I bought the CRD today!

Desert_Busa · **Posted:** Sun Mar 23, 2008 3:38 pm

05infernoCRDL wrote:

"FUEL TEMPERATURE SENSOR

DESCRIPTION

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 SER-
VICED separate from the housing assembly.

OPERATION

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"

Straight from the FSM (misspellings and all).... one would
imagine if the temp gets too low or too high retmil64, et all, are
correct, the vehicle will probably go into limp mode. I have been
in limp mode, it is no fun.

Thanks for the great input. I need to read that FSM a bit closer. :oops:

240F falls in the range... Too cold diesel has a problem. 284F is a bit much, remember the flash point. What I'm visioning here is a recirculating heater and pump combo. This will make sure that there is no cold oil in the system before running on wvo/svo.

Limp mode sux... I wonder what causes it. It's happened twice in 34k miles. The first time was before the lift pump and right after fueling up at 8k miles. Maybe air in the line, the temp was in the 70's. The second time there was a lift pump and I had been on the road for a while. The temp was in the 90's. Both times I was running ULSD from Love's, and the engine was at temp. This seems like random failures. Maybe it's telling me diesel is too viscus of an oil for the crd. I don't know.

Side comment: We could take these random failures and make a statistical chart to show that randomness is as good as technobabble. :roll:

SW engineer quiz of the day. What is the following?
3, 4, 4, 5, 6, 8, 11, 16, 24...

retmil46 · **Posted:** Sun Mar 23, 2008 4:01 pm

284 F is the upper end of the SENSOR RANGE for the fuel temp sensor. The fuel temp SETPOINT that will cause you to go into limp mode is 170 F.

Only apparent way you could get around this would be to completely bypass the stock fuel filter assembly when running VO.

But then you have another problem - stock fuel filter assembly bypassed, no flow thru it, and a stock fuel heater that is always "on" when the ignition key is in the "on" position. Besides the fact that the fuel temp sensor will still be reporting what it sees for fuel temp to the ECM (ie, reporting ambient temps while you're pumping 200 F VO to the engine), and will throw a CEL if disconnected.

As Chief Engineer Montgomery Scott once said, "the more complicated you make the plumbing, the easier it is to stop up the drain."

Desert_Busa · **Posted:** Sun Mar 23, 2008 4:42 pm

DadsDiesel wrote:

If you can't stomach a $6K repair bill for an IP that dies early... Then experimenting isn't for you.

15K miles/year / 24 mpg X $4/gallon #2 = $2500 Just to put things into perspective.

FWIW - C.

Where did the $6k figure come from? I've heard a new engine is $10k+. The install would be really high, but...

More on the cp3 IP:
http://www.lostjeeps.com/forum/phpBB3/vie ... ht=#249350
performance cp3 Dmax kit $3099
http://www.pacificp.com/index.php?main_ ... cts_id=105

Maybe there's a rebuilding shop somewhere. The above is rebuilt. I saw a post for $650 replacement pump. No link though... Guess the dealer will get a call tomorrow.

The CP3 is used in the Cummins and Dmax why are we having problems thinking about svo? Sounds like a SW issue. This thing should be able to take 200F svo.

Does anybody have proof that we should not do svo or wvo?

I agree if you're not willing to get your hands dirty this and most of 4wheeling is not for you. Things are going to break.... Things can be rebuilt.
On the other hand bikes are really cheap, I have $400 total in my fixie. It does fine in heavy traffic and only occasionally flats.

Desert_Busa · **Posted:** Sun Mar 23, 2008 4:50 pm

retmil46 wrote:

284 F is the upper end of the SENSOR RANGE for the fuel temp sensor. The fuel temp SETPOINT that will cause you to go into limp mode is 170 F.

Where did this come from? 170F will still work... I only suggested higher because we could go up to below the flash point... when the engine is running, the diesel just before hitting the cylinders, will be much higher then 190F.

onthehunt · **Posted:** Sun Mar 23, 2008 10:35 pm

Quote:

I know Golden fuel systems had an issue, but the motor was ran out of oil. The link was a for sale link on youtube. The link is no longer available

If I remember that link whoever owned it didn't run it out of oil, they didn't change the oil soon enough. I don't remember exactly how many miles, but it wasn't a crazy amount. Polymerization of the oil is a real concern with wo hence the 3000 mile oil change recommendation. Uoa would be mandatory I would think.

gmctd · **Posted:** Sun Mar 23, 2008 11:16 pm

Dodge and Dmax don't have an Inlet Fuel Temperature Sensor to limp them out at temps over 160degF - it's a Jeep thing, prolly due to the compact package and small fuel tank - not enuff cooling capacity

retmil46 · **Posted:** Mon Mar 24, 2008 2:38 am

It's not the MECHANICS of making WVO/SVO work on this vehicle that's the problem - it's all the bloody ELECTRONICS AND SENSORS on it that you're going to have to deal with or find a way around. Fuel temp sensor and stock fuel heater are the first and most obvious, but I'd bet not the last, electronic/electrical roadblocks you'd need to work around. If the ECM doesn't like what it sees thru it's inputs, game over.

Desert_Busa · **Posted:** Tue Mar 25, 2008 10:22 pm

retmil46 wrote:

It's not the MECHANICS of making WVO/SVO work on this vehicle that's the problem - it's all the bloody ELECTRONICS AND SENSORS on it that you're going to have to deal with or find a way around. Fuel temp sensor and stock fuel heater are the first and most obvious, but I'd bet not the last, electronic/electrical roadblocks you'd need to work around. If the ECM doesn't like what it sees thru it's inputs, game over.

Young grasshopper, thermistors are the easy ones to get by. It's just a resistor in parallel to reduce or in series to increase resistance. basic circuits

dieseltoyz wrote:

Ironically, I believe the only people who should have WVO systems installed on their vehicles are those who have the ability to install them themselves. How's that for a sales pitch? Wink

Well said... If the thermistor fix is a mystery, this should not be installed on your jeep.

I'm sure there might be some pressure things to figure out, but with the oil in the diesel viscosity region all should work well.

I bought the CRD today!

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