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Another 7.3 consuming oil thread...

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Another 7.3 consuming oil thread...

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  #1  
Old 04-12-2018, 06:14 PM
FAL Grunt II
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Another 7.3 consuming oil thread...

I have been through about 15 threads between here and powerstroke forum and I am sure I missed it but...

97 F-350, 7.3L, somewhere around 300,000 miles.

I have paperwork on the motor as being rebuilt less than 50k ago from the previous owner... however the seller had half a dozen different motors laying around, not confident this is the motor that was rebuilt. Doesn't really matter, when I bought the truck, I bought it assuming it was NOT the rebuilt motor.

Motor started burning a lot of oil SEEMINGLY after the clutch let go and the throw out bearing grenaded. Had a shop drop the transmission and replace the clutch.

I have gone through the basic normal stuff, fuel filter is clean, fuel is clear and green. Pulled the air on both sides of the turbo and the air intake side is clean and the intake manifold side is clean. Exhaust is not wet.

Truck does not smoke at idle, but it does smell of burning oil. The truck does not smoke when driving down the road. It will smoke white if I put it in second on an incline and ride the clutch a bit longer than normal. It will smoke when hauling a load like an excavator, tow motor, skid steer, etc. It will smoke under heavy acceleration going uphill. Rolling down a hill at high RPM it does not smoke.

Runs great, has power, starts with no issue. If it is REALLY cold (say less than 10) and I do not plug it in, if I cycle the glow plugs it fires after the second turn over crisply and with authority. If I do not cycle the glow plugs it will start after the 4th or 5th turn. WHEN it starts, it WILL billow white smoke for 10 to 15 seconds, and after it starts to warm a little will turn to a light blue smoke. After it starts to warm up the blue smoke either goes away or is so difficult to see I can't tell it is there.

Last Friday I topped the oil, filled the fuel tanks and drove 97 miles at 70 mph. Parked the truck for 3 hours in a new, clean, parking lot. Not a drop of oil under it. Drove 97 miles back at 70 mph. Took over 3 quarts of oil to bring it back up into the crosshatch of the dipstick. Drove a total of 194 miles.

As I said... I am sure I missed something. I feel like I have most of the basics covered, and I am at a loss to know what is going on.
 
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  #2  
Old 04-12-2018, 09:26 PM
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Check and see if your fuel filter aint black, if it is your injector O rings are bad and need replacing, you could have bad glow plugs or a bad glow plug relay, both are easy to test. You can ohm the Glow plugs thru VCH the two outer most pins on each plug are the GP connectors OHM should be between .8-1.0 ohm anything over or less means you have a dud and needs replacing. As for the GP relay a simple test is by using a test light with KOEO and testing the two bigger terminals on the GPR both should ne energized if one dont turn on could be a bad GPR or the wiring leading into the PCM.(when the engine is cold) The glow plugs should always be cycled when starting a cold truck.
bad injectors can also cause the white smoke in cold climate.
 
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Old 04-13-2018, 06:16 AM
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Sounds to me like you may have a broken o-ring on an injector. With clean oil in the truck it may not show oil in the filter yet and if the o rings have not deteriorated from age the black sign may not be there.
 
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Old 04-13-2018, 07:29 AM
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Fuel filter was the first thing I checked.

Just for reference in case my version of clean isn't really that clean. There is a small amount of particulates you can see in the bottom.


I have not checked the glow plugs, that is an interesting idea. This is where I am not a mechanic, so I may be ignorant to the issue, but how does a bad glow plug cause an engine burn 3 qts of oil?

I always cycle the glow plugs, in fact regardless of the temperature outside if the dash says wait to start, I wait. A friend asked if the truck was hard starting, when I told him it always started he suggested trying it once without the glow plugs to see if it would start cold.

Again, I am not a mechanic, and I am asking your help, but it seems odd that if the o-rings are leaking, there is no oil in the fuel, which I would suspect would be evident given the QUANTITY of oil it is consuming.
 
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  #5  
Old 04-13-2018, 08:22 AM
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No a bad glow plug wont cause oil cunsumption but it will cause your other plroblem you posted. That fuel looks dirty looks blue which is a sign of oil geeting in there, and since your adding oil often the oil is kept clean and not turning your fuel filter black.
 
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Old 04-13-2018, 09:08 AM
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The glow plugs run for 90-120 seconds. If you 'cycle' all your doing is shutting them off and back on. After the wait to start light goes off wait another 10-15 seconds and then start it. It uses oil sometimes and not other times?
 
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Old 04-13-2018, 11:13 AM
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need to know your IPR% duty cycle, that can tell us if an oring is going

whats your MPG been like? if it has been improved a bit, then you know where the oil is going

if it smell like burning oil more at 1/4 tank than a full tank, that could mean oil in fuel too
 
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Old 04-14-2018, 09:45 PM
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I figured out an easy(but messy) way to test the oil in fuel when I pulled my injectors. Maybe it's been done before, but I have never read anything on the topic yet.

I had taken out the 4 fuel banjo bolts on the block to put Riffraff banjo bolts in, right AFTER I had the injectors pulled, and before I tested the system. Otherwise I probably would have never come up with this method.

There will be oil in the fuel passage inside the block from the injectors being pulled, noticeably black diesel/oil combo. So, if an injector oil o-ring is gone, you'll see it come from that for sure. Then depending on what side you see oil coming from, you'll know it's one of those 4 injectors in that bank.
 

Last edited by ProjectDually; 04-14-2018 at 09:47 PM. Reason: autocorrect woes
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  #9  
Old 04-16-2018, 10:00 AM
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Thanks for the responses everyone.

Z31, Thanks for your thoughts, I thought the fuel looked pretty fresh and clean. Compared to videos I found online of 7.3's with known bad o-rings, which their fuel looked terrible! I am color blind, so that probably doesn't help! I was just comparing fresh diesel to what was in the bowl.

Old Bird, I always let them run for however long the dash says wait to start. Once that light goes off I start it. Are you saying I should wait an additional 10-15 seconds AFTER the light turns off to start the truck? To my knowledge it always consumes oil. It wasn't until after I had the clutch replaced that I noticed it consuming oil, and it started all of a sudden in a BIG way. I wasn't in the routine of checking the oil every fill up, noticed the one day the motor had a slightly different sound. I figured it was due to the 5 degree temperature. Looked everything over and checked the oil. There was only a tiny bit on the bottom of the stick. Since then it has been rapidly using more and more.

knottyrope, I would have to take it into a shop to get the IPR%. At that point it would be cheaper to just replace the O-rings. As to mileage, I have not tracked it closely, so unfortunately cannot comment as to increase or decrease. It would be nearly impossible to tell as it is not a daily driver. Interesting thought on the smell, never thought of that. I will have to try and remember to look at that. I am going to run both tanks down to about an 1/8th and then check the fuel filter again and see if there is a change in smell.

Project Dually, Thanks for your comments. Yes, that would be a good way to confirm, though if I am that far into it, it is because I have already decided to change the O-rings!

At this point, everyone seems to be pointing to O-Rings. For what diagnostics cost around here, I will probably go ahead and replace them and eliminate the variable.
 
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Old 04-16-2018, 10:49 AM
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Make sure you use only Motorcraft/Alliant O rings ONLY! Dont cheap out and do autoparts store or ebay brand ones. Good luck and hope it resolves your issue.
 
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Old 04-16-2018, 11:01 AM
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if you have an android device

buy a scanner to monitor your engine

https://www.amazon.com/Vgate-Bluetooth-Scanner-TORQUE-ANDROID/dp/B00AAOOQJC/ref=sr_1_1?ie=UTF8&qid=1473776759&sr=8-1&keywords=vgate+OBD2 https://www.amazon.com/Vgate-Bluetooth-Scanner-TORQUE-ANDROID/dp/B00AAOOQJC/ref=sr_1_1?ie=UTF8&qid=1473776759&sr=8-1&keywords=vgate+OBD2

Torque Pro
https://play.google.com/store/apps/d...g.prowl.torque

Use the communication in the profile
SAE J1850-PWM

make sure you add in Ford PIDs

https://play.google.com/store/apps/d...ch.CarGaugePro

people like it cause it will pull codes, buzz test and CCT

Warning, Some OLD PCM's have to be flashed before you can pull codes
 
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Old 04-16-2018, 11:02 AM
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there should only be 1.5v across IPR coil at idle aka 14% duty cycle and any more means an oil leak somewhere under VC

IPR should not leak, change orings if it does

Valve covers removed you should only see small spurt of oil returned from top of injectors, if more is coming out then oring or injector could be the issue.
Crank engine manually (not from key) and no oil should be coming out from injectors, if there is oil coming out, Injectors oring might be bad or injector could be.


Laser heat probe can help show which cylinder is the issue or use crayons to see which port melts last
 
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Old 04-16-2018, 12:57 PM
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FALL, that's what I'm saying, after the wait to start light goes off wait another 10-15 minutes. Sounds like you have bigger problems, good luck on everything.
 
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Old 04-16-2018, 02:11 PM
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Originally Posted by oldbird1965 View Post
FALL, that's what I'm saying, after the wait to start light goes off wait another 10-15 minutes. Sounds like you have bigger problems, good luck on everything.
Glenn, tipping that tea jar a few times today, lol. I know you meant seconds.
 
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Old 04-16-2018, 11:26 PM
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Ha-Ha Jim, when your waiting after the wait to start light goes off it seems like minutes when you have to get someplace, lol.
 
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