Big Diesel, MPG increase ideas?

[ps2fixer]

Yea the shifts are pretty fast. I normally drive gas engines with roughly 1/2 to 3/4 throttle except initial take off and I'm a "slow" driver compared to most other vehicles on the road. I shifted my T100 at around 2500-3000rpm. Peak torque I think is like 3600rpm

With my diesel, I'm probably taking off about as fast as a "normal" driver. It's by no means fast, but I take off harder in it vs my 4.0L v8 Lexus, but it likes to down shift at the wrong time and such so I don't get to really drive it the way I'd like.

The vroom-clutch-vroom-clutch reminds me of a semi driver with a manual =). I've been driving my truck similar, light throttle for take off (2nd gear generally) and rev out to ~2k rpm and shift into 3rd. Beyond that I give it quite a bit of throttle and was targeting 2k rpm, but I'll try 1500ish. Probably slow me down a bit, but I'm generally not in a rush anyway.

On the idling to cool down I figured that was from larger vehicles. I guess the idea is to make sure the turbo cools so the oil doesn't overheat in it. I was thinking it might be turbo related.

My fancy cardboard radiator block probably has around 1.5sqft opening. When I make something better, I plan to put it on the front facing side of the grill and probably block it off completely for winter. There should easily be enough air for the fan to catch if it starts to get too warm, the front end isn't exactly sealed on these trucks lol.

My sister (12 years younger than me) hasn't gotten her license yet but has the permit (2nd year now, she's been slow at getting the test over with). Anyway, she's never touched a manual vehicle before, my dad and I and her boyfriend have been telling her she needs to atleast get the experience once just so she knows how to drive one. Never know when a situation comes up where she has to drive a stick. The truck is stupid easy to drive, stalling is just about impossible. The owner's manual did suggest taking off in 3rd! gear for icy conditions and I stalled the engine. Could just be because of the turbo boost leak, but I think I'll continue with the 2nd gear route except when loaded. I'd think using 1st gear would save some clutch life, but I suspect it would get worse mpg since it's basically start moving and shift instantly. With new fluids and the trans shifting a little easier, it probably wouldn't be a big deal. My T100 is a bit like that, 1st gear into the intersection and 2nd gear half way through it.

If I can actually hit 30mpg with this truck, I think I'll effectively have the record for the best mpg for these trucks or atleast a close 2nd. If I remember right, used motor oil and trans fluid contains more energy so they generally give better mpg too. Fix some areo, drive right and might be able to hit pretty high 20's. Guessing pretty extreme measures would have to be done to get near 30mpg though. That'd put me at like +100% over the mpg rating on these trucks. I kind of wonder what kind of mpg I'd get just from a tune switch, steady speed 60mph with the topper on. Maybe that front bumper gives better mpg than I'm thinking, it does go down a long ways, so it's acting a bit like an air dam.

Also not sure what IDH is, google said interior door handle. My truck is pretty simple, it has a mechanical fuel pump so it should be in a pretty ready state to start while rolling. I haven't tried it yet, not really planning to P&G with it even though it sounds like diesels do quite well with that style of driving.

With my truck while in higher gears, like 1/2 throttle vs full throttle I don't really feel any difference in the take off speed. I do see the HPOP pressures go up in relation to the throttle, I'd assume it's dumping more fuel but maybe it's just requesting higher pressure to inject and burn more efficiently. I'm not used to drive by wire systems yet, the delay from lifting up on the throttle to shift is a bit annoying, I have to remember to lift off the throttle first, clutch and shift. It's only like a 100ms delay but if I do it too early it dry rev's the engine to like 3000rpm.

[Piotrsko]

The IDH/IDM combination is what calculates and controls how long and when the injectors open, should be under the passenger side wheel arch cover. Reminds me of the 50¢ mod where you place a quarter in the connector for the injector to block connector to keep the connections tight and prevent misfires. Hpop pressure is what forces the fuel into the cylinders, more pressure leads to more fuel being injected given a constant duration firing signal assuming everybody but 8 has enough fuel to fully reload.

[ps2fixer]

I see on the IDH/IDM.


Update on the repairs and such, vibration I'm getting at about 35-45mph is a bent drive shaft. I have a parts truck with a drive shaft that should be good, will just have to put new u-joints in that one.

Also found the truck was undercoated in the past, probably why it's not rusted out. Whoever undercoated it didn't know what they were doing, but something is better than nothing. Like the tail gate, they got the inside of where the linkages are for opening the tail gate, but they missed the lower part where they are known to rust out. There's even an access hole to spray it inside there already.

[teoman]

Look at Cogeneration.

IF you are using the LPG for heating, an internal combustion engine turns most of its energy to heat. So you can get your heating that way with the additional benefit of getting electricity.

[ps2fixer]

Originally Posted by teoman

Look at Cogeneration.

IF you are using the LPG for heating, an internal combustion engine turns most of its energy to heat. So you can get your heating that way with the additional benefit of getting electricity.

Not a bad idea, but I think an engine running 24/7 is much more expensive than buying electricity. My primary heat source is wood, so wood gas could be a thing, there's lots of standing dead ash (hard wood) in my state. I've wanted to build a gasifier just haven't really dedicated much time to side projects like that.

I've done the math on my corolla engine before, assuming at idle it creates enough power at idle and it didn't consume more fuel than the engine with no load (it most likely will), according to the scan gauge it eats about 1 gal per 3 hours which ends up being 8 gals per day. Even at $2/gal that's $16 per day. My power bill is sub $100, I used to have it way down like $30. Anyway, at $100, 30 day month, that's $3.33/day. Our heating season is roughly 6 months here and I probably use around 12 face cord of hard wood which is around 2 face cord per month. $16 for fuel * 30 = $480/mo vs electric + rough cost of the wood I use ($60/face cord going on the high end) is $120 (2 face cord) + $100 (high electric bill), = $220. Less than half the cost of a small (1.8L with low rpm peak torque) 4 cylinder gas engine idling for a month.

It's hard to beat massive corps that can do things at massive scale. If I recall correctly, even if I mimic what they do and turned a turbine but did it at home owner sized output, it still is massively less efficient than larger scale. Besides that, they likely buy their fuel in massive quantity via contracts, so probably get some of the best prices on the market too.

It's pretty interesting it's fairly close, 2:1 ratio about, I didn't conciser the heat off the engine for home heating as a secondary benefit.

[MeteorGray]

This is an interesting thread for me because I bought a '96 F250 diesel new in 1996 and am still using it. I promised one of my grandsons I'd give it to him when I'm too old to drive, but since I'm only 77, that may be a while yet. (Not too old to dream)

I bought the truck strictly to haul a travel trailer, so that's why I only have about 77000 miles on it at this point.

Because this is a fuel economy forum, I'll say that hauling a 27-foot Airstream trailer I average around 16MPG at my towing speed of 60MPH. Hauling a squared-off Jayco trailer of about the same size, I realize about 14MPG towing. The difference involves towing round v square at highway speed.

Not towing, I average around 23MPG at 55 MPH and 21MPG at 70MPH, but as I noted, I rarely drive it without something tugging on its tail. My differential is a 3.55, which has worked out well for me.

Just one more note: I converted the factory warm-up valve on the turbo to an exhaust brake with two electric switches: one on the electrically-actuated solenoid on the valve which sends engine oil to the exhaust valve to open and close it; the other on the torque converter lockup circuit so I can assure the converter is always locked up coming down a grade with the exhaust brake in play.

This truck was a wise choice in 1996 for me. It still is.

Good luck with yours.

[ps2fixer]

Thanks for the reply, interesting to see you get similar numbers as what I'm seeing. My trucks at 190k miles too.

I was planning to use the exhaust brake as an actual brake to slow the vehicle/load down, but my area is very flat so big hills are rare. In the 220 mile trip north of me, I think I hit 3 hills I had to down shift on and down the hills in gear 5th gear no throttle would actually slow me down with the load I had. Anyway, the keyword in the first sentence is "was", the valve is leaking oil so will need to take it apart and replace the seals or buy the delete kit. I did unplug it though, it wanted to come on while driving even after warmed up a fair amount.

It kind of blows me away, my dad paid around $14k for his 96 and it had something like 80k miles on it, so probably around 4-5 years old at the time. Today trucks in my area in similar shape are $9k-15k. It's not the same effective price because of 20 years of inflation, but pretty crazy how that one worked out. Not many vehicles you can drive for 20 years and potentially sell for the same price you paid for it.



I let my cousin drive the truck yesterday. He used to drive a VW TDI with the turbo plugged up (never whistled). He had a pretty funny comment when he got done. "So that's what torque feels like". Kind of funny he loved the turbo sound, of course that's probably like liking the loud exhaust on a gas car too, you'll want to hear it sing more.

Anyway, progress has been slow on the truck, but been slowly racking up some miles on it. So far I'm at around 150 miles for 1/2 of the front tank which should be roughly 9 gals. I had the same effect before when trying to estimate mpg off that and it was pretty far off. I suspect once it hit's "E" it has 1/8 or more of a tank of fuel yet. 300 miles per tank would put me around that 24mpg figure again with a lot more shorter trips on it.


Since winter is starting to hit pretty good here now, I've been reading a bit up on fuel gelling. Sounds like general advice is to carry a spare filter, some diesel to refill the fuel filter bowl, and some anti gel. I'll have to stop at the place I've been getting my fuel and see if they can provide any data sheets on what their diesel is rated for against gelling since I don't fill up too often. I wish I had a garage and in theory in extreme cold I could push some heat out there from my wood stove (it has pipes for heating water).

Another thing I could do is setup an electric fuel pump and bypass the stock manual pump. In that case I wouldn't need anything on hand for a road side filter change to keep the air out of the injection system. Just turn on the pump, wait long enough to purge the air out, and start up.

I've read that some bio diesel mixed diesel can gel as warm as 40f and #1 diesel can be good to -40f. Sounds like the more general numbers are around 20f and below for #2 and -5f for #1.

Worst case, I'll have a backup gas vehicle to get where I need to go, but the car doesn't exactly haul much lol.

Also interesting that I read WMO (waste motor oil) doesn't gel. I've been reading up on how to process WMO for running in a diesel and there's a million people with their own opinions but haven't seen much proof of anything bad, just expired uploaded pics at best. It sounds like with my powerstroke, the most wear will be on the injectors and maybe fuel pump, like more wear than normal, but nothing too crazy. Also there's been mention of more carbon build up in the cylinders and injector tips. Sounds like people have good experience running around 50/50 blend of diesel + WMO, and some people run up to around 85% WMO to 15% gas or diesel. Clearly the WMO has to be filtered well and probably best to test the ph level and neutralize it to prevent acidic related problems. Used transmission oil is probably a better source, but not sure how many transmission rebuild places there are around me. People rarely change their trans fluid in my area. Heck I put 80k miles on my corolla and didn't even think about trans fluid till now. I suspect starting a new thread on the WMO/trans fluid would get the best results, not sure if there's many people here that are well educated in that area though. Worst case I do have a spare engine (more like injectors) encase of any issues. I'm sure it's best to start small and work my way up to fine tune the process.

[cRiPpLe_rOoStEr]

Originally Posted by ps2fixer

My sister (12 years younger than me) hasn't gotten her license yet but has the permit (2nd year now, she's been slow at getting the test over with). Anyway, she's never touched a manual vehicle before, my dad and I and her boyfriend have been telling her she needs to atleast get the experience once just so she knows how to drive one.

I learned to drive on manuals before I got the chance to drive an automatic, and even though I prefer automatics because of my bad knees I'm sure the ability to drive a manual whenever actually needed is still a valuable asset.

Never know when a situation comes up where she has to drive a stick.

Reminds me of the days when a rental car with automatic transmission in my country was uncommon.

The truck is stupid easy to drive, stalling is just about impossible.

I'm sure it might not be nearly as hard to start uphill as some underpowered econoboxes I learned to drive with. The only thing that annoys me when it comes to some American-designed trucks is the foot-activated parking brake.

[ps2fixer]

Originally Posted by cRiPpLe_rOoStEr

I'm sure it might not be nearly as hard to start uphill as some underpowered econoboxes I learned to drive with. The only thing that annoys me when it comes to some American-designed trucks is the foot-activated parking brake.

Up here, 99% or more of the parking brakes don't function for anything domestic made. Every Toyota I've used with the center console style pull lever parking brake worked fine. My 1990 Lexus one even works, but the shoes are bad inside the rotor (4 wheel disc brakes with an inner drum for the rear parking brake).

My sister is around quite a few people that drive manuals, so if something happened to them and she was the only driver, she would either have to drive the vehicle, or wait for help. She can be kind of strange sometimes, like when I changed the trans fluid in my truck, she wanted to watch/help. She got the chance to pull her first drain plug, did about 100x better than me for how much oil got on her hand.

I suspect she's torn a bit between trying to be a "girly girl" like online (movies, advertising, etc) suggests women "should" be like, and a country girl as that's where she lives and the people around her act like.



Small update, went about 145 miles till the front tank hit 1/2. Should be interesting to see what the final tally comes out to so I can better judge the fuel usage with out filling. If the gauge was perfect and "E" was truly empty, that should be 9.5gal or 15.3mpg, but I know that's not how pretty much any vehicle is. I'm guessing "E" might be say 20% of the tank, so half should would be something like 7.6gal or 19.1mpg which is pretty close to what I'd guess I'm getting. Best case 25% for the E line would be about 20.4mpg, or the gauge is so wildly off it's a crap shoot xD. Either case, I guess I'm somewhere between 19 and 21mpg with a lot of short trips, like 8-10 miles country back road style driving.

I did do the idle engine oil temp check and the oil heated up one degree while idling, I only waited a couple mins though since I was empty and it was a fairly easy trip on the truck (very little boost).

Also, found the drain on my fuel bowl is effectively clogged up, even with the engine running it very slowly drips. Fuel heater was unplugged and the element separated from the plate and the bottom of the fuel bowl was quite dirty. For not running with no fuel heater (the heat of the engine should heat the fuel on it's own fairly well). If the fuel is going to gel, then it's too late to heat it afterwards. I read it might be for any water build up to stay water and not ice. Either case, it's something like $80 from rock auto and I read a lot of people not bothering replacing theirs so probably going to cheap out unless there's a solid reason to have it in there. If it's just to heat the fuel up, using the engine coolant heat to heat it up seems more logical than an extra electrical load on the engine.

Oh, I did drive a bit faster for one trip, was running late etc. I could watch the fuel needle drop lol.

[cRiPpLe_rOoStEr]

Originally Posted by ps2fixer

Up here, 99% or more of the parking brakes don't function for anything domestic made. Every Toyota I've used with the center console style pull lever parking brake worked fine.

I drove a Renault Clio II with a pull-lever parking brake and a Nissan XTerra WD22 with the pedal-activated parking brake, both not working. But it seems like the pull-lever type is usually easier to work on.

My 1990 Lexus one even works, but the shoes are bad inside the rotor (4 wheel disc brakes with an inner drum for the rear parking brake).

The good old drum-in-hat layout. People either love it or hate it...

My sister is around quite a few people that drive manuals, so if something happened to them and she was the only driver, she would either have to drive the vehicle, or wait for help.

Much better to know how to drive a manual than eventually becoming stuck in a life-threatening situation.

She can be kind of strange sometimes, like when I changed the trans fluid in my truck, she wanted to watch/help. She got the chance to pull her first drain plug, did about 100x better than me for how much oil got on her hand.

Few girls demonstrate such a will to learn how stuff works, but anyway, I don't believe it has anything to do with women not being so inclined to enjoy such jobs. People in general seem to be quite lazy and mediocre nowadays.

I suspect she's torn a bit between trying to be a "girly girl" like online (movies, advertising, etc) suggests women "should" be like, and a country girl as that's where she lives and the people around her act like.

I met some country girls who are still closer to what you refer to as "girly" than some urban girls, yet they got the ability to deal with situations their urban counterparts weren't familiar with.