Big Diesel, MPG increase ideas?

[Piotrsko]

On the 2000 and probably the 2001 trucks, the alternators are kept off until the assorted heaters come up to temp. In my truck that means you are running off the batteries for a full 5 minutes after start, so good batteries are essential in addition to cold start capabilities. You'll know it's time to do something when performance degrades to one crank session unless you like jumping. Really cold means sometimes cycling the key to get the glowplugs and fuel heaters going a couple of times. Btw the block heater needs heavy duty extension cords unless you like house and truck fires.

You'll like FORscan, my version had suggested items to check for code issues

[ps2fixer]

Yea FORscan has been pretty neat. My 2001 truck doesn't run the glow plugs, the ground signal from the PCM doesn't work, I see a lot of mentions of a diode that can burn out. No clue if the fuel heater is functioning or not, but the element appears good.

Finding a quality 100ft extension cord is quite a challenge, my dad bought one years and years ago and recently at harbor freight I found about the same thing but probably made in China, but 12 gauge, 100ft cords are hard to find. My house has quality wire (rewired myself) with a new breaker panel, so the house side of the wiring should be good =). I haven't thought out the best route for hooking up the block heater, thinking heavy extension cord and plug/unplug from within the house, maybe try a timer but their limit is 15 amp and my dad mentioned it's 1500w.

It seems kind of silly to not run the alternator, but I guess the load is more than what the alternator puts out so maybe it would damage it. Sounds like that truck just about requires a block heater for winter, that's a pretty massive drain on "starting" batteries. Long long ago my dad built a truck and he used a heavy equipment battery for the starting battery and it worked really well for him, tons and tons of capacity (nearly 3x the physical size of a normal battery) and it wasn't much more than a standard starting battery. I make harnesses and battery cables for my small business, so toying around with idea's like that shouldn't be too hard to build a custom set of battery cables for.

It seems to me, the factory battery setup is just barely enough to get a truck going in the middle of winter and to recharge the batteries from such a drain would take a while. The engines start pretty quick once warm so should take a ton less power for starting/stopping after the initial start I'd think.

Crazy thing on cold starts, my dad's backhoe with a Perkins in it has no glow plugs and even with a low battery it fires right up in the cold. I'd guess it's higher compression since there's no turbo on it. Google says it should be around 23.5:1, so yea a fair bit higher compression. I'd think an engine starting off with a higher compression ratio would be ideal for the intake valve being delayed open style idea. Too bad it couldn't be enabled/disabled on the fly. Cold starts leave it high compression, once warm drop it to the lower compression ratio (but still full power stroke) and have a turbo on it that can spool up to offset the lower compression and such for power/efficient burn.

I noticed the 2001 truck doesn't have a vacuum pump either, looks like everything that was vacuum on the older trucks is electronic on that truck. The "brake booster" setup looks interesting, looks like an electric motor, but not sure how that works.

[freebeard]

Finding a quality 100ft extension cord is quite a challenge.... 12 gauge, 100ft cords are hard to find.

Compare the cost with Romex underground cable: DDG/?q=romex+underground+cable+cost+per+foot

[ps2fixer]

Originally Posted by freebeard

Compare the cost with Romex underground cable: DDG/?q=romex+underground+cable+cost+per+foot

First result on amazon came up $88 (100ft spool), locally it might be cheaper. I paid around $120 for mine. I just pulled it out, it's 100ft 10 gauge, was thinking 12 gauge for some reason. It's stranded wire instead of solid core wire, so better for plugging/unplugging (lower chance of breaks). Not a bad idea to wire an outlet near the parking area though and cycle via breaker or similar.

[cRiPpLe_rOoStEr]

Originally Posted by Piotrsko

On the 2000 and probably the 2001 trucks, the alternators are kept off until the assorted heaters come up to temp.

Even though at a first glance it might seem logical to decrease the load on the engine while starting, the relatively higher electrical demand not only due to the starter which needs to be beefier in order to overcome the higher compression in a Diesel but also the heating elements required to ensure the cold start ability becomes a matter of concern. No wonder Diesel versions of older trucks had dual batteries while the gasser versions had a single one. I also remember some trucks fitted with an externally-mounted battery under a flatbed, which was an usual mod in my country in order to allow fitting a larger battery which couldn't be placed inside the engine bay.

[ps2fixer]

Originally Posted by cRiPpLe_rOoStEr

Even though at a first glance it might seem logical to decrease the load on the engine while starting, the relatively higher electrical demand not only due to the starter which needs to be beefier in order to overcome the higher compression in a Diesel but also the heating elements required to ensure the cold start ability becomes a matter of concern. No wonder Diesel versions of older trucks had dual batteries while the gasser versions had a single one. I also remember some trucks fitted with an externally-mounted battery under a flatbed, which was an usual mod in my country in order to allow fitting a larger battery which couldn't be placed inside the engine bay.

My dad put in a heavy equipment battery in a gas truck he built, 70's era v8 olsmobile engine, direct drive starter. He loved the massive battery and no concern of running low on charge while starting. Something like the link below is what he had. The physical size was about 3 normal car batteries. I'm half tempted to mount one of those behind the cab under the box just for the insurance of having no problems starting the truck in winter. I'm pretty sure I saw one somewhere for around $170 vs $185 retail for a stock style Interstate. The coldest nights here would be quite a challenge to start, but the block heater should make things a lot easier.

https://www.seamar.com/item/ISB4DXHD/BATTERY-4D-12V/

The older trucks had dual batteries too, but the glow plugs are something like 160-180 amps and takes 30-60secs+ to heat the engine enough to start in cold weather. Ironically, these trucks have an exhaust brake that restricts the exhaust flow to help heat the engine quicker.


I had a chance to scan my good truck yesterday, only one code stored for the TPS. It might be flagging because of the boost leak though (fairly poor throttle response), on the scanner, the readings seemed fine in live data mode.

[Piotrsko]

Fuels heaters get noticeably warm to the touch after one key cycle and no start. The tps get dirty or worn out at one location on the sweep. Easy replacement but not cheap, also not worth rebuilding. There's a cute little vacuum pump system behind the pass battery that is used mostly for running the A/C control system and not much else. It does have a reservoir but unless the system won't switch from defrosting windows to floor heat, believe it to work unless the front axles wont switch from 2wd to 4. There's a seal that goes bad in the hubs that is a joy to replace. Everything else is electric or hydraulic (power steering pump) There's a valve supposedly in the system for rapid warm up which can be used as a jake brake, but I haven't found it, must be on the crowded passenger side. 60 degree fuel and oil means you dont need glowplugs. And until it gets to zero, fuel return usually keeps the fuel from gelling while driving, but doesn't stop water freezing in the pump

[ps2fixer]

Originally Posted by Piotrsko

Fuels heaters get noticeably warm to the touch after one key cycle and no start. The tps get dirty or worn out at one location on the sweep. Easy replacement but not cheap, also not worth rebuilding. There's a cute little vacuum pump system behind the pass battery that is used mostly for running the A/C control system and not much else. It does have a reservoir but unless the system won't switch from defrosting windows to floor heat, believe it to work unless the front axles wont switch from 2wd to 4. There's a seal that goes bad in the hubs that is a joy to replace. Everything else is electric or hydraulic (power steering pump) There's a valve supposedly in the system for rapid warm up which can be used as a jake brake, but I haven't found it, must be on the crowded passenger side. 60 degree fuel and oil means you dont need glowplugs. And until it gets to zero, fuel return usually keeps the fuel from gelling while driving, but doesn't stop water freezing in the pump

Is that in context to the 2001 or 1995? The 95 has a vacuum pump on the driver's side which runs brakes and ac controls. The 2001 truck's 4x4 button sounds to be electric but I didn't physically look for the motor.

For the "exhaust brake" as people have been calling it, it's on the bottom side of the turbo, just on the exhaust side going to the engine. It has a servo style motor that activates it while cold and has a back pressure sensor to open/close the valve within reason. My one truck has a major boost leak, so it closes it off completely and bogs the engine a fair bit. I read putting it on a switch (direct powering it) works well for an exhaust brake/jake brake, but haven't seen any videos of people using it. I don't have big hills here, but a backup way of slowing down is always a plus.

[Piotrsko]

Im only good on 1995 1/2 and later 2000 + 7.3s. (Bump hoods). hmmm AFAIK I don't have that valve, will know better next week when my new up pipes get replaced. Yes they can be powered by switch, but I think it parallels the other one on the manifold.

[cRiPpLe_rOoStEr]

Originally Posted by ps2fixer

I'm half tempted to mount one of those behind the cab under the box just for the insurance of having no problems starting the truck in winter.

I would be totally tempted to do so.

The coldest nights here would be quite a challenge to start, but the block heater should make things a lot easier.

Eventually it would be enough even if you forget to plug the block heater on.