Bad night..bad fuel injector

[ShogunR32]

When I was leaving work my car started misfiring out of nowhere at start up. I drove home with a blinking cel reluctantly. I get home and scan it for codes and it tells me the issue is with cyl 2. I had a 17646 code for open circuit on the injector. I unplug the injector, tap it and check the wiring and everything appears fine except for one thing...the injector on cyl 2 is black not blue and has a part number of 0280156061 not 0280156065 like the other 3. I plug everything back in and start the car and everything is fine at idle. I check block 062 and it reads 11.3% 88.7% 14.8% 7.4% duty cycle. That black injector at idle is at almost 90% duty cycle. I was wondering if anyone knows if the black injector is compatible or not? Does the code plus the high duty cycle mean the injector is faulty or dirty?

[5ktq]

282 vs 317 cc/min, so not a great match but probably close enough to run ok I guess

The fact the car is throwing a code and that injector has been changed leads me to believe there is probably a problem with the wiring intermittently, PO probably tried swapping the injector to resolve it


block 62 is the throttle plate position / potentiometers..? that's not related

PS I don't think the motronic is capable of firing individual injectors different lengths of time. They're fired sequentially, but all for the same amount time. should be a measuring block with the injector time in ms somewhere.

I guess having one smaller injector will have the end effect of having that cylinder somewhat lean, and the other 3 very slightly rich (as the computer / O2 is assuming all are the same)


I think AMB should be 282 stock, so.. not sure then. guess your one injector is original and the other 3 arent.

the 317cc is from AWP (180hp engine in GTI), the weaker mk1 TT, etc.

[ShogunR32]

Perfect, I've put 12k miles on the car since I got it and it never did it before. I couldnt see any visible damage on the wiring except for the boot being split and the wires touching the valve cover. Im wondering if the wires got baked or something. Anything i can do besides tearing apart the fuel wiring harness?

[5ktq]

see my update

Can you post the full code, it should say something like short to B+ or short to ground, or open circuit, and intermittent or not


Oh i see you wrote open circuit, and the fact the car mostly doesn't run on 3 (runs on 4 most the time) means its intermittent. Could be bad connection at the injector, injector itself could have intermittent connection inside


you could try moving the injectors and see if the fault follows the injector or stays the same spot, that would rule out the injector or the harness

[ShogunR32]

Im a little confused, the black one (0280156061 ) is 317cc and the 3 other ones are 282cc(0280156065)? When i went back to the car it misfired again on cyl 2. I swapped the black injector into cyl 1 now and put a blue one in cyl 2. I just started the car and its not throwing a code. Of course this has to happen when im about put on my brembos

[bwizard]

see my update

Can you post the full code, it should say something like short to B+ or short to ground, or open circuit, and intermittent or not


Oh i see you wrote open circuit, and the fact the car mostly doesn't run on 3 (runs on 4 most the time) means its intermittent. Could be bad connection at the injector, injector itself could have intermittent connection inside


you could try moving the injectors and see if the fault follows the injector or stays the same spot, that would rule out the injector or the harness

The fact that the code reads "open circuit" says it's a wiring issue. Not to say that the issue could not be with the injector however if it has ran fine with said amount of fuel for 12k tells me the the Ecu didn't just finally decide there is a fuel problem that would show in o2 sensors or fuel trims. Basic electrical lesson. A closed circuit makes a loop, like a circuit track start to finish. Imagine 100 yards of that track missing that would be an open. So as I have explained in other previous posts if a code is "open circuit" there is some sort of wiring issue. Now it could be the wires,the Ecu, the injector, a relay, or a fuse, but some where there is a "open" in the "circuit" that when the Ecu does it's check it is open enough to set a hard code.


Also my wife's b6 a4 a common issue is the harness gets very hot and brittle and wires cross could be injector/engine harness cut open the plastic sheathing I bet you find brittle wires. Replace wiring/harness. Now also if it's a amb and it's cyl #2 also that is misfiring check engine light flashing "stating cat converter damage" could be blown head gasket/ cracked head. Personal experience on both issues.
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[bwizard]

The fact that the code reads "open circuit" says it's a wiring issue. Not to say that the issue could not be with the injector however if it has ran fine with said amount of fuel for 12k tells me the the Ecu didn't just finally decide there is a fuel problem that would show in o2 sensors or fuel trims. Basic electrical lesson. A closed circuit makes a loop, like a circuit track start to finish. Imagine 100 yards of that track missing that would be an open. So as I have explained in other previous posts if a code is "open circuit" there is some sort of wiring issue. Now it could be the wires,the Ecu, the injector, a relay, or a fuse, but some where there is a "open" in the "circuit" that when the Ecu does it's check it is open enough to set a hard code.


Also my wife's b6 a4 a common issue is the harness gets very hot and brittle and wires cross could be injector/engine harness cut open the plastic sheathing I bet you find brittle wires. Replace wiring/harness. Now also if it's a amb and it's cyl #2 also that is misfiring check engine light flashing "stating cat converter damage" could be blown head gasket/ cracked head. Personal experience on both issues.
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Are you burning coolant yet?

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[ShogunR32]

I replaced the head on the car when i bought it due to it having a cracked head/cold start issue. I got a rebuilt awm head installed and it has not misfired or caused an issue since. Its late but I was able to swap the injector from cyl 2 to cyl 1. Tomorrow morning I will start the car and see what happens. Btw, how bad is it if it happens again and I have to drive home on 3 cylinders again? Im guessing since its the fuel injector messing up there is no fuel building up and I should be ok

[bwizard]

Fuel is also a lubricant for your upper cylinder rings a short drive would not be too bad. But longer not good. Open that harness to the back of the head and at least from the injector plug to the back of the head where it gets the hottest, isolate each wire with electrical tape. My wife's blew fuse #29 driver side dash panel,and the 40 amp Maxi fuse, near the Ecu when her wires crossed as I was diagnosing the #2 misfire. That is when I discovered the brittle harness.

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[bwizard]

Fuel is also a lubricant for your upper cylinder rings a short drive would not be too bad. But longer not good. Open that harness to the back of the head and at least from the injector plug to the back of the head where it gets the hottest, isolate each wire with electrical tape. My wife's blew fuse #29 driver side dash panel,and the 40 amp Maxi fuse, near the Ecu when her wires crossed as I was diagnosing the #2 misfire. That is when I discovered the brittle harness.

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Check the coil pack harness also

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[Furly]

For future reference, when the check engine light is flashing it means turn your car off and dont drive it til its fixed. A simple issue can turn into an engine failure.

[Kevin C]

Fuel is also a lubricant for your upper cylinder rings a short drive would not be too bad. But longer not good.
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Um... No. Any fuel wash is a really bad thing and will take a cylinder out pretty quickly. If it is a non firing injector, its less of an issue, still not running on all cylinders causes all kinds of problems.

For future reference, when the check engine light is flashing it means turn your car off and dont drive it til its fixed. A simple issue can turn into an engine failure.

This /\

[ShogunR32]

Guys I am not new and understand what the blinking cel means It was not bucking/ sounding very violent. It was just blinking cel from the heavy vibrations from the 1 cyl not firing. If there was no fuel being dumped im not sure anything is harmed other than my motor mounts. Anyways, i drove the car today and it has not misfired yet so I will keep driving it. Are there any fuses or relays that may have acted up and caused this random open circuit?

[aysix]

Did it rain? Possibly moisture getting into ECU box.

[ShogunR32]

It rained a little but the car was in a garage not getting wet and the ecu box has no cracks/looks properly sealed. Btw I lost your number cause I got a new phone. Shoot me a text if you ever come back to the wonderful state of ct

[Charles.waite]

Wait are the injectors supposed to be TT386 injectors? Stock injectors? I'm confused...

There are Black long neck injectors that look the same as the 386cc TT injectors that lots of people confuse for them since they look the same except for the baby blue color. Their flow is MUCH less than the 386cc injectors...

[ShogunR32]

The car is on a stock tune and there should be stock injectors in there. What I think might have happened is that the previous owner didn't realize at first that the car was leaking coolant into cyl 2 because of the head issues(I swapped a new awm head in when i bought it). He might've swapped the different injector in there thinking that might solve the misfire issue. Fast forward about 10k miles to yesterday and I get a open circuit code and misfire for that same cylinder. Since I swapped the injector last night I have put on about 30 miles with no misfire and code yet. Well see if this was just a random occurrence.

[Charles.waite]

I've got a full set of working (when I removed them) OEM injectors from my 1.8t. If you want them shoot me a PM. I'll let the go for super cheap (aka not much more than shipping) since I have no use for them...