Index 12 failure

[Keith1k]

I bought used index 12 injectors, long story short one failed.
The cylinder 3 injector fuel locked my engine and bent one rod. I'm now questioning if these are even real index 12s.
Any opinions or advice would be welcome.

 

[TiAgAu]

Well that's not good!

Any index can fail unfortunately. That's some old Index 12's from 2015.

 

[carabuser]

They look genuine to me. Flow correction numbers are unique, markings look genuine and the metal stampings are there.

Do you have any logs of the engine running? Curious to see if there was any early signs of failure.

 

[IQraceworks]

How are you thinking that a bad injector bent a rod? Did it fill the cylinder full of fuel when the car was sitting...and then hydrolocked when you tried to start it? That's the only way I can think of how it would bend a rod. More info please.

 

[Keith1k]

I wasn't trying to log anything, just leaving work. When I got on the hwy, I rolled into it then wot and blew the tires off. I felt the miss as soon as I got off of it. It felt just like a hole in the piston. I turned around, headed back to work and parked it. The next day I pulled spark plugs and #3 was still soaked with fuel. The strange thing is the JB4 logged nothing, pulled that crap out the next day.
I swapped #3 injector with my spare, it ran fine with a slight lope at idle.

 

[IQraceworks]

I wasn't trying to log anything, just leaving work. When I got on the hwy, I rolled into it then wot and blew the tires off. I felt the miss as soon as I got off of it. It felt just like a hole in the piston. I turned around, headed back to work and parked it. The next day I pulled spark plugs and #3 was still soaked with fuel. The strange thing is the JB4 logged nothing, pulled that crap out the next day.
I swapped #3 injector with my spare, it ran fine with a slight lope at idle.

Is there a chance the rod was already bent? I don't know how a rich or lean injector would bent a rod?

 

[wheela]

Is there a chance the rod was already bent? I don't know how a rich or lean injector would bent a rod?

This supposedly happens to the s55 guys running full e85. They have different style injectors, but supposedly the combination of high e-content (low lubricity) and high injector duty cycle can cause the injector to stick open, flooding the cylinder to the point of hydro-lock. I'm not sure how they conclude hydrolock vs. the opposite (super lean causing detonation), but they seem to have high incidence of blow motors in those scenarios, and they seem to attribute it to hydrolock. I haven't dug into it at all since I only run 93. This is the first I've heard of it on n54, so I had wondered if the n54's piezo style injectors were just more robust to sticking open?

 

[IQraceworks]

This supposedly happens to the s55 guys running full e85. They have different style injectors, but supposedly the combination of high e-content (low lubricity) and high injector duty cycle can cause the injector to stick open, flooding the cylinder to the point of hydro-lock. I'm not sure how they conclude hydrolock vs. the opposite (super lean causing detonation), but they seem to have high incidence of blow motors in those scenarios, and they seem to attribute it to hydrolock. I haven't dug into it at all since I only run 93. This is the first I've heard of it on n54, so I had wondered if the n54's piezo style injectors were just more robust to sticking open?

If the engine is running at a pretty high RPM, I can't image a suck injector would be able to supply enough fuel to hydrolock a motor...but who knows. I guess anything is possible.

 

[Keith1k]

It's running flex fuel with an E68 mix. I believe the JB4 malfunctioned, I never felt it pull like that before. It should have been around 20 psi. It definitely happened at this moment, was running perfect prior to this.
I also have port injection, so who knows what happened.
The JB4 is removed, I'll be running Reflex plus w/ PI when it's back together.

Back to the injectors, the guy said they were resently purchased with only 1200 miles on them. I should know better....
Thanks for all the input!

 

[wheela]

If the engine is running at a pretty high RPM, I can't image a suck injector would be able to supply enough fuel to hydrolock a motor...but who knows. I guess anything is possible.

I guess the other factor is some of those guys are running very high (3000 psi+) fuel pressure to hit their fuel mass targets. Not sure what the max pressure rating is on those injectors?

 

[JohnDaviz]

If the engine is running at a pretty high RPM, I can't image a suck injector would be able to supply enough fuel to hydrolock a motor...but who knows. I guess anything is possible.

Let us take another route. It is called "Thinking".. Not something you will find in your FB research.

The internet says an s55 injector from Kies (first result i found. Can be wrong) can flow around 22g/s @ 100 bar (1450psi). Let us just assume this is the max flow.
What is the remaining volume at TDC? I have no idea.
1 liter of pump fuel weights around 720 to 775grams. So 22 grams are around 30ml of pump fuel. So as soon you hit 1450psi or more you are constantly injecting 30ml of fuel into your combustion chamber. Yeah. Most will leave unburned through the ex valve. But only so much possible.

Now.. Why do you assume high rpm? Hydrolock and stuck open injectors are not a thing during high rpm. This can happen any time. It happened most likely happened when hitting WOT and fuel was just filling the cylinder.

My guess with thinking about the issue is.. It wasn´t high RPM but if an injector failed and was stuck open it is ALWAYS injecting fuel without any PWM operation.

Now.. Still something you can´t imagine?

 

[IQraceworks]

Let us take another route. It is called "Thinking".. Not something you will find in your FB research.

The internet says an s55 injector from Kies (first result i found. Can be wrong) can flow around 22g/s @ 100 bar (1450psi). Let us just assume this is the max flow.
What is the remaining volume at TDC? I have no idea.
1 liter of pump fuel weights around 720 to 775grams. So 22 grams are around 30ml of pump fuel. So as soon you hit 1450psi or more you are constantly injecting 30ml of fuel into your combustion chamber. Yeah. Most will leave unburned through the ex valve. But only so much possible.

Now.. Why do you assume high rpm? Hydrolock and stuck open injectors are not a thing during high rpm. This can happen any time. It happened most likely happened when hitting WOT and fuel was just filling the cylinder.

My guess with thinking about the issue is.. It wasn´t high RPM but if an injector failed and was stuck open it is ALWAYS injecting fuel without any PWM operation.

Now.. Still something you can´t imagine?

Wow.....condescend much? Honestly, if you are going to be a total tool, I'm not even going to waste my time attempting to have a logical/technical back and forth discussion with someone like you. Have a nice day.

 

[carabuser]

I had stuck open injectors on my Z4 about 6 years ago. It had been running rough for a week or so but it got to the point where the car would barely move. I pulled over and called BMW recovery (under warranty at the time) and while on the phone walking around the rear of the car I noticed that fuel was actually running out of the exhaust pipe while the car was shut off. I lost about 1/8th of a tank.

So when they stick open fully, they certainly flow enough fuel to cause issues, certainly on a cold engine where that fuel may not get chance to be fully evacuated or burned due to ignition cut.

 

[JohnDaviz]

Wow.....condescend much? Honestly, if you are going to be a total tool, I'm not even going to waste my time attempting to have a logical/technical back and forth discussion with someone like you. Have a nice day.

I hope you could at least follow my thoughts. If not. Just ask your usual FB groups what to do Have a nice day. Oh.. And keep us posted when you fit the second piston.

 

[IQraceworks]

I hope you could at least follow my thoughts. If not. Just ask your usual FB groups what to do Have a nice day. Oh.. And keep us posted when you fit the second piston.

Wow...you seem really bitter. Try to be more positive....life's too short to be a jerk all the time.

 

[JohnDaviz]

Wow...you seem really bitter. Try to be more positive....life's too short to be a jerk all the time.

Yeah... So you learned something today?

 

[IQraceworks]

It's running flex fuel with an E68 mix. I believe the JB4 malfunctioned, I never felt it pull like that before. It should have been around 20 psi. It definitely happened at this moment, was running perfect prior to this.
I also have port injection, so who knows what happened.
The JB4 is removed, I'll be running Reflex plus w/ PI when it's back together.

Back to the injectors, the guy said they were resently purchased with only 1200 miles on them. I should know better....
Thanks for all the input!

Is there a chance that one of the port injection injectors could have stuck open? And not the DI injector?

 

[Keith1k]

It wasn't the port injection, running rough at idle pi was not active.
Rich miss fire resolved it self when DI injector was replaced.

 

[IQraceworks]

It wasn't the port injection, running rough at idle pi was not active.
Rich miss fire resolved it self when DI injector was replaced.

I was just asking because you said that you rolled into the throttle and went to WOT......that's when you first felt the miss. So I figured that if you were at WOT...maybe the port injection acted up and dumped a bunch of fuel in the cylinder or something.



"I wasn't trying to log anything, just leaving work. When I got on the hwy, I rolled into it then wot and blew the tires off. I felt the miss as soon as I got off of it. It felt just like a hole in the piston. I turned around, headed back to work and parked it. The next day I pulled spark plugs and #3 was still soaked with fuel. The strange thing is the JB4 logged nothing, pulled that crap out the next day.
I swapped #3 injector with my spare, it ran fine with a slight lope at idle."

 

[Keith1k]

I know it was the DI injector that caused the rod to bend. My question was are these counterfeit injectors. I was told the are old index 12's from 2015. How can you determine manufacturing date of these injectors?