Hello everyone!!

[See man]

I just signed into this tonight looking for information about converting my 1995 6.5 turbodiesel to mechanical injection pump I got a 4L 80 E transmission OBD1 computer and I’m just tired of getting injection pump code check engine light come on goes into limp mode gotta pop it up in Neutral shut it off start it back up light goes away runs fine until you put it under too much of a load floor it and it’ll throw the code and go back in the limp mode if you’re just driving it without the trailer your ok unless you floor it and by the time you hit 80 mph if your lucky Service engine light comes on into limp mode. I’m so tired of this i’ve changed Motors before because I blew one up so it’s had different injection pumps different lift pumps so I know it’s not the injection pump or the crankshaft position sensor anything like that. Tried countless different P DM’s with no changes. I was talking to a guy on Facebook a couple years ago that converted his to a mechanical pump he had it dynode to the wheels 390 horse he said it was all expensive and long process Just wondering if it’s even worth doing it but I like my truck there is not any rust good four-wheel-drive truck I’ve had many years wondered what you guys thought ?

 

[Husker6.5]

Welcome, @See man. There are a couple of people on here that have done such a conversion, and there's even a complete write up of what all goes into doing one here in our technical library. You've come to the right place!

 

[Will L.]

Welcome.
And welcome to the I hate ds4 club too! Haha
Check with your local dmv/ emissions control folks first. Here in southern Nv- that becomes a no-go.

Once you are good- the trans gets controlled by a stand alone. Leroydiesel.com sells one, there are a couple other options as well.

Hate the factory gauges as they all suck too. So back before our dmv went on the crazy train, I did an aluminum plate and mounted gauges in there, and pillar pods.
Try from junkyard or maybe the truck restoration places for throttle pedal assembly from the 92 truck. Otherwise get a pedal with cable from the hot rod suppliers like summit.

If you want a more powerful 6.5- that is a complete build in itself that costs more money than many would realize. Search N8in8or build thread. He did a “how to” and put up awesome numbers. Do all the math before you start. Getting the db2 inplafe of the ds4 is easy swap. Keep the ds4 lower timing gear, even of you can get the time keeper set from Leroy to eliminate the chain. Many of the trans controllers need that crank position sensor to tell rpm. 390 to the wheels on a 6.5 is quite an accomplishment- never seen that power level last 150,000 miles more than a couple times. And they are not gm blocks...

You can search Bobbie Martin book on how to swap ds4 to db2, but things like trans controller is easier no days than getting the tcm to replace the ecm.

There is a ton of YouTube videos of people showing high numbers on gas cars, like the corvette one I spoke about here a few weeks ago. People watch it and believed it until I pointed out the cheat factor in there and the video poster removed my post where i did the math and showed he was inflating numbers by near 30%! And since we can’t run a 6.5 to 5252 rpm- you can’t honestly tell the real numbers.
Not gonna say outright the Facebook dude lied- or couldn’t happen... but will say I have met and proven many people wrong at the dynos. All it takes it rig with identical gearing and tire size that can hit 6,000 rpm, and swap trucks without allowing any program changes in the dyno. Also different dynos give different results as covered on yet another thread here not long ago.
All that said- you need to understand you won’t hit high numbers without huge costs, and doubt you will hit that number and have a reliable engine long term. No way I would bother trying without beginning with a p400 if you want 200,000 miles from it. That will put current build over the $15,000 range.

 

[See man]

Welcome.
And welcome to the I hate ds4 club too! Haha
Check with your local dmv/ emissions control folks first. Here in southern Nv- that becomes a no-go.

Once you are good- the trans gets controlled by a stand alone. Leroydiesel.com sells one, there are a couple other options as well.

Hate the factory gauges as they all suck too. So back before our dmv went on the crazy train, I did an aluminum plate and mounted gauges in there, and pillar pods.
Try from junkyard or maybe the truck restoration places for throttle pedal assembly from the 92 truck. Otherwise get a pedal with cable from the hot rod suppliers like summit.

If you want a more powerful 6.5- that is a complete build in itself that costs more money than many would realize. Search N8in8or build thread. He did a “how to” and put up awesome numbers. Do all the math before you start. Getting the db2 inplafe of the ds4 is easy swap. Keep the ds4 lower timing gear, even of you can get the time keeper set from Leroy to eliminate the chain. Many of the trans controllers need that crank position sensor to tell rpm. 390 to the wheels on a 6.5 is quite an accomplishment- never seen that power level last 150,000 miles more than a couple times. And they are not gm blocks...

You can search Bobbie Martin book on how to swap ds4 to db2, but things like trans controller is easier no days than getting the tcm to replace the ecm.

There is a ton of YouTube videos of people showing high numbers on gas cars, like the corvette one I spoke about here a few weeks ago. People watch it and believed it until I pointed out the cheat factor in there and the video poster removed my post where i did the math and showed he was inflating numbers by near 30%! And since we can’t run a 6.5 to 5252 rpm- you can’t honestly tell the real numbers.
Not gonna say outright the Facebook dude lied- or couldn’t happen... but will say I have met and proven many people wrong at the dynos. All it takes it rig with identical gearing and tire size that can hit 6,000 rpm, and swap trucks without allowing any program changes in the dyno. Also different dynos give different results as covered on yet another thread here not long ago.
All that said- you need to understand you won’t hit high numbers without huge costs, and doubt you will hit that number and have a reliable engine long term. No way I would bother trying without beginning with a p400 if you want 200,000 miles from it. That will put current build over the $15,000 range.

Yep I been seeing it’s just time for a Duramax truck that’s the way to go but I’ll just use the the old 95 to plow snow and just run to town that’s a 17 mile trip where I live. I’m really surprised what I’ve been offered for the truck $6,000 is the highest so far. But it’s a very reliable truck gets 12 mile to the gallon on the highway because it’s running at 2,400 at 70 mph and that’s with 285/16 tires before with the factory size it was running 2,900 rpm at 70mph I ordered a air dog lift pump going to run it at 15psi it Ran so much better at that pressure the stock pump was going about down to zero full throttle loaded last night I did away with the stock filter canister and put a huge screw on industrial fuel filter and mounted to the firewall right above where the old one was. And put 30psi gage on one of the ports. The 2 year old Mighty might holly 15psi is running 4psi at idle and close to 0 just reving to 4,500 and back to idle. The air dog pump is on the way cost me dam near $400 but it’s 100gph adjustable from 7-70 psi I’ll run it at 15 like I had it 2 years ago I think that pump lost its pressure with in a month I bet because the light didn’t come on for about a week then right back to the annoying limp mode wish the was a way to fool that before that truck will do like 90mph in the 1/4 mile when it’s got good pressure. On the old motor I moved the adjuster underneath the top of the injection pump now that made one hell of a difference felt like a new truck I was amazed but an oil line blew on the cooler line and spun a some main bearings going 70-75 down US31 before I seen the blue smoke in my mirrors it was to late lol so I won’t do that adjustment to this motor it’s only got 40,000 miles on it now and carry’s 50 psi oil. Hot so I don’t want to hammer this one apart lol

 

[DieselAmateur]

In short, yes a mechanical swap is possible and worthwhile if you want to avoid computer gremlins forever. Downside with your setup is needing to purchase a standalone controller for the auto trans. This is why I personally prefer the manual trans but understand the automatic having its benefits and whatnot

the 1995 is also advantageous in having the single stat crossover which means the DB2 throttle bracket will have no clearance issues. In lieu of fabricating your own you want to snag throttle & cruse cables and bracket from '92 or '93 year trucks as these were the only years that had the mechanical IP. Might take a minute to find, but they're out there

You can make respectable power with this platform, but there are a lot of modifications to build up from stock. Just do the math on what you want to invest, and how much you really value being able to work on your own engine and have fewer computers in the system vs a newer rig with more electronics and more expensive components to replace

 

[Will L.]

12 MPG?!!!? Thats My hummer that has Ridiculous aerodynamics, weighs 10,000 lbs and I drive like a jerk- seriously.
No way a pickup should get as low as 12, unless there is way bigger loss of mpg than I can imagine. Can Any of you guys confirm that?

 

[ak diesel driver]

I'm sure it's the rpm along with wind drag. My mileage goes down drastically after 65

 

[DieselAmateur]

I only get 13 mpg non- highway driving (not much better at 15mpg on highway) but I have a high rise truck cap covering a bed full of tools and lower compression in the engine. Interested to see if things are any different once truck is back online with DB2 and bigger turbo

 

[dbrannon79]

Welcome @See man, my 95 is still DS4 from factory and I usually average 14mgp's with mixed driving. your mileage depends a LOT on driving habits and how heavy your foot is. anything over 65mph and any economy goes out the window on these rigs. only way to get around that is lower your gears to at least 3:73's and install a gear vendors overdrive unit. but the lower gearing also lessens your "get up and go" power.

since I swapped from 4:10's to 3:73's on mine, I have noticed the better highway drive-ability and have achieved 16mpg's before, but that's only for long freeway trips without having to slow down any. what I have found is the acceleration from stop make it gulp the fuel. for me it's "if i'm not in a hurry" then easy on the go pedal at the lights LOL.

converting to all mechanical DB2 in your rig will be somewhat straight forward except for the trans side of things. you will need a stand alone trans controller for that since the 4l80e relies on several sensors that go to the DS4 pump for it to shift. your current PCM sees any issue with those sensors and it will go into limp mode along with any over boost situations. keep her under 12 PSI max and the PCM will be happy.

There is lots to learn from these guys here, great knowledge and experience too! Lord knows I'm still learning from everyone here

 

[WarWagon]

I’m just tired of getting injection pump code check engine light come on goes into limp mode gotta pop it up in Neutral shut it off start it back up light goes away runs fine until you put it under too much of a load floor it and it’ll throw the code and go back in the limp mode if you’re just driving it without the trailer your ok unless you floor it and by the time you hit 80 mph if your lucky Service engine light comes on into limp mode.

Be easier to start with "What code, exactly?" paperclip etc to read the codes out.

The primitive ECM is limping to say save the engine. It's a serious problem to limp the ECM. However the fix may be a simple as a cracked boot on the vacuum system or weak vacuum pump for the turbo.

Check the mirror for smoke when this is happening.

 

[MrMarty51]

Be easier to start with "What code, exactly?" paperclip etc to read the codes out.

The primitive ECM is limping to say save the engine. It's a serious problem to limp the ECM. However the fix may be a simple as a cracked boot on the vacuum system or weak vacuum pump for the turbo.

Check the mirror for smoke when this is happening.

That exactly was going to be my question.
What are the codes that is showing ?
My guess is they all relate to turbo boost and or lack of vacuum to control that boost.
Most likely that the vacuum pump has crapped the bed and is kicked out of residence. Could also be the boost control solenoid or even the waste gate actuator.
Show us a list of them codes so We know what is going on.
Oh yeah, I drive the K3500 at 62-63 MPH and get 16+.
The other day, drove to Billings and return, 300+ miles, every effort I possessed, kept the speedo at 58MPH. I dont know what fuel mileage I got but at 72 to 73 MPH that trip would be over 3/4 on the gauge. 58 MPH was barely over 1/4 on the gauge. I did an extra 60 mile trip at 58 MPH and the gauge was still at less than a half a tank used.
Guess You can figure out at what speeds I’ll be driving at from here on, until fuel prices drops below $3.00 a gallon any how.

 

[93detroit]

You have much more self control than me! I've driven from Miles City to Billings. Anything under 80 is DANGEROUS!

 

[dbrannon79]

WOW! I wish my rig could get that kinda mileage. I barely manage to make 400 miles to empty. and that's light foot'n it around!!

 

[SnowDrift]

12 MPG?!!!? Thats My hummer that has Ridiculous aerodynamics, weighs 10,000 lbs and I drive like a jerk- seriously.
No way a pickup should get as low as 12, unless there is way bigger loss of mpg than I can imagine. Can Any of you guys confirm that?

I get (got) 14 regularly. I don't race stoplight to stoplight.

 

[MrMarty51]

I get (got) 14 regularly. I don't race stoplight to stoplight.

I did the run, from home to Tongue River Reservoir cabin and back to Miles City, 318 miles on the ODO, driving 63 MPH, I dont remember how many gallons but it worked out to just over 16 MPG. That was all highway, except for the 18 miles of very rough road getting into and back out of the cabin site. A lot of steep rough gravel and sandstone trail.
From this last run to Billings and back, I have not yet fueled the truck. it just seems to be too good of mileage to be true, so, I dont want to take any chances of driving it much farther until I do fuel up. I did reset the trip meter, but, it was exactly 48 miles from where I did reset the meter after I fueled the truck.
It wont be until I get some money from either snow removal or the SS check to fuel time. Then We shall know the rest of the story. LOL

 

[Husker6.5]

I used to get consistently 17-17.5mpg out on the Interstate with the cruise control set at 75MPH on the K2500 Burb - as long as I wasn't bucking any headwinds - until the IP started going out and my mileage began slipping down to where I was getting at best barely 15 mpg out on the highway and sometimes the mid 14s!

 

[Big T]

I used to get consistently 17-17.5mpg out on the Interstate with the cruise control set at 75MPH on the K2500 Burb - as long as I wasn't bucking any headwinds - until the IP started going out and my mileage began slipping down to where I was getting at best barely 15 mpg out on the highway and sometimes the mid 14s!

Would get the same out of the ‘95 and the ‘94, both of which had 4.10s. The ‘99 would get 16-16.8 mpg and it has 3.73s. I have not done a test with the new injectors in.

 

[Twisted Steel Performance]

I must be doing something very wrong... I took the time to correctly set timing @8*btdc @ 1500rpm.... I can show over the last 4 years interstate @70mph on cruse in the dually 20-22mpg... 5 speed manual, 4:10 gears, 215/75/16 tires...

 

[Big T]

I must be doing something very wrong... I took the time to correctly set timing @8*btdc @ 1500rpm.... I can show over the last 4 years interstate @70mph on cruse in the dually 20-22mpg... 5 speed manual, 4:10 gears, 215/75/16 tires...

Much of the difference is probably due to the 265/75/16 tires we’re rolling on.

 

[93detroit]

The turbo has a big effect on fuel mileage. The closer to zero boost at cruising speed, the better economy will be. Like Chris said, timing is very important. I run mine a little lazy to protect the head gaskets at lower rpm. Climbing mountains or running in FL also affects mileage significantly.