Oil and gas mixing?

Tiny
MASON23
  • MEMBER
  • 1991 DODGE DAKOTA
  • 2.5L
  • 4 CYL
  • 2WD
  • MANUAL
  • 130,000 MILES
Engine has a rough idle for a minute after starting and the oil smells like gas. I’ve changed the spark plugs and wires and am wondering. What else could be causing this?
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No
Sunday, December 4th, 2022 AT 10:39 PM

5 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi,

If you are getting fuel into the oil, it could be a couple of things. First, if the fuel pressure regulator is failing, the pressure can get too high and leak from the injector when you shut the engine.

Also, a stuck or weak fuel injector can also cause this to happen. When an injector solenoid is energized, the plunger is retracted, lifting the needle valve off the seat. This allows the pressurized fuel to spray into the intake manifold. When the solenoid is de-energized, spring pressure closes the valve. Because of the year and mileage, I have a feeling the spring is too weak to close the valve and fuel pressure drains off when the engine is off.

I have a question. When you start the engine cold, do you ever see any dark smoke from the exhaust or an odor that indicates a rich fuel mixture? If my theory is correct, the engine is slightly flooded when this happens causing the rough idle.

Remove the air filter assembly and have a helper start the engine and then turn it off while you watch for a spray from the injector. See if it leaks off when the key is first turned on (engine off) and if it leaks when the key is turned off.

Note: If you have a lot of fuel in the oil, change the oil and filter to prevent bearing damage.

Let me know.

Joe

See pic below.
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Monday, December 5th, 2022 AT 6:47 PM
Tiny
MASON23
  • MEMBER
No, it has occasionally had white smoke after starting before though. It also sometimes will rev up after letting of the gas.
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Tuesday, December 6th, 2022 AT 5:28 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Based on outside temperatures, white smoke could be normal, or it could indicate coolant getting into the combustion chamber.

Have you checked the fuel pressure and are you certain there is nothing leaking from the injector? That is where the fuel would come from unless you have a misfire, and the fuel is not being burned.

Let me know.

Joe
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Tuesday, December 6th, 2022 AT 3:02 PM
Tiny
MASON23
  • MEMBER
I haven’t checked it yet, but I will now. Thank you.
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Monday, December 12th, 2022 AT 9:07 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi,

I haven't heard from you. Have you been able to check things and make any progress?

Let me know.

Joe
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Tuesday, December 13th, 2022 AT 6:54 PM

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