"water in fuel" sensor operation?

dgeist · **Posted:** Sat Jan 08, 2011 4:28 pm

This question is for anyone who's actually torn apart their fuel heads and messed with things. I have an original head and a CAT adapter that has finally started leaking (out, thankfully since I have a pump) at the heater plug. I'm wanting to replace it with a stanadyne FM100 and I have all the basics assembled (filter, heater, temp sensor, etc). I'd like to have the water-in-fuel sensor work as well and I'm wondering if anyone has looked at the electrical attributes of the stock unit. I'm having unseasonably cold weather and have no good garage space to open 'er up and stick the fluke meter on it, so I'm hoping one of y'all have...

Is the CRD's sensor simply a contact closure sensor that completes the circuit on the line when there's enough conductivity in the can, or is it a powered sensor doing something intelligent (i.e. power, ground, and signal out to the computer)? I want to either physically mate the stock sensor to the FM100's bowl or buy a stanadyne WIF setup and mate it to the factory wiring, but the electrical behavior will be the deciding factor.

Thanks.
Dan

warp2diesel · **Posted:** Sat Jan 08, 2011 5:37 pm

WIF sensor has two probes that short out when they are in water, simple.
Since water is heavier than fuel, the water goes to the bottom, so let Sir Isac Newton rest in peace and put the WIF sensor at the bottom.

ATXKJ · **Posted:** Sat Jan 08, 2011 6:38 pm

when you change a filter you can look at it - 2 wires plastic divider

SPN-87 · **Joined:** Tue Mar 09, 2010 3:09 pm **Posts:** 53

dgeist wrote:

...Is the CRD's sensor simply a contact closure sensor that completes the circuit on the line when there's enough conductivity in the can, or is it a powered sensor doing something intelligent ...

Nothing intelligent

Simply two probes/wires.
My mechanic installed OEM WIF into Stanadyne see thru boil.

dgeist · **Posted:** Sat Jan 08, 2011 7:24 pm

ATXKJ wrote:

when you change a filter you can look at it - 2 wires plastic divider

Yep, but it's been a LONG time since that was plugged into anything (like 3 years). I know it's two-pin but didn't know if it was simple conductance or if the computer was measuring a particular drop in the Ohm on the line.

The physical use of the old sensor in the new bowl is the easiest IF I don't have to hack up either, but I doubt the threads are similar. We'll see when I get a chance to look later this evening.

Dan

warp2diesel · **Posted:** Sat Jan 08, 2011 7:56 pm

I made an adapter on my lathe and screwed it into my Racor bowl.
There are metric to SAE hydraulic adapters that you can buy if you don't want to make the adapter.
Nice thing about the Chrysler WIF sensor is that it fits the harness plug.
Clean it off first with something that won't melt the plastic or screw up your injection system (like the same stuff you clean your MAP sensor with) and you should be good to go.

dgeist · **Posted:** Sat Jan 08, 2011 8:58 pm

warp2diesel wrote:

I made an adapter on my lathe and screwed it into my Racor bowl.
There are metric to SAE hydraulic adapters that you can buy if you don't want to make the adapter.

That would be pretty sweet (being able to buy a simple adapter). Any ideas what such a beast would be called and who might carry it?

Dan

"water in fuel" sensor operation?

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