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Post Number:#1  PostPosted: Sun Apr 03, 2016 9:04 pm 
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Location: Oracle, AZ
This procedure is basically in line with the cleaning procedure shown in the Maxima Service Manual except the special tools are not used. It

requires an Injector Pressure Tester and a Drill Press. If you do not have these tools, let the injectors be serviced at a Diesel Service shop. Be

prepared to de-assemble and re-assemble the injectors several times. . I have bought my pop tester on Ebay for $85.00
Attachment:
File comment: Injector Pressure Tester
Diesel tester.jpg
Diesel tester.jpg [ 28.34 KiB | Viewed 366 times ]

Injectors can be rebuild here for $222 .00 for all six injectors + S/H. Buying the Pop tester and the Drill Press will set you off by ~ $150.00 If your

injectors are over 200K miles, you'll need new injector nozzle assemblies regardless.


Warning: Use eye protection. Do not place any part of your body into the injector stream. It will cut through your skin.
Use these instructions at your own risk. I am not responsible for anything.


Precautions:
Work on injectors must be done as clean and dust free as possible
Do not disassemble more than one injector at a time to prevent mix-up
Never interchange parts from different injector assemblies
Do not touch the injector needle with bare hands. Use rubber gloves or oil soaked rug

Tools & Supplies Needed:
*Injector Pop (Pressure) Tester
*Bench Drill Press
*Bench Vice
*Air Compressor for compressed air
*22mm wrench & 17mm wren
*6" chisel
*medium size mechanics hammer ~ 14oz.
*anvil or a block of steel
*a small rectangle of aluminum or copper sheet metal
*BBQ Bamboo Skewers (at Target $1.59)
*small wooden block (hardwood preferred)
*1 pt clean diesel fuel with some oil added to fill the pressure tester
*a can of penetrating oil

Cleaning Procedure:
1) Install the TBT injector into the Pop Tester
2) Pump and notice the spray pattern and opening pressure.
3) Install the injector into a vice and using the 22mm wrench, disassemble.
4) layout the parts on a clean wooden board or rug
5) install the bamboo skewer into the drill press, shorten if to long ( 4"- 5")
6) carefully remove the needle from injector nozzle and set aside
7) Brush off the outside carbon build-up from the nozzles bottom with a brass brush.
Start the drill press and press the tip of the skewer into the nozzle hole. Clean both sides, 2-3min as shown in pictures.
Attachment:
File comment: Injector inner parts
Injector Rebuild1.jpg
Injector Rebuild1.jpg [ 94.14 KiB | Viewed 366 times ]

Attachment:
File comment: Skewer installed in drill press
Injector Rebuild2.jpg
Injector Rebuild2.jpg [ 127.38 KiB | Viewed 366 times ]

Attachment:
File comment: Cleaning the injector nozzle
Injector Rebuild3.jpg
Injector Rebuild3.jpg [ 82.77 KiB | Viewed 366 times ]

Attachment:
File comment: Cleaning the injector nozzle, other side.
Injector Rebuild5.jpg
Injector Rebuild5.jpg [ 78.96 KiB | Viewed 366 times ]


This cleans the carbon buildup from the nozzle hole.
8) Remove the skewer from the drill press and install the injector needle, grabbing only the smaller part of the needles end with the chuck
9) Start the drill and press the wooden block against the needle tip. If the wood is to hard drill a couple of small holes (1/32", 1/16") into it. Make sure you clean the whole tip.
Attachment:
File comment: Injector nozzle needle
Injector Rebuild4.jpg
Injector Rebuild4.jpg [ 65.19 KiB | Viewed 366 times ]

Attachment:
File comment: Cleaning the injector needle
Injector Rebuild6.jpg
Injector Rebuild6.jpg [ 81.82 KiB | Viewed 366 times ]

10) clean the injector nozzle body and needle with compressed air. Important: spray both parts with penetrating oil or dip in ATF before reassembly. Carefully insert the
needle into the nozzle. Do not force it. Needle should sink into the nozzle body from its own weight. It the needle fails to sink smoothly from any

position, replace the whole injector nozzle assy. Blow off all other parts with compressed air. If the opening pressure and spray pattern was within

spec. you can reassemble the injector body (58-72 ft/lb) and test the injector again. It should start discharging with a sharp crackling/snapping noise at set pressure.
Otherwise continue to "Adjusting The Injection Pressure".

Adjusting The Opening Pressure
After a run-time of 100k miles the injection opening pressure will be lower then specified. My engine just turned 200k miles and my injectors tested

in the range of 1000 - 1200 PSI (69-82 bar) as opposed to 1800-1920 PSI (124-132 bar). I am pretty sure that this is a second set of injectors. So I had
to increase the opening pressure in the range of 700-800 PSI (48-55 bar). This is a trial and error procedure so be prepared to disassemble and re-assemble the injectors several times.
The regular service method of changing the opening pressure is to change the distance washers inside. For the home mechanic it is unpractical since it requires a bunch of different size washers that are hard to get, if at all. The procedure below doesn't require to change the distance washer. Keep the old one in place.
Procedure:
1) place the injector spring flat onto a piece of aluminum or copper sheet metal and lay it on a steel block or anvil.
2) place the chisel tip between the spring coil and hit it with the hammer. Just a light blow, not to hard. By spreading the spring, a higher opening pressure is achieved.
Attachment:
File comment: Spreading the spring
Injector Rebuild7.jpg
Injector Rebuild7.jpg [ 96.92 KiB | Viewed 366 times ]

3) I had to give 3 to 4 blows to arrive at the correct pressure, so each blow was about 200 PSI worth. That is a ballpark figure. Turn the spring after

each blow and use different spot (coil) on the spring. Start with 2 hammer blows to get the hang out of it. Clean off the parts with compressed air,

reassemble the injector and test it with the pop tester. Always include the distance washer when reassembling the injector. It comes handy when

you have to decrease the opening pressure. I was able to adjust the opening pressure with this method to within 100 PSI ( 7 bar) of the specified

value.
4) Use new crush (copper) washer and heat-shield washer for final engine installation (12-15 ft/lb). I am open to comments.

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Post Number:#2  PostPosted: Tue Apr 05, 2016 11:22 pm 
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Joined: Sun Nov 27, 2005 6:58 am
Posts: 451
I recommend not letting any of the injector internal parts get near a rug. Even an almost microscopic fiber from a rug can be enough to foul the inner working of the injector. Especially the needle drop test (which should even drop at an angle less than vertical).

Also, instead of spreading the coils of the spring with a chisel, hopefully a reasonably priced shim kit is still available from Peachparts? I don't like the idea of stressing that spring, possible setting up a future scenario for breakage. I HAVE seen a broken spring in an injector body before.


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Post Number:#3  PostPosted: Wed Apr 06, 2016 12:02 am 
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Found a shim kit here:
https://mercedessource.com/store/variab ... washer-kit


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Post Number:#4  PostPosted: Wed Apr 06, 2016 11:03 am 
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Joined: Sun Jun 03, 2007 11:09 am
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Location: Oracle, AZ
Carimbo, great find. Do you have a source for the bottom washers (heat shield)? I am having a problem with locating them.
A recent order at NissanPartsdeal.com was cancelled due to NLA. Any "Ersatz" ideas?

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'86 Ford Escort Wagon Diesel MT Sold 07-17-08


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Post Number:#5  PostPosted: Wed Apr 06, 2016 9:52 pm 
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dieseldorf wrote:
Do you have a source for the bottom washers (heat shield)

Few years back I got some locally from a marine equipment repair shop. Brought them a sample, they looked at it, they quickly decided it looked very familiar to them (I kind of remember a popular Yanmar engine used them) and they sent me along with a set in a plastic bag. I'll see if I can find the receipt, which has the P/N.


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Post Number:#6  PostPosted: Tue Apr 12, 2016 10:48 pm 
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Can't find the invoice, sorry.


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