Help 05 340 8.1 going into guardian mode

liv2ryde100

liv2ryde100

Active Member
May 17, 2012
901
long island
Boat Info
07' 40 sundancer
Engines
cummins 5.9 380's
Hey I have an alarm going off and boat entering guardian mode when trying to plane off. Any idea?
 
Could be water pressure, could be a sensor... hard to tell. Probably have to put a diagnostic computer on to find out.

When's the last time your impellers were changed?
 
Now I have this code... Prt emct ovrht. And I get that without the motor running.
 
Probably the I.A.C. (Idle Air Control Valve) Swap with other engine and if problem moves over, there you go.
 
Kreole Kid said:
Probably the I.A.C. (Idle Air Control Valve) Swap with other engine and if problem moves over, there you go.
Click to expand...

IAC - That's a different symptom... won't idle.

liv2ryde100 said:
Now I have this code... Prt emct ovrht. And I get that without the motor running.
Click to expand...

"Prt emct ovrht" is port motor Exhaust Manifold Coolant Temp overheat.

Are you closed cooling? Sounds like it. If so check your anti-freeze level.

Here's the codes:
http://cd8ba0b44a15c10065fd-24461f3....vanillaforums.com/editor/m1/512au5re9znf.pdf
 
There is a heat sensor located in each manifold that is to protect the engine. You will see the plastic end sticking out of the manifold with a small black wire attached. Have you felt the manifolds with your hand? You should be able to briefly touch them at any time while the engine is running - they'll get hot, but not red hot. If they aren't out of the question "hot" it may be a bad heat sensor. Coolant does NOT flow through the manifolds. Seawater is pumped from the bottom to the top, through the stainless elbow and then out the rubber exhaust hose. If there is a lack of seawater it may be enough flow to cool the engine's antifreeze but not enough to cool the hot exhaust manifolds afterwards.
 
Thanks everyone, quick update my mechanic says it's a bad sensor in exhaust manifold. Boat never ran hot, and now with the motors ice cold the alarm goes of without even starting the motor. Gonna swap it out tomorrow and see how it goes. Thanks again!
 
sfergson727 said:
NEVER NEVER NEVER take a suspected bad IAC and put it on a good engine. Bad things happen to your ECM when you do that.

If anything, you could take a good IAC, and put it on a bad engine and see if it fixes it, but take that bad IAC and throw it away (or save it for the insurance company to inspect, but don't ever put it on another engine)
Click to expand...


Oops, I forgot about that drama Scott.

Sorry about the misinformation.
 
Well hopefully the sensor is my problem because it's a lot cheaper than the iac valve haha
 
sfergson727 said:
NEVER NEVER NEVER take a suspected bad IAC and put it on a good engine. Bad things happen to your ECM when you do that.

If anything, you could take a good IAC, and put it on a bad engine and see if it fixes it, but take that bad IAC and throw it away (or save it for the insurance company to inspect, but don't ever put it on another engine)
Click to expand...

I was wondering just how long it would take for you to chime in.....
 
Just an update. I picked up the new sensor and we decided to jump it out before installing it. Good thing we did, the code was coming from the starboard motor port manifold. What's tricky is that the motors are in backwards with the v drives so the port manifold is actually on the right side of the boat. Anyway the sensor worked and all is good. 30$ part
 
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