Water in fuel light

[Lakey]

A few weeks back the water in fuel warning light came on just near home. I got home and bled the filler as per the instructions in the manual and caught the fuel I drained in a jar. No obvious sign of water so I pulled the sender electrical connector and gave it a bit of a clean (blew it out and pushed it in and out of the connection a few times) and the light disappeared.

Left the drained fuel in the jar for the night and next morning still no sign of water so I figured it was just a dodgey connection and we kept using it.

Week or so later lights on again. Jiggle the connection again and light goes out. Happened a couple more times including it going out again by itself.

So, last week getting the 90K service I asked them to look at it and the report comes back that they found some water in the filter! What are the chances that there would be water in the filter but not in the trap at the bottom? My understanding is it is a trap but am I wrong about that? If it's not then maybe I need to think about an aftermarket water trap.

[old Jack]

Interesting question.

I cannot say for sure but I have a theory.

It could be possible to have water droplets on the outside of the filter screen that are not large enough to drop off the filter medium and settle to the base of the fuel bowl and therefore trigger the sensor and being able to be drained off. Now once fuel is flowing through the system it could be possible for enough of the water droplets that are attached to the filter screen, to be detached from the filter and held in suspension so that the water do the "water in diesel" sensor is triggered.

I will need to do some reading and research to see if this is a plausible theory.

OJ.

[littleriver]

So you changed the fuel filter right ?

...

[SwampFox55]

A few weeks back the water in fuel warning light came on just near home. I got home and bled the filler as per the instructions in the manual and caught the fuel I drained in a jar. No obvious sign of water so I pulled the sender electrical connector and gave it a bit of a clean (blew it out and pushed it in and out of the connection a few times) and the light disappeared. Left the drained fuel in the jar for the night and next morning still no sign of water so I figured it was just a dodgey connection and we kept using it. Week or so later lights on again. Jiggle the connection again and light goes out. Happened a couple more times including it going out again by itself.

Squirt some RP7 on the contacts inside the plug and then vigorously open and close it a few times to clean the contacts. Then respray it again to wash out the residue and mop-up the excess with a cloth. It doesn't have to be dry, just not saturated when you put it back together for the last time. This method fixed an intermittent immobiliser circuit on my Magna Sports that had bi-metal corrosion on the contacts in a plug.

190408

[Lakey]

Thanks OJ.

So you changed the fuel filter right ?

...

Yeah done as part of the service.

Squirt some RP7 on the contacts inside the plug and then vigorously open and close it a few times to clean the contacts. Then respray it again to wash out the residue and mop-up the excess with a cloth. It doesn't have to be dry, just not saturated when you put it back together for the last time. This method fixed an intermittent immobiliser circuit on my Magna Sports that had bi-metal corrosion on the contacts in a plug.

190408

I was going to get some cantact cleaner which I figure would be useful for other potential future electrical issues but I might give the WD40 a go first.

I think it may be in the connection given it's location so close to the battery and this current 'sealed' or low maintenance battery seems to have an awful lot of seepage, outgas residue or whatever it is all around it.

[Kingbrown]

The wires that enter the white bung at the bottom of the filter would be prone to breakage. Might be worth checking continuity of the water switch on the sensor side of the connector.
Sensor is normally closed when there's no water present I believe.

[old Jack]

The wires that enter the white bung at the bottom of the filter would be prone to breakage. Might be worth checking continuity of the water switch on the sensor side of the connector.
Sensor is normally closed when there's no water present I believe.

Circuit diagram shows the water in fuel filter sensor is normally open and this is what I would have expected.


OJ.

[Lakey]

Had the light come on again a couple of times now. Drain the bottom of the filter again and still no sign of water.

Looking at the manual the switch appears to be a float switch so I'd imagine it needs a fair bit of water to make the switch do it's stuff?

So I'm thinking it's electrical rather than fuel related at this point. Again looking at the manual it looks like the whole filter housing needs to come off to change the filter and access the switch, anyone confirm? Presumably I'd need to replace the seal if I pull the filter off?

[Kiwi downunder]

I'm getting the same problem with my fuel filter warning light,
I followed the instructions and bled the trap, cant say I had moisture as made a mess of things,
Diesel everywhere!
Was reset the following day when the wife had taken the PB back to service company only to be told there was no warning light up.
Happened again today, both times on very warm days, unplugged sensor and lamp goes out. (N/O contact then)

Also: I just had the fuel filter changed some 5 weeks ago. The problem has only just started. Could this be an aftermarket filter issue?

Trying to figure out what the problem may be.
Any and all ideas welcome.

2012 PB Challenger LS Auto/ standard

Just found this:
Diesel fuel exposed to high temperatures accelerates the formation of solid particulates, which could end up clogging the fuel filter.
Maybe this is the problem as it is 33degrees in Adelaide the days this happened.

[littleriver]

I'm getting the same problem with my fuel filter warning light,
I followed the instructions and bled the trap, cant say I had moisture as made a mess of things,
Diesel everywhere!
Was reset the following day when the wife had taken the PB back to service company only to be told there was no warning light up.
Happened again today, both times on very warm days, unplugged sensor and lamp goes out. (N/O contact then)

Also: I just had the fuel filter changed some 5 weeks ago. The problem has only just started. Could this be an aftermarket filter issue?

Trying to figure out what the problem may be.
Any and all ideas welcome.

2012 PB Challenger LS Auto/ standard

Which after market filter do you have ?

...

[old Jack]

Just found this:
Diesel fuel exposed to high temperatures accelerates the formation of solid particulates, which could end up clogging the fuel filter.
Maybe this is the problem as it is 33degrees in Adelaide the days this happened.

Interested in where this info came from, can you supply a link so I can check it out.

I really do not think it is a fuel temperature issue.
If the filter was blocked then the engine would struggle to run correctly. The fuel pump sucks fuel through the filter at full pump capacity all the time and unused fuel is then returned to the fuel tank for reuse. Problem is the fuel that is returned is very hot after being greatly pressurised by the fuel pump, this fuel is college when it is returned and mixed with the fuel in the fuel tank. However when fuel tank levels are low and ambient temperatures are high the fuel in the fuel tank can get very hot. There is a fuel temperature sensor which inputs into the engine ECU. If the fuel temperature increases too much then the ECU reduces engine power, this is to protect the fuel injectors. In ambient temperature over 36C you should not run the engine for extended periods at low fuel levels (below 1/8 of a tank, fuel low light ON).

My suspicion is it is a faulty sensor, plug connection or wiring.

OJ.

[Scooby]

If it the same screw on filter as the Pajero I have seen the wiring pull in the bottom of the sensor from not unplugging it before screwing off or just getting it tangled on things. This combined with hot weather might be all it takes.
If the filter hasn’t been on long you should be able to reuse seals.

[Kiwi downunder]

Fuel filter

Sorry for late reply but I cannot tell what the replacement fuel filter type is. (without removing it)

The fuel warning light is now constantly on.
Time to take it back for a inspection/ re work by Auto Masters.
I have already purchased a new sensor and suspect it is either damaged/ broken or does not fit the non oem fuel filter correctly.

What with the other issues I have found i.e. leaking engine coolant and reused hose clips, I suspect the service mechanic to be the real cause. (lack of experience)
Slowly slowly catch a monkey.....

Link to hot diesel/ solid particulates...

https://www.agriculture.com/family/living-the-country-life/john-deere-maintenance-monday-hot-diesel-fuel

[Kiwi downunder]

Faulty sensor/ wire twist

Update:
Replaced the fuel sensor, and all looking good.
Yes, someone didn't unplug the old sensor as you can see the wire twist.

Why is it so hard to find a good tradesman these days, seems like everyone I try for servicing screws up something...

And yes I serviced it myself, thanks to this site and some great youtube videos.

[linds_72_99]

We've just gone through a similar problem with our PC Challenger. Water in filter light started coming on so removed the bung and emptied several times to get the light off. Intermittently light kept going on and off several times a day or over a week. Collected emptied fuel from filter and this looked pretty clean. Replace filter with genuine Mitsubishi with no change. Got the car serviced with Mitsubishi and they just cleaned the filter sensor, light was off and advised to replace sensor if problem persisted. Light straight away back on end of that day, so now replaced filter sensor with genuine part $106 and seems to be fixed now. 3 days with no light and I'll updated if this changes.