Engine/Transmission (1994 - 1998) Fuel heater question

[ahansen]

My '95 would not start, I will change the fuel filter but while working on it I found that the fuel heater is not working. I think the fuel temperture sensor is the problem. First, can I use the truck with out the fuel heater ( I live in Wisconsin)? Second, can I purchase just the sensor or do I need to purchase the whole fuel heater unit?



Thanks, I just purched this '95 and still learning about diesels.

 

[illflem]

Welcome. First of all how do you know the heater isn't working?

Most that don't work have burned up wires.

You should be fine without the heater unless it gets way cold, like -30. Make sure you run blended winter fuel and a anti-gel additive for extra insurance.

All parts for the heater are available separately from Cummins for a reasonable price.



Don't think the heater is the cause of your no start, it's most likely a leaking fuel return hose. It doesn't have to leak fuel to suck air, the cause of most hard/no starts. Do a search for return line for much info.

 

[ahansen]

Using the Hayes repair book, I was able to test the relay and the heater. All looked ok expect that I could not get a connection though the heater temp sensor. Also, one of the connections from the relay to the heater was brittle and dark. I did clean the pre filter in the heater. I think I will put it back together, get the part from Cummins and then try to swap out the temp sensor.



Thank you for your help.

 

[Cooker]

If Cummins can't dig up the part numbers for you let me know. I just went through this a few months back.

 

[Missouri Mule]

ahansen,

Fuel heater sensor sends data to pcm. PCM grounds heater relay.



Fuel heater turns on when fuel temp reaches 40 degrees and turns off when it warms it up to 80 degrees.

(You mite be able to take temp of fuel before starting up in morning).



I would double check the wire that looks burnt and make sure it is still making good connection.

 

[RWorth]

I replaced my fuel sensor and harness as well as the heater. The temp sensor was wired in series with the fuel heater. My new system did not work at first. Pulled the temp sensor and wire harness out to check the operation of the sensor. Used a Fluke 87 an ice cube and a wire jumper. Set the ice cube on the sensor and waited until I heard the sensor click put the meter on the wire harness and there was no continuity. Found a broken solder connection on the brand new sensor. I re-soldered and checked the circuit again and everything was working.

 

[Darel]

Just take your heater out!

I had a hard start problem and, while my heater was working, it was sucking air around the wiring pigtail, making me lose prime. Try just removing your preheater and perhaps your hard start will be fixed, too. I've gone without and the truck has been A-OK below zero for several months now.

Darel

 

[dremelts]

The connector on my fuel temp sensor burned to a crisp and the part has been on backorder from Fleetguard since Dec. 9.