Fuel Temperature

Turbo Tim · **Posted:** Sun Jul 27, 2008 9:09 pm

My Dodge Cummings doesn't have any stinkin' glow plugs!!!!!!!!!!
It does have a cermic air heater in the intake manifold though...

warp2diesel · **Posted:** Sun Jul 27, 2008 9:12 pm

tjkj2002 : Slap a turbo on your 3.7L gasser and you have a stronger argument that it is a Jet Engine with a Torque conversion device that drives the wheels.
Your two cycle (toy race car or what ever) that uses a glow plug to get it hot enough to run with out spark and run at full speed is not a Diesel by any definition.
Have fun racing or what ever you do with your two cycle.

warp2diesel · **Posted:** Sun Jul 27, 2008 9:17 pm

GMCTD: Did you get some dyno specs to come to the conclusion on the fuel temp of 120f? If so a thermostatic controlled valve would be the way to control the temp. Greater than 120f send it to a cooler out in front of the radiator, under 120f send it back to the tank. Also a switch to shut off the fuel heater would be a good idea.

flash7210 · **Posted:** Sun Jul 27, 2008 9:56 pm

tjkj2002:
You are correct about those "real" diesels starting just fine without glow
plugs.
However, they do have devices that assist in cold starting. Example:
Detroit 6V-53T (M113A3) and 8V-62T (HMMET)- Both have air box heaters.
Interestingly enough, the heater use a spark plug. Basically a nozzle
sprays fuel and the spark plug ingnites it, thus heating incoming air. If you
ever find either of these engine with a crankcase full of fuel this is the first
place to look.

Old Big Cam Cummins (old 5-ton) and 902 (M9 ACE) and 902T (M2/M3
Bradley)- use Ether bottles for cold starting. Maybe not all models but most
of the ones I've worked on.

GM 6.2/6.5 (HMMWV all models)- glow plugs, duh. I still say its waaay too
similar too an Olds 400 to be a coincidence.

Ok I cant remember who made the engine but the old Deuce-and-a-half
used a multifuel compression ingnition engine. Supposedly you could run it
on MOGAS but I've never seen it. It had a distributor type
injection and in the center of the pump had a screw for "dialing in" the
type of fuel used.

Continental V-12 (M-88 and all 60 class chassis)- Ok, so this one DID NOT
HAVE ANY COLD START ASSISTANCE. At least not that I ever noticed and
if it did it was passive, requiring no operator activation.
(so in other words it didn't have it)
But this was a unique engine (at least to me). I mean, no where else have
I seen a +600 horse, all aluminum, air-cooled, V-12, twin turbo diesel.

So this is the mojority of my diesel engine experience. Just to point out
that many, many different diesels HAVE SOME SORT of cold start assistance.
Whether or not it is needed is debatable but they are there in one form or
another.

dkenny · **Posted:** Sun Jul 27, 2008 9:59 pm

techincally true the cummins don't have glow plugs but the intake heater serve the same purpose.
my DD doesn't these either!! NO HEATERS

other thoughts

if you going to run boidiesel keep the fuel cool..the cooler the better. heat and air increase the oxidation of the fuel.

-dkenny

tjkj2002 · **Posted:** Sun Jul 27, 2008 10:18 pm

flash7210 wrote:

tjkj2002:
You are correct about those "real" diesels starting just fine without glow
plugs.
However, they do have devices that assist in cold starting. Example:
Detroit 6V-53T (M113A3) and 8V-62T (HMMET)- Both have air box heaters.
Interestingly enough, the heater use a spark plug. Basically a nozzle
sprays fuel and the spark plug ingnites it, thus heating incoming air. If you
ever find either of these engine with a crankcase full of fuel this is the first
place to look.

Old Big Cam Cummins (old 5-ton) and 902 (M9 ACE) and 902T (M2/M3
Bradley)- use Ether bottles for cold starting. Maybe not all models but most
of the ones I've worked on.

GM 6.2/6.5 (HMMWV all models)- glow plugs, duh. I still say its waaay too
similar too an Olds 400 to be a coincidence.

Ok I cant remember who made the engine but the old Deuce-and-a-half
used a multifuel compression ingnition engine. Supposedly you could run it
on MOGAS but I've never seen it. It had a distributor type
injection and in the center of the pump had a screw for "dialing in" the
type of fuel used.

Continental V-12 (M-88 and all 60 class chassis)- Ok, so this one DID NOT
HAVE ANY COLD START ASSISTANCE. At least not that I ever noticed and
if it did it was passive, requiring no operator activation.
(so in other words it didn't have it)
But this was a unique engine (at least to me). I mean, no where else have
I seen a +600 horse, all aluminum, air-cooled, V-12, twin turbo diesel.

So this is the mojority of my diesel engine experience. Just to point out
that many, many different diesels HAVE SOME SORT of cold start assistance.
Whether or not it is needed is debatable but they are there in one form or
another.

Yay most of those tactical trucks do have cold start kits but how many do you actually see with the ether bottle or known how to use it?That was the first thing we did as mechanics was to take any ether bottle off so the idiot drivers wouldn't turn there trucks into bottle babies.When I was in the Marines all the big trucks had a ether cold start systems that we disabled,along with the deep water fording kits(except for HMMWV's).The LVS(MK48) had the Detriot 8V92TA like the Hemitt but also had a ether cold start which was also disabled,2 strokes and ether don't mix very well,it would always blow the head gaskets.The newer LMTV's and FMTV's use a automatic ether cold start sytem which is computer controlled,it will inject ether at will since the military's switch to JP8 fuel.The older M800 series manual 5-tons(cummins 240's) used one single glow plug in the intake with a nozzle pointed at it that sparyed ether,great way to blow apart the aluminum intakes,we had to disable all of those since those intakes aren't cheap.All of those vehicles started just fine below freezing with no starting aids,sure a few cranks but not really longer then when it was warm out.Now the HMMWV uses glowplugs,there just lucky to start,period.

Uffe · **Posted:** Mon Jul 28, 2008 3:01 am

What the hell is this?

Why do you listen to a guy who's clearly bought the wrong type of KJ?

Luc.Blais · **Posted:** Mon Jul 28, 2008 6:53 am

I won't argue with the physics on temperature on diesel fuel. But, I live in ultra cold climate and I can tell you that the cooler it gets the better the CRD performs. (if it starts of course) not sure if it's the cool air or the cold diesel but it sure works great when it's cold. I'm talking -35C or -31F...

Joe Romas · **Posted:** Mon Jul 28, 2008 8:17 am

Uffe wrote:

What the hell is this?

Why do you listen to a guy who's clearly bought the wrong type of KJ?

EXACTLY

And as my departed dad would have said He's throwing S@#T into the game

talking about all his old diesel technoligy that has very little to do with modern light duty diesel applications. Big diesels are rarely shut down so rapid starting in cold weather is a non issue. For easy starting and low emmissions some type of "pre heat" is needed be it glow plugs or air box heaters and arguing about air box vs glow plugs is also a non issue

TDI's even have "after glo" that leaves the glow plugs on after starting for a short time :idea:

Speaking of VW diesels when they designed the basic engine design they are still using back in the very early 70's (block, crank and so forth) they designed it so it was able to support both gas and diesel applications. It was/is not a converted 1955 chevy V8 as GM used :shock:

I've got one of those yellow Chineese single cylinder diesel generators without any preheat and boy does it smoke on start up in warm weather. I can't wait to see how it works when it's cold outside :cry:

I picked it up not running cheap as a toy :oops:

His responses have shades of "REFLEX" all over them :evil:

flash7210 · **Posted:** Mon Jul 28, 2008 8:53 am

tjkj2002 wrote:

flash7210 wrote:

tjkj2002:
You are correct about those "real" diesels starting just fine without glow
plugs.
However, they do have devices that assist in cold starting. Example:
Detroit 6V-53T (M113A3) and 8V-62T (HMMET)- Both have air box heaters.
Interestingly enough, the heater use a spark plug. Basically a nozzle
sprays fuel and the spark plug ingnites it, thus heating incoming air. If you
ever find either of these engine with a crankcase full of fuel this is the first
place to look.

Old Big Cam Cummins (old 5-ton) and 902 (M9 ACE) and 902T (M2/M3
Bradley)- use Ether bottles for cold starting. Maybe not all models but most
of the ones I've worked on.

GM 6.2/6.5 (HMMWV all models)- glow plugs, duh. I still say its waaay too
similar too an Olds 400 to be a coincidence.

Ok I cant remember who made the engine but the old Deuce-and-a-half
used a multifuel compression ingnition engine. Supposedly you could run it
on MOGAS but I've never seen it. It had a distributor type
injection and in the center of the pump had a screw for "dialing in" the
type of fuel used.

Continental V-12 (M-88 and all 60 class chassis)- Ok, so this one DID NOT
HAVE ANY COLD START ASSISTANCE. At least not that I ever noticed and
if it did it was passive, requiring no operator activation.
(so in other words it didn't have it)
But this was a unique engine (at least to me). I mean, no where else have
I seen a +600 horse, all aluminum, air-cooled, V-12, twin turbo diesel.

So this is the mojority of my diesel engine experience. Just to point out
that many, many different diesels HAVE SOME SORT of cold start assistance.
Whether or not it is needed is debatable but they are there in one form or
another.

Yay most of those tactical trucks do have cold start kits but how many do you actually see with the ether bottle or known how to use it?That was the first thing we did as mechanics was to take any ether bottle off so the idiot drivers wouldn't turn there trucks into bottle babies.When I was in the Marines all the big trucks had a ether cold start systems that we disabled,along with the deep water fording kits(except for HMMWV's).The LVS(MK48) had the Detriot 8V92TA like the Hemitt but also had a ether cold start which was also disabled,2 strokes and ether don't mix very well,it would always blow the head gaskets.The newer LMTV's and FMTV's use a automatic ether cold start sytem which is computer controlled,it will inject ether at will since the military's switch to JP8 fuel.The older M800 series manual 5-tons(cummins 240's) used one single glow plug in the intake with a nozzle pointed at it that sparyed ether,great way to blow apart the aluminum intakes,we had to disable all of those since those intakes aren't cheap.All of those vehicles started just fine below freezing with no starting aids,sure a few cranks but not really longer then when it was warm out.Now the HMMWV uses glowplugs,there just lucky to start,period.

Well damm 63B! Whats all the arguing over? You know whats goin' on.
You know how it works. You know that no diesel engine really needs any
kind of cold starting aid.

(This was all just a big d__k contest. Guys, pull up your pants, contest is
over.)
(I think GMCTD is being modest :wink:

)

The truth is, in the civillian world, manufacturers have to be able to sell a
product that has mass appeal and makes buyers comfortable. This is why
the Jeep CRD, Ford PowerStroke, GMC DuraMAX, Dodge Cummins, VW TDI,
and so on, have glow plugs. Glow Plugs make it so the engine will start up
reliably in any environment. Thats it, end of story! Everyday people, driving
everyday vehicles want to be able to hop in, turn the key and go. Glow Plugs
are simple and cheap and are easy for people to understand.
I'm not saying that the ol' 2-stroke Detroit is difficult, but most people are
afraid of it and think "thats only for big rig trucker types."

gmctd · **Posted:** Mon Jul 28, 2008 9:36 am

Ahhhh - chaos, confusion,and contentious conflict - my work here is done..........................

curtis · **Posted:** Mon Jul 28, 2008 12:09 pm

gmctd wrote:

Ahhhh - chaos, confusion,and contentious conflict - my work here is done..........................

Well said.... :lol:

05infernoCRDL · **Posted:** Mon Jul 28, 2008 1:07 pm

Joe Romas wrote:

EXACTLY

And as my departed dad would have said He's throwing S@#T into the game

talking about all his old diesel technoligy that has very little to do with modern light duty diesel applications. Big diesels are rarely shut down so rapid starting in cold weather is a non issue. For easy starting and low emmissions some type of "pre heat" is needed be it glow plugs or air box heaters and arguing about air box vs glow plugs is also a non issue

TDI's even have "after glo" that leaves the glow plugs on after starting for a short time :idea:

Speaking of VW diesels when they designed the basic engine design they are still using back in the very early 70's (block, crank and so forth) they designed it so it was able to support both gas and diesel applications. It was/is not a converted 1955 chevy V8 as GM used :shock:

I've got one of those yellow Chineese single cylinder diesel generators without any preheat and boy does it smoke on start up in warm weather. I can't wait to see how it works when it's cold outside :cry:

I picked it up not running cheap as a toy :oops:

His responses have shades of "REFLEX" all over them :evil:

Our CRD's have an after glow function too... Just to add a bit more to the convo.

ATXKJ · **Posted:** Mon Jul 28, 2008 9:24 pm

I wonder if 3camp ever got his answer?

guy's 1st post and he gets a couple of pages of discussions about military/commercial Diesels and glow plugs -

he must think we're really weird. (can't say he'd be wrong)

gmctd · **Posted:** Mon Jul 28, 2008 9:35 pm

Not if he read the third post from his .................

BVCRD · **Posted:** Wed Jul 30, 2008 12:22 pm

tjkj2002 wrote:

curtis wrote:

gmctd wrote:

Not even true for Diesel fuel - fuel temp in the pump is best at ~125degF - might wanna do some reading\research\fact finding B4 passing off gasser(patooie!) tech(?) as Diesel compatible - that's the sorta myth\superstition stuff that breaks Diesel engines - even best intake air temp for best economy is ~150degF, so no super-chilled air into the inlet, either - remember, or FYI: gassers (patooie!) are spark-infested engines - Diesels are heat-combustion engines - too cool is just as inefficient as too hot, because the fuel is not trucked in with the intake air charge, and the stoke is not dependent on temperature\density - no icy cool cans for Diesel engines

2X that, Ice cold diesel fuel is as bad as hot diesel fuel.

Stick to gas dude :lol:

Why your CRD is just a over-glorified gas engine,bet you didn't know that,all light/medium duty so called diesels are just a gas hybrid engine.Like I said TRUE diesels do not need glowplugs,they use 100% cylinder heat to combust fuel/air mix,even at startup.You can thank GM.

Oh and "ice" cold diesel is alot colder then 32 degrees,about 15 degrees is the standard gel point in most diesel fuels.

Bet ya didn't know our CRD engines are a true diesel and have roots back to a marine diesel. :roll:

retmil46 · **Posted:** Sun Aug 03, 2008 12:00 pm

Uhhh guys, if you'd done a search, you would have found we discussed this very topic to death (fuel temp, not cold starting aids) over a year ago.

Around 170 to 180 F fuel inlet temp, as sensed by the temp sensor on the filter head, will cause the ECM to put the vehicle into limp mode. This is mainly to protect the CP3 injection pump - hot thin diesel fuel doesn't lubricate the pump very well.

Long before it gets to that point, the ECM will start cutting back on fueling and power once you start getting much above 120 F.

ECM on this beast seems to like seeing fuel temps between 80 and 120 F for the best performance and fuel economy. Too cold, fuel economy drops like a rock. Too hot, same deal with fuel economy and performance wise it becomes a gutless wonder.

If nothing else, in hot weather on a long trip, don't let it drop below a 1/4 tank minimum - the fuel return line is dumping more and more heat into a tank with less and less fuel. If you're on the bottom half of the tank and start noticing a decrease in performance, such as when pulling back onto the interstate from a rest area, pull over at the next convenient fueling station and top off the tank with some "cold" diesel - should be back to it's old self when you get back on the road.

A small power steering fin and tube cooler in the fuel return line mounted behind the grille is more than enough to cool off the fuel and keep the fuel tank at or slightly above ambient even in high 90's temps. When the weather starts cooling off and ambient temps start routinely dipping below 70 F, a couple pieces of cardboard wrapped around the cooler is all that's needed for winter driving.

As far as the fuel being too cold - well, that's why there's an electric fuel heater in the fuel filter assembly for cold weather. After a few miles, the return fuel from the engine will start warming up the tank and eventually reach the point where the heater is no longer needed.

gmctd · **Posted:** Sun Aug 03, 2008 6:04 pm

Nice to see you're still hanging about, retmil46

3camp · **Posted:** Mon Aug 04, 2008 10:04 pm

Thanks retmil46 That is what I was looking for. Did you get from the factory manual?

Turbo Tim · **Posted:** Mon Aug 04, 2008 11:49 pm

Ok, somewhere someone posted that they put a 160 Ohm resistor in series with the fuel temperature sensor (on the fuel filter head) and got good mileage and good power again.
So with that dangerous information in hand I just went out and plugged in my AE laptop program and looked at the injector timing and fueling levels. I noticed that I had 127* fuel temps (because it’s Phoenix and it’s 130* degrees outside off the asphalt!). I stabbed the pedal a few times and noticed how the engine responded and how it was fueling it.
Next I disconnected the fuel temp sensor and it showed -100*F on the display.
The pedal response was incredible!!!!!! This thing was totally different.
I didn’t drive it that way but now I’m thinking. Now before anyone out there starts with the crap about adding a cooling system to the fuel line, DON’T. It’s 130*+ off the road and adding a “Cooler” might just be adding a heater to the fuel here.
So if someone was to sneak in extra resistance to the sensor line to make it read say 50* F or so, what would happen? Any damage to the engine? Better performance? Better fuel economy? Anyone try it? I think I am. I’ll let you know.

Fuel Temperature

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