Need help Lean/knock sensor code 2005 vlx hammerhead 383

[Stuart]

I've got an issue with my 05 vlx 383 hammerhead.  It runs perfectly, no stalling or hesitating. stays at 160 degrees.  when i just drive it easy with no tanks filled or wedge down i have no check engine come on.  when loaded down tanks full i take off and in about 10-15 seconds every time the check engine alarm goes off.  boat still runs fine, doesnt get hot all seems perfect.  shut it off, drain tanks and drive it and no check engine anymore.  ive replaced fuel filter, plugs, iac unit and new fuel pump still no change.  any ideas????  any help much appreciated!!

Edited August 25, 2021 by Stuart

[csleaver]

Do you know if there is a fault code associated with the check engine alarm?

[Stuart]

i dont remember the code number but it said knock sensor, lean on bank 1 i think.  This problem started last season.  I had a boat mechanic read the code but he couldnt get to it.  I put a fuel filter and new iac on it and the problem stopped but now its back agaiin.  I put another fuel filter on it but didnt help  thanks for your help

 

Edited August 26, 2021 by Stuart

[csleaver]

The diagnostic manual has guides for testing and repairing issues mainly based off of the diagnostic code or the symptoms of the running issue.  I doubt there would be a lean code since O2 exhaust sensors were not used by Indmar until 2006.

If you had a fault code for the knock sensor I would first check that the knock sensors are actually plugged into the wiring harness.  Sometimes they don't get plugged back in after winterization when the knock sensors are removed from the block to drain the seawater from the cooling system.

You likely have a MEFI4 ECM and here is a link to the diagnostic manual.

https://www.m2omarine.com/fckimages/pdf/INDMAR-service/03.pdf

Page 7-1 (PDF 222) has a list of symptoms and diagnostic guides to follow.

Page 5-86 to 5-89 (PDF 143-146) has a non-scan tool diagnostic guide for DTC 44 Knock sensor inactive.  There also a section for diagnosis using a scan tool.