Recurring Injector Issue

B6/7 S4/RS4
#1

Hi, I have had an issue with a couple of injector locations since owning the car. I say locations because I keep replacing the injectors, all will be ok for a bunch of months then after a long while I’ll feel some stumbling, scan the car and voila fucking injector code in the same location.

As above the symptoms are usually some light stumbling. I know it’s the physical injector that eventually goes bad because I have moved them around after getting a code on a cylinder and the code will move to the new injector location.

The weird part is it has been almost always on cylinder 4. So what could be going on that would cause injectors in that location to periodically shit the bed?

So far it hasn’t been a big deal though if I could stop buying injectors once or so a year I wouldn’t be upset (never mind I’ve gotten a nice face full of gas once when changing them out).

Thoughts?

#2

Is it always the same cylinder or are multiple cylinders failing?

#3

Same one. Number 4 (except once in # 7 a long time ago and never came back)

#4

There is a chance its not the injector but the wires. Try swaping the injector to a different location and see what happens. Chances are the ijector might be bad or its just the wires. There is a chance that a short in the wires can be causeing the ijnector to fail

#5

That’s the thing. I did that before and the code followed the bad injector.

So Ive been buying a new one, swapping it in and I’m good… For a while. Then many months go by and the frigging injector starts failing in the same number 4 spot again.

#6

Well, I am not familiar with the electronics of these cars, but my inclination would be toward an electrical problem causing the injector to “fry” for lack of a better word.

How much voltage and amperage is supposed to be going to the injector during pulse? 12-14V and a few milliamps?

Bad insulation on the wiring?

I would guess it isn’t mechanical or fuel related since it is so isolated and keeps happening.

I could be way off, but just feeding a thought.

#7

Damn it! I just read this after I posted my post. I knew I should have practiced my speed reading more.

Well… I agree with ChrisK.

I think the injector is actually the secondary problem from the effect of the real problem (bad wiring). Once the injector is bad, you move it and you see the secondary problem move. The wiring is still bad on #4 which is why even with a new injector on #4, it also eventually fails.

#8

Yeah for sure the failing injector is a symptom. I’ll maybe have the wiring looked at. This may be tough to diagnose.

#9

do you what specifically the code is?

and ever try getting the bad injectors tested after removal? there are companies that do injector cleaning and testing, and they may be able to point in the direction of the failure mode.

my guess would be something off with the wiring damaging the electrical components in the injector (solenoid).

#10

Yes. I suppose a code would be good.

16588 - Injector: Cylinder 4 (n33): Circuit Malfunction P0204 - 004 - No signal/communication - Intermittent.

#11

i’d put my money on the wiring to the injector.

#12

I can perhaps close this thread as I MAY have discovered the root issue. The clip from the harness to the injector on Cyl 4 won’t engage properly so it is always a slight bit loose. My new theory is that it’s not the new injector itself but the act of replacing the injector that remedies the situation by snugly reseating the harness to the injector… If true I’ve spent a bit more on injectors than I perhaps should have… Oh well (plus this is still just a theory but a good one).

#13

A poor connection can raise resistance at the connection, and cause additional heat, also it can damage the pins on the connector and injector. Replace the connector, AND pins, and see what you get. How do the pins on the failed injectors look?