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Discussion Starter · #1 ·
My 2007 fj cruiser has a problem. I started it up today and it made a dieseling sound and acted like it didn't want to start which it has never done. It has 184000 miles and I drive it an average of 101 miles a day. Oil looks ok. Filter ok. Has never had anything done like a tune up, or timing chain replaced, only routine oil changes and new spark plugs once (3 years ago). It still has original battery. Rode hard n put up wet. :( I was told I may have gotten bad fuel. What's wrong with it and how can it be fixed?
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My 2007 fj cruiser has a problem. I started it up today and it made a dieseling sound and acted like it didn't want to start which it has never done. It has 184000 miles and I drive it an average of 101 miles a day. Oil looks ok. Filter ok. Has never had anything done like a tune up, or timing chain replaced, only routine oil changes and new spark plugs once (3 years ago). It still has original battery. Rode hard n put up wet. :( I was told I may have gotten bad fuel. What's wrong with it and how can it be fixed?
Thanks.
That's a pretty minimal description of the actual symptoms. Some additional information would be helpful:

1. Was the start you describe the first start of the day, or a re-start after the engine was already up to operating temperature?
2. What was the ambient temperature?
3. Had the previous day's cold-start exhibited any unusual characteristics?
4. Did the engine crank more slowly than usual?
5. How long did it crank before the engine started?
6. Once the engine started, did it run roughly, or immediately run at a steady idle?
7. Describe the "dieseling" sound in more detail.
8. Did the "dieseling" sound occur only while cranking, or only after the engine started, or ??
9. Were subsequent starts that day normal in every way?
10. Has the engine exhibited any changes from "typical, normal" operation? Longer cranking time until the engine starts? Higher or lower idle speed? Roughness under load?
11. The last time the spark plugs were changed, were they conventional plugs, or plugs with platinum/iridium electrodes?
12. Is your check-engine light on?

As far as routine preventive maintenance, you've never changed the transmission fluid, or changed out the engine coolant, or changed the lubricant in the differentials or the transfer case, or flushed the brake fluid?
 

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I'm like 99% sure an electronically fuel injected gasoline engine cannot diesel. Power is cut to the injectors, preventing them from firing when the engine isn't running. Dieseling only occurs in engines that are carburetor, or have mechanically actuated injectors.
 

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Obviously there is not enough information to make a proper diagnosis, so you will have to investigate various possibilities like:
1. Cam train/valve train timing.
2. Crank position sensor (ignition/spark related influences).
3. Fuel system (pressure & injector function).

It sounds like you are saying there is mechanical noise associated with the issue? Is the noise in multiple cylinders or just one or is it just on one side of the engine or both? If there is one bank or both banks that are mechanically noisy, then it may be a clue to look at items associated with Cam/Valve timing events and their associated controls (timing chain tensioner, phase timing actuation, chain or guide wear, etc.)? GL
 

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Plug in a scan tool, check your codes on google or post them here.

Your check engine light is on, yes? That's a much better way of diagnosis, here we're all just guessing.
 

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I'm like 99% sure an electronically fuel injected gasoline engine cannot diesel. Power is cut to the injectors, preventing them from firing when the engine isn't running. Dieseling only occurs in engines that are carburetor, or have mechanically actuated injectors.
I think the OP may be confusing "dieseling" with some other issue. Normally, dieseling is associated with a hot-engine shut-down, where the engine continues to "run" erratically at very low speed, knocking loudly, even with the ignition shut off, due to hot spots in the combustion chamber igniting residual fuel.

Electronically fuel-injected engines can also experience short-duration dieseling during a hot-engine shut-down if any of the injectors are leaking. Normally, there is residual fuel pressure in the injection system, and a leaky injector will continue to leak for a short time after the ignition system (and the fuel pump) are turned off.

True "dieseling" during a gasoline-engine cold-start should be almost impossible, although severe pre-ignition (knocking) could occur if there was some gross defect in ignition timing, or "cross-firing" between adjacent spark plug wires in a distributor-type ignition system.
 

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I'm betting it's going to be a mechanical problem rather then a performance problem. Possibly a locked up A-C compressor, alternator bearings or idler/tensioner pulley bearings.
 

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I actually have this same thing occurring in a Mitsubishi right now and it's caused by a fuel pump beginning to fail. The pressure required for the injectors to operate is insufficient to pop them consistently resulting in a "dieseling" effect until the pump builds sufficient pressure, sometimes I have to kill it and restart to get it kicked off. This has happened twice before and both times it was the in tank pump.

Probably not what's going on here but just an example of a possible failure. Gearwrench and FJtest are far more equipped to tackle this question.
 

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Discussion Starter · #10 ·
that's a pretty minimal description of the actual symptoms. Some additional information would be helpful:

1. Was the start you describe the first start of the day, or a re-start after the engine was already up to operating temperature? First start
2. What was the ambient temperature? Cool, 40-45 temp outside.
3. Had the previous day's cold-start exhibited any unusual characteristics? No
4. Did the engine crank more slowly than usual? Yes
5. How long did it crank before the engine started? 2 seconds at the most
6. Once the engine started, did it run roughly, or immediately run at a steady idle? Ran rough for 3 or 4 seconds and thats when it made a dieseling sound and shook a bit more than normal.
7. Describe the "dieseling" sound in more detail. Ran rough for a few seconds only at start up, putt-putting like it was going to die. Sounded like my f250 powerstroke. Did not do it after i shut it off.
8. Did the "dieseling" sound occur only while cranking, or only after the engine started, or ?? Just after start
9. Were subsequent starts that day normal in every way? Yes
10. Has the engine exhibited any changes from "typical, normal" operation? Longer cranking time until the engine starts? Higher or lower idle speed? Roughness under load? No
11. The last time the spark plugs were changed, were they conventional plugs, or plugs with platinum/iridium electrodes? Bosch conventional
12. Is your check-engine light on? Yes

as far as routine preventive maintenance, you've never changed the transmission fluid, or changed out the engine coolant, or changed the lubricant in the differentials or the transfer case, or flushed the brake fluid?
i take it to a lube and tire place every 3000 miles to get everything check, topped off, and changed. They use a synthetic blend. Got premium gas and put in a fuel treatment and it is ok now. For now.
 

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The check engine light is on?

Why didn't you mention that in your initial post??

That's BY FAR the most important indicator of what's going on.

What OBD-II fault codes triggered the CEL? If you don't know, get the codes read out through the diagnostic port, and post ALL of them here.
 
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