No engine light, engine flooding

JAREDPG351

MEMBER
2010 FORD FOCUS
2.0L
4 CYL
2WD
AUTOMATIC
116,000 MILES

About ten days ago I replaced the spark plugs in this car with new iridium plugs. Knowing I would be removing the connectors to coils I disconnected battery as best practice (at least I have always thought). After replacing spark plugs the engine started right up seem to run fine and gave no engine light to elude to an abnormal run condition. However, during the run I heard a noise from the fuel rail I have never heard in any car. It was a very loud sound like there was high pressure situation in the fuel rail. Sounded like listening to high pressure/velocity fluid flowing through a pipe. Fast forward a week later my niece (it is her car) tries to start the car Monday morning to find it will not start, but does sound like it is trying to. I go and look at the car and find that it is flooded due to the spark plugs being wet with gas. It was miserable cold so I had the car towed to a repair garage who mysteriously got it running in no time and I went and picked it up. They could find nothing wrong with the car and said the plugs were fouled and needed to be changed again. However, after picking it up and running the car it seems to run fine and again there is no engine light for misfires or rich condition or anything. They must have gotten the engine unflooded. Some how I have never heard of this clear flood procedure on fuel injected cars (probably because I have never seen a fuel injected engine flood). So I imagine they simply used the clear flood procedure to start the engine. I know ECM's lose their memory and fuel trims when the battery is disconnected but the car had been running for 9 days before this flooding occurred. Any ideas why a fuel injected engine would flood when there is no abnormal sensor conditions causing the engine light to come on? She did fill the car up with gas before parking it on Sunday night before all this happened, but said she did not top it off or overfill it. I have since checked the fuel pressure and it was at 55 psi which my manual shows it should be. Also, the loud noise in the fuel rail seems to have gone away now. Any help is greatly appreciated.

1 Reply

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

There are a couple of reasons that I could think of why something like this could occur on returnless style fuel system vehicle. The first and most obvious would be a problem with the fuel pump driver. This is what controls the amount of fuel being delivered to the engine by varying the amount of voltage the fuel pump receives. The second would be a short to power in the circuit that provides voltage to the fuel pump causing it to over driven. Also you could have a stuck open fuel injector that would just dump fuel into a cylinder, but that's usually just one cylinder and the vehicle would still start and just have a miss in that cylinder. Please get back to us with what you can find out.

Thanks,
Alex
2CarPros