True enough. But odometer failure is usually pretty apparent and also easier to check for now days with GPS. Only thing you have to account for is if you have non stock tires and/or gears.
Sudden Gas Mileage Drop / Poor Fuel Consumption, HELP!
- Thread starter Gascan
- Start date
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Gascan
All chaps, no jeans.
- Thread starter
- #23
Appreciate all the replies! I’ve replaced both O2 sensors earlier today and will post an update after putting some miles on the thing. Also, the coolant has been flushed and replaced when I did the radiator; but I’ll keep an eye on coolant temp.
Disclaimer: Keep in mind that the motor has 299,XXX miles on it and consumes oil like it’s going out of style. The downstream O2 didn’t look any better.
Disclaimer: Keep in mind that the motor has 299,XXX miles on it and consumes oil like it’s going out of style. The downstream O2 didn’t look any better.
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A valve seal job may be in your future.
Why? Most of the causes of massive oil consumption are due to valve stem seals. The bottom end on these are stout as heck. I think it was @scottryana that posted a pic of the 1FZFE rods compared to a Chevy motor that put out 800 HP. The Toyota unit was at least three times the size.You're much more optimistic than I am... A full rebuild or swap is in my future for sure!
I would just pull the head and look at the crosshatching and if it looks good, just do a full head job and replace most of the moving parts you take off and call it a day. The first motor lasted 20+ years and almost nobody ever reports lower end problems on trucks that were at least marginally maintained. I bet that gas will become so rare that driving that truck won't make sense before the motor wears out again.
You could do the main crank seal and oil pump gasket too, just to be safe and because those are known leakers, especially at your mileage.
A little late but before replacing the sensors you should just reset the computer. Clean your sensors should also help because O2 last a good while. Regardless even after the O2 change you should reset the ECU by disconnecting the battery for 10 minutes.
Why do you suspect the rings?
It's Florida. Remove the egr, cats, you don't need no stinking emissions..
If the coolant sensor is bad and the ecu thinks the engine is cold it will run rich as f......
If the coolant sensor is bad and the ecu thinks the engine is cold it will run rich as f......
.
Blue Smoke is oil.
Black smoke is fuel.
White smoke is coolant.
Blue smoke on start-up is valve seals/guides.
Blue smoke on acceleration is rings
Blue smoke on deceleration is valve seals/guides
Black smoke is fuel.
White smoke is coolant.
Blue smoke on start-up is valve seals/guides.
Blue smoke on acceleration is rings
Blue smoke on deceleration is valve seals/guides
Gascan
All chaps, no jeans.
- Thread starter
- #33
UPDATE...
Fuel mileage has gone up by approx. 1 MPG (from 7.5 MPG to 8.5 MPG) after replacing the O2 sensors. This is still lower than the 10.5 MPG it got around town a little over two months ago.
It’s progress but something is still off. No CEL’s in approx 200 miles since resetting the ECU. Could really use some help as I’m at a loss at the moment...
Fuel mileage has gone up by approx. 1 MPG (from 7.5 MPG to 8.5 MPG) after replacing the O2 sensors. This is still lower than the 10.5 MPG it got around town a little over two months ago.
It’s progress but something is still off. No CEL’s in approx 200 miles since resetting the ECU. Could really use some help as I’m at a loss at the moment...
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Clean your throttle body, upper intake plenum (including the EGR tubes). I had the codes but I did that and immediately did much better in MPG.
How old is your catalytic converter? If it is partially clogged it will kill the fuel mileage. If its burning that much oil as in your statement in your first post, the cat is likely long dead. Oil through the cat it can clog the cat. The fix would be to find the source of burning oil, repair it, and replace the cat. If you just replace the cat without fixing the source of the burning oil, it will kill the new cat.
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Gascan
All chaps, no jeans.
- Thread starter
- #36
Again, the increase was pretty sudden, so I don’t think this points to a clogged cat or dirty intake manifold.
Question for the experts: Can the distributor go out of timing on its own, over time (no pun intended)?
Will try to check my timing later today (have never done this before)...
ppc
M Go Blue
A sudden decrease in fuel economy is one of the signs of a clogged cat. Clogging can occur rapidly not necessarily slowly overtime when the catalyst melts down.
Timing will not change on an EFI motor unless there is some type of failure such as the bolt securing the distributor coming loose. In older (pre EFI) points type engines the timing would change as the dwell angle changed.
Timing will not change on an EFI motor unless there is some type of failure such as the bolt securing the distributor coming loose. In older (pre EFI) points type engines the timing would change as the dwell angle changed.
Gascan
All chaps, no jeans.
I would say the symptoms you already have would be enough for me to pull the cat and take a look.
Gascan did you get this resolved? What was the cause?
