when ALH injectors leak any other detection?

Besides pop tasting for an ALH injector to find out if it is leaking, is there any other way or symptoms once injectors are torqued on engine that will telegraph any of them are leaking out? how do we find out?

You can look in vcds and check the injection balance field 13.
http://forums.tdiclub.com/showthread.php?t=376916

eddieleephd said:

You can look in vcds and check the injection balance field 13.
http://forums.tdiclub.com/showthread.php?t=376916

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That will only show differences between injectors. If all of them are leaking or all of them are worn out, you won't see a big deviation.

Kevinski4 said:

That will only show differences between injectors. If all of them are leaking or all of them are worn out, you won't see a big deviation.

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Good point, it is another way to see what's happening and if they're in spec.
look through these

http://www.forums.tdiclub.com/showthread.php?t=303504


http://forums.tdiclub.com/showthread.php?t=189609

UhOh said:

greenskeeper said:

alternatively all four could be wearing "evenly"

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BINGO!
That's what this deviation is all about- compensating for various imbalances. Injectors and nozzles aren't the only things affecting the balancing act (cylinder compression differences being a big contributor). And, I believe that it's possible that a speed sensor issue could cause a variation as well: the "ring?"

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I'll answer that question with another question(s). If injectors drip, would the glow plug get wet? Or could you simply probe the GP opening for a leak?

BobnOH said:

I'll answer that question with another question(s). If injectors drip, would the glow plug get wet? Or could you simply probe the GP opening for a leak?

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Depends, depends, and depends.
It all depends on multiple factors, how much fuel and how long it dripped, when it's leaking and what temperature the engine is at.
The pulling of a glow plug and a sniff test would be viable for smaller amounts to some extent.
Probably the best test is the redneck pop test, pull the injector and hook it back to the line and crank the engine a few cranks. See how, when, and if it pops as well as if it drips after you stop cranking.

so the verdict is you can only detect the leak by pop testing injectors

MAXRPM said:

so the verdict is you can only detect the leak by pop testing injectors

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You can redneck pop test them on the car then leave it sit to see if it leaks.
Really no way to know for sure without removal.

Subbing for info and reference links.

Also a PSA: please don't taste your injectors!

A few years back, I removed the injectors and hard lines from the engine of car that would not start (brought to me that way... long story).

Anyway, I flipped the hard lines around so that they were pointing toward the windshield and reconnected them to the IP. I installed the injectors and placed a water bottle (clean and dry) over each injector.

I had someone to crank the engine over while observed the injectors. Did that procedure several times to see if any of them were bleeding off.. Worked pretty good..

Normally an indication of an injector issue would be hard starts, nailing, excessive smoke (usually white, unburned fuel), uneven running, missing, etc. Granted they'd have to be pretty bad to get to that point.

I think context here would go a long way, as in what exactly are you looking for or trying to solve? While it can happen, it is pretty rare that the Bosch VE TDI injectors outright fail. They can wear and have a less-than-ideal spray pattern, but even that is often not really manifested as anything other than a stumbly start with perhaps a bigger start up puff, especially when cold, and maybe less than ideal (ideal being +/- 1.00) injector balance values, and maybe a wee bit less fuel economy. But in most cases you are talking 1/4 million mile cars or more, and the difference won't be drastic.

well I got these symptoms, white smoke at start up, smokey, and I pulled all 4 glow plugs and 1 was wet, now my car does not burn oil so oil is ruled out, does anyone have a link to Redneck inj testing or video?

Subscribed.

So send your injectors out to someone who can properly check them.

I think there's a misconception that the injectors in an AHU or ALH can continue to leak after the injection event and throughout exhaust, intake and compression strokes.

Not so. The VE pump only suppplies fuel to the injector during injection. Then the high pressure plunger rotates to the next cylinder. There's no path for fuel to reach any injector other than the next cylinder when the plunger is at the bottom of its stroke.

I suppose at that point the 100 or so psi case pressure would be applied to the injector so it might start dribbling early.

I don't know if these engines have delivery valves that maintain residual pressure in the fuel pipes. If they do then that minute amount of fuel in the pipe could bleed off after injection, probably before the piston reached BDC.

MAXRPM said:

well I got these symptoms, white smoke at start up, smokey, and I pulled all 4 glow plugs and 1 was wet, now my car does not burn oil so oil is ruled out, does anyone have a link to Redneck inj testing or video?

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Redneck way is to pull the injectors, one at a time, turn the line reconnect injector. Stick a pop bottle over it securely and have someone crank while you watch what happens.
You're looking for evenly distributed mist and equal amounts being injected. After the injector stops injecting you're looking for dripping.
Yes, an injector can leak after injection event because the holes are not shaped, or sized, properly. That's why we are concerned about it. If you think that compared to the Injected quantity, what can drip out afterwards is small, you're quite mistaken because it's continuous. The largest factor is that it drips onto the cylinder and wall, then during combustion ignites and burns a hole. There goes that engine... A properly working nozzle does not leak fuel afterwards because the fuel must be forced through, yet a burned injector can drip, and a badly burned one...

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As I mentioned in Post #10, I did the bottle method of inspection/observing injectors. The "injection" is nothing but a "fog" that's amazing to watch.

I suspect, that upon firing (the instant of injection), the explosion and fire burn away any residual fuel (talking properly functioning injector).

So, when is a leaking injector going to leak, as the pressure builds before injection or is it a dribble thing at the completion of injection. Seems if there is a lot of white smoke, there'd be a lot of dribbling going on. Low air or cold starting (no GP function) can cause white smoke as well as late timing...

eddieleephd said:

Yes, an injector can leak after injection event because the holes are not shaped, or sized, properly. That's why we are concerned about it. If you think that compared to the Injected quantity, what can drip out afterwards is small, you're quite mistaken because it's continuous. The largest factor is that it drips onto the cylinder and wall, then during combustion ignites and burns a hole.

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Where does that continuous flow of fuel come from that drips out?

Andy mentioned a possibility I didn't, leakage before the proper pressure is achieved. I can see that causing the white smoke of incomplete combustion. I don't see it causing damage.

It's a drip, every time there's an injection event that lands on the metal.

Let me ask you how those tiny ants make a mound. They don't do it all once. Same as the Injectors leaking.


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When do they drip, before injection or after?

In my opinion, instantly before injection, a drip would be burned immediately without any smoke, especially white smoke.

I cannot imagine a drip after injection as the pressure to open an injector is gone. However, a badly worn injector, might not seal properly, but how does it drip when compression is pushing against it.. And, it would seem that the explosion from the event would burn any residual fuel in and about the five holes of the injector. Any leakage thereafter would be part of the next power cycle and be burned.

Think about this, drip (drop) is a lot of fuel. I doubt an injection event involves what we would think what a drop of fuel looks like.

We know white smoke is unburned fuel. Choke off the air (closed ASV, for example) and there will be loads of smoke. That time one or more GPs do not glow, smoke. An injector that's almost at the injection cycle at start-up is likely to inject without firing... smoke. Those first compression strokes that miss-fire on a very cold engine at start-up.... smoke. And, late timing can result in a smoky start-up. Lastly, along with late timing, combine any or all the other possibilities of white smoke and there can be a cloud!

I think smoky starts, by far, has something to do with other things besides drippy injectors.

I agree with Oilhammer's assessment along with KLXD's comment in Post #15.

Does this have anything to do with the question?

The OP's signature _________________

1/4 mile run----13.98 sec. @ 105.37 mph 8 years ago
I dynoed at 275HP at LCD back then, now 2.0 TDI with the real bolt ons, HP and TQ who knows???

eddieleephd said:

It's a drip, every time there's an injection event that lands on the metal.

Let me ask you how those tiny ants make a mound. They don't do it all once. Same as the Injectors leaking.


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You still haven't splained where the continuous flow comes from. The pump will only supply so much each stroke.

If the injector is leaking bad enough that it actually puts out drips that could hit the piston that cylinder would probably be dead and would certainly show up in the idle balance as was mentioned earlier.

These aren't common rail systems with a constant 10k psi or more on the injector.

I'll add to the discussion. My 02 Jetta had a streaming injector that completely melted down #2 piston. The scenario I experienced when it happened was a strange loss of power for 3 or 4 seconds then normal running for a minute or so then it was just like I turned off the key while I was driving 75mph with cruise on, on level ground about 100 miles into my trip.

I was lucky to have enough rolling momentum to get it to a very wide shoulder space just past an off ramp and a coworker was about 20 miles behind heading to the same account as I was, it was a cold January day last year.

Once I towed it to the shop, I pulled the glow plugs and found #2 melted. Engine was locked up solid. Inspection with my boroscope showed carnage in the cylinder and melted piston. It also took out the hot side impeller of the 17/22.

I had well over 300k miles on the car, I had purchased it new and it had been hot rodded with all the mods for over 250k miles (17/22, Kerma custom tune, 11mm pump, etc.) Clearcoat was failing, it was on its 5th drivers door window regulator, rust was back on the fenders again, and I had just purchased my 335d a month prior, so I decided to sell the car to Richard as is.

He swapped the engine, detuned the car, installed VNT15 and stock injectors, and sold it to a customer who has since retuned the car and installed a 17/22 and larger injectors with a Malone tune.

I really wish I could have kept the car as a spare but parking space limitations at my house and the cost for a repaint along with engine swap and new turbo just didn't make sense financially.

KLXD said:

You still haven't splained where the continuous flow comes from. The pump will only supply so much each stroke.
If the injector is leaking bad enough that it actually puts out drips that could hit the piston that cylinder would probably be dead and would certainly show up in the idle balance as was mentioned earlier.
These aren't common rail systems with a constant 10k psi or more on the injector.

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The fuel pressure coming from the IP is a wave, not a sudden event. The injector
has springs which only allow the needle to lift when the pressure reaches a set level.
If the nozzles are worn or damaged they can leak at a lower than desired pressure.

Yes, that's an intermittent flow when the pump is on that cylinder, not continuous.

I'm asking where the continuous flow mentioned comes from.

What's a streaming injector? Seems there would have been a huge cloud of smoke...... thus, stop immediately.

I've read about injector holes (five of them) becoming plugged causing the vast major of the injected fuel to flow out one or two holes, thus, creating a blow-torch effect which results in extremely concentered temperature spot(s) on the piston. I suspect that's what happened in Dogdot's incident.

I cannot imagine a continuous flow at all.

If I remember correctly, the old IDI injection systems operated on about 1800 PSI. The system on the ALH engine puts out about 2800 PSI. Seems the CR system may put out 10X that amount. So, are we seeing "leaking" injectors with the latter? Is it a major problem with the CR engines?

I changed my injectors from .013 holes to my genuine bosios R520 and car fires up right away and no white smoke, car runs way better, although it starves for fuel at high rpm, but it is good, injector #2 glow plug came out wet, now I'm going to try to do redneck pop testing, I am going to try to send them out for balancing, any one knows a good reliable place where they truly balance them, in the past they were a few members that claimed that they balance them and they were not doing it.