Big Diesel, MPG increase ideas?

[ps2fixer]

Interesting you guys had axle problems. My family has overloaded stuff for a long time, I'm not aware of anyone having axle issues. Bearing failures, yes, like my dad's tandem axle trailer that was home build (no suspension) had the front wheel bearing fail and the whole wheel came off the trailer, hub and all while loaded at the scrap yard.

I drove an astro van to college for a short time, only paid $100 for it, was only going to scrap it. It was rusted out, only 2 doors worked on it, and the rear end had a major grumble (ring & pinion gears worn out). I did a few burn outs with it but never hauled anything with it. Wasn't half bad, too bad the last owner was a slob and the van stunk and food was pressed in the carpet and such. After fixing some problems it had, no one would give me $400 for a running/driving vehicle, so I scrapped it and got something like $600 out of it.

I sort of had an axle failure on a yard truck, first 4x4 toyota I got and the guy said the wheel bearing was bad. Thought nothing of it and hauled it hom on a car dolly. The second or 3rd time driving it around my yard out back, a log caught the tire just right and the axle slid out something like 2ft. The axle bearing was GONE, the only thing that was keeping the axle in was the bearing races till I hit that log just right to pop it out. Cut brake line and 4 bolts and I swapped another one in and used it till the frame broke. The frame was completely trashed when I got it, it had atleast 50 chainsaw bars welded to it by the last owner.

My dad did break a heavy 3/4 ton front axle before, but that was in a wreck with a large pine tree, it also broke the frame behind the axle.

For fun I've been watching videos about the 7.3L power stroke, and it sounds like it's quite an engine. There's a 5 second truck on the drag strip, and the guy listed off a ton of stuff that's stock on the engine, stock block, heads, crank are the ones I remembered. Even the 2JZ Supra engine isn't *that* strong, the block is good to about 1000hp, stock internals are good to about 600hp, atleast based on people that talk about their built machines. Of course that's not really the focus of this site (max power), but a lot of tactics used can sometimes be applied for better mpg. They used NOS instead of propane, basically the same effect though for a diesel.

[freebeard]

I wasn't kidding about air curtains.

ecomodder.com/forum/showthread.php/external-air-curtains-38924.html

That front airdam/bumper is a prime candidate. JulianEdgar would, I'm sure, be helpful on sizing the duct.

[ps2fixer]

Originally Posted by freebeard

I wasn't kidding about air curtains.

ecomodder.com/forum/showthread.php/external-air-curtains-38924.html

That front airdam/bumper is a prime candidate. JulianEdgar would, I'm sure, be helpful on sizing the duct.

I haven't forgotten about your mention, I've been pretty busy lately. I took a quick peek at the thread/video and first impressions looks like it's a solid idea, but I mainly just looked at the basic design of it, didn't get to watch the video fully.



I picked up another parts truck for cheap again, exact same color and year as my truck, just automatic and rusted out. Runs great, trans works great. $900. I'm the kind of person to buy parts vehicles to have parts on hand if/when something breaks. Extra parts I sell to recoup costs, in theory I could sell the engine for around $1200-2000 and the trans should be worth $500ish. 100% I am not a fan of automatics in diesels, thing wanted to hold 2k rpm+ before it would shift, overdrive wanted 2500rpm to shift unless I let off the throttle to convince it to shift early. Horrible mpg shift pattern, I guess it's designed all out for towing, or it's programmed that way by an aftermarket programmer. Btw the truck came with a pair of good batteries, saving my dad around $300 from buying new ones for his truck, plus we have parts to swap over to test on his truck to get it going again (transmission shift problems). It also has a bunch of new parts on the engine, vacuum pump ($150ish), fuel pump, tentioner, and starter from memory.

I just got the starter in for the 2001 truck, too bad I didn't wait to save the $113.

[freebeard]

Don't be put off by that aluminum extruded airfoil section. A flat plate will get 80+%, the significant factor is the converging duct, with exit maybe 2/3 the area of the entrance. Too much and it would choke off the airflow.

[wjohn]

Originally Posted by ps2fixer

Ironically, a dually was in my list of machines to buy, like you said, a truck for being a truck. If you don't haul anything that actually requires duals, you could run single tires in the back, 2 less tires of wear to expense for, and the lower rolling resistance of 4 tires on the ground instead of 6.

About the only thing I kind of wanted was a truck that was new enough for my OBD2 reader (scan gauge 2). Instant mpg is kind of nice to have, but with out it, it's still possible to learn and improve on tank to tank fills.

It's interesting you got so much worse mpg while hauling a vehicle. With my T100 hauling a Camry or another Toyota pickup (not T100, the smaller ones), I generally got better mpg while in tow than empty. I think it's because of the things you mentioned, basically preserving momentum when possible and planning ahead more. I didn't really try to push the T100 for mpg too much, but no areo mods, driving 45mph home one night from my parents, I hit around 25mpg average. In my tacoma I could hit about 27mpg doing the same thing (also 4x4, manual, but standard cab, same engine). One difference is, I used a car dolly, I suspect you used a car hauler?

So far it seems diesels like high gearing. I'm kind of glad the red truck has 3.55 instead of the 3.73 or 4.10. My dad would prefer the 4.10, but he generally goes all out with loads too.

Does your Dodge have a double overdrive transmission? The Ford 6 speed is creeper gear, 2nd - 4th are normal gears, then 5th for over drive, 6th for a 2nd over drive.

I have thought about pulling the duals off, but for as little as I drive the truck I don't think it's worth the trouble. Although I have not done an A-B comparison to see how much difference it actually makes. I did actually blow one of them out on my trip with the U-haul trailer and it was nice to have no problems with the second tire right next to it. Sometimes I do wonder what kind of MPG I could pull with a regular cab 2WD 2500... But I do not regret getting this truck at all since it seems to have been taken care of and never owned by a 16 year old.

Yeah, I think aerodynamics were the main killer when I was towing that car hauler - same thing when I have a bunch of stuff stacked up in the bed, even if it's only 1500 lbs. or so of equipment. If I hadn't been trying to maintain ~60ish on the interstate with that trailer and the car on top of it, it would've done much better. The trailer itself was almost unnoticeable but once I put the car on you could tell it was there at higher speeds. I bet it wouldn't dip much from normal unloaded figures if I were doing 45-55 MPH. I can't really complain about the fuel economy though.

That's pretty impressive fuel economy with the Toyota and a trailer. I would've been in the market for one, but they're not cheap either if rust free (even around here) and definitely can't handle as much trailer weight as I needed - similar to your reason for upsizing.

I would personally hate having 4.10s in this truck. I don't think I'd want the RPMs any higher at 65 MPH but I'm also not trying to tow a 20K trailer or something. 14K is the most I can legally do and that's adequate for me. The NV5600 6-speed that Dodge used in these has a creeper first gear and then only one overdrive gear, with 5th being 1:1. I like the gearing. Top gear could maybe be a little taller, but not significantly.

I too agree that having an automatic in a diesel is pretty awful. I haven't driven a newer truck with one, so I assume they've significantly improved, but then again you don't get a choice anymore. No more manuals

[Isaac Zachary]

I've driven lots of big diesels with automatic transmissions. With the right transmission they're not bad at all.

The only think I hate about some newer automatics are the push button controls. Living in Colorado it's absolutely necessary to gear down to go down the mountain. And those trucks with those pesky push button controls I'm always hitting the wrong button, neutral, reverse, up instead of down, the radio on/off button, etc. You name the button, and I've pushed it trying to downshift.

[cRiPpLe_rOoStEr]

Originally Posted by wjohn

I too agree that having an automatic in a diesel is pretty awful. I haven't driven a newer truck with one, so I assume they've significantly improved, but then again you don't get a choice anymore. No more manuals

The newest automatic Diesel I drove was a '06 Toyota Hilux with the 1KD-FTV turbodiesel and a 4-speed transmission which my grandpa used to own, and even though I had been more used to manuals I never actually objected to automatics. The first time I drove an automatic was in 2004, a Pontiac Trans Sport with the 4-speed transmission and the 3.8 V6 with port injection. Last time I drove a non-CVT automatic was in a Jeep Renegade in 2015 already fitted with a 6-speed transmission.

Even though I am not unfavorable to automatics, which actually fare better than manuals under specific circumstances, another thing that has recently got my attention is the increasing acceptance of single-clutch automated-manual transmissions for commercial trucks and urban transit buses in my country.

[ps2fixer]

Update on the parts trucks. The 2001 truck that I bought non-running had a fair few issues. The PCM is bad for telling the glow plug relay to activate (it ground through it), over ride is to short the relay out manually, or run a wire into the cab with a button to manually ground the relay. Not a big deal and no replacement parts required to test things out.

The fuel filter was pretty dirty, under the filter where the heating element is was nasty, it plugged up my dad's vacuum suction thing a few times to extract it out. Fuel pump was only pumping air and tank read just over 1/4 tank, so figured maybe the screen was removed or the plastic broke apart so threw in another 3-4 gal of diesel and it started pumping fluid. Filled fuel filter housing half with diesel, half with ATF, cycled the key to work the air out, manually hit the glow plugs, and after a fair amount of cranking it came to life.

Took it for a quick spin in the woods and it seems to shift quite well, smooth and seems to pick a lot better rpm's for the shift points vs the older trucks. Overdrive light is flashing when not moving, but while moving it goes off and shifts fine. The flashing light means there's a transmission code, but most cheap scanners can't read it, so there's *something* still wrong with the transmission circuits.

The two other trucks I have both have new OEM style starters, I bought the "high torque" denso style starter since a ton of videos claim it's better and cranks faster and requires less battery power to go. I've confirmed, it is the fastest cranking starter out of the 3 trucks I have by a fair bit. Once the engine is warm, holy crap does it crank fast. Here's the link if anyone needs a starter for their 7.3L, it fit the 2001 truck just fine, about 1/4in clearance on the cross member that people mention they have to grind down. Trick for installing is keep the nose cone low in the hole, all about the right angles and such.

https://rover.ebay.com/rover/1/711-5...9&toolid=10001
-Affiliated Link: I do make a small amount if someone buys the item through this link, if this isn't allowed, let me know.


Anyway, kind of nice getting 1 good and 2 parts trucks, and both parts trucks could technically be made road legal again even though they are pretty rough body wise. The $900 red parts truck is so rigged up it's crazy someone was actively driving it as a daily driver, the second battery was barely hooked up, the battery cables on that side are trashed, similar to the 2001 truck's battery cables.

I've driven plenty of gas automatics, they aren't bad, but the f250 auto I'm not a fan of. I drove my dad's truck when I was under a driving permit yet, I don't remember how it shifted though, he had a programmer on it though so it changed the shift points from factory.

I agree, personally, 3.73 is the lowest I'd want on a diesel, the 3.55 seems fine but I haven't put a load on my truck yet, being a stick I can control everything so shouldn't be a big deal, run in 4th gear if needed.

Just got around $265 of more parts ordered for the good truck, u joints, ball joins (upper and lower), fuel filters for all the trucks, and the pickup tube for the 2001 truck to fix that issue.

Anyway, just got word my dad's pole barn door blew in from the wind we had lately, so better get over there and help get it back on the track.

[Piotrsko]

Known issue on the fuel tank is either the inlet screen fell off, or got plugged. There's a mod called harpooning where you add a quick install nylon fitting in the bottom of the tank that stops the 1/4 minimum and reduces the #8 cylinder Injecting an air fuel mix AKA called "cackle". Crud in the bottom of the fuel bowl means nobody changed the fuel filter or used very dirty fuel. I've never had THAT issue. Heck, I never had the water in fuel light come on.

[ps2fixer]

The 2001 truck did have water in the fuel, it sat in the bottom of the filter housing. The crud probably came from the element, it's not burnt out but I'm pretty sure a bit came from that. I saw a video showing those pickup screens in the tank, so figured that must be the problem with it sucking air. At least it's not a fuel line leak. $17.50 part from rock auto so I just bought the OEM setup. It's not a bad idea to have a screen on the pickup, if the screen gets plugged, then there's some pretty major fuel system issues and it might have saved the pump. After we cleaned the housing and pumped some fuel into it, no water in it, and once we got it running, no more water in fuel light.

Shifting gears a bit, I have a laptop with an OBD2 to USB adapter and for fun read the 2001 truck, holy crap does it have a ton of PCM based codes set. Nothing too major, lot of bulbs and indicator malfunctions logged. I researched and found the software can handle the older ford trucks too, so hooked it to the 1995 parts truck and it had a few codes set too, map, back pressure, and low fuel pressure (it was leaking fuel so makes sense). It was cold last night so didn't get to scanning my good truck or throwing batteries in my dad's truck. We did pull my dad's truck computer and popped it in the parts truck to test. Transmission shifts fine, so his computer is good. Pretty much narrows down his problem to the solenoid shift pack, like $150 now, used to be $300+ when the truck first messed up.

For anyone interested, the scan software I used was FORscan which is designed to pull specalized ford codes and such (PCM, ABS, etc). It seems to work well, but I haven't poked around too much, mainly wanted to read codes, but it appears it can do live data, logging, etc. I read it can reprogram parts too that normally has to be done at the dealer, but you have to have the paid version ($10 for a year).

https://forscan.org/home.html

Here's the adapter I used, worked on my windows 7 laptop that's starting to age. Thinking about dedicating it as a vehicle scanner. I originally planned to setup a carputer which is why I had the adapter on hand and everything already. Kind of advanced, but I wanted it to log and analyze how I take off at different points of my routes (gps based) and use that data to learn how to drive the car better for mpg. Instant is nice, but calculating the "best" for my vehicle would be a neat programming project. Anyway, I never fully got around to it, but it works pretty well for a scanner, the adapter does NOT like the cold though, was ~20F last night and it was connecting/disconnecting on the laptop. Took it inside and warmed up for an hour, then it worked fine.

Here's an ebay link for the adapter, affiliate link so I can earn a little if a purchase is made.
https://rover.ebay.com/rover/1/711-5...0001&customid=

Seems like we are just about like we are trying to become power stroke specialists or something. Got every truck running and driving except my dad's. We can't drive 4 trucks, so might end up fixing one up well enough to be a daily driver and sell the 2001 or parts truck to make a profit and recoup some money. It seems like a running/driving truck is bare min $2500 and I keep finding ones with issues for around $1000, $1500 isn't bad for headroom for repairing one, if a major part is needed like ecu, buy a whole parts truck.

I'm scheduled to get my good truck legal at SoS (DMV for other states) on Monday, and the parts to fix it should be here Wednesday.

Also, found out Costco has really cheap batteries, might be worth buying the membership ($60) just to buy them. retail the Interstate batteries are like $185 each, they are $99 each at costco for the same thing. We do have a set of batteries, one set are blems with no labels, so no clue of age or brand, other truck has the walmart everstarts, they seem to do ok, but don't have a lot of backup power after the glow plugs go for a bit, so kind of weak for the truck (probably sat a lot at too low of voltage for too long).

Pretty crazy, 6 pages for the thread, and I don't even have the truck legal yet xD. #1 thing to do is fix the truck and make it happy, get a base line to compare against, and improve things from there for mpg.

Anyway, Merry Christmas to everyone, hope you guys are having a good time with family. Sounds like I'll be working on my dad's truck with him lol.