrong i’m only out the cost of parts for a stud job which isn’t as much as say, buying new injectors.

Puking fuel out the exhaust would lead me to believe a hurt cylinder, which you’ve ruled out, or a stuck open injector. If you cancel injectors, do any of them make the smoke go away or diminish? Can you watch short term fuel trims? One that’s puking fuel will be way off from the other cylinders


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[Connor M]

Puking fuel out the exhaust would lead me to believe a hurt cylinder, which you’ve ruled out, or a stuck open injector. If you cancel injectors, do any of them make the smoke go away or diminish? Can you watch short term fuel trims? One that’s puking fuel will be way off from the other cylinders


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I'm not sure how to shut off individual cylinders on my solus ultra or check trims but I pulled contributions a third time because I really wasn't buying the results I was getting and got waaay different numbers now, IDK why. -28, -35, and the like. 6 or 7 injectors were out of wack so I'm thinking new fuel system entirely. Still just the misfire code. (and it sounds like it has a bad skip too) My best guess is hpop failed and took out the injectors. New lines, New rails, deleting the fuel bowl and the hfcm and putting in a regulated return and lift pump. Gonna drop and clean the tank and put a straw or a sump in, whole 9 yards and just eliminate the fuel system. If that isn't the problem, well, the spare long block is coming out of storage and I'll have a pile of brand new fuel system parts to drop in.

 

[6.0 Tech]

I'm not sure how to shut off individual cylinders on my solus ultra or check trims but I pulled contributions a third time because I really wasn't buying the results I was getting and got waaay different numbers now, IDK why. -28, -35, and the like. 6 or 7 injectors were out of wack so I'm thinking new fuel system entirely. Still just the misfire code. (and it sounds like it has a bad skip too) My best guess is hpop failed and took out the injectors. New lines, New rails, deleting the fuel bowl and the hfcm and putting in a regulated return and lift pump. Gonna drop and clean the tank and put a straw or a sump in, whole 9 yards and just eliminate the fuel system. If that isn't the problem, well, the spare long block is coming out of storage and I'll have a pile of brand new fuel system parts to drop in.

Does it sound like it skips when cranking it over with the signal wire? Or is there excessive blow by when it’s running?


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