can some one tell me in simple steps how to turn the fuel up, but my 6.5 is mostly stock cept for the exhaust how much would i be able to turn it up without hurting something

You have a '94 truck and an OBD I computer. The good news is you can electronically turn the fuel rate up fairly easily with a computer chip swap. Stock fuel at WOT is only 63mm cubed. A "race" chip and a #9 PMD chip will give you 80mm cubed.


This is a BIG increase. After you chip the computer you might want to bump the timing up on the Injection Pump to get more efficiency or fuel management. This requires a small turn of the Injection pump to the driver's side and a bi-lateral reader like a Tech II.


After you do this you really should have a pyrometer in the cab to watch out for high exhaust temps which could shorten you're ride someday. All of this can be done in not much time but can cost a little money, but it's worth every penny!!

You can buy a chip, increase resistance on FSD connection or bump the optical sensor.


The chip and calibration resistor have been coved somewhat.


The optical bump is TDG's tweak but I can cover it.

can i be done without a Chip? we r talkin some pretty big bucks for a chip, if it can be done i would rather take it to my school and let my auto teacher help me tweak the fuel?

OBD I programs are all 63mm. OBD II programs are close to 75mm.


OBD II has to be reflashed but the cost and gains really aren't worth it.


I forget how much the chip cost me but as you will find out to make the truck run faster really takes some work and coin.

Charlie prior to Bill Heath's latest version I would agree 100%, current version is much improved over the other reflashes including his; that I tried & returned for lackluster performance, also for those running his early max torq chip he is offering for repeat customes a discounted price to upgrade, to latest program there also.

Here goes.


http://www.dieselplace.com/forum/uploads/2B1_ip1.jpg


This is the top of a DS-4 pump. The 6 torq bolts are all that holds it down.


http://www.dieselplace.com/forum/uploads/4Z5_ip2.jpg


Open the lid and you'll see the white wire going down to the encoder pickup, the T40 bolt is all that holds it in place. I use a T40 bit in a socket driver to break it(it's torqued down). Then move the encoder to the passengerside 1mm and retorque it. If you don't move it too far all's well, but say you go 2mm instead and the truck will rough idle. Move the encoder back 1/2 toward original position and try it again. with a scann tool reading timing you should see desired 4.5-5.5 deg. and actual is based on where you have the pump positioned. I run actual at 8.0 deg.

QM,


I opened my IP and lossened the 40T and slid the block under it towards the passenger side, but now I see in your post to slide the encoder over. Is the encoder connected to the block under the 40T bolt? Did I slide it the right way? After putting it back toghether and running it, it seemed to jump out of the hole stronger, but then fall off a little over 1000 RPM. It was so easy, Ill go back in tomorrow and mess with it some more and see what it does. Thanks for showing the procedure.

Over the last month with all this IP trouble I've had, I must have had the cover off and moved the encoder pickup 40-50 times. It is easy, it takes me 5-10 min start to finish. You can advance it to the point that the truck rough idles and if you move the block it doesn't change anything unless the encoder pickup moves a little relative to it, but the way you described moving it may have retarded it. I will use a probe to hold the encoder pickup and another to slide the block. Sliding the encoder to the passengerside is the same as sliding the block to the drivers side when it's all loose. It's the relative offset between the two that your increasing/decreasing with each move. My suggestion is to move the pickup to the passenger side till it rough idles and then set it back a little. The APP get's more responsive the further you go. Make sure to idle it for a second and give it a rev when your testing your change. You know you're there when it throws your head back in the seat at 30% APP.Edited by: quantum mechanic

On a side note, I posted earlier that advancing it too far could result in a surge at idle, well I have discovered after some work on mine this weekend that this is not due to the optic change but rather a worn out timing chain causing a bounce in timing which the computer tries to compensate for. Very considerable gains in fuel quantity can be easily achieved with this trick, and as long as you remain somewhat conservative and the rest of the motor is in good shape, you can do so without a problem.

Good to see you Tex! It's been a little slow without your inputs.


I'm realyy curious as to the Fuel solenoid and it's potential for HD rebuild and recalibration to higher than 75mm3. Am I pissing in the wind or is there potential for improvement?


Edited by: quantum mechanic

Good to be back thanks QM.


I got your email about the fuel solenoid and tried to email you back, but to you and everyone else who emailed me, I wasnt' ignoring you, I wrote replies but my Outlook has a problem and I can't send emails right now.


but anyway, to answer your question recalibration is definitely possible, changing the calibration resistor will tell the computer to keep the solenoid closed longer to achieve desired fuel quantity or bumping the optic sensor will increase fuel delivery without the computers knowledge. As far as modifications to the solenoid itself, not really possible, the FSOL is 3 pieces, none of which are serviceable, when they're worn, they're worn out.


http://www.dieselplace.com/forum/uploads/15D_FSOL.jpghttp://www.dieselplace.com/forum/uploads/FSOL_cap.jpg


In case you can't read the writing, and so anybody at this shop, which I am not affiliated with in anyway shape or form, these pics are borrowed from www.realdiesel.com (http://www.realdiesel.com).


These picures show the solenoid, armature and cap. Looking at the cap first, which serves as a stop for the armature, you can see where they've pounded together which means the armature will now make a longer stroke than it was designed/calibrated for and will likely cause a Code 36. The solenoid underneath can't really tell from the pics as to its condition, but they are notorious to have cavitation erosion which weakens the magnetic pull, and the same can happen to the underside of the armature. So these pictures show you what a worn out fuel solenoid looks like, atlease 2 pieces are worn out and in need of replacement. You will also notice the small Torx screw in the top of the armature, if this screw loosens or breaks, and I've seen both, it will not only destroy the rest of the solenoid, but could also hold the poppet valve underneath closed, causing an engine overspeed or runaway problem, which I have also seen happen.

I'm going to pull to fuel sol off the 5068 pump and see how worn the cap and armature are as well as the condition of the torx screw. Remember that my 5068 was racing and throwing code 36. It had not let me use the cruise control because the truck would surge. With the 5288 pump installed it didn't do this, making me think that the 5068 pump (fuel sol) was the cause.

Torx screw is unserviceable, tightening or replacing it will throw out the factory set perpindicularity. I am almost positive when you take the cap off you will find the armature in pieces, or atlease free spinning. FSOL is almost definitely the cause of your problems. The only other option is the optic sensor.

How expensive is the fuel sol? Remember that the optical was $322. I plan on getting this pump going again and into something 4wd and chevy in the future.

The FSOL is not really a field service Item, we use a special tool to mount the head and screw the FSOL down until desired travel is achieved. its expensive, I'm not sure on the exactly price, but the armature alone is about $100.

I might want to start making more friends who work in Diesel service shops. The rebuild price on these pumps is frightning.

It would be a good idea, I happen to know 'good' 5521 cores can be bought dirt cheap, and if you could get your hands on one, they're usually very good shape inside and have either CT or electronic problems.

QM,


After driving my truck the next day, I realized that what was feeling like a fall off in power was the truck up-shifting earlier than it was before. I'm not sure why unless more power input to the trans could be allowing it to up-shift sooner. Anyway thats just a guess, but when I stay on the throttle there definately seems to be more power. The adjustment was so easy when I make to the dyno I'll move it around between pulls to see the real advantage. Additionally, I believe the encoder is connected to the block, and I did move it the correct way. Since there is only one bolt inside there and it's on the block the encoder could not be independent relative to the block under the T40. I'll keep messing around and let you Know.http://www.dieselplace.com/forum/smileys/Cool.gif

Ok, when you said block, I was thinking lock plate. The tranny may shift sooner but if you hold the pedal down a little more it won't shift as fast and vice versa where if you let it up a touch while accelerating it will upshift everytime.


Dyno's should be an average of 3 or more runs, so you could change it but not every run.Edited by: quantum mechanic

The only problem with you guys is that you have so many good ideas I keep tweaking on my truck and burning up a bunch of fuel testing it out. Keep'em comming. Thanks

Here's what it will look like leaning over the hood of the truck, well as best as I can depict it on MS Paint. The black circle is the T40 bolt, with the lockplate under it, and the optic sensor pickup underneat those two. What you want to do is slide the optic under the lockplate to the pass side as shown. Normally, most stock pumps will be very close to centered looking at the lockplate compared to the pickup, Limit of Advance would look something close to that and I don't reccommend going further, this will be plenty ;)


http://www.dieselplace.com/forum/uploads/3Z9_optic.JPG

That's an excelent graphic depiction there TDG. I think you just nailed it for anyone who'd try it.


I got the wrong size screw today, I got a 4x10mm just a little bigger but similar.Edited by: quantum mechanic

I got more....


http://www.dieselplace.com/forum/uploads/3ED_DS1.JPG


This was going to be my attempt at explaining how moving the optic makes more fuel/advances timing by moving the cam pulse relative to the cam ring, but I never finished it.Edited by: Texas Diesel Guy

OK, I see the poppet valve,armature(where my screw broke)and see it's arangement. Why is it that you say I'll never get it back togather? Did something change when that screw broke and i'm missing it?

To set the armature to .005" travel you'll have to pull the head out of the housing. Which can be done I guess. And set up a dial indicator that measures to the ten of thousandths. The 5 thousandths needs to be dead on. Adjust by screwing the armature coil in to limit the travel. I have in the past tried to reuse such armatures as your's and have had no luck. When it's worn it's scrap.

It served it's purpose for my education. Any thoughts on why the screw might have broken with so little wear on the plate.

happens fairly often, see it a couple times a month, out of ~50 pumps. Too uncommon to replace everytime, but thats why I say, worn = worn out. Every piece of the fuel solenoid is especially critical to get proper opening setting of the poppet valve and a solid CT. If its worn, the stroke will be too long and your setting will be off and it won't last as long. If its worn on one side, then it will side load and break.

Mine was hardly worn but it was worn only on one side, I guess side loading broke the screw. perhaps the broken screw is more of the effect and the side loading was the cause. Either way, with a new fuel solenoid, I won't have to set the armature, just reassemble it, right?

no, the solenoid has to be reassembled and the crush washer underneath replaced and the solenoid is screwed down to the head until you have exactly 5 thou opening clearance of the poppet valve.

You were right about the uneven wear as I think you should be able to see in the picture.


http://www.dieselplace.com/forum/uploads/D8E_armature.jpg


The shiny ring in the center is the screw heads wear.


So .05" movement

No the wear is the marks that look like the top of the solenoid, and you will see wear on the opposite side of the armature that looks like the inside of the cap. The shiny circle is just from the screw being torqued down at the factory, and from the shaft spinning just before it came apart.