HELP! Repeat direct injector failure 200 OPTI

[AZEK]

Have a nightmare on my hands. 6 blown direct injectors in less than a year and no one can figure out why. Looking for any and all feedback thanks in advance.

· 2006 Mercury Optimax 200HP Serial# 1B379977, current hours on motor 375
· Only Mercury authorized dealer has worked on motor
· Boat used 20-30 times per year consistently
· Over 10k invested in repairs
· Have ran Mercury Quick-Kleen and Quick-Kare fuel additives faithfully
· 4/18/2011 power head failure @ 142 hours cause undetermined
· 3/13/17 #4 & #6 direct injector failure cause undetermined. Replaced with Mercury factory parts, 371 hours on motor
· 4/20/17 motor ran bad again arranged for a trip to lake with mechanic so he could see himself
· 7/8/17 lake trip found #2 & #5 cylinders not firing. Sent #1, 2, 3, and 5 injectors to Brucato to be cleaned and flow tested. Result #2 & #5 DI’s out of spec/defective failure unknown.
· 9/27/17 needed second opinion took to a different Mercury authorized dealer. They replaced #2 & #5 DI’s cause of failure unknown.
· Used boat 8 times between 9/27/17 and 12/22/17 with no issues
· 2/3/18 motor runs terrible off trailer #4 & #6 direct injectors bad cause undetermined. These were already replaced and under warranty boat is in shop now.

Since injector issue started motor has never run bad while on the water. It goes on trailer running fine and comes off the trailer running like crap with DI failure. Obvious something is taking the DI’s out and no one including Mercury can figure it out.

[Savage]

Inspect the internals on the AIR COMPRESSOR.

[EuropeanAM]

Cascading failures are quite common when only a portion of the system is cleaned, validated and serviced.

That’s why we require the ENTIRE system at one time- hoses, rails, injectors, and DI’s.

[AZEK]

Inspect the internals on the AIR COMPRESSOR.

This has been done was told compressor is fine.

[Savage]

This has been done was told compressor is fine.

This requires disassembly of the compressor, not just pressure testing.

[castforcash]

I'm guessing when the compressor was replaced there were metal particles that got into the fuel system. This is why Don and Savage recommend having the whole system checked out and having ALL the injectors flow tested.

[Savage]

^^^^Yep^^^^ or the cycle will continue to repeat itself, like it already has.

[AZEK]

I'm guessing when the compressor was replaced there were metal particles that got into the fuel system. This is why Don and Savage recommend having the whole system checked out and having ALL the injectors flow tested.

Guys the compressor has never been replaced, it has been inspected by 2 Mercury mechanics and they have said the compressor is fine. The injectors have been cleaned and flow tested I listed that in my original post. They have found no debris in the injectors, fuel rail or anywhere else that is why they are having difficulty diagnosing what is taking the injectors out. At this point they do not figure it is fuel related so we are looking at it being electrical related, ECM, wiring harness or something else. I am at a loss I am not a mechanic just hoping someone has had a similar experience with this that can give us a clue on what else to look for. Appreciate the feedback.

[Savage]

What specifically failed on these DIRECT injectors? Exact specifics are needed. I'm sure RichZ @ Brucato could shed some light on your situation for you, what have they told you about the failures?

[leo13]

They fail by having excessive flow. This is believed to be caused by excess wear on the seat and face of the valve element. The actual cause is from galling of the stem to guide. They are both made from the same or similar materials (austenitic sst) which is highly prone to galling. The direct injectors rely on a return spring to close the valve. The extra friction causes a slow return which increases the duration.

What specifically failed on these DIRECT injectors? Exact specifics are needed. I'm sure RichZ @ Brucato could shed some light on your situation for you, what have they told you about the failures?

[Savage]

I know the types of failures, I want the OP to tell his story.

[AZEK]

I know the types of failures, I want the OP to tell his story.

From the Brucato report: On preflow these four injectors were found to be erratic with the percentage of imbalance out of tolerance at all three test points. #2 at first was stuck open then was low at WOT and IPT. #4 injector misfired. Once cleaned and brought to operating temperature #2 remains low at WOT and #4 is high at IPT. Therefore #2 & #4 injectors need to be replaced. Injector #1 and #3 are stable and in spec.

Only 4 injectors were flow tested because the other two had just been replaced. The latest two injectors to fail were the first two replaced so now we have new injectors failing as well. Neither dealer has been able to tell me why or how they are failing. I was told the ohm out correctly so they don't think they failed electrically. But I'm beginning to wonder if I am getting solid information from dealer.

[Savage]

I would ask your Dealer specifically how they are determining that a Direct Injector is bad. I too am wondering about the information that the Dealer is giving you.

[AZEK]

I would ask your Dealer specifically how they are determining that a Direct Injector is bad. I too am wondering about the information that the Dealer is giving you.

I have asked that but will ask again when I go there today. They hook their laptop up and run misfire tests etc and determine it from there. What ever cylinder that is not firing has had the bad DI. I think it's pretty obvious that the DI is failing because when they are replaced the motor runs fine until the next one goes.

[AZEK]

Guys received this update today from the tech that is working on the motor.

I am wondering if there is a chance that the air compressor may have been leaking some water into the flow stream of the air system. Unfortunately when I took the compressor apart to check for metal, the oring seal was broken so we can’t test it with any real certainty. All I can do is replace the orings and test it again.
The ECM has been tested and the harness ohmed out to the limit of our testing. I cannot say they are not causing the problem. If the ECM driver were to stick closed and damage the Injector, I would have no way to test for it unless I was hooked up to it and actively testing at that exact moment.
Replacing the wiring harness and ECM could be done to rule them out but it would be around $2709 just in parts.
I will be pulling the boat up this week and replacing the direct injectors and taking another look at the compressor.

[Rich Z]

They fail by having excessive flow. This is believed to be caused by excess wear on the seat and face of the valve element. The actual cause is from galling of the stem to guide. They are both made from the same or similar materials (austenitic sst) which is highly prone to galling. The direct injectors rely on a return spring to close the valve. The extra friction causes a slow return which increases the duration.

Agree! AZEK, the dealer that is diagnosing this issue is one of the best.

[EuropeanAM]

Only 4 injectors were flow tested because the other two had just been replaced. The latest two injectors to fail were the first two replaced so now we have new injectors failing as well. Neither dealer has been able to tell me why or how they are failing. I was told the ohm out correctly so they don't think they failed electrically. But I'm beginning to wonder if I am getting solid information from dealer.

This is unfortunately QUITE common. Direct (Air) Injectors will often fail in a cascading fashion (bad or high-flow injectors damaging newer, otherwise good injectors). Additionally, CARBON present in the rails and hoses is often passed into freshly cleaned injectors, damaging surfaces of the moving components (and resulting in an unacceptable duration, AND/OR intermittent operation).

Ask your dealer to back up, clean, and VALIDATE every component starting at the AIR FITTING on the air compressor, and ending at the Direct Injector (ALL SIX OF THEM) inside the cylinder. Then, and ONLY then can you say with any level of certainty that the system will function properly, as every single related component has been validated, cleaned and serviced.

[AZEK]

Really appreciate the feedback guys will be taking this info to my dealer and pray for a better outcome than what I've had.

[AZEK]

They fail by having excessive flow. This is believed to be caused by excess wear on the seat and face of the valve element. The actual cause is from galling of the stem to guide. They are both made from the same or similar materials (austenitic sst) which is highly prone to galling. The direct injectors rely on a return spring to close the valve. The extra friction causes a slow return which increases the duration.

Leo13 appreciate your feedback, so if we know what makes them fail how do we prevent more DI's from failing by cleaning the ENTIRE system as EuropeanAM suggests?

[EuropeanAM]

Yes...