Injector Pump out of spec should i even run it?

[vw-tim]

so i just ordered all the stuff i need to make my inector pop tester i went with this

http://www.northerntool.com/shop/tools/product_200333147_200333147

and then ordered all these parts from http://www.mcmaster.com/ :

5269K311   METRIC STEEL COMPRESSION TUBE FITTING, ADAPTER FOR 6 MM TUBE OD X 1/8" NPT MALE PIPE 3.47
50925K343   COMPACT EXTREME-PRESSURE STEEL THRD FITTING, 3/8"MALE X 1/8"FEM PIPE, HEX HEAD BUSHING,6000 PSI   1.53
3845K23   GLYCERIN-FILLED GAUGE - 1% MID-SCALE ACCURACY, 2-1/2" DIAL, 1/4" BOTTOM, 0 - 3000 PSI    18.49
50925K345   COMPACT EXTREME-PRESSURE STEEL THRD FITTING, 3/8"MALE X 1/4"FEM PIPE,HEX HEAD BUSHING, 6000 PSI   1.30
50925K198   COMPACT EXTREME-PRESSURE STEEL THRD FITTING, 3/8" PIPE, FEMALE X FEMALE X MALE TEE, 4500 PSI 7.11

so i guess we will see how it all comes together!

[TylerDurden]

Go for it, dude.

A pop tester is a great tool for tuning/maintenance.

... as they wear it takes more advance to make them pop at the right time.

Check that... Worn injectors have lower break-pressure, don't they?

Maybe the OP has later, higher break-pressure injectors. Earlier injector spec was 120bar-142bar. (Plus the IP might be a yellow-dot, 107A.)

[8v-of-fury]

I see nothing about a yellow dot pump that could cause there to be a need for a higher break pressure.. the yellow dot pumps must have come equipped on engines with higher stock break injectors to warrant the 1.15mm of timing..

What internally of the pump would cause that? Nothing I can see.

[TylerDurden]

I see nothing about a yellow dot pump that could cause there to be a need for a higher break pressure.. the yellow dot pumps must have come equipped on engines with higher stock break injectors to warrant the 1.15mm of timing..

What internally of the pump would cause that? Nothing I can see.

I suppose the "yellows" might have been matched with higher bar injectors (no indication they were)... but if they weren't , maybe the cam ramps or roller-ring have a shifted orientation relative to 0^o.

[92EcoDiesel Jetta]

And dump dirty fluid into the injectors?

Nah, inline filter between the rez and the pump.

Good idea to circulate the fluid a few times through the system without an injector in place, to flush the crud out before testing.

But the  filter is not absolute in filtering all debris so some dirty fuel is going to go into the injector.

[vw-tim]

Okay so alittle update i was reading through the Bentley and it said to crack each injector as the engine was running and if one didnt change the engine noise then it was faulty. So i did that and all of them seem to be working.

Also the IP im using isnt a Yellow dot.

Also to just help me fully understand this more the shims are usually the only part on the injector that needs to be replaced because thats what really controls the point of pressure that the injectors release fuel at?

there was some talk of injectors with an earlier break point or a later break point are there different type of injectors that were used through out the years?

[TylerDurden]

The shims are the means to calibrate the the opening pressure. The spring holds the pintle down until the fuel pressure raises it up and the fuel sprays into the pre-cup. Thicker shims hold the injector closed longer, as pressure rises higher to the break point.

The nozzles are a wear-item, which can be replaced if they are spraying poorly or not closing properly.




Nozzle diagram:

[ORCoaster]

I find that by using my breaker bar held on top the nut and inserting the 1/2 inch socket keeper on my ear I get the best isolation of injector noise.  Some are soft others a rap or tap.  I only wish I had a pop tester.  Could make one but time is short all the time.

[vw-tim]

Alright guys so i got my injector pop tester made! and it works great! But now im just wondering what is a passable injector? I only tested a single injector on it and just decided it was best to ask on here to see what i need to look out for reading through the bently it says they should pop at about 1758-1840ish psi. So the injector i tested was poppin at 1400 psi around there does this mean i need to open it up and get another shim basicly how should i go about testing these?

and a pic of the setup:

[TylerDurden]

Nicely done.

That seems kinda low.  I'd number them and pop them all. See how many are that low.

It's important to have them all close*, as well as within spec. Spray pattern should be a narrow cone, with no dribble after cutoff.

("Bar" might be the preferred unit of pressure to compare to spec.)


*Edit to clarify: It's important to have them all closely match in break pressure.

[wolf_walker]

I see nothing about a yellow dot pump that could cause there to be a need for a higher break pressure.. the yellow dot pumps must have come equipped on engines with higher stock break injectors to warrant the 1.15mm of timing..

What internally of the pump would cause that? Nothing I can see.

I suppose the "yellows" might have been matched with higher bar injectors (no indication they were)... but if they weren't , maybe the cam ramps or roller-ring have a shifted orientation relative to 0^o.

I went round and round with injector part numbers and supercessions awhile back.  There are several PN's for NA injectors, I don't remember if I ever figured out what the diff was.  And it wasn't TD or AAZ, just across the 1.5 and 1.6 versions sold in the US.

[vw-tim]

Okay guys so i went through all 8 injectors i have. here is what i got. The injectors #1-4 are the ones that were on the engine #5-8 where ones i pulled of this other head i had.

Injectors:

#1 - 1600psi
#2 - 1500ish psi more or less it was hard to tell exactly
#3 - 1700psi
#4 - 1600psi
#5 - 2000ish psi
#6 - 100ish and up psi as soon as pressure was applied it would just start leaking out
#7 - 1800 psi and it leaks
#8 - 2600 psi leaks

So my question now is how should i go about getting injectors to spec? Or should i just buy new rebuild injectors? Would the rebuild injectors be at the correct spec?

[745 turbogreasel]

Swap the shims around till you have 4 the same.  Thicker shim = higher pressure.
Good spray and cutoff without dribble is more important than actual pressure.
Let me guess, #6 was in a destroyed hole?

[vw-tim]

Swap the shims around till you have 4 the same.  Thicker shim = higher pressure.
Good spray and cutoff without dribble is more important than actual pressure.
Let me guess, #6 was in a destroyed hole?

So should i clean up all 8 and open them all up and take all 8 shims and measure them and pick out the 4 thickest and go from there? What if none of these shims work? Is there any place that sells shims

[vw-tim]

Also im thinking about just spending the money on rebuilt injectors from GAP or maybe another place that might sell them cheaper. My concern is if i get these injectors should they be set up to spec like i shouldnt even worry about pop testing them or could i get them and they still might need different shims to get them to spec i dont know why but i just wanna make sure before i purchase them if i will just be able to put them in and time the Injector pump and be all good to go?

there are these for the 1.5L :

http://www.germanautoparts.com/Volkswagen/Rabbit/Fuel/68/1

but i did notice that these were alittle cheaper but they are for the 1.6L Turbo diesel :

http://www.germanautoparts.com/Volkswagen/Rabbit/Fuel/68/3

Are the Breaking points different with each of these?