I must say, the optic bump and this site kick a**. My truck responded to the optic bump very well. I thought that I had surely bumped it too far but it idles smooth and runs great. I might bump it more until it idles rough and then back it down. Thank ya'll again for all the great information. I wish I had found all this out years ago. I can't wait to go for more boost when I get a pyro.

:cool2: I'm glad it worked for you. Not every truck owner likes it but I woudn't go back.

Naw I wouldn't mess with it again for nothing if you happy just leave it be there.

my truck has a really rough idle, we'v searched and searched and cant find whats causing it, think this might help my problem?

no, but I'd still bump it.

What is the optic bump?

Advancing the optic sensor to the pass side by just a mm or so. Somehow this got nigknamed the 'bump'. What it does is advance injection timing and increase fuel delivery, more power more snap.

Perfect, where is the Optic sensor? I'm doing that tonight

Do we have to check timing or it's enought going by ear ? :cookoo:

Optic-bump definately made the throttle feel snappier, I wouldn't go back. Since it's free and easy you can keep going back in and fine tuning it, and worst case you can always go back to stock. I recomend draining the fuel out (just absorb the fuel with a lint free rag in the bowl less than 1/4 cup,in mine) the first time so you can mark the block for reference, then you can keep re-tweeking it with fuel in the bowl, refencing your mark. Have fun!

Ok, now I am "horny"....How do I do this bump ?

Use the search feature and look for the pic's canadian rigger posted with reference lines from start to finish and back again.

Looked at pics can't tell from pic thought were this sensor is at. On mine I am assuming it's under the Radiator hose? What do I loosen to get it to slide to pass side?

It's under the lid of the injection pump dead center on the upper engine under the front of the lower plenum of the intake manifold. You'll have to remove the upper plenum at least.

I forgot about the facory upper intake possibly being in the way, since I haven't been running that system for over 18 months now. There are six t-25 screws holding the lid on, I pull the fuel return line off of the lid and pin it off to the side. Once the lid is loose just move it over to the side careful not to pull the wiring connecting the lid to the optic sensor. Loosen the t-40 bolt inside and slide the block towards the passenger side 1mm. Note that the metal piece directly under the t-40 is not what you're trying to move it's the block under that metal that you want to slide over to the passenger side.

I'm glad I have an old 5067 pump sitting in the basement to learn on before doing it to the pump on my truck.

Yeah, practice is good, you don't want to jab your screwdriver in the the data disk *doh*! This has got to be the easiest mod to do, and you can tune it to your liking, once you get the hang of it, you can go in change it and put it back together in under 10 min. and its fully recoverable too, and if your not impressed, well atleast you didn't spend any money ;)

Good thing I practiced on the old 5067 in my basement first. I dropped the T-40 down into the pump and it's nowhere to be found! :D

Mental note to self: DON'T LET THAT HAPPEN WHEN YOU'RE DOING THE BUMP TO THE PUMP IN THE BURB! :eek:

Ouch, yeah, you'll probably want to use a 3/8" drive bit holder with O-ring holder for this, as you will need a ratchet/extension to break it loose.

And a hardend T-40 bit. They really have some torque on them from the factory and if you don't press down hard you can strip that bit out.

Did the bump to the pump in the burb yesterday. Moved it no more than 1mm to the passenger side. Noticed no difference in seat of pants dyno. Maybe I need to bump it more?

are you sure you moved the actual sensor under the lock plate? Sometimes people try this and just shift the whole cam ring, which will move fairly easily, need to be sure that your moving the sensor and changing its position on the cam ring, otherwise you haven't done anything.

I did exactly as this picture from CR describes...

http://www.dieselplace.com/forum/uploads/BZE_afterbump4.jpg

I used a flat-head screwdriver to scribe a tiny line where the top left arrow is pointing to before the bump. That line is now approximately one mm farther left (toward passenger side) than it used to be.

Maybe I'm still missing something?

There is some play between the lock plate and the screw too, I'd go in and try again if I were you.

Just found this picture...

http://www.dieselplace.com/forum/uploads/BZE_afterbump41.jpg

I might have to pull the pump lid and take a look again to compare to this pic, but I'm not sure what objects the dimensions in the picture are referenced to?

Dimension 3 looks like its referencing the distance between the side of the block the t40 is in and the edge of the flat area of the underlying block. Dimension 1 looks like the distance between the edge of teh T40 and the block it's screwed into (which never changes).

There is some play between the lock plate and the screw too, I'd go in and try again if I were you.Dimension 1 looks like the distance between the edge of teh T40 and the block it's screwed into (which never changes).So my statement is incorrect? That lockplate can move a little related to the T40?

I'll have to dig in and try it again, and set up those two dimensions as the picture describes

Try it again on your pump in the basement, move it a lot just to get an idea of exactly what it is your trying to accomplish.

I think I figured out what you're trying to measure in the photo, after holding a print of it next to my spare pump and monkeying around a bit.

Both measurements are from the edge of the epoxy filled area, and after the bump you want three times the area adjacent to the epoxy on the passenger side than there is on the driver's side.

The bumped optic pictured above is bumped a little too far, isn't it?

Me thinks i have a better pic, i'll look for it, edit it and show what needs to move in a minute or two or three or four.....

I hope this helps, be sure to loosen the T-40 enough so the parts move freely, about 1 turn loose should make it fairly easy to move. I'm not 100% certain here but all these pumps should have a scribed line on the cam ring and if thats true you can move the optic to the drivers side to see it if its not visible to start with, then move it back 1mm past its previous setting to the passenger side.

CR: Your pictures and descriptions are a little disheartening cuz they show EXACTLY what I did. But I'll open up my pump again and bump it a little more to see if it makes a difference. My guess is I'll bump it too far and it'll idle rough as hell, and I'll have to go back in a third time and unbump it. But I guess I'll be getting pretty quick at it by the third time around.

As far as the rough idle from too much bump goes, does it idle rough all the time or just when cold? Does it damage the motor to idle too rough?

Thanks CR & TDG.

I think if its bumped extreme you may not be doing the pump any good but TDG will chime in on this when he see's it i'm sure. I think the last picture with the line barely visible is where my 00 is at now IIRC. I never noticed any power change except more black smoke with mine, reflash is what made my difference but i'm having some troubles that are starting to show that i think were there from the beginning, probably the reason it wasn't noticable to me. Once i figure out my troubles i'd put $100 on making the 9 second mark or better.

NOTE: The first pic is bumped about 1mm to the drivers side, that is so you can see the line only!!! The line should actually be covered by about 1mm of the optic to the passengers side!

Can we get pictures of where and how??

Sounds interesting........

Only good on a DS-4 unless there's a corresponding routine you could do on a d-max pump.