Engine/Transmission (1998.5 - 2002) High fuel temperature?

[rweis]

Would you have to drop the tank to find the second return tank port?



Would the second port be fairly obvious, or could you post a pic of the tank module, or is it fairly obvious in the SM diagram (if there is a SM diagram).



Will the current fuel return mate with the second port fittings? Will they reach the second port without modification?



Is there much pressure on the return line? I would think not since it is open ended in the tank.



If we are going to cool the fuel, what about using something like a H7B (~ 27k) transmission cooler? LARGE capacity, LOTS of plates, use to HOT temperatures, designed for a more difficult job than cooling fuel, and you could put a fan on it as well for heavy use like heavy towing.



Probably overkill, but if you are going to do it, design extra capacity into the project and not do it twice.



Bob Weis

 

[tractorface]

The extra port on mine was a plastic hose barb with a cap on it. You could reach it from below if you were persistant. You would need to change from the Quick connect fitting on the hard plastic hose to a piece of rubber hose and a hose clamp. This would be the biggest challange to doing it with the bed on the truck. The hose does go down into the fuel just like the one in the bucket so there has to be some pressure. Not sure how much. As for the cooler I think your right on, my choice would be a remote mount cooler with a fan. Like the nascar guys run on the rear axles. Not sure a cooler mounted by the radiator would do any good and could do harm. I'm thinkin we need to get some guys running temp gauges on the supply so we can see if/how bad a problem we have/don't have. I have all the stuff just don't have the time yet. I'll get to it soon though cause I am so curious. I'd post a picture of the module but I did away with mine long ago. Do a search I have seen some nice pics posted on the TDR of just what you are looking for. I wonder why DC installed the extra fitting? Makes me think maybe they were anticipating a problem on either the supply or the return.

 

[WestTN]

Well, my memory wasn't very good. I just checked my service manual and it states that the fuel heater has a temperature sensor. When the temperature is above 75 +/- 8 degrees it shuts the heater off. Below 45 +/- 8 degrees it turns the heat on. At zero degrees the heater consumes 300 watts.



Now I wonder what the heck runs at 168 degrees?

 

[rweis]

I already have a remote H7B for the transmission with a fan. Just duplicate that setup for the fuel. It would seem like if you are going to all the trouble of doing the H7B then you would complete the job with the alternate return line, although dropping the tank to get to the line is no small task. If you are going to have to drop the tank anyway, can you reroute the primary fuel return line inside the tank to the general tank volume area?



Alternative is leaving the tank lines where they are and cool the return line or cool the supply line only. Does not seem like quite as complete a solution though.



Of course we may not have established that it is even a problem quite yet. Getting data on it would be a good approach before we "ready, fire, aim".



I wonder why DC put the return and the pickup in the tank module? Winter conditions?, already filtered?, easier for manufacturing?, ideas?



Some of the TDR members have dropped the tank and been inside the tank module. What does it look like generally?



Bob Weis

 

[ThrottleJockey]

Bob,



Imagine a cannister with a D shaped cross section made of white semi translucent plastic as long as the fuel tank is high. Two pieces that slide in and out of each other like those old fashioned pirate telescopes in the movies.

Upper end is open with a flange on it that rest on the threaded opening on top of the fuel tank, easy to stick your arm down inside to retrieve the fuel gauge float and sender unit tucked inside, about a gallon and a half capacity with the bottom of the unit made of the finest filtering material I have ever seen. (Mine was torn a bit. )



I fixed my fuel level sending unit by re-bending the arm to make better contact with the reostat(sp?) thingy.



There are no baffles inside the stock tank, and the fuel INSIDE the module does not drain easily through the ultrafine mesh filter material. Perhaps this feature keeps fuel readily available around the fuel pick-up line in the event of sloshing. Rerouting a line would be child's play, in or out of the module. You could drop a stand pipe down in there if you wanted or there's even room for the entire lift pump.



To borrow a phrase from Marco, 'Clear as mud?'



Brian