injector upgrade?

[SChandler]

Friend of mine had 475k on his '89, then he popped a head gasket. The cylinder walls looked brandy new. Still had the crosshatch and barely any ridge on top.

That's about where the mileage was on my 90 when the head gasket let go in it. Same deal here, crosshatch clearly visible on the cylinder walls and no noticeable ridge at the tops of the cylinders. The only thing I wish I'd done when we had the head off would have been to r&r the cylinder head - I think the valve guides are worn out since it tends to puff blue smoke when the motor is started. Oh well, I know that now I am a lot less concerned about the longevity of the bottom end then I was then.

[PToombs]

You don't "need" to do the injectors. You could get them pop tested and reshimmed so they are the same. You can gain mileage, if they are not popping at the same pressure.
Sounds like your mechanic is a part time proctologist. Trying to stick it.............
you get the picture.

[KD]

Well John, your problem is WAY out of my league! I'm at least as green as you at all this, so you're going to have to ask the pros. Although, I do believe I've read a thread or two from others with your problem on here. Have you done a search?
However, from what you've described, to my limited knowledge it does make sense that it's in the fuel supply line somewhere. I think you're right to do a pressure check first. Cheap, easy, and it'll help in the diagnosis. AND if you put a gauge there permanently you'll have something new to look at in the cab!
One thing you haven't said is if your truck's intercooled. If it's not, there's no need to buy new injectors. The 9mm one's Cummins put in there can handle more fuel than your IP can give them. If it does have an I/C, then I've read varying reports about how successful a new set is. Some guys find they don't really get that much of a gain. And still the easiest, and for sure the cheapest, way of getting more HP is to tweak your IP anyway.
As I said though, cause and effect. Tweaking the IP will mean less pressure from the LP. That's not so good 'cause then your nice new IP has to work harder than it needs to. It also means higher EGT's, which is bad esp. if you're towing. That can be remedied by various methods, but then you're paying more $$$.
It's hard work trying to do things right but with the least money spent! Maybe you're right; if you need to replace the IP then do that and get the injectors, instead of messing with the whole lot!
Good luck, and keep us updated as to how you get along. I can't wait to get home and start messing with mine. I haven't seen or driven her for 4 months now, and I got another 6 weeks to go.
Keran

[fourwheelininajeep]

Hey Guys I used to be on here all the time but got busy with my house and my new wife(woohoo the honeymoon continues) any way everybody seems to agree as I do that your stock injectors will cut the bill just fine. My truck had a leaky injection pump between the hydralic head and pump. I rebuilt it I just took it apart and took pictures of everything, i noted every little step and I was extremely clean and meticulous. If you ever have one a part you will see what I mean. Rebuild kits for them are like 30 bucks and they are not that complecated if you take it easy dont force anything. My initial thought about your racing and dying problem is something wrong with the governer but without tearing into the pump I couldnt tell you. Here is how I tuned my truck and I am crazy happy. My truck is a 1990 3/4 ton with the stock getrag 5 speed. I consitently get 22 miles to the gallon but put out probably without dino somewhere in the 250 to 275 range and 550 on the torque. The fuel screw at the back of the pump is important but not the only way to get some fuel to the engine. On top of the ip there are four flat head screws holding down a diaphram with whats called the fuel pin. Take off those four screws and take the fuel pin out you will see a slide pattern where a needle can ride on that pin. This works like an old carberator the more boost pressure comes into that diaphram the farther down that pin is pushed allowing the needle to come out and allow more fuel to the engine that works like a pressure dump the farther the needle sticks out the longer the pressure is put to the injectors hence more fuel but it has to see boost pressure before it dumps a lot. Here is my 2 cents, take that out and if you feel comfortable grind it down. Research it on this forum its really easy just take your time. Then turn your screw in maybe 1.5 to 2 turns after you drive it a couple of times pull the pin back out and look at the trail. Some molly lube or something colored for lubrication works good that way it slides smooth but you can check you slide pattern. The beauty of this is you only get the fuel and power when you want it when the boost comes on hard but when you ease into the throttle and only boost in the 5 to 10 psi range you shouldnt see a whole lot of smoke and get decent fuel economy. There is also a spring in there if you get a lot of premature smoke tighten up the spring and take the cap off of the top of the plate where the 4 flat head bolts go through and loosen up the smoke screw.

[fourwheelininajeep]

The other thing I wanted to add is get some gauges in that thing even if it is intercooled, my dads truck has a banks kit on it with water meth and a 12cm housing but he still runs in excess of 1300 degrees if he pushes it with the fuel screw in 3 turns and a full grind on the fuel pin. Thats with only 30 psi of boost and 300 hp at the rear wheels and 750 ft lbs of torque.
If its not intercooled its going to be even worse especially if you turn it up since those have a bigger injector. If you start looking at a different injector remember size doesnt matter fuel spray and pop pressure can deffinetely affect it. My dad put a set of diesel care and performance 30 hp injetors in his truck that acctually have a smaller hole but different spray he now gets 24 mpg and gained quite a lot at the top end, it cleared up the smoke and lower his egts by about 200 degrees at wot.

[boomer]

thanks 4-wheel and kd.

So...if I am mechanically inclined (and I am) I can handle a rebuild? Scares the crap out of me....after watching the youtube removal and install tutorial.

governor ? maybe you are right...but I ahve zero experience with IP's...and the rest of waht you said is a bit over my head...without having the thing sitting on the bench in front of me. visual I guess.

where can I get the 30$ rebuild kit?
Where can I get that cool injector with a smaller hole like your dad has.

24mpg? WOW WEE! I get abotu 16 now....so that is remarkable!

if you have time...could you kinda walk me thru the rebuild and talk like Im a 8 year old?....that way I'll "get it".

if not....thanks for the help you've already given
John

[fourwheelininajeep]

Hey John
You may want to print this out so you can read along as you work on it cause its going to be a book.

If you go back to the home page and click on the link "the good stuff" then scroll down to the 14th thread or somewhere around there if its changed its called "ve assembly instructions with pictures" now that is for a 4bt which is a 4 cylinder volkswagon but it is identical to the 6bt that is in our trucks. Minus the 2 extra ports and the 2 extra ridges on the cam plate, look at the pictures and tell me what you think. To tell you the truth if you are inclined enough and have the tools to get the pump off you could probably rebuild the pump with no issues. I would first familiarize myself with how the top of the pump works start by pulling the top of the pump off for this you will need an angle allen wrench as one of the 4 bolts that hold the top on is in a recessed area behind the diaphram like I was explaining to you in the other thread. After you get those 4 bolts out slowly seperate the top from the rest of the pump, but before you yank it off there will be a spring attached from the fueling mechnism(sorry dont know the technical term for it) to the throttle linkage, its kind of hard to get that to seperate as it has a spring loaded clip holding the spring on, I know sounds weird but when you look at if you will know what I mean. Pay attention to the orientation of how that comes off it will make reassembly a lot easier also if you watch how the top comes off there is a needle type rod as I explained in that other thread, there is only one way that this goes back together if you can see how it comes a part it will help you a lot when you go back together becasue you can get it wrong and have a heck of a time getting the top to sit down on the pump. When you get the spring seperated then you can seperate the top and bottom and look at the internals and you start to get a sense of how these work. There will be a cam plate that has 4 rollers on it, as the pump spins the cam plate rotates and the rollers stay stationary this creates the pulse motion to build pressure, you will see the other end of where the spring attaches and the governer attaches also that is what controls how long you fuel for, if you slide the whole mechanism back and forth youll see it move a collar down farther on the distributor, this is the pressure dump, when the distributor(that big long shaft that works its way towards the firwall and is connected to the cam plate) moves away from the front of the pump towards the firewall it pushes into the hydralic head and builds pressure in excess of 3500 psi when the stroke gets to a certain point the hole in the distributor that the collar ive been talking about covers is uncovered it allows all that pressure to be released back into the pump that is how you control the amount of fuel. The destibutor is hollow with a hole in the end and 2 holes on the side one hole that looks like a woodruff key cutout with a hole in it is to allow all that pressure to go into the port that it aligns with pushing that pressure out through the hydralic head and into the port that corresponds with that hole, then it goes through the popet valves at the end of the pump( you can see these sticking out of the back of the hydralic head) where the lines attach to. So this piece is important to understand if you understand it you will understand how to get more power by tweaking the pump. When you look at this fuel mechanism you will see a screw come through the side of the pump closest to the firewall that is your fuel screw it drastically increases the amount of time the collar is over the hole making it fuel more and thus more power. The governer works against that spring that you pulled off thats connected to the top of the pump to also push against the throttle machanism to again dump the pressure. This spring is the spring that everyone talks about the 366 spring that is the model number, the spring is just a higher tension meaning that it holds the governer in the closed postition longer meaning more fuel and higher rpms. After familiarizing yourself with everything you move on to the hydralic head, there are 4 torx bit screws that hold the hydralic head to the rest of the pump(the hydralic head is the portion of the pump closest to the firewall and it is where all the ports for the lines come out of) to seperate the hydralic head from the pump take off those screws but be carefull the hydralic head and pump have springs pushings against them so take the 2 that are diagnol from each other all the way out then the remaining 2 take out equal going a couple of turns at a time, a clamp of some kind works good here, a wood clamp or anything. Before you pull the remianing 2 screws out clap the entire assembly together with a clamp that you can slowly release pressure. Then pull the 2 screws out and slowly release pressure on the clamp, you will see the distributor slowly slide out of the hydralic head when you get out far enough the springs will finally slack it is very important that you pay attention at this point becuase if you dont watch how every little thing is oriented then you can put it back together wrong and your truck will not run, finally you can pull the hydralic head all the way out when you do make sure you have it sitting on a bench as the springs, the pressure dump collar the distributor and probably the cam plate will all fall out on the bench take those pieces and immediately lay them out in order of how they came out, make sure they are on clean shop towels or whatever you have. Then pull the rest of the stuff out that didnt come with it you should get a cam plate with a washer in the middle of it on the distribtor side, this washer is improtant is adds the depth the distributor needs to build its pressure, then the 4 rollers along with rods that go through them and washers make sure you see what side the washers come out of if there on the outside of the rollers or the inside. Before you can go any further you need to make a tool, get a 13 mm socket and grind off 3 sides, the fuel mechnism has 3 sided bolts that are a 13 mm i belive you can remove those by grinding a socket down to work then remove the governer assembly pretty straight forward its a allen head with a lock nut put a wrench on the lock nut and loosen it then use the allen head to thread it out, watch the 2 shims that will come out between the case and the governer remember how they came out so you go back together with them after you remove the fuel mechanism and governer we have to go to the bottom of the pump and remove the timing advance if you look at where the rollers sat in the pump you will see how the timing advance works there is a rod that comes up through the bottom of the pump that moves back and forth this rotates the whole roller and mounting assembly creating a timing advance this is primarily used when its cold. On the bottom of the pump you will see 2 plates one on each side one is just a plate and the other has a line coming from the front of the pump and connected to an acctuator take that line off and pull the 2 torx bit screws and pull the cover off be careful and watch what comes out when you pull the cover, then go to the other side the block side of the pump and pull that cover with 2 torx screws in it pull that cover and see what comes out, then go back to the inside of the pump you will see a metal clip that holds a retaining pin that keeps that timing advance rod in place, pull the clip and retaining pin the pull the timing advance rod towards the top of the pump this will allow the timing advance assembly to come out of either side of the pump, then you can pull the roller assembly out of the pump the rest of it is pretty simple you take the front shaft out that has the gear for the governer on it the gear will have 2 rubber vibration dampers in it then you can seperate the gear from the shaft 2 more torx screws and the back of the vein pump will come off then you can see the vein pump pull the 4 veins out and the drive for them, thats basically it, if you want now you can familiarize yourself with how the governer works and how the vacuum diaphram on top of the pump work pull the 4 flat head screws on the top that you removed in the beginning and you will see a big rubber diaphram slowly pull this up and you will see how as it is pushed down by pressure it allows the needle to recess into the top and allows the fuel mechanism to keep the collar over the hole longer dumping more fuel, this uses manifold pressure to push down on the diaphram so when you go to boost it dumps the fuel you need to compensate, a spring and a star wheel will come out with it, go to the hydralic head that you removed and look at it, then remove the 6 port poppet valves at the end, these are a one way valve that allows the pressure to stay in the lines instead of back feeding into the pump, and at the top of the hydralic head there is a fuel shutoff solenoid that is a port and a solenoid that when opened allows fuel to be draw into the end of the hydralic head to allow fuel into the pressure chamber at the end of the hydralic head there are a bolt inside a huge nut, if its not leaking dont mess with it this is for a timing tool and pressure tester, but it has to hold the 3500 psi so if its not broke dont fix it or you may open a can of worms. Okay starting to get carpeltunnel or whatever it is give me a couple of hour break and I will post reassembly intructions.

[fourwheelininajeep]

I typed up the entire write up and the web site asked my to log in again because I was dormant for so long so here we go again. This time I will save it.

When you pulled the pump off you should have marked the ip gear in relation to the other gears so you can make sure it goes on the same orientation, it will only go onto the pump shaft one way put it can be any rotation compared to the motor, paint on a screw driver works well or a grease pen, you should also mark where the pump is timed at, if you look at the studs that the pump bolts to you see the oblong where the pump can be loosened and rotated this is how you set you timing, if the to moves toward the engine it advances if it moves away it reatards it, all the way retarded is tdc, and all the way advanced is 12 degrees.

Now for the assembly

Start by cleaning everything thoroughly, you should be able to see yourself in them, make sure that everything is layed out exactly how you took it a part. OCD is a quality trait when working on these where talking about clearances that a micrometer cant even detect there so close so any dirt any anything can cause huge problems, clean everything with carb and choke cleaner, and wash your hands between every step, any grease anything in your fingernails anything. Reassembly should take a couple of hours atleast make sure you have a couple of bottles of wd40 laying around, it is a good lubricant and has the same characteristics as diesel fuel. Start by replacing all of the seals, leaking or not they all come in the rebuild kit so use them. Little piece of advice put a thin film of wheel bearing grease or something like that on all the rubber seals this will help reduce friction when assembling and help condtion the seals for long life, it will keep them from getting brittle and cracked. Start the same way you stopped, put the vien pump together,watching your orientation of the viens they only work one way. The ven pump is very important it puts the entire ip under a couple of psi so that fuel can be pushed into the ports and it doesnt loose fuel. Some of the old cummins didnt even have a lp they relied entirely on the vein pump so it is important that this is done right, if you have any question go to the thread and look at the picture dont forget the 2 torx bit screws, put new rubber dampers in the gear for the governer and reinstall on the front shaft then put the woodruff key back on the shaft and insert it making sure the key fits into the vien pump. Then reimstall the fuel mechanism that controls the fuel dump sleeve. Then install the bracket for the rollers with the advance for cold start rod still installed, then go to the bottom of the pump and istall the advance mechanism making sure its exactly as you pulled it apart go a head and put the rollers into the holder but carefully they are kind of tricky. Then move onto the cam plate and hydralic head. Before you put the hydralic head on it is a good idea to install the 6 poppet valves the bolt in the end after cleaning them and installing new copper washers and install the fuel shut off it is a lot easier to do it now then when the head is on the pump you may consider putting a new fuel cut off on for like 12 dollars at your local parts store its a lot easier to do when the pump is off and torn apart. The cam plate can go on 2 different ways when you pulled it a part you need to watch the orientation compared to the shaft coming into the front. Now onto the distributor. The only way to put it together is install the return springs washers and return plate onto the distributor and intall it into the hydralic head Before you do spray everything down with wd 40. TAKE YOUR TIME THE DISTRIBUTOR IS HOLLOW AND CAN BE BROKE SLOWLY WORK YOUR WAY WITH IT AND BY NO MEANS DONT FORCE IT OR HIT IT WITH A HAMMER if it doesnt slide in easily its because you have it cockeyed and it will never go take it back out and try again, wiggling genty from side to side will help out(sorry about the inuendo but after this step it gets difficult so take a break cool off and laugh for a minute then you will be fresh so you dont mess anything up if you dont understand read the last 3 lines slowly). Now that were all ready to go make sure that everything is in its place, the washers that go at the end of the hydralic head that the return springs push on, those are important, the little spacer that goes into the cam plate, the truck wont run very well without it if at all. When you are sure that everything has been preassembled you can slowly feed the distributor in through the pump housing, make sure that the fuel mechanisms little nipple fits back into the pressure dump sleeve once you have that aligned set the distributor all the way in and make sure that the cutout on the distributor and the location nubby on the camplate are alignment, when they fit in together gently push the hydralic head into the pump housing, now take it all a part and do it 3 more times until you are sure that everything is going together the way its supposed to. When you are confident that it is exactly the way it came a part put the screws in and tighten them down. Watching everything as you pull the hydralic head in making sure nothing looks squished. You can now play with the pump move the fuel mechanism back and forth make sure the fuel dump sleeve moves well without binding, you can even install the gear on the front loosly and rotate the whole assembly and watch everything making sure it all works the way its supposed to. Now you can assemble the governer and install it. Then again rotate the pump and make sure the governer rotates, the top can now be installed. I would highly suggest if your going to do this than spend the extra 40 dollars or whatever it is now and get the bigger 366 spring you will not be dissapointed, the fuel shutoff for the governer with the stock spring is 2600 rpms and starts to taped at 2400. The new spring keeps fueling until 3600 and starts to taper at 3200, even if you dont want to run your truck that high of rpms for a long perioud of time it comes in handy if you are pulling a grade and the tranny keeps upshifting before you gain momentum or in a standard ifyou hit the governer before you gain enough to get boost in the next gear up its awesome and it woke my truck up like crazy. Now we install the spring that attaches to the throttle linkage and connect it to the fuel mechanism with that hooked up you can gently set the top of the pump down on the housing and bolt it down. If you take your fuel screw out for dissasembly(it makes it a lot easier) you now reinstall that making sure that you put it exactly the way it was when you removed it. And check your idle and full throttle adjusted and make sure they didnt move. You are basically done, make sure everything looks good, make sure you reinstalled the diaphram and fuel pin and put the star wheel pretty close to where it was if you even pulled it. Then reinstall the pump making sure to put the gear on the same way it came off. Timing is very important for power also the sooner you get that fuel in there the better performance you will get, there are 2 ways to advance timing, you can follow the sweep of the pump and rotate the top of the pump towards the head this gives you 12 degrees, or you can acctually install the pump gear one tooth off this will give you 10 degrees of advance along with the pumps 12 degrees you would have 22 degrees of advance, I think that is overkill unless your at like 13000 feet above sea level, I would just advance the pump as far as it would go and stick with 12 degrees of advance my truck runs well there. After you have the pump installed and the lines hooked up REPLACE YOUR FUEL FILTER AND LIFT PUMP then use the lift pump lever to hand bleed the entire system dont be suprised if you have to crank for a while you will know when you have good pressure cuase the lift pump handle will go soft. If you cant get the lift pump to push any fluid try bumping the motor over slightly you may be at the top of the cam lobe and the pump wont return to build pressure, when your sure the pump is fully bled have someone crank it over as you crack each line at the injector until you get fuel to each one. When you get 3-4 of them bled you should start seeing smoke and it should one to fire or acctually fire. When it does start it may run bad and knock for a couple of seconds and then miss for a while but after a couple of minutes it should purr like a kitten. For safety sake before you start the truck pull the clean air duct to the turbo and have a board ready just in case something on the pump wasnt adjusted correctly and it goes to runaway throw the board in front of the inlet to cut air off and kill the engine, trust me its a safety net you dont want to avoid, its not likely it could happen but possible. After the truck runs for a while shut it off and check for leak then restart it and go drive it. Once you have determined that the pump is feeling all right we can talk about tuning this thing for power.

I spent 10 days rebuilding this pump I took digital pictures of my entire dissasebly of every step so if I had any question I knew what I did so it should take atleast a couple of days if you take your time and write a bunch of notes if you cant take pictures draw a diagram so you dont forget something and write everything you can. Im sure I forgot something cause its been about six months now since I dug into mine but its still running strong. Take your time and good luck, any questions Ill be happy to help where I can If you do mess up and you cant figure it out steve at diesel care and performance is awesome he will rebuild it for 500 even if its in pieces