Well gang... I've been playing with theories and ideas for long enough now its time to put them into a design and see if it actually works. We all know the 24V's seem to take a good tumble in MPG's as the winter sets in well ISX proved that with the 12V engines with static timing that MPG's don't change. Well if you look at it the only thing that could be tossing this out the window is the IAT sensor on the 24V is changing the VP44 performance. Most know that colder air produces better HP/TQ because colder air is denser and requires more fuel to keep balanced. Well if you reverse this and warm the air (in theory) the VP44 should retune and burn according to the manifold temp. So what I've done tonight is fished through my resistor pile and found 3 I'm going to use for test candidates. Orange - White - Red - Gold = 3.9K Ohm = 116*F IATRed - Violet - Red - Gold = 2.7K ohm = 132*F IATRed - Black - Red - Gold = 2.0K ohm = 148*F IAT So now tomorrow I'm going to pull 3 test runs on the same piece of highway... Seeing if the highier the IAT temp increases the MPG or not... I'll can give you something to think about... Grid heaters are NOT controlled directly by the IAT... With the 2.7K Ohm resistor in place before even starting the grid heater still where hitting as normal. So there is more to the grid heater that the IAT temps... ... On the cutting edge again...

Regarding circuit in post 294 above I found DPDT automotive relays to be rare and PCB mount. Would use two SPDT relays such as the following: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=Z2247-ND Both coils would be wired in parallel and consume about 120 mA each. Anyone keen enough to build it?

I would but getting frieght into and out of this state seems to be expensive anymore...

I've got my first MPG/High Idle System built! It will be going out to a customer for some testing, I'll let everyone know what I know about the numbers and such.

Ok...

I've made another shopping run to McCall and back with the weather starting to warm up a bit at 45-50*F still have my winter fronts in place I'm now seeing a constant 23.5 MPG in the 70 mile run up to McCall, ID and back home...

But it still seems that warmer ambient air is better for MPG's than cold... I think there is a certain amount of air drag, gear lubes being cold, etc... But the number is still increasing.

--- Update to the previous post...

I've got my first MPG/High Idle System built! It will be going out to a customer for some testing, I'll let everyone know what I know about the numbers and such.

Come on prowelder where is the picture of it?

Ok...

I've made another shopping run to McCall and back with the weather starting to warm up a bit at 45-50*F still have my winter fronts in place I'm now seeing a constant 23.5 MPG in the 70 mile run up to McCall, ID and back home...

But it still seems that warmer ambient air is better for MPG's than cold... I think there is a certain amount of air drag, gear lubes being cold, etc... But the number is still increasing.

--- Update to the previous post...

Come on prowelder where is the picture of it?

Okay, okay:

This is the first one ever!!!!:hyper:

Okay, okay:

This is the first one ever!!!!:hyper:

Thanks really nice work!

Got a question on the high idle. can you activate the high idle with the key on already or do the switches have to be set before the key is turned on?

Got a question on the high idle. can you activate the high idle with the key on already or do the switches have to be set before the key is turned on?

You can hit the switches while the truck is already running. Once the criteria is met (low IAT temp and a coolant temp below the threshold), the high idle will kick in.

Got a question on the high idle. can you activate the high idle with the key on already or do the switches have to be set before the key is turned on?

You can hit the switches while the truck is already running. Once the criteria is met (low IAT temp and a coolant temp below the threshold), the high idle will kick in.

Yep you can flip the switches after the truck is started, which is how I normally do my IAT.

Cool thanks. Working on a side project for the high idle. More of an auto setup. I will share as I make progress.

I have been reading some old posts Treads from Turbo Diesel Register, were several people have stated that that there is a fuel temp sensor and compensator in the VP44 for fuel temp changes. One person had claimed that by cooling the fuel he was able to obtain 2mpg better with a unloaded truck. Just wondering if anyone else had heard of this or can add any light on this. Thought I would bring this up in this thread since the question was asked, what could be causing worse fuel mileage (sensor so on) in cold weather when compared to the non ECM/PCM trucks.

I have been reading some old posts Treads from Turbo Diesel Register, were several people have stated that that there is a fuel temp sensor and compensator in the VP44 for fuel temp changes. One person had claimed that by cooling the fuel he was able to obtain 2mpg better with a unloaded truck.

Just wondering if anyone else had heard of this or can add any light on this. Thought I would bring this up in this thread since the question was asked, what could be causing worse fuel mileage (sensor so on) in cold weather when compared to the non ECM/PCM trucks.

If that was true then all the truck running a AirDog/FASS system without a fuel heater in the dead of winter up north should be seeing this increased fuel mileage with temps as low as -40*F. If you wanted to prove that point just unplug your fuel heater and take a ride. Like today its barely 32-34*F here and snowing again...

But its true there is a fuel temp sensor in the VP44 but the only people that can see it as far as I know is the Edge Juice owners.

--- Update to the previous post...

Report time again...

Hauled the travel trailer to Caldwell, ID and spent the night down there.

From the last time I hauled down Ontario, OR I got ~9 MPG without the fooler and without winter fronts.

Now on this trip still set at 140*F IAT temp half the grill covered with winter fronts I got 12 MPG this trip. This include bucking winds on the last 30 miles of the leg down to Caldwell, ID and then drive in the heavy rain coming back. Weather was floating 35-45*F

I have been running a FASS 95 Without the stock filter and fuel heater for years and can tell you that the cold fuel didn't improve my mileage at all and I live in Alaska. The IAT fooler did improve the mileage. I've been working on a fuel heater design using engine coolant but don't have it worked out all the way. Lately I've been thinking of trying to use the factory filter top that has the heater element in it and machining a dummy bottom to just use the heating element to see if that helps the mileage by heating the fuel. Now if I can find a chunk of aluminum big enough to fit I will turn it in my lathe.Jim

Okay, okay:

This is the first one ever!!!!:hyper:

awesomeness!

If that was true then all the truck running a AirDog/FASS system without a fuel heater in the dead of winter up north should be seeing this increased fuel mileage with temps as low as -40*F. If you wanted to prove that point just unplug your fuel heater and take a ride. Like today its barely 32-34*F here and snowing again...

But its true there is a fuel temp sensor in the VP44 but the only people that can see it as far as I know is the Edge Juice owners.

--- Update to the previous post...

Report time again...

Hauled the travel trailer to Caldwell, ID and spent the night down there.

From the last time I hauled down Ontario, OR I got ~9 MPG without the fooler and without winter fronts.

Now on this trip still set at 140*F IAT temp half the grill covered with winter fronts I got 12 MPG this trip. This include bucking winds on the last 30 miles of the leg down to Caldwell, ID and then drive in the heavy rain coming back. Weather was floating 35-45*F

The main point I was trying to make is if there is a temp sensor and the VP44 calibrates to changing fuel temps., it's another variable that the ECM may take into consideration with its algorithm. Just throwing it out there.

The main point I was trying to make is if there is a temp sensor and the VP44 calibrates to changing fuel temps., it's another variable that the ECM may take into consideration with its algorithm. Just throwing it out there.

Now I don't know but I think that the electronics in the VP44 make the final fuel calibrations based on the fuel temp sensor and the information sent by the ECM from its fueling maps and adjusted by the ECM based on the readings from the APPS sensor, IAT sensor, MAP sensor, and coolant temp sensor. In other words I believe the VP44 electronics uses the fuel temp sensor to make the final adjustments to the injection cycle. I doubt that the VP44 electronics sends the fuel temp to the ECM and waits for the info to come back to do the injection cycle. Now it may well send the fuel temp back to the ECM after the injection cycle is finished. It surely would be interesting to know exactly how it calculates it all and where, whether it's done in the VP electronics or the ECM electronics or both. It would make it easier to figure out how to make adjustments for better mileage.

It would make it easier to figure out how to make adjustments for better mileage.

No joke... If there was information about the ECM and it programming it would make life easy...

The temperature sensor in the electronics of the VP44 is only used to de-power the VP44 if fuel temperature if it gets too hot. I assume this is to protect the VP44 mechanically since lubricity gets worse with rising temperature. Only the ECU (Cummins electronics on drivers side of block that is EPA certified) is allowed to calculate the fuel/timing curves which is based upon the engine sensors such as the IAT. You can gleem the above information from the write-up on the "smart controller" I loaded in download section of this site. The PSG error code for "fuel temperature too high" is "005" which is not a code we see directly.

Well I've got a little glitch in the High Idle/ MPG system... when the MPG switch is flipped it is showing -40 at the IAT... I used a 2.2k resister and that's what I got when I tested it with my meter. The high idle side is working fine, just the MPG switch... Mike I'm going to try to email you my diagram so maybe you can help with some ideas.

Looks like I got my high idle box a few months to early. Can we send in for an upgrade?

Okay, okay:

This is the first one ever!!!!:hyper: