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Fuel Injector Testing and Tuning

ak diesel driver said:
the ones I've seen have a groove in the pintle, maybe get out a magnifying glass
Click to expand...
For pressure to slip by so it lifts ? I think thats how they work but all the injectors I had tested, mainly pencil type, never leaked more than a drip over an allotted amount of time.
The video of the mercedes injectors leaked next to none and the new India Bosch units I got, most all of those leaked, quite bad. Only 2 that leaked not a drop, one pop testing and chattered just fine. In My opinion how they all should be.
 
The one injector that I removed from the truck.
Used some jewelers rough and spun the pintle within the nozzle.
I am not sure if I had the rough completely cleaned out of the nozzle, when i put it back together it leaked way more than it did on the initial test.
I used some more B&P cleaner, blow dry, reassembled, still leaked bad.
Dismantle, back to the drill press. Spun the pintle in the nozzle for maybe a half a minute.
Went to the house, a container of detergent and hot water and also got several of those fancy tooth picks thats shaped like a knife blade on one end and a fuzzy feather on the other end. Dipped the nozzle in the soapy water, used the fuzzy end of the tooth pick for a brush, it fits through the pintle hole. Twisted the tooth pick several times round and round until I was satisfied that the grit and possible metal was removed. Rinsed in fresh water, blow dry, a couple drips of diesel from the test pump for lube in the nozzle.
Assembled, attached the injector to the test stand, cinched the two halves together, tightened the line nut.
Pumped the pressure 1600 PSI and tightened the wheel valve handle. Timed the leak down. A minute and a half it dropped 200 PSI.
Thats fantastic. The injector will chatter but cant yet get it to pop.
Going to do another dismantle and add about ten thousandths and retest.
I do have some of that Maguirars PLASTX polish compound, used for headlights and such, that might be finer than the jewelers rouge. I will try that on the next injector and see how that goes.
More to come.
 
Added 0.012 shims.
That increased the pressure that it will leak up to over 2,000 PSI.
More difficult to get it to chatter with the limited stroke on this pump.
Still does not do the single pop.
Something still not right.
Be nice to get the injectors to perform all three functions just by screwing with them.
The next question, will they be prone to failure within a few miles, weeks or months ?
 
sounds like your on the right path. Your giving me inspiration for when I get around to try my hand at this with the ones I have.


@Rockabillyrat might be able to give some tips and tricks on these units as what to look for and the to do's when it's holding but not chattering.
 
dbrannon79 said:
sounds like your on the right path. Your giving me inspiration for when I get around to try my hand at this with the ones I have.


@Rockabillyrat might be able to give some tips and tricks on these units as what to look for and the to do's when it's holding but not chattering.
Click to expand...
Maybe it is going to require some more polishing on the pintle and the pintle seat within the nozzle. It could be that the groove wore through is partially honed out but still enough of it left for the fuel to get enough volume between the pintle and the seat and lift the pintle to make it leak by but not to slam shut to pop.
I’ll mess with it some more but maybe not for a while yet today.
 
How fast are you pumping the tester? I do it pretty fast to get them to chatter. If you go too slow they will open and just stream out. You need to simulate a pump by building a lot of pressure fast. Keep in mind that the pop tester volume is 100s of times more fuel than a single injection event when its on the engine. A pump flowing 100cc/1000 is only putting putting out .1cc every spray.
 
Rockabillyrat said:
How fast are you pumping the tester? I do it pretty fast to get them to chatter. If you go too slow they will open and just stream out. You need to simulate a pump by building a lot of pressure fast. Keep in mind that the pop tester volume is 100s of times more fuel than a single injection event when its on the engine. A pump flowing 100cc/1000 is only putting putting out .1cc every spray.
Click to expand...
Yup, very very rapid pump.
Not sure I will get to play again today. Have to keep reminding myself that I am suppose to be walking only, and even that on a limited basis.
Absolutely no bending, lifting or twisting. Poking around in the garage violates all of those rules.
And so, I better just back off for a while.
 
Yup! Only go slow when check for the droplet. Otherwise act like you are jacking up a rig to change the tire, and last one home gets no desert!

On that DMSO- USE EXTREME CAUTION!! If you smoke cigarettes- dont even mess with it!!
Anyone thats ever got it on their skin knows its crazy stuff. I used to have to tend the horses that were injured or old and run that stuff on their hurt joints.
Every now and then get it on me, like on my forearm and within a minute or so it tastes like you drank carburetor cleaner. That stuff soaks into your bloodstream and carries throughout your body is the way I understand it.

There are some chemicals, nicotine being the most common one, that it can carry into your system. Back in the late 80’s I had to go get some and take to Grandma about 100 miles away, arthritis was tearing her up and I guess that helped her. This was before FDA approved it on people. The people version is super watered down dmso, And I understand why. A decade later one of my uncles had to go into the hospital and nearly died because he was using dmso but was smoking a couple packs a day. Well handling the cigarettes he would touch some of the tobacco and had the dmso on his skin. It fast tracked the nicotine to him and had a heart attack.

The blood tests got reran 3 times before they realized what was happening. The nicotine content in his system was through the roof. Dr said he would have had to smoke 3 cartons a day for months to get that much nicotine in him. Once he found out about the dmso he demanded the entire family that was around him to come in. He had a cop there and explained anyone bringing him pure dmso again would be charged with his murder.

So- whenever you use it- wash away all the oil products you can first with brake cleaner or similar. Let it dry and go wash and rinse very well first. Put on the nitrile or rubber gloves. Just rinse with clean water if you get it on your skin- but out of curiosity if you want to see of that taste thing is real- don’t get carried away with it or use as a prank.
You don’t know what chemicals someone may have on their skin.

For those that enjoy filling out paperwork on freedom of information act- look into previous uses by some gubmint agencies with its use. Hint- splashing someone is not as trackable as cordless hole punchers sometimes. Nuff-said.

Yes, I always have some on hand. But i keep it like any severe medication- no where near where any kids, even teens, can get to it.
 
Will L. said:
Yup! Only go slow when check for the droplet. Otherwise act like you are jacking up a rig to change the tire, and last one home gets no desert!

On that DMSO- USE EXTREME CAUTION!! If you smoke cigarettes- dont even mess with it!!
Anyone thats ever got it on their skin knows its crazy stuff. I used to have to tend the horses that were injured or old and run that stuff on their hurt joints.
Every now and then get it on me, like on my forearm and within a minute or so it tastes like you drank carburetor cleaner. That stuff soaks into your bloodstream and carries throughout your body is the way I understand it.

There are some chemicals, nicotine being the most common one, that it can carry into your system. Back in the late 80’s I had to go get some and take to Grandma about 100 miles away, arthritis was tearing her up and I guess that helped her. This was before FDA approved it on people. The people version is super watered down dmso, And I understand why. A decade later one of my uncles had to go into the hospital and nearly died because he was using dmso but was smoking a couple packs a day. Well handling the cigarettes he would touch some of the tobacco and had the dmso on his skin. It fast tracked the nicotine to him and had a heart attack.

The blood tests got reran 3 times before they realized what was happening. The nicotine content in his system was through the roof. Dr said he would have had to smoke 3 cartons a day for months to get that much nicotine in him. Once he found out about the dmso he demanded the entire family that was around him to come in. He had a cop there and explained anyone bringing him pure dmso again would be charged with his murder.

So- whenever you use it- wash away all the oil products you can first with brake cleaner or similar. Let it dry and go wash and rinse very well first. Put on the nitrile or rubber gloves. Just rinse with clean water if you get it on your skin- but out of curiosity if you want to see of that taste thing is real- don’t get carried away with it or use as a prank.
You don’t know what chemicals someone may have on their skin.

For those that enjoy filling out paperwork on freedom of information act- look into previous uses by some gubmint agencies with its use. Hint- splashing someone is not as trackable as cordless hole punchers sometimes. Nuff-said.

Yes, I always have some on hand. But i keep it like any severe medication- no where near where any kids, even teens, can get to it.
Click to expand...
I had tried it years ago when I had tennis elbow. Sheaf cartilage runs in, like a tube, wore through. Cant say it really helped but seems it didnt hurt too. I do remember that taste. 😹
I had dried my hands thoroughly of DMSO then rinsed the pintle and nozzle with B&P cleaner. Yeeeeouch. Skin burned and itched like crazy. Was not expecting that reaction. I immediately realized what it was, DMSO carried B&P directly through the pores, probably blood stream too. No amount of warshing with detergent and water carried that out. Suffered through it. Next time dummie, wear the black plastic gloves.
 
Will L. said:
Its no joke- sometimes when instructions say wear gloves, they mean wera gloves.
Click to expand...
I went for years without any kind of hand protection. About the last fifteen years of working for the DOT that I became aware of the damage being done to my body. Not just the hands but everything that the solvents affect when they soak through the hyde.
An old timer transmission man, dang good friend, he once mentioned that He didnt understand why his hands was shaking like they do. I told him if he had ever been in solvent cleaning parts for such a duration that his arms became numb to the armpits ? Why yes quite a bit. Told him I can not imagine how much nerve damage we have done to ourselves.
Sad but true.
Now many times when driving, my hands will begin to shake on the wheel of the vehicle that I am driving.
Yup, I use the gloves way more often than I ever did before, and, it now is too little too late but every little bit helps.
 
When I had a broken kneecap. I used , it DMSO, was written that a 25% solution should be used. I decided that 100% concentration would work better. It was a big mistake.... my knee was burning like I had injected jalapeno into my leg. and sprinkled grated chili on the open wound. quickly washed off with cold water. Burns from demexide are also treated with demexide, diluted to 25%. A marching compress soaked in 25% helped me, dulling the pain from a fracture and removing the swelling.
 
Yup. Grandma used to out on the pure stuff. She would use the roll on bottle like you use on a horse. Except she would start to roll it on a paper towel or paper napkin that would be discarded, then just touch the ball to the sore joints and not roll it, and never rub it in.

Too much is an eye opener for sure. Nice description there Denata,

Any word from the shop with your injectors?
 
Will L. said:
Yup. Grandma used to out on the pure stuff. She would use the roll on bottle like you use on a horse. Except she would start to roll it on a paper towel or paper napkin that would be discarded, then just touch the ball to the sore joints and not roll it, and never rub it in.

Too much is an eye opener for sure. Nice description there Denata,

Any word from the shop with your injectors?
Click to expand...
Not yet.
Thought I’d give them until the end of next week.
If I have not heard from them by then, the next Monday I’ll throw out a call to them.
 
Was waiting for a phone call from the folks over at Pro Tech diesel.
No call, injectors arrived without warning.
I called the shop, the gal put the technician on the phone. He said He didnt do anything to the injectors, just tested them.
The work order said, test and adjust as necessary.
The cost was $88.00 and that included the freight back to MC.
I checked each injector with the my tester, not a one leaked down, every one of them popped at 1900 PSI.
I dont know what He did but to Me that is a perfect score.
I would highly recommend getting injectors tested before installing them.
 
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