99 4.0 SOHC flooding problem at start up.

[Pe68olds]

I have a 99 Explorer with a SOHC 4.0. It has 90,000 miles and I have owned since new. The problem started last winter. It would flood and not start unless you held the gas pedal to the floor. During the spring and summer, it starts fine. It only happens when it gets cold. I took it to the dealer and have new plugs and an intake gasket replaced last winter. Today it flooded again! The dealer can't seem to fix the problem. Any ideas on what is wrong??

 

[BrooklynBay]

Welcome to this forum! It could have a bad fuel pressure regulator or engine coolant temperature sensor.

 

[Cobraguy]

funny how it only does it when it's cold outside. That tells me something is happening that is temp related. Engine coolant temp sensor is the first place to look. ECM logic richens the mixture on start up. The colder it is, the richer it becomes. Flooring the accelerator tells the ECM that you are clearing a flood condition and shuts off all the injectors. I can't think that this would be that hard to find. Are you taking this to a Ford dealer? Are you leaving it with them over night now that it's cold?

 

[budwich]

I don't think it is a temp sensor problem.... cause it floods when it cold which the temperature sensor would normally be at for cold. If it were flooding when its warm out, then it might be a temp sensor problem. Sounds more regulator like. Not sure when ford ex's went from "return line vacuum regulator" to computer controlled regulator but maybe this is about the right year??? If not, then maybe the vacuum regulator is leaking.

 

[Pe68olds]

funny how it only does it when it's cold outside. That tells me something is happening that is temp related. Engine coolant temp sensor is the first place to look. ECM logic richens the mixture on start up. The colder it is, the richer it becomes. Flooring the accelerator tells the ECM that you are clearing a flood condition and shuts off all the injectors. I can't think that this would be that hard to find. Are you taking this to a Ford dealer? Are you leaving it with them over night now that it's cold?

I have taken it to a Ford dealer. They found the leaking intake gasket and said it was fixed. Now on Tuesday it flooded again. Very frustrating!

 

[Cobraguy]

That is a horrible diagnosis. Think about it. It makes no sense. Well, if you took it to Ford and told them to fix the problem...and they didn't...they aren't done and they need to credit you for the gasket repair since it didn't fix it.

Why don't they hook up their diagnostic equipment and see what it's doing when it's cold?

 

[teal94gt50]

Do what cobraguy said and take it back to the dealer (as long as its not mine, lol) J/K!!! Did they verify the concern? That should have been the first thing to do, verify and have IDS hooked up to read the values of the various inputs, and retrieve codes. You may have an IAC sticking closed also, that can easily cause a no start/flood situation when cold, and have no codes in the system.

Will

 

[Cobraguy]

There is someone who's thinking about it! And I like what he's thinking. You MUST leave the car there overnight so they can park it outside and diagnose it when it's cold.

 

[Pe68olds]

There is someone who's thinking about it! And I like what he's thinking. You MUST leave the car there overnight so they can park it outside and diagnose it when it's cold.

Thanks for the responses. I have left it over night and they could not find the problem. It does not happen all the time. That is what is so frustrating about it.

 

[Pe68olds]

Do what cobraguy said and take it back to the dealer (as long as its not mine, lol) J/K!!! Did they verify the concern? That should have been the first thing to do, verify and have IDS hooked up to read the values of the various inputs, and retrieve codes. You may have an IAC sticking closed also, that can easily cause a no start/flood situation when cold, and have no codes in the system.

Will

What is an IDS and a IAC? The IAC sticking may be the problem. The flooding does not happen all the time. It is sporadic. It seems when I get an appointment at the dealer, the Explorer runs and starts fine when they leave it over night. Is there something I can do to prevent the IAC from sticking?

 

[teal94gt50]

The IDS is our diagnostic equipment used to retrieve codes and to watch what the inputs are sending and what the outputs (should be) doing.

The IAC is the idle air control valve. It is what lets air bypass the throttle plate so your truck will idle. A lot of the times they get carboned up or "sticky" and don't respond as they should. This can result in a no start situation cold. If you want to try yourself, you can somewhat clean it out w/ some carb cleaner. This will usually help, but it really should be replaced.

Doing this yourself is very easy w/ the SOHC motor. Remove the plastic engine cover (4 7mm bolts)

Unplug the IAC valve, it's smack in the middle of the intake (2 pin connector) and remove the 2 bolts (8mm I think?)

Replace the valve and the gasket, and all done

Will