engine temp VS milage - Diesel Truck Forum - TheDieselGarage.com
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post #1 of 18 (permalink) Old 01-13-2007, 02:34 AM Thread Starter
 
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engine temp VS milage

well every now and then I notice I get junk fuel milage for 1 or two tanks then it is good again.. today I put two and two togeather and realized this is when it gets real cold outside.

my theory is that the engine cannot stay warm enough to have the egpv stay open. Does anyone know what peramiters the EGVP uses for its control?

and for people using them, do grill covers work good and what is the max temp you can use them in?

I find the truck warms up way to slow compared to my old f150.

Steve
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post #2 of 18 (permalink) Old 01-13-2007, 04:45 PM
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The EBP valve is closed with throttle below like 20%, and engine speed less than 1400 RPM. Engine coolant needs to be below 140*F as well.

Now, different PCM programming versions have different values for these numbers, so they are a ROUGH GUIDE and nothing more.

So, no matter what, the EBP valve will NOT close while you are driving down the road, it is basically only active at low engine speed + low throttle position + coolant temp., if any one of those increases, it is OPEN.

You WILL lost economy due to denser air, stiff tires and lubes, plus #1 diesel has less energy than #2, so when the percentage of #1 increases (as it must or you gel-up), you lose some power and economy.

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post #3 of 18 (permalink) Old 01-13-2007, 07:19 PM
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i thought it was based on RPM and oil temp?
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post #4 of 18 (permalink) Old 01-13-2007, 10:18 PM Thread Starter
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Quote:
Originally Posted by John_G
The EBP valve is closed with throttle below like 20%, and engine speed less than 1400 RPM. Engine coolant needs to be below 140*F as well.

Now, different PCM programming versions have different values for these numbers, so they are a ROUGH GUIDE and nothing more.

So, no matter what, the EBP valve will NOT close while you are driving down the road, it is basically only active at low engine speed + low throttle position + coolant temp., if any one of those increases, it is OPEN.

You WILL lost economy due to denser air, stiff tires and lubes, plus #1 diesel has less energy than #2, so when the percentage of #1 increases (as it must or you gel-up), you lose some power and economy.
dense air will give you better fuel mileage. our cold weather here isn't enuf to real freeze up anything, we are having a cold snap right now and it is -8c at night and about 0 during the day (32f)

sense most of my driving is city driving back and forth to work, the trip is about 10 miles and I can actually hear when it is closed so i know when it is closed and when it is open as the engine sound changes.

I wonder if all of the parameters you mentioned have to be met before it will open instead of just one. Or at least the coolant temp and throttle position. I could see me being under 140 and less then 20% quite often.

Steve
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post #5 of 18 (permalink) Old 01-13-2007, 10:45 PM
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Nope, dense air increase DRAG more than it increase burn efficiency, but I see where you are comming from.

'93 F-250 HD, 7.3L IDI, 5spd - FARM TRUCK
I Support: Trailer brakes an every axle over the towing vehicle's GVW; CDLs for RVers; Safety inspections for ALL vehicles and 6 axle trucks (97K GVW proposal).

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post #6 of 18 (permalink) Old 01-14-2007, 06:24 AM Thread Starter
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Quote:
Originally Posted by John_G
Nope, dense air increase DRAG more than it increase burn efficiency, but I see where you are comming from.
ok I understand when you are looking at it as wind resistance. but we are talking 30mph speeds and not every tank only every 3rd or 4th, when the temp drops from say 40 degree to 33 degrees so I wouldent thing that would make any difference from air density. I guess realy the only way to know would be for me to buy a winter cover and try it.. but at what seasonal temp should I remove the grill cover?

Steve
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post #7 of 18 (permalink) Old 01-14-2007, 06:53 AM
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Your thermostat may not be working correctly. I am going to put in a 203* thermostat from dieselsite.com in my truck when I get a chance.

The 94 and 95's had a 203* but was changed to 190* on 96 and up along with a water pump change so you cant just buy one for a 95 truck and put it in.

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post #8 of 18 (permalink) Old 01-14-2007, 09:27 PM
 
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I had a 95 and went to napa and got a 215 thermostat and it worked great.It was still in the truck when I traded it in. The temp run about middle of normal and I got better fuel mileage.
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post #9 of 18 (permalink) Old 01-15-2007, 06:44 AM
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hmmm i wonder if it will help me get better? i get about 17.9 now (25-40 degrees) and around 19 in summer, but ever since i bought my truck the dash gage only gets to the n or maybe the O but thats as far as it has ever made it even in the hot summer
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post #10 of 18 (permalink) Old 01-15-2007, 03:01 PM
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winter fuel is going to give u worse mileage. and obviously if u let ur truck sit to warm up anymore then u do in the summer that will have an affect on it to.
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