Can someone explain the fuel filter light? HJ47 Land Cruiser (1 Viewer)

[vincent85]

Hey guys,

I am in the middle of a full frame off for me and my veteran buddy who are doing a Alaska/Pan-American trip. When I bought the truck it ran, but had ton of small issues. One being this filter light did not work.

I attached some picture of the light and what I believe to be the filter near the vacuum reservoir. Anybody know how this works and the concept behind it? I think it has to do something regarding water in the fuel line? That way I can figure out to get it to work when I rebuild it.

 

[roscoFJ73]

Thats a water sedimenter. The filters are attached to the engine on a 2H. And yes you are correct ,it should light up when it senses water.
The bolt on the bottom is for releasing the water. Its a good idea to check it periodically.I would even remove it and flush it and check for corrosion being 35 years old. Or you could ditch it and fit something new
Usually a warning light should light up when the ignition is turned to ON.

 

[vincent85]

Hey Rosco!,

I was just sending some info to Michael a little bit ago about the Donaldson air filter setups. Thanks for the info.

This is the only real piece I don't quite understand, but I do get the theory of it all. Can you recommend something new or what people have used? I have not seen allot on this. If you have a link to some literature as well on this setup, that would be awesome.

Where does the filter attached to the 2H at?

 

[vincent85]

This is it here: http://www.toyotapartsoverstock.com...ukey_driveline=0&ukey_trimlevel=0&modelYear=0

Not sure what a aftermarket kit would be

 

[Tapage]

what I use ..

 

[vincent85]

Tapage, how does that work for you? Does that still work in conjunction with your fuel filter light? What model is that filter setup?

 

[watrob]

Filter light should come on for a few seconds when the ignition switch is turned to ON, this is becausse Bulb Check Relay is running which shows you the filter light bulb is working, the light goes out as you go to START. If the light stays on or comes on while the engine is running you need to drain the water from the filter canister.

 

[lostmarbles]

From the way it is wired, if the filter warning light comes on, it may also mean you have a problem with your alternator's charging performance:

Filter light should come on for a few seconds when the ignition switch is turned to ON, this is becausse Bulb Check Relay is running which shows you the filter light bulb is working, the light goes out as you go to START. If the light stays on or comes on while the engine is running you need to drain the water from the filter canister.

I think in the case of this particular warning light it may be the alternator-wiring-link rather than the bulb-check-relay that causes it to come on before the engine starts running Rob/Watrob?

 

[roscoFJ73]

Hey Rosco!,

I was just sending some info to Michael a little bit ago about the Donaldson air filter setups. Thanks for the info.

This is the only real piece I don't quite understand, but I do get the theory of it all. Can you recommend something new or what people have used? I have not seen allot on this. If you have a link to some literature as well on this setup, that would be awesome.

Where does the filter attached to the 2H at?

There is so much available out there its hard to know where to start. You could ditch an under the floor set up because they can be vulnerable.
Having one in the engine bay is easy to check visibly. If your cruiser has died in a mud pool ,you dont want to have to climb underneath to check for water in the fuel.
You could use the Denso filter and pre filter from a 1HZ/1 HDT engine (7* 8* 10* series and Prado), in fact , I think they only stopped using them in 06 when the V8 diesel arrived.They Denso type dont have a large reservoir for the water , but you might be able to plug in the water sensor from the 47 series.
The sensor sits at the bottom of the main filter bowl.
The prefilter is cheap and makes the toyota main filter last longer.

But there is a plethora of options out there , some have pre heating for fuels , some have built in primer pumps.They come with built in water sensors or sensors seperate to the main filter , or no sensors

You could also go to a truck/tractor/earthmoving wrecker and get something good off a similar sized engine.
You need something with a flow rate no less than approx 60 litres and hour. Even though the engine only uses a max of 20 litres an hour, it recycles the fuel back to the filter.
Look for names like CAV/Delphi(like tapage is using) Stanadyne , and a 100 others. Anything from Japan, USA or Europe will be good.

The best bit about the one Tapage is using is that is it is universally replaceable in any country in the world and the delphi 296 filters are cheap.
I had one with a primer and it worked well. That glass bowl is quite tough but easy to inspect. I had mine on the inside fender in front of the brake boost (RHD).

The filter on a 2H is usually attached to a bracket on the engine/fuel pump area , it will have fuel lines coming and going.You cant miss it

 

[roscoFJ73]

LostMarbles

the way it is wired, if the filter warning light comes on, it may also mean you have a problem with your alternator's charging performance

I have often wondered if they have wired it like that to remind you the warning system is not operative.

 

[Henry James the 47th]

Three things will activate that light:

-water in the sedimenter causes its float switch to ground the circuit
-the bulb check relay activates it at the first key position via the bulb check relay
-a fault in the alternator charging circuit

First you'd want to determine if the bulb in the warning light is burnt out or not. If it is not burnt out and the light does not come on at the first key position, then the bulb check relay is suspect. Then check the function of the float switch in the sedimenter. It's a simple on/off switch which grounds the circuit when the float rises. You should be able to get the dash light to come on by moving the float manually.

If the light stays on after the engine has started, and you know the sedimenter to be clean, then it is the alternator that will need inspection.

 

[lostmarbles]

Filter light should come on for a few seconds when the ignition switch is turned to ON, this is becausse Bulb Check Relay is running which shows you the filter light bulb is working, the light goes out as you go to START. If the light stays on or comes on while the engine is running you need to drain the water from the filter canister.

.....
-the bulb check relay activates it at the first key position via the bulb check relay......

Are you guys both sure it is your "bulb check relays" (and not your alternator regulators) that turns on your filter lights when you're getting ready to start your vehicles?

This is a 1983 wiring diagram and I can't see the bulb check relay connected to the filter light:

 

[Henry James the 47th]

A 1981 schematic for your consideration. I think they changed the wiring around when Superglow came on the scene in October of 1982.

Looking at the drawing, the bulb check relay does not seem to connect to the sedimenter light. The sedimenter circuit has a wire running through a diode and over to the regulator, terminal 'L'

 

[Henry James the 47th]

Here's a larger view showing the sedimenter circuit relative to the regulator. Follow the dotted line...

 

[Henry James the 47th]

I had assumed that the bulb check relay was activating both the brake and 'filter' lights at the 'ST' position on the ignition switch, however I appear to have drawn an erroneous conclusion...

 

[lostmarbles]

I had assumed that the bulb check relay was activating both the brake and 'filter' lights at the 'ST' position on the ignition switch, however I appear to have drawn an erroneous conclusion...

Hi Chris.

Yeah. I'm thinking that the same thing that triggers the filter light to tell you when your alternator isn't charging also triggers it to illuminate when you're getting ready to start - because at that time your key has again moved forward, and, as with an alternator failure, there's again no charging current.

On my 1979 BJ40, my bulb check relay only tests my brake warning lamp (that'll tell me if I have low fluid levels) and even then, it only tests it when my key is in the start/crank position.

 

[vincent85]

Wow this was a huge help! The model he has btw Rosco is a Delphi 296. So I really like the idea of putting mine next to my brake boost so I can visibly see it like you had in yours.

 

[roscoFJ73]

Wow this was a huge help! The model he has btw Rosco is a Delphi 296. So I really like the idea of putting mine next to my brake boost so I can visibly see it like you had in yours.

Glad to help. If you get one with a primer pump it can replace the whole set up. Im not sure if you can get the Delphi 296 type filter housing with a sensor though.
They are also sold as CAV296 and Lucas296. I think its all one company now.


I had one like the one on the right ,the round thing on top is the primer. The bowl on the left is an extra water trap.

 

[roscoFJ73]

This is the 70 series flitration used from 90 to 06 .The one on the right is the main filter and the black wire going underneath is the water sensor.The one on the left is the pre filter.
The fuel comes into the engine bay,into the prefilter on the left,then to the main filter and then across to the RH side of the engine bay to the fuel injection.
Its also used on Hiluxes ,Prados ,Dynas and Coaster buses. Mitusbishi and Isuzu use something

 

[roscoFJ73]

This one is off a Mitusbishi Monterey turbo diesel,looks very similar to the toyota 70series particuarly the sensor bit.
Im sure I saw the same unit on a Mitsubishi Canter as well.
Whatever you choose, the price and availability of filters is important.
Nice little promo about a water trap with alarm
http://www.goldcoastdieselspecialist.com.au/