Can you "flood" a fuel injected engine?

[Scout1]

Vehicle is a 1999 Grand Caravan with the 3.8L V6 and 95k miles. This summer I went to the effort (a LOT of effort) to replace plugs and plug wires. Runs super now-a-days. Until a couple of weeks ago, my wife comes in and tells me the van won't start. Sure enough, crank and crank with an occasional sputter, but won't start. I got it to start briefly by flooring it during cranking, but it died again after a few seconds regardless of feathering the throttle.

I let it sit a day and came out to the same thing, starter turns it over with an soccasional fire. Again motored briefly. Humm... must be a sensor out I figured. I smelled a strong gasoline smell from the exhaust during cranking. I got an old spark plug and did a check on a couple of the front cylinders and the spark seemed weak and intermittent. Again, the crank or camshaft position sensor I was thinking. Then my son wanted to see if we could get it to catch again and maybe it would stay lit if we held the throttle down. Sure enough, it caught and raced and stayed running. Smoothed out and ran perfectly.

I still figured some sort of sensor problem was going to rear it's ugly head, but it's been a few weeks now and the van continues to run perfectly. So the question, was it just flooded? This van has never started hard and never required any throttle during starting. Any ideas why it did this?

 

[hattaresguy]

Crank position sensor maybe? Any codes coming up?

 

[Scout1]

Nope, no codes. I forgot to mention that. I have a reader and checked it several times since I couldn't believe it would behave that way without throwing a code!

 

[yonyon]

You can get your plugs wet sure enough. Crank with a weak battery; crank and let go a few times before it fires up; try starting it with a fault such as an unplugged coolant temp sensor. If it doesn't happen again don't worry about it.

 

[Kuato]

I've seen similar behavior with water in the gas.

Where did your wife purchase gas just before the problem? I'd avoid that station.

 

[JimPghPA]

Wet plugs are shorted out plugs. But that usually happens only on very cold days.

The only time I ever saw a wet plug was after a cousin tried to start his new Cadillac on one of the coldest days we ever had here, -20 Fahrenheit. When temperatures get that cold the battery capacity goes way down, and the load on the starter goes way up, resulting in the battery voltage being low, possibly to low to provide a hot enough spark.

The first few seconds of cranking are probably the most critical, if the voltage remains high enough to get a good spark and if the fuel is good enough to vaporize at the temperature it is exposed to, then the engine starts. If the voltage is too low and the spark is too weak, and the fuel does not vaporize in those cold cylinders, you end up with wet plugs, and you may have to replace all the plugs to get it to start, not a fun job in bitter cold temperatures.

It is not anywhere near that cold now, but if your battery voltage is dropping too low because of a bad battery, or a bad starter, you could possibly end up with wet plugs. Bad gas might cause wet plugs, but you would probably have to have a significant amount of water in the gas for it to cause problems at the ambient temperatures we have had lately.

So how strong is your battery, and how good is your starter? Is the battery voltage dropping too low to give a good spark while the engine cranks? Also, something as simple as a poor battery connection, or a bad battery cable, could cause low voltage to the car, resulting in poor spark and wet plugs.

Some people would try ether. I would probably only use ether on an engine that was a few months away from going to the bone yard.



Good Luck.

 

[eljefino]

A sensor won't give you a yellow spark. Low power through either bad battery or bad coil will.

However sensors can and will flood if they go far enough out of spec (but still give plausible data and don't throw codes.) Also basic problems like leaky fuel injectors or bad regulators can flood.

 

[Mud]

Symptoms sound similar to defective IAC (Idle Air Control) valve. Will not always throw a code.

 

[A_Harman]

Yes, fuel injected engines can be flooded.
Maybe leaky injectors? If you can get a pressure gauge to connect to the Schrader valve on your fuel rail, you can see how quickly the fuel pressure drops after you shut the engine down.

You did the right thing by flooring the accelerator to get the engine started. Most modern EFI systems have a flood-clear function that shuts off fuel if it senses high throttle opening under cranking conditions.

 

[hypervish]

Try slamming the dashboard above the gauges next time it won't start.

These stupid vans have an issue with the solder joints on the back of the gauges, which will cause intermittent starting. May or may not be the problem here.

If you slam the dash a few times next time and it starts, pull the cluster out and touch up all of the solder joints.

 

[punisher]

Memories:

The new for 1995 Lincoln continental had a tranverse FWD V8 24V setup. A lot of engine to fit in that car. Anyways:

We started to see them come in on the hook, no start, no compression. We were baffled by the first one. ~40 PSI compression. Tough to diag because you would expect the plugs to be a bit wet with no combustion. Squirted some oil down the cylinder, boom, compression back well over 100 PSI. Put the plugs back in and it cranked right up, smoked out the shop really well, but it ran fine once the oil burned off.

Turned out there was some PCM calibration error that could command the injectors on and wash down the cylinders enough to kill compression. Some times you could get them to start just by holding down the accelerator and kill the injector flow, sometimes you had to squirt some oil in the front 4 cylinders to get compression up enough to start.

 

[Scout1]

Interesting... You're saying flooring a fuel injection engine during starting will actually shut off the fuel? I didn't know that!

As for the Battery, it did seem a little weak when my wife first told me about the problem. But I have one of those chargers with a 50 amp starting mode and put that on so it turned over strongly but still wouldn't start. But perhaps the battery was weak enough when she tried, it soaked the plugs.

The only other thing I forgot to mention was this happened after a heavy rain, first of the season here in Seattle. I almost wonder if a connection got wet or something. It's a stretch, but...

Ha ha... I'll definitely beat on the dashboard next time. Kick the tires a few times too, that ought to help!

 

[Scout1]

We always gas up at Costco which seems to be pretty good gas with a ton of additives. I kind of doubt there would be enough water in there to cause problems. Wouldn't it get soaked up by that 10% alcohol anyway?

 

[The_Eric]

A couple of things to keep in the back of your head if you have problems again:

If this is a flex fuel engine, the O2 sensor can go bad and the engine won't always "see" the correct fuel. Chryslers of this vintage used the O2 to identify the fuel being used.

Another issue that can lead to the same issues you're seeing is the wire insulation on the fuel injector harness under the upper intake will degrade with oil and wires will short together. The one I worked on flooded so bad that fuel was dripping out of the exhaust manifold collector gasket and the customer thought that they had a fuel leak.

 

[JimPghPA]

I am not familiar with that engine or the ignition system it has in that application, but the “right after the rain” clue reminds me of some vehicles that had a distributor at the back of the engine and if the big gasket above the fire wall was bad rain would get all over the distributor, and could cause problems if there were any areas that let rain in. So among other things, it probably would be a good idea to inspect it for water getting to the ignition parts. You could park it in the same spot facing the same way and hose it down to see if water is getting to ignition parts. Also I have heard of some vehicles having wet ignition problems because the flexible rubber flaps around the front suspension were not in their proper place after someone had worked on the front end for an alignment or something, and then the vehicle was driven through some big puddles when it rained.

Just a couple of thoughts about how water can find its way into areas where it can cause problems.

 

[artificialist]

Cars with EFI typically have a "Flood clear mode" when you floor the gas pedal hand hold it there when you turn the key. I had to use it while working on a Nissan Quest that was having some intermittent starting problems.

 

[Warstud]

Sounds like moisture from the rain made it's way into the electrical system.

 

[artificialist]

Originally Posted By: Warstud
Sounds like moisture from the rain made it's way into the electrical system.

What happened was they we disconnected the ECU to test the knock sensor circuit. AAfter we plugged the ECU back in, the car wouldn't start.

I blew on it like an NES cartridge, and then the car started after flood clear mode was used.

 

[disallow]

Originally Posted By: JimPghPA
the coldest days we ever had here, -20 Fahrenheit.


-20F is cold, but not that cold. It was -40 here the other day, any my truck started, though she didn't really appreciate it...