Engine Misfire fault

[ChrisMia]

After a head change and a lot of small others faults , one persists the engine misfire

I checked all, change the rotor and cap, test the coil and distributor, clear and test the cps

check the wires, remove and reinstall the distributor to check the timing, checked cylinder pressure 145~150 all

the engine works great without load, idle and fast ok. But when I tested in water, idle speed in forward ok

however when I put power began a little misfire and chokes until 25 mls.

The image is of the vessel view screen and the fault began with the ignition in on before start the engine


The only thing I didn't check were the injectors.

The engine is a 2011 3.0 MPI EC


I'm stuck with this fault

 

[ChrisMia]

After I checked all the fuel system , pressure valve , injectors and lines , the misfire fault persist.

I quit , will call a mechanical

or does anyone has a tip .

 

[ChrisMia]

What I really cannot understand is how the system identifies the fault only with the ignition on, without starting the engine.

 

[muc]

Misfire is a fault that’s so important that it “latches” on and can only be cleared with a scan tool or a lot of run cycles without a problem.

Is this the engine that’s missing the catalyst?

 

[ChrisMia]

Misfire is a fault that’s so important that it “latches” on and can only be cleared with a scan tool or a lot of run cycles without a problem.

Is this the engine that’s missing the catalyst?

I understand, but there really is a fault, which only occurs with the engine under load.

If there wasn't a real failure, I would not be concerned only with the error code​​​​​​.

Yes it is the engine without the catalyst, but this was solved by installing this

https://www.amazon.com/gp/product/B0...UTF8&psc=1​​​​​​
O2 Sensor For Check Engine Light Adapter Plug Spacer with Built-in Mini M18X1.5 Catalytic Converter

Thank you

 

[muc]

Misfire code is set when the computer detects the crankshaft speeding up and slowing down when it shouldn’t. It might be very important or it might not. Only way to tell is to look at the misfire counters with a scan tool.

It it might be hard to diagnose the engine without replacing the catalyst. The work around your using won’t allow the engine to go into closed loop, so it’s stuck with the legacy tables and whatever was last written into the long term fuel trim. My experience has been that the fuel trim goes crazy during the time that the catalyst is burning out and then your stuck with that until the engine goes back into closed loop to rewrite them.

 

[QBhoy]

Hi
this could be caused by something as simple as water in the fuel or a damp diz cap after storage.
Does your MPI 3.0 actually have injectors or is it a TBI ? Never seen one to be honest.

 

[achris]

...Does your MPI 3.0 actually have injectors or is it a TBI ?

As described on the box, MPI (=Multi Port Injection), not TBI/EFI...

Chris.......

 

[QBhoy]

As described on the box, MPI (=Multi Port Injection), not TBI/EFI...

Chris.......

Very true Chris....but from looking at these badged 3.0 MPi...they sure don’t look like the usual MPI V6 and v8 system we all are familiar with. I’ll need to look again but they still look like a tbi system to me.

 

[achris]

...they sure don’t look like the usual MPI V6 and v8 system we all are familiar with.

I wonder if that because 4 cylinder inline, vs a V configured 6 or 8...

I’ll need to look again but they still look like a tbi system to me.

Have a look at this diagram of the injector rail and the injectors. Looks a lot like half a V8 injected engine to me...

https://www.mercruiserparts.com/bam/subassembly/30916/13809/90

Chris.....

 

[ChrisMia]

Hi
this could be caused by something as simple as water in the fuel or a damp diz cap after storage.
Does your MPI 3.0 actually have injectors or is it a TBI ? Never seen one to be honest.

I hope it is simple, but I have already changed the fuel, the filter is new and I checked all the ignition and injection, maybe some ECM problem but then only with more experience to find out.

My engine have injectors in the intake manifold.

 

[ChrisMia]

Misfire code is set when the computer detects the crankshaft speeding up and slowing down when it shouldn’t. It might be very important or it might not. Only way to tell is to look at the misfire counters with a scan tool.

It it might be hard to diagnose the engine without replacing the catalyst. The work around your using won’t allow the engine to go into closed loop, so it’s stuck with the legacy tables and whatever was last written into the long term fuel trim. My experience has been that the fuel trim goes crazy during the time that the catalyst is burning out and then your stuck with that until the engine goes back into closed loop to rewrite them.

I agree with you, the only situation that makes me think is because the fault show in the Vessel View before starting the engine. Last error memory ?

 

[achris]

... Last error memory ?

It's called a 'stored code', meaning that the fault was serious enough for the ECM to store it, so it can be diagnosed later. Stored codes are generally cleared (by using proper software, not vessel view) after being assessed and repaired, then the code is cleared. Even if you manage to fix the problem, until someone with the right software (usually Diacom from Rinda) gets in and clears the codes, they will remain.

Chris......

 

[QBhoy]

I wonder if that because 4 cylinder inline, vs a V configured 6 or 8...



Have a look at this diagram of the injector rail and the injectors. Looks a lot like half a V8 injected engine to me...

https://www.mercruiserparts.com/bam/subassembly/30916/13809/90

Chris.....

Yeah. It sure does Chris. This is not what I was thinking at all. Fair play. I’ve never seen these up close at all.