Mefi 1 v8 EFI Fault's Codes.

[Nordo06]

Hello everyone, New to the forum, I apologize in advance for my English, I use a translator.

The problem is not permanent, it may work fine for 4 hours out of 10 hours of use.
 Both hot and cold.

However, it starts all the time with no problem.

 

I'm having some trouble with a Mercruiser 305cid 5.0 efi v8 engine using the Mefi 1.

-1 Slow down idlle. (400 rpm)

-2 no power (rpm limited)

-Smoke and oil consumption. 

 

Using a code reader with a paper clip and a continuity multimeter. I get 3 fault codes.

-14 high temperature ECTs

-21 TPS Trothle Position Sensor (high signal)

-33 MAP manifold absolute pressure (signal high)

 

In case of doubt, last year I changed / realized:

The sensors:
(all new)
-Ect Temperature probe.
-Map sensor
-Time
- knock sensor.

-Ignition:
(brand new) distributor, coil, cable, spark plug

-injection:
new injectors, and TBI rebuild .and new kit fuel regulator pressure

- Check the electrical harness according to the mercruiser procedure. (pin by pin/connector by connector)

- Check engine compression. Over (10.5Bars) on all cylinders.

 

I'm out of ideas. (I'm afraid of a faulty MEFI 1 ECU)

By chance do you have any?

Thanks for reading.

Sorry again for my pronunciation and my writing.

Good day friends

Edited March 6, 2023 by Nordo06

[justgary]

12 hours ago, Nordo06 said:

-Smoke and oil consumption.

This should not happen.  Check the compression again, but also do a leakdown test.

https://www.pegasusautoracing.com/document.asp?DocID=TECH00137

Is this engine multi-port, or throttle body injected?

[Steve B.]

That translator works well.

[Nordo06]

5 hours ago, justgary said:

Cela ne devrait pas arriver. Vérifiez à nouveau la compression, mais faites également un test de fuite.

https://www.pegasusautoracing.com/document.asp?DocID=TECH00137

Ce moteur est-il multiport ou corps de papillon injecté?

Hello Just Garry.
Thank you for your reply.

This motor is mercruiser 5.0 v8  305 cid small block  EFI MONO- POINT INJECTION (2 injectors in TBI) 

  Indeed the oil consumption should not be present.

It is this oil consumption that influenced my compression test the last year . (Suspicion of cylinder rinsing and/or cylinder head problem).

Thank you very much for your link.

Being a DIY enthusiast, I will try to make a pressure test system. (2 pressure gauges, 1 non-return valve, a bit of piping/bolts, and that should be enough, right?.)

Let's say that I try as many manual mechanical solutions as possible before removing the engine.

Edited March 6, 2023 by Nordo06

[Nordo06]

5 hours ago, Steve B. said:

That translator works well.

Good morning SteveB
Yes I try to read myself in both languages, in order to be able to avoid the maximum of distortion..

The main one goes to google translate 

[Nordo06]

 

Hello friends .

A year later, I know. But I don't have time for my boat, this last moment. compressions being OK I buy a valve leak tester.

I'm afraid for the results.

Question : for a good leak test, the piston must be in the Low position? thank you, and good luck to all

 

Thank's all friends

Edited April 24 by Nordo06

[Woodski]

@Nordo06 -  piston should be up at the top of the stroke commonly referred as ‘top dead center’.  Best practice, engine should be warm.

[Nordo06]

Ok thanks for the advice.

I found a video of the fumes if that helps.https://youtube.com/shorts/P5dM53fUkE0?si=hYDM9xagVuYgRNiI