Diagnosing rebuilt engine - burning oil, lean, and low power up inclines
#1
Diagnosing rebuilt engine - burning oil, lean, and low power up inclines
Starting a thread to document my work and get some help.
Symptoms
Specs
Diagnosis
To summarize, there are 3 primary issues:
Running a tad lean, burning excessive oil, and low power up steep inclines.
What to check next? I think the plan is to replace the fuel injectors with ebay remans (may have a vacuum leak in the intake), and replace spark plugs to hopefully address the lean issue. I already replaced MAF. O2 sensors were new w/ the rebuild (bought from Atlantic british).
For the oil burning, on my first break-in I did mess up a bit and spike the engine to 4k rpm almost immediately. Maybe the rings are bad (but compression is good). Valve stem seals were replaced by the machine shop. I need to be able to figure out whether its rings or seals?
For low power, I have no clue. The compression is perfect. Even if I was burning oil and running lean, I would think with good compression I should be able to tackle these inclines no problem?
Symptoms
- Burning a quart of oil every ~250 miles
- Running lean, with +6% LTFT on both banks. STFT are more erratic at idle and quick acceleration. Sustained acceleration the trims stabilize around +/- 3%
- Low power up steep inclines (cannot pull 4th, wants to stay in 3rd @3,000 rpm going 55 mph)
- Low MPG (uncalibrated ultragauge showing 9.5)
Specs
- Rebuilt w/ top hat sleeves
- Professional valve job on heads
- Kent H180 Torque camshaft
Diagnosis
- Perfect idle, ~680 rpm
- Perfect oil pressure and temps
- 180 PSI compression on all cylinders
- Carbon sooty plugs, some have white speck deposits. I think running lean and my short-trip heavy driving style account for this. Not sure about the white specks though
- No apparent blue smoke out of exhaust
- Performance seems great on everything other than steep inclines
- screeching can sometimes be heard at 4k+ rpm
- PCV separator super clean, replaced with Frame PCV valve
To summarize, there are 3 primary issues:
Running a tad lean, burning excessive oil, and low power up steep inclines.
What to check next? I think the plan is to replace the fuel injectors with ebay remans (may have a vacuum leak in the intake), and replace spark plugs to hopefully address the lean issue. I already replaced MAF. O2 sensors were new w/ the rebuild (bought from Atlantic british).
For the oil burning, on my first break-in I did mess up a bit and spike the engine to 4k rpm almost immediately. Maybe the rings are bad (but compression is good). Valve stem seals were replaced by the machine shop. I need to be able to figure out whether its rings or seals?
For low power, I have no clue. The compression is perfect. Even if I was burning oil and running lean, I would think with good compression I should be able to tackle these inclines no problem?
Last edited by Jeff Blake; 04-30-2018 at 02:06 PM.
#3
No engine codes other than an intermittent pending P0441.
White specs from my research suggest oil burning, residue can be leftover zinc or other elements in the oil. I don't know anything about detonation... wouldn't the knock sensors pick that up? I do get a ticking, and it sounds like its coming from the fuel rail (using a stethoscope, sound is strongest on the fuel rail).
White specs from my research suggest oil burning, residue can be leftover zinc or other elements in the oil. I don't know anything about detonation... wouldn't the knock sensors pick that up? I do get a ticking, and it sounds like its coming from the fuel rail (using a stethoscope, sound is strongest on the fuel rail).
#4
Break in oil
what oil did you use? It sounds like your rings have failed to seat. One old school remedy would be to remove all plugs, spray Wurth Rost off into cylinders and let soak overnight. Crank engine a few times with the plugs still out to remove extra, plugs in, run and oil change after.
did you do a leak down test or any other diag besides what you posted? You did lots of work so far......
did you do a leak down test or any other diag besides what you posted? You did lots of work so far......
#6
what oil did you use? It sounds like your rings have failed to seat. One old school remedy would be to remove all plugs, spray Wurth Rost off into cylinders and let soak overnight. Crank engine a few times with the plugs still out to remove extra, plugs in, run and oil change after.
did you do a leak down test or any other diag besides what you posted? You did lots of work so far......
did you do a leak down test or any other diag besides what you posted? You did lots of work so far......
Haven't done a leak down test, but since I have great compression, what can a leak down test tell me? My concern is that you can have good compression and still leak oil past the valve guides and oil control rings. While this may be happening, it doesn't account for low power on inclines
I did do that, bit hard to see due to focus. Saw some carbon buildup but didn't look excessive. I'll check again when I replace the plugs.
#8
Pretty sure its dino, nothing internet says anything about it being synthetic
Checked the dipstick today after a day trip. 90 miles of highway driving, plus 3 hours (~40 miles) of off-road driving (10-25mph, lots of hills, heavy engine breaking). Dipstick is down 1/4" -- how much is that... 0.25 quarts?
Checked the dipstick today after a day trip. 90 miles of highway driving, plus 3 hours (~40 miles) of off-road driving (10-25mph, lots of hills, heavy engine breaking). Dipstick is down 1/4" -- how much is that... 0.25 quarts?
#9
Pretty sure its dino, nothing internet says anything about it being synthetic
Checked the dipstick today after a day trip. 90 miles of highway driving, plus 3 hours (~40 miles) of off-road driving (10-25mph, lots of hills, heavy engine breaking). Dipstick is down 1/4" -- how much is that... 0.25 quarts?
Checked the dipstick today after a day trip. 90 miles of highway driving, plus 3 hours (~40 miles) of off-road driving (10-25mph, lots of hills, heavy engine breaking). Dipstick is down 1/4" -- how much is that... 0.25 quarts?
#10
Lots of positive reviews on the yellow tops!
Are the plugs seated properly with the sealing metal washers being slightly compressed? Please rule that out.
A second consideration is your PCV valves on the pass and driver side. If they are blocked or not attached your engine will chug oil. As posted previously- NOT using synthetic now is a good thing. At 14.99 a gallon, rotella is a deal and you can always add in the zinc additive and change it all out a few times while you sort this out.
Lastly, the noise on the fuel rail could be a sticking injector. Have you ruled that out, or moved it on a trail basis? You can clean and reinstall the plugs to reread what deposits wet/dry etc that show.
On a last inspection, I would look at the oil pick up screen. Left over sealant or contamiments from rebuild? If the top hat liners are designed to seal up the deck- what are mods or machining did the shop do?
Are the plugs seated properly with the sealing metal washers being slightly compressed? Please rule that out.
A second consideration is your PCV valves on the pass and driver side. If they are blocked or not attached your engine will chug oil. As posted previously- NOT using synthetic now is a good thing. At 14.99 a gallon, rotella is a deal and you can always add in the zinc additive and change it all out a few times while you sort this out.
Lastly, the noise on the fuel rail could be a sticking injector. Have you ruled that out, or moved it on a trail basis? You can clean and reinstall the plugs to reread what deposits wet/dry etc that show.
On a last inspection, I would look at the oil pick up screen. Left over sealant or contamiments from rebuild? If the top hat liners are designed to seal up the deck- what are mods or machining did the shop do?
Last edited by mirrajumper; 05-01-2018 at 07:37 AM.