and how does it effect performance and why do we need one?

_________________
Hers 05 kj ehm, egr delete, unplugged fuel heater, exhaust improvements
His 96 12 valve 5/12's, 62/65/14, built pump, Hamilton head and cam, fluidampner, high speed floormats
His 91 12 valve stock

Which one? There are several.

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2005 sport crd-SOLD No regrets

oops sorry'
How does the fuel temperature sensor that is attached to the fuel filter housing next to the fuel heater work?

_________________
Hers 05 kj ehm, egr delete, unplugged fuel heater, exhaust improvements
His 96 12 valve 5/12's, 62/65/14, built pump, Hamilton head and cam, fluidampner, high speed floormats
His 91 12 valve stock

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

... I even included the factory grammatical errors for authenticity...
That what you were wondering?

Dan

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2005 Silver CRD Limited
245/75R16 GoodYear Duratracs
Fumoto drain | ProVent CCV Filter
Stanadyne FM100 filter | Cummins fuel pump
GDE Eco | SEGR | BoulderBars | FrankenLift | Frankenskids

I did!

I wonder how this can happen

_________________
Dave

'06 CRD Limited, Lt. Khaki, MOPAR Slush Mats/Skids, DrawTite Front Hitch, Mag Lite, Yakima Bars, Thule Bike Rack, Fumoto, ORM, 245/70 Revo 2

Wish list: Lift, Boulder Bars, Something Bigger in the Front and Back, More Lights

Exactly, I'd like to know what "to warm" is

Regardless, I'll like to get a functional unit on an ohmmeter and measure resistance at some specific temperatures (and perhaps plot a curve) or find someone's OEM coolant sensor or something.

_________________

2005 Silver CRD Limited
245/75R16 GoodYear Duratracs
Fumoto drain | ProVent CCV Filter
Stanadyne FM100 filter | Cummins fuel pump
GDE Eco | SEGR | BoulderBars | FrankenLift | Frankenskids

so what setting does it default to if it has no signal? Hopefully it is the max pressure setting as that is what we need all the time.
A recent study found that 125f. was the optimum fuel temp. for diesel in otr trucks

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Hers 05 kj ehm, egr delete, unplugged fuel heater, exhaust improvements
His 96 12 valve 5/12's, 62/65/14, built pump, Hamilton head and cam, fluidampner, high speed floormats
His 91 12 valve stock

Hope this isn't like the Detroit Diesel DDEC logic, computer goes wackey and the engine won't run. Was a common problem to get a small air pocket at the sensor while priming a system after changing filters. Would default to injector closed (no fuel delivery) if it can't read a fuel temp. Could crank the engine over all day long, simply wouldn't start.

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2005 Liberty Sport CRD, Lt Khaki, sunroof

Thankful to now be an EX-CRD owner.

It seems to work just fine with it unplugged. I did ehm and orm and unplugged the fuel heater and temp sensor. Took it around the block and ok so far. Will report back later.

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Hers 05 kj ehm, egr delete, unplugged fuel heater, exhaust improvements
His 96 12 valve 5/12's, 62/65/14, built pump, Hamilton head and cam, fluidampner, high speed floormats
His 91 12 valve stock

The fuel temperature sensor is integrated into the fuel filter housing, along side of the fuel heater. The sensor detects the temperature of the fuel and supplies that information to the ECM.

The sensor ranges from - 40°F (- 40C) to 284°F (140°C). If the engine is cold, the actual value sent will read ambient temperature.
The value rises after the engine has been started. The fuel temerature sensor IS NOT SERVICED separate from the housing assembly.

The element inside the heater assembly is made of a Positive Temperature Coefficient (PTC) material, and has power applied to it by the fuel heater relay anytime the ignition key is in the “on” position.

PTC material has a high resistance to current flow when its temperature is high, which means that it will not generate heat when the temperature is above a certain value.

When the temperature is below 7°C (45° F), the resistance of the PTC element is lowered, and allows current to flow through the fuel heater element warming the fuel. When the temperature is above 29°C (85° F), the PTC element's resistance rises, and current flow through the heater element stops.

Voltage to operate the fuel heater is supplied from the glow plug module, through the fuel heater relay, when the ECM senses the ignition (key) switch.

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2005 Black CRD Limited w/105,000 miles
Mann Provent 200, Airbox Mod, ORM Mod
New 545RFE, TC & Redesigned pump @ 25,020 miles
New EGR Flow Control Valve @ 25,020 miles
New Transfer Case input/output seals @ 32,787 miles
SEGR Kit @ 52,000 miles
SunCoast TC and Transgo Shift Kit @ 52,000 miles

Ummm, that's the sensor AND the heater.... right?

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2005 Silver CRD Limited
245/75R16 GoodYear Duratracs
Fumoto drain | ProVent CCV Filter
Stanadyne FM100 filter | Cummins fuel pump
GDE Eco | SEGR | BoulderBars | FrankenLift | Frankenskids

Yes, I was trying to describe the operation of both. First the sensor then the heater. Did I omit something?

_________________
2005 Black CRD Limited w/105,000 miles
Mann Provent 200, Airbox Mod, ORM Mod
New 545RFE, TC & Redesigned pump @ 25,020 miles
New EGR Flow Control Valve @ 25,020 miles
New Transfer Case input/output seals @ 32,787 miles
SEGR Kit @ 52,000 miles
SunCoast TC and Transgo Shift Kit @ 52,000 miles

Consider this concept: What good is a temp sensor if its located in the same physical space as the heater element? Seems like it would distort the temp data being sent to the ECM and give you wacky performance. Would make more sense to have this closer to the pump and/or in the common rail.

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2005 Liberty Sport CRD, Lt Khaki, sunroof

Thankful to now be an EX-CRD owner.

Understood, but that's where DCX unfortunately located them right next to each other in the fuel filter head. Here's a quick diagram. #7 Fuel Temp Sensor, #4 Fuel Heater

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2005 Black CRD Limited w/105,000 miles
Mann Provent 200, Airbox Mod, ORM Mod
New 545RFE, TC & Redesigned pump @ 25,020 miles
New EGR Flow Control Valve @ 25,020 miles
New Transfer Case input/output seals @ 32,787 miles
SEGR Kit @ 52,000 miles
SunCoast TC and Transgo Shift Kit @ 52,000 miles

when temp sensor is unplugged it seems to default to a lower rail pressure setting thereby reducing performance. My wife reports that since I unplugged the sensor and heater and did the orm performance has gone down and it does not have the same get up and go. Since my housing is leaking I am going to replace before plugging back in.
As I now understand it the fuel temp sensor moderates rail pressure depending on temp input to ecm Unplugging defaults to hot fuel which lowers rail pressure so i guess we need to keep it plugged in until we find a way to defeat it.

_________________
Hers 05 kj ehm, egr delete, unplugged fuel heater, exhaust improvements
His 96 12 valve 5/12's, 62/65/14, built pump, Hamilton head and cam, fluidampner, high speed floormats
His 91 12 valve stock

That's why I like the design of the Racor units (heater in bottom of bowl). Not sure if the bungs in the top of the units are on the inflow or outflow side, but regardless, it's got to be better than being right next to the heater in a pocket of AIR

Lou, I was just giving you a hard time for the formatting of the copy-paste

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2005 Silver CRD Limited
245/75R16 GoodYear Duratracs
Fumoto drain | ProVent CCV Filter
Stanadyne FM100 filter | Cummins fuel pump
GDE Eco | SEGR | BoulderBars | FrankenLift | Frankenskids