Low Power - New to this site

[Kevin Hendress]

Folks - I am new to this site, so if this has already been answered I am sorry. Here is my dillema, I own a 1994 6.5LTurbo 3/4 Ton Pickup, Shortbed, Ext Cab, has about 130,000 miles.

I bought it one year ago from a local dealer. I collect antique tractors and use it to pull a bumper hitch trailer or gooseneck. Prior to owning this truck I had a 3/4 Ton Ford (Gas ~350?) and it pulled great. But a buddy of mine has a 6.2L Chevy and gets great performance...ie 19mpg even when pulling.

So, my problem is that I have a lack of power when pulling, for example I own a 25' PJ Gooseneck Trailer (14k GVW) and with a 1940 JD B tractor (weighs ~4300lbs) I can only run 70 mph at 3k RPM, going downhill I can at times hit 75 mph @ 3200 RPM. I have had the lift pump replaced, the diesel pump relaced, the fuel filter replaced, air filter replaced all within the last 6 months.

Still I can not pull, it will drop 5-10 MPH on a hill, lowest I've hit is around 50 then drops in to "low" and pulls it up the hill.

The accelerator can be at about 25% depressed to get the 70 MPH, after the 25% it really does not matter.

I am trying to figure out if I need to buy something for the truck or does it need a over-haul or what? I just got it back from the dealer as the sensor for the oil pressure to lift pump was bad and they said everything else was meeting spec.

Here is a photo of my load....
http://www.juniorscomputer.com/kevin/tractor/JDB_1940_trailer.jpg

I am also having problems with it wanting to overheat when pulling, runs over 210 deg. Also, the MPG that I get is not all to good, maybe 10 mpg loaded or empty.

When empty I run in Over Drive and when loaded I run in Drive.

This is the first time I have owned a Diesel...so I am new to everything...any help would be greatly apprecaited.

Thanks!
Kevin

[dslpwr]

HEY KEVIN;
FIRST YOU NEED ABOUT $2500.THEN BOOST AND EGT GAUGES, EXHAUST, CHIP AND INTERCOOLER.
I ALWAYS TOW IN OVERDRIVE, AND LET IT DOWN SHIFTS WHEN IT GETS READY.
AS FOR RUNNING HOT MAKE SURE FAN CLUTCH IS WORKING.
215 IS NOT HOT.

[patrick m.]

Kevin, dslpwr is right on. Read some of the posts on this forum, paying attention to everyone's description of their rig and mods at the bottom of their post.
Many include the type of load/trailer/camper they haul.
From this you will be able to determine the mods you can employ on your truck to get better performance, and fuel economy and overall towing satisfaction.
Or, do it the easy way, add everything dslpwr suggests ;)
By the way, welcome aboard.

[Kevin Hendress]

Thanks for the information! Could you explain a few things to me though :D

What is a Boost & EGT Gages, what do they do? The exhaust your refering to would be a different exhaust system right? Any idea about where to purchase the parts? Some information in regards to what each part will do to help would also be grealty appreciated.

Dslpwr - do you have any trouble with the trans running in OD? I did that before in a few trucks and both had trans problems right after (or during) the pull.

Thanks!

[rjschoolcraft]

I tow 8000 lbs + in OD all the time with my 4L80E Suburban. No sweat.

EGT gage measures exhaust gas temperature...keeps you from cooking your engine.

Boost gage measures manifold pressure, so you know what your turbo is doing.

Your truck must be a light 3/4 ton, since I can see six lug aluminum wheels in the photo. That means your engine is probably the L56 with EGR. That trailer is pretty big for that truck, but 70 mph is decent speed.

[Kollin Syverson]

From what I am reading, you are getting some false information. You NEVER EVER want to tow in overdrive, unless you are towing a push lawn mower perhaps. Read your owners manual it tells you there not to tow in OD. Mileage seems a bit low for your truck, depending on your gear ratio. I usually get 10-12 with my 3500 dually, which I consider to be normal with 4:10 gears. Your RPM seems a bit high even if you have 4:10 gears. I usually run about 2500 at 70. I would also recommend a transmission temp gauge.

[rjschoolcraft]

Kollin Syverson:

Do what you want to...

Yes, the book and door jamb say not to tow in overdrive...but I've logged over 60,000 trouble free miles towing 8000 + lbs. (GCVR of 16,300+) in overdrive with a total of over 173,000 miles on the transmission. My uncle has a 96 with five speed...he towed in OD. You decide.

If they put the exact same transmission in motorhomes that weigh over 18,000 lbs and tell you it's OK to use overdrive, what's the difference?

The original reasons for that prohibition comes from the earlier days of OD transmissions that had light duty gearing for the OD speed range. You accumulate stress cycles rapidly on a gearset when it is used continuously. The early transmissions didn't have enough fatigue life if you used the OD with any load...hence the prohibition. By designing the gear teeth to lower compressive and bending stresses running solo to accomodate towing, you can have the fatigue life necessary to allow towing. The 4L80E is nearly bullet proof in my experience.

If you get gages, you will see that your coolant temperature and exhaust temperature will be much lower while the boost pressure will be higher when towing in OD as compared to direct. Fuel mileage is significantly better as well.

Bad information?...I don't think so. ;)

[BuffaloGuy]

From what you are saying it sounds like something is not quite right with your truck. I have pulled side by side with a 454 and the 6.5 will leave it in the dust when loaded. My mileage loaded is normally 15 with really big loads (20,000 lbs.) getting 12 mpg. 4:10 rear end with manual trans.

I would get a turbo boost gauge and an exhaust temp. gauge installed. You'd be really surprised what you can learn with just these 2 gauges.

My feeling is that you don't have enough turbo boost. This will not only make your truck run weak but it will make your mileage suffer and you motor run hot too. Get the gauge and check it out. Check back here and you'll get it running better in a jiffy!
Ken

[CareyWeber]

Originally posted by Kollin Syverson:
From what I am reading, you are getting some false information. You NEVER EVER want to tow in overdrive, unless you are towing a push lawn mower perhaps. Read your owners manual it tells you there not to tow in OD. Mileage seems a bit low for your truck, depending on your gear ratio. I usually get 10-12 with my 3500 dually, which I consider to be normal with 4:10 gears. Your RPM seems a bit high even if you have 4:10 gears. I usually run about 2500 at 70. I would also recommend a transmission temp gauge. Kollin Syverson,

That is for trucks with the 4l60E / 700 trany only. 4L60E means a Gasser all 6.5TD had 4L80E tranys, and they are made to tow in overdrive.

4L80E = towing in overdrive ;)

Carey

[autocrosser]

They did put a sticker on the 95 diesel trucks with the 4L80E transmissions but in 96 it wasn't there. I have many miles with a 7500lb trailer in and out of the mountains in overdrive. Unfortunately over 55mph it will downshift to 3rd instead of just dropping out of torque converter lockup. I believe if it could be made to just do that it would eliminate a lot of downshifts.

If you are getting black smoke with you los of power check your cat converter. They plug up sometimes and restrict the power and will also cause overheating when trying to tow a load.

[Shuck]

Not to hijack the thread here, but I owned a 1991 1/2 ton 4x4 with the 6.2 in it - I am pretty sure that had the 4L60 transmission. On top of that, it had some insanely high gear ratio in the differentials. I'm not exactly sure but it was something like 3.04 or 3.06. Towed in O/D all the time with that truck. Up hills, I downshifted (and went a whopping 40 mph). Sold the truck last May with 178,000 miles on it and never had to touch the tranny...or the engine. The only things it needed in its entire life (my dad bought it new in 1990) were one new set of front brake rotors, a pitman arm, and a glow plug controller. That is it other than gas, oil and the other consumables. It was ready for a new set of injectors when I sold it, but my point is that the transmission went forever and I worked the crap out of it.

[Kevin Hendress]

This next week I plan on installing "something" on my truck...just got to decide where to start and of course would prefer not to spend a huge amount of $$$$$$$.


I did watch today and with no load or trailer at 65 mpg I am running at 2200 RPM. Which I think means I have 4:10 gears, but not positive.

I don't have lots of black smoke pouring out at anytime, there is a little whne I really gun it...but not that easy to see unless its dark and hits a light right.

I will be pulling my load from Iowa to Indiana this Saturday as I move back to Purdue...so I might try OD if I feel adventourous....just don't want to get stranded along the road with my trailer and a load of personal belongings.

Thanks!

[Kollin Syverson]

Ronnie

I am speaking from my past experiences.

1984 GMC 6.2 4X4 diesel OD automatic = 2 trannys
in 120,000 miles. Towed in OD on first tranny.

1988 Chevy 4X4 OD automatic = 1 tranny in 125,000 miles

1995 Chevy Astro Van AWD OD automatic = 2 trannys in 86,000 miles


1983 Chevy 4X4 4 speed manual = 0 trannys in 190,000 miles

1995 3500 4X4 6.5 TD 5 speed manual = 0 trannys in 82,000 miles.

If you are getting that kind of mileage towing in OD from an automatic thats great, but from my past experience, I will never buy another automatic. Maybe its just my luck :(

Lets move on

[tom.mcinerney]

The EGT gage might be best bet to start , in that it'll let you know when to back off. But i agree with Buff Guy that your boost is probably low, so suggest start by measure that.
Can search threads on boost and other gages. Advertiser John Kennedy[Kennedy Diesel] can set up with good gage(or set of gauges)-- probably justified if regularly tow. Could rig up a fuel press/vacuum gauge for temporary troubleshoot check....