Engine trouble

[Tahoe Mike]

Hello Crew,

 

I have a 2002 Malibu Wakesetter XTI with engine problems.

Last summer engine had trouble with the idle and stalling.  Had to be towed twice.  Old mechanic couldn't find out the problem.  At the end of the year had a second mechanic diagnose the problem with correct software.  Error code # 51 appeared.  Mechanic sent ECM to Los Angles and it was "re-flashed", then the boat was put away for the winter.  I installed a new IAC sensor.  The beginning of this summer put the boat back in the water and it ran okay for two short outings.

The next few times going out the engine would randomly rev up with the alarm going off.  Sometimes the alarm would briefly go off even if the RPM's were fine.  Went out again and the engine died and had to be towed in again.  Mechanic couldn't get the boat running and later said it had the same error code # 51, again.  Mechanic put in another ECM (not cheap).  Now the boat starts but have the same problem of revving up and alarm going off.  Back to square one. 

Mechanic is stuck and I don't want to keep starting it in fear a third ECM will be needed.  

The mechanic said the IAC, TPS, fuel pressure, etc is all working good.  

About to go to a third mechanic. 

Any ideas???

Thanks, Mike

 

       

[Steve B.]

Again hate to throw money at issues like this, but, injectors, coil, rotor, cap, etc?

Steve B.

[Woodski]

Throwing more parts won't solve you root cause, a repeat of the same error code has some underlying issue.  What specifically is EC #51?  If you are frying the ECM, there probably is some voltage spike issue as a root cause.  Why did the ECM need a re-flash?

[oldjeep]

10 minutes ago, Woodski said:

Throwing more parts won't solve you root cause, a repeat of the same error code has some underlying issue.  What specifically is EC #51?  If you are frying the ECM, there probably is some voltage spike issue as a root cause.  Why did the ECM need a re-flash?

DTC 51 -  ECM Calibration Checksum Error

Unfortunately not much in the manual

 

Edited August 9, 2019 by oldjeep

[justgary]

That smacks of a grounding issue to me.  The ECM will get confused if you let the voltage brown out.  Check all of the power connections at the helm and engine, including the starter and alternator.  Pay extra attention to the forgotten things like the ground straps behind the heads and also make sure that the cannon plug has good, clean connections.

[Tahoe Mike]

Hello, 

 

Thanks for the replies! 

The ECM needed a second re-flash because after the first re-flash, the problem was not fixed.

 Before the mechanic hooked up the ECM after the second re-flash, he disconnected grounds, wires etc.  Then the mechanic cleaned and checked for corrosion and re connected the wiring (3-hours).  

The mechanic had the diagnostic computer hooked up and started it. Boat ran good in the slip for about 20 minutes. 

After 20 minutes, the SAME problem started again slight rev up with alarm them back down. Once it revved up with alarm three times in a row. 

Back to original problem.  Mechanic is at a loss. 

Error code # 51 is apparently the ECM.

Still don’t know the cause / problem. 

Thanks for the input!!!

Mike

 

 

 

 

[Woodski]

@Tahoe Mike - I would do a search on this site, a couple of members here have done some in MEFI work and root cause and had an in depth discussion on MEFI issues.  I don't remember the specific thread but simply use MEFI or MEFI 4 as a search and it should pop up. 

@oldjeep - Agree, not very helpful.  Need to know the why IMO.

Edited August 10, 2019 by Woodski

[Tahoe Mike]

A different mechanic came by today and found green corrosion on a wire near the distributor cap. 

Took the boat out for 11/2 hours and ran like a champ.  Drove the boat all over the lake under every condition no problems.  However coming into the slip it died, but then started right back up and started several times since in the slip.  Mechanic is coming by tomorrow and I might be good.  

The original IAC was put back in the boat as well.

I will post with an update in the following few days.

Thanks for all the input and suggestions so far.

Mike

 

 

 

  

[bus1junkie]

any update?? I've got a 2002 Wakesetter with similar problems. Code 51 will immediately come back a second after clearing. ECM will not signal fuel pump relay to run but I can. If I add a little fuel to throttle body is will burn that fuel so ignition is ok but ECM won't flash injectors. I can make them work and they have voltage when key is on but ECM won't flash them. Any ideas? Thanks in advance.