Rough idle for 5 seconds when starting from a hot soak

476 Views 10 Replies 5 Participants Last post by DDS-029, 14 d ago

Aussy

Discussion Starter · 19 d ago

Hey guys,

Thank you for taking the time to read my post and help out.

Recently just bought a 2016 Escape titanium with the 2.0L

Noticed only in the summer time, when we shut the vehicle off when it’s hot and go to start it, the RPM’s will drop below 500 and it will have a rough idle for about 5 seconds then the RPM’s will stabilize and it runs perfectly.

I have changed:
Spark plugs
Evap canister purge valve
Battery (BMS was reset with new battery)
Air filter

I have no coolant consumption or oil consumption. All Evap test’s have passed.

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bigbirchlake

· #2 · 19 d ago

One thing that comes to mind is a "leaky fuel injector". When this occurs, after driving and shut off, a small amount of fuel will leak past the injector into the cylinder. When the engine is restarted, it can take a few seconds for the engine to burn off the extra fuel (rich for a bit) so you can have a rough idle for a few seconds until that cylinder cleans up and the proper fuel is again being delivered.

How many miles are on your engine? Any check engine light?

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murcod

· #3 · 18 d ago

Has the A/C been left on when it occurs? That would cause an extra load on the engine when it restarts.

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Aussy

Discussion Starter · #4 · 18 d ago

bigbirchlake said:
One thing that comes to mind is a "leaky fuel injector". When this occurs, after driving and shut off, a small amount of fuel will leak past the injector into the cylinder. When the engine is restarted, it can take a few seconds for the engine to burn off the extra fuel (rich for a bit) so you can have a rough idle for a few seconds until that cylinder cleans up and the proper fuel is again being delivered.

How many miles are on your engine? Any check engine light?

98000km are on the engine. The leaking fuel injector does make sense. The problem is this only happens when it’s warm outside (only in the summer). Too my knowledge if it was a leaking injector causing a rich condition, I would think that would happen all the time regardless of temperature. I was almost thinking a temporary vacuum leak. That’s why I replaced the purge valve for the evap system. But still no luck.

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Aussy

Discussion Starter · #5 · 18 d ago

murcod said:
Has the A/C been left on when it occurs? That would cause an extra load on the engine when it restarts.

A/C is always left on. But again this only happens in the summer when it’s warm outside. The A/C compressor sometimes turns on during the winter when HVAC is placed on defrost to remove any humidity in the cabin. I will try tomorrow with the A/C switch off and keep you updated. Thank you!

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bigbirchlake

· #6 · 18 d ago

Another possibility is something like a "coolant temp sensor". The input from this sensor to the computer is directly involved with fuel/air ratio on starts. So if this sensor is giving erroneous data to the computer where it thinks that the temperature is colder than it actually is, it could send a rich fuel mixture to the engine.

You didn't answer....any check engine light or have you ever seen one? If so, gotta scan for codes for clues.

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Aussy

Discussion Starter · #7 · 18 d ago

bigbirchlake said:
Another possibility is something like a "coolant temp sensor". The input from this sensor to the computer is directly involved with fuel/air ratio on starts. So if this sensor is giving erroneous data to the computer where it thinks that the temperature is colder than it actually is, it could send a rich fuel mixture to the engine.

You didn't answer....any check engine light or have you ever seen one? If so, gotta scan for codes for clues.

I will look at live data with the ECT sensor. That’s a good idea. Thank you.
Sorry about the one question, no check engine light and no codes present in the pcm

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ajef7885

· #8 · 17 d ago

Does your car exhibit rough idle right after a fuel fill up too? That itself is a symptom of the purge valve solenoid possibly going bad. Did you change the vent at the canister or the solenoid at the engine? Everyone saying you have to replace the whole hose and assembly at the engine. Dorman makes a unit that has quick couplings. You just cut the tubing and push them into the couplers. 2013 Ford Escape P1450 check engine, purge valve replacement - YouTube

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ajef7885

· #9 · 17 d ago

ajef7885 said:
Does your car exhibit rough idle right after a fuel fill up too? That itself is a symptom of the purge valve solenoid possibly going bad. Did you change the vent at the canister or the solenoid at the engine? Everyone saying you have to replace the whole hose and assembly at the engine. Dorman makes a unit that has quick couplings. You just cut the tubing and push them into the couplers. 2013 Ford Escape P1450 check engine, purge valve replacement - YouTube

Vapor Canister Purge Valve | 913-430 | Evaporative Canister Purge Solenoid Repair Kit | Dorman Products

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Aussy

Discussion Starter · #10 · 17 d ago

ajef7885 said:
Does your car exhibit rough idle right after a fuel fill up too? That itself is a symptom of the purge valve solenoid possibly going bad. Did you change the vent at the canister or the solenoid at the engine? Everyone saying you have to replace the whole hose and assembly at the engine. Dorman makes a unit that has quick couplings. You just cut the tubing and push them into the couplers. 2013 Ford Escape P1450 check engine, purge valve replacement - YouTube

No rough idle after filling up. I have already replaced the purge valve solenoid. All evap tests have passed just recently.

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DDS-029

· #11 · 14 d ago

Not surprised that if it has a leaky injector that it starts okay in cold. "Cold" starts require a little richer mixture. Remember setting or pulling a choke?

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