fuel head fix

dgeist · **Posted:** Wed Jun 13, 2007 9:50 am

So, I sent a note to the Racor technical support line and got the following (summarized):
------------------------------------
[me]
I Assume the available fuel heater is an always-on
Positive-Temp-Coefficient type? Yours is 200w at 12v, correct? so I should just need a connector?
[him]
The fuel heater is resistance type, and it has a thermostat set for 45°F on
and 85°F off.
[me]
WIF sensor...The engine computer triggers at 30-40 kilohms. Is this within
the specs of your screw-in sensor detecting the water in fuel condition?
[him]
The fuel sensor (not the 30880) is simply two wires that sit in the diesel
at the bottom of the bowl. If water is present, the electronics must see
the lowered resistance. In your case, you could see if the electronics
will work by simply sticking two wires in water and seeing if the
water-in-fuel light turns on. Some systems require an internal resistor,
and we carry those too.
[me]
Do you have a fuel temp sensor available?
[him]
No. We do not have an aftermarket temp sensor.
------------------------------------------------------
So, not exactly the technical data I was looking for but mostly good nonetheless. Sounds like the heater is pretty generic and those specs are about identical with the factory unit. As for the WIF, I assumed there was some kind of analog logic involved, but if it's as simple as resistance passing between the wires in submersion, then only the size of the wire and their distance apart would make them function any differently. That might require a resistor or two (as the fellow stated).

Anyone have any insight into finding a replacement for the temp sensor? I'm not able to find ANY references to a diesel-specifc sensor, so I'm guessing this is similar to a sealed coolant-temp-sensor that you'd see in a bung on any modern engine.

Dan

LanduytG · **Joined:** Sun Dec 11, 2005 6:59 am **Posts:** 188

dgeist wrote:

So, I sent a note to the Racor technical support line and got the following (summarized):
------------------------------------
[me]
I Assume the available fuel heater is an always-on
Positive-Temp-Coefficient type? Yours is 200w at 12v, correct? so I should just need a connector?
[him]
The fuel heater is resistance type, and it has a thermostat set for 45°F on
and 85°F off.
[me]
WIF sensor...The engine computer triggers at 30-40 kilohms. Is this within
the specs of your screw-in sensor detecting the water in fuel condition?
[him]
The fuel sensor (not the 30880) is simply two wires that sit in the diesel
at the bottom of the bowl. If water is present, the electronics must see
the lowered resistance. In your case, you could see if the electronics
will work by simply sticking two wires in water and seeing if the
water-in-fuel light turns on. Some systems require an internal resistor,
and we carry those too.
[me]
Do you have a fuel temp sensor available?
[him]
No. We do not have an aftermarket temp sensor.
------------------------------------------------------
So, not exactly the technical data I was looking for but mostly good nonetheless. Sounds like the heater is pretty generic and those specs are about identical with the factory unit. As for the WIF, I assumed there was some kind of analog logic involved, but if it's as simple as resistance passing between the wires in submersion, then only the size of the wire and their distance apart would make them function any differently. That might require a resistor or two (as the fellow stated).

Anyone have any insight into finding a replacement for the temp sensor? I'm not able to find ANY references to a diesel-specifc sensor, so I'm guessing this is similar to a sealed coolant-temp-sensor that you'd see in a bung on any modern engine.

Dan

I guess I don't understand way you want a temp prob. The temp sensor in the Racor is built into the bowl. As for testing the water sensor you need to diconnect the sensor of the OE harness. Then stick the wire into a glass of well water or the like. If the light goes on then all you need to do is get the Racor probe and hook it up to the OE harness. If you have to have the OE sensor on the )OE harness to make the light go on then you will need the whole Racor WIF kit.

Now for the heater. Check the voltage on the OE harness with the switch on and see if you have voltage. If so the the temp sensor in the bowl will take care of it. But what I'm willing to bet is you will not have voltage unless its cold out. I bet the ECM is controlling it. Which is still OK its just that the ECM will do the controlling instead of the bowl sensor.

We have used hundreds of Racor filter heads and they all work the same. WIF sucks and is very sensitive.

Greg

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

Quote:

I guess I don't understand way you want a temp prob.

It's not that we want one... it's used by the PCM on the CRD to adjust fuel rate on the high pressure fuel pump to allow for variance in fuel temperature... not having it connected causes a computer fault code and the PCM can no longer adjust fuel pressure to compensate for fuel temperature. This is not a heater temp probe - it's part of the fuel engine managment system.

LanduytG · **Joined:** Sun Dec 11, 2005 6:59 am **Posts:** 188

Ranger1 wrote:

Quote:

I guess I don't understand way you want a temp prob.

It's not that we want one... it's used by the PCM on the CRD to adjust fuel rate on the high pressure fuel pump to allow for variance in fuel temperature... not having it connected causes a computer fault code and the PCM can no longer adjust fuel pressure to compensate for fuel temperature. This is not a heater temp probe - it's part of the fuel engine managment system.

OK Is that what the 2 plugs are on the head. One for the heater and the other for the fuel temp? If thats the cause thats is a piss poor design. All other electronic diesels have them else where.

Greg

Ranger1 · **Joined:** Mon Oct 17, 2005 7:40 pm **Posts:** 1137

Yes. Agreed. If we can find a replacement temperature sensor that works like the OEM, we could locate it inline somewhere as well with a different fuel head. Just need the specs on the temp sensor, which are sadly lacking in my FSM. Could test resistance over a range of temps on a spare fuel head with an ohmmeter I suppose.

dgeist · **Posted:** Wed Jun 13, 2007 10:26 am

LanduytG wrote:

I guess I don't understand way you want a temp prob. The temp sensor in the Racor is built into the bowl. As for testing the water sensor you need to diconnect the sensor of the OE harness. Then stick the wire into a glass of well water or the like. If the light goes on then all you need to do is get the Racor probe and hook it up to the OE harness. If you have to have the OE sensor on the )OE harness to make the light go on then you will need the whole Racor WIF kit.

Now for the heater. Check the voltage on the OE harness with the switch on and see if you have voltage. If so the the temp sensor in the bowl will take care of it. But what I'm willing to bet is you will not have voltage unless its cold out. I bet the ECM is controlling it. Which is still OK its just that the ECM will do the controlling instead of the bowl sensor.

We have used hundreds of Racor filter heads and they all work the same. WIF sucks and is very sensitive.

Greg

Greg, the reason I wanted to replace the temp sensor is from the manual:

An negative temperature coefficient (NTC) resistor..
integrated in the fuel temperature sensor alters it’s
electrical resistance in line with the fuel temperature
(the resistance drops as the temperature rises). The
ECM uses this reading to calculate optimum engine
performance under all driving conditions. If the fuel
is to warm, the rail pressure in the system is lowered.
The controlled quantity of the fuel rail pressure
solenoid is reduced and the fuel temperature is lowered

So, basically, I wanted to make sure that this is as plug-and-play as possible and don't want to short-circuit any safety measures on the engine. I don't know what the behavior of the engine is if the sensor is unplugged, if it throws the CEL, etc. Just trying to avoid that headache.

As for the temp sensor on a racor being in the bowl... their docs look like they have a heater and/of WIF sensor in the bowl. On the factory unit, that's a PTC resistor type that's "always on". It's triggered below 45F and is completely off if above 85F and is powered by the glow plug module and relay. The factory temp sensor is actually the same kind of device, but I think has a MUCH lower resistance and has a curve between -40C and 140C.

Is the WIF really that useless? I got the impression from the CAT conversion thread that only the MOPAR one stunk

- Again, first diesel here... just trying to apply good engineering principles to make it last longer and stay serviceable.

Dan

Joe Romas · **Posted:** Wed Jun 13, 2007 10:33 am

LanduytG wrote:

OK Is that what the 2 plugs are on the head. One for the heater and the other for the fuel temp? If thats the cause thats is a piss poor design. All other electronic diesels have them else where.

Greg

That is the case and it is a PPD :roll:

There's 12 volts at the heater whenever the key is on. The heater is a self regulating thing. As the temperature goes up, so does the resistance of the heater reducing the current and therefore heat. So the temperature probe is just for fuel temperature and does not control the heater

Stan Wright · **Posted:** Wed Jun 13, 2007 11:35 am

LanduytG wrote:

Now for the heater. Check the voltage on the OE harness with the switch on and see if you have voltage. Greg

The fuel heater is a relay-controlled 20 amp circuit, and is always on with the key. It should handle the 200-watt Racor heater.

If I were to install the Racor filter I had planned to leave the temperature sensor connected to the puck and tie it up inside the engine compartment. My theory was the fuel tank and engine compartment would start off at ambient temperature and both would get warmer during use. This is by no means exact but I thought it might be close enough and it would be one less trouble code.

bbertram · **Joined:** Mon Dec 19, 2005 4:17 pm **Posts:** 144

This morning I did a test with my jeep. Every morning since I installed the CAT filter the jeep would stall after about 5-10 seconds of running. I would have to prime the filter and be on my way. This morning I did something different, I didn't just let it idle, I gave it some throttle for about 5-10 seconds, brought it up to 1700 rpm or so. It didn't stall. I will try this again for the next while and then stop doing it and see if it actually works.

Stan Wright · **Posted:** Thu Jun 14, 2007 10:12 am

bbertram wrote:

This morning I did a test with my jeep. Every morning since I installed the CAT filter the jeep would stall after about 5-10 seconds of running. I would have to prime the filter and be on my way. This morning I did something different, I didn't just let it idle, I gave it some throttle for about 5-10 seconds, brought it up to 1700 rpm or so. It didn't stall. I will try this again for the next while and then stop doing it and see if it actually works.

I had a similar experience after I changed the filter. I finally revved the motor for 10-15 seconds and I haven't had a problem since. That was a few weeks ago.

dgeist · **Posted:** Thu Jun 14, 2007 1:46 pm

Joe Romas wrote:

LanduytG wrote:

OK Is that what the 2 plugs are on the head. One for the heater and the other for the fuel temp? If thats the cause thats is a piss poor design. All other electronic diesels have them else where.

Greg

That is the case and it is a PPD :roll:

There's 12 volts at the heater whenever the key is on. The heater is a self regulating thing. As the temperature goes up, so does the resistance of the heater reducing the current and therefore heat. So the temperature probe is just for fuel temperature and does not control the heater

Also of note. The aftermarket heater that is available with the Racor is thermostatically controlled, not a PTC resistor.

Goglio704 · **Posted:** Mon Jun 18, 2007 6:42 pm

I tried to remove the temperature sensor from my failed fuel heater and discovered you can't. I had tried previously to remove it by unsnapping the catches and pulling straight out. This didn't work so I decided to cut the plastic latches. Once they were cut I could rotate the plug - bad idea. The conductors twisted off and I learned that the actual temp probe is glued in there. It looks like it is potted in epoxy.

I also discovered the word ELTH molded into the plug. If you Google ELTH and diesel you will eventually find a few pictures of heaters like ours, but no specs or sales. They sell only to the automaker's from what their website says.

dgeist,

You are correct that the temp sensor is similar to the heater. It does vary its resistance with temperature, but it is opposite of the heater. The sensor's resistance goes down with temperature increase. The common name for this NTC temperature detector is a thermistor. Thermistors come in a variety of calibrations and ranges. If the specifics of this one can be determined, we can buy one in a pipe thread mounted form for approximately $60. Unfortunately, I have really screwed mine up at this point, but I'll see if I can get an idea of its electrical properties.

danoid · **Posted:** Tue Jun 19, 2007 11:27 am

Joe Romas wrote:

My local import parts place has verified from BOSCH that the OEM filter is a BOSCH oem filter. RFCRD has stated the filter head/heater is a stock off the shelf BOSCH unit. So that may make it easier to find a replacement since most all parts of the fuel system are BOSCH.

What might the Bosch part number for this filter be? I'd like to have a second source for purchasing.

techTim · **Posted:** Sat Jun 23, 2007 4:34 pm

I looked at this unit back when I was first researching the liberty purchase. maybe something, maybe not, but you guys have run with the RACOR idea, maybe this will spark some discussion too.

http://www.ramcoperformance.com/turbofyner.htm

again, I love this board, you guys are great brains and together we are making this CRD what the engineers might have had in mind.

hatchetman · **Posted:** Sat Jun 23, 2007 5:30 pm

Dealer replaced my leaking fuel filter asembly Thurs and it is a noticeable difference. Seems like the slight shutter at acceleration to cruise is gone and acceleration seems quicker. And no they did not flash the ECU. My CRD has not had the F37 done to it. :evil:

Joe Romas · **Posted:** Sun Jun 24, 2007 8:21 am

danoid wrote:

Joe Romas wrote:

My local import parts place has verified from BOSCH that the OEM filter is a BOSCH oem filter. RFCRD has stated the filter head/heater is a stock off the shelf BOSCH unit. So that may make it easier to find a replacement since most all parts of the fuel system are BOSCH.

What might the Bosch part number for this filter be? I'd like to have a second source for purchasing.

He didn't get the BOSCH number. I suspect once the allowable "new part, dealer only" time limit has passed they will be available everywhere. When a automaker releases a new part, even a new size battery, they have exclusive rights to it for a number of years. (Exstortion?) I ran into this when I had my first rabbit diesel back in 78. VW was the only source for batteries and oil filters several years. Fram even released a filter a year early, withdrew then from the market and the following year they were back after sitting on a shelf somewhere getting beat up and dusty :cry:

fuel head fix

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