Caterpillar 3406e overspeed sensor

[JLR]

Anyone know anything about a Cat 3406e overspeed sensor 2 fault. It shows a code 273. Sensor 2 I am told, has already been replaced. Thanks.

 

[JLR]

Anyone?

 

[doc g]

I know that sometimes the code for the error is not correct and that when u hook up the laptop to the engine you can find out more specifics. I had one that was telling me the rack position sensor was bad and it was a bad connection. The diagnostics in the onboard computer are crude compared to the info that can be had with the laptop hookup . ....I wouldn't run out and buy an over speed sensor until u have it checked out by a Cat guy......Pat

 

[Cricket]

Is the fault de-rating the engine or is it just throwing an alarm notification?
Most of the CAT sensors have a primary and a second sensor as back up.
First thing to do is to find it and then unplug it and plug it back in.
I've heard of chafed harness issues, which apparently are tough to find, never had any of those.
We chased intermittent sensor issues a few years ago and it ended up being a bad ECM, think it was a cam shaft speed sensor showing a fault.
Unfortunately we were at the WMO so we were dependent on Albin CAT in OCMD which diagnosed the issue incorrectly multiple times that week.
Did a lot of engine shutdowns and restarts to get through the week.
Didn't get it resolved until we got back to NJ and our regular Ransome CAT guy figured it out right away.
Some read the computer diagnostics better than others.

 

[Glory]

Check the connections at the sensor and at the ECM, any green, ir corrosion should be addressed.

You might also want to check the engine speed sensor(s) and SRS, or crank position sensor for green.

 

[JLR]

Thanks. I have been corrected. It is a code 723. I will check those overspeed sensors and the wiring as well. I just have to find out where they are on the engine. Much appreciated. By the way, they did NOT interfere with the engine operation.

 

[JLR]

Any recommendations for a Cat guy on Long Island other than H.O.Penn. No beef with them but prefer smaller, hungrier tech guys.

 

[JLR]

Is the fault de-rating the engine or is it just throwing an alarm notification?
Most of the CAT sensors have a primary and a second sensor as back up.
First thing to do is to find it and then unplug it and plug it back in.
I've heard of chafed harness issues, which apparently are tough to find, never had any of those.
We chased intermittent sensor issues a few years ago and it ended up being a bad ECM, think it was a cam shaft speed sensor showing a fault.
Unfortunately we were at the WMO so we were dependent on Albin CAT in OCMD which diagnosed the issue incorrectly multiple times that week.
Did a lot of engine shutdowns and restarts to get through the week.
Didn't get it resolved until we got back to NJ and our regular Ransome CAT guy figured it out right away.
Some read the computer diagnostics better than others.

Any chance you might elaborate on your overspeed sensor faults and ultimate diagnosis of a bad ECM? Sorry, these are my first CATs and I would like to be as efficient as possible in chasing down this fault.

 

[Cricket]

I'm not totally sure it was an overspeed sensor, could have been a crank position sensor??? Basically they are all the same to me when it comes to diagnosis and repair.
Issue first showed up on the way in from fishing, engine had a little hicup and thru an alarm and code. Shut it off, restarted all good. Fished probably another 5-6 times and no issues. Went to the WMO and the first day the engine did the same thing on initial run up out of the inlet, turned off, restarted, and it did it almost right away. tried to reboot 1 more time and the alarm wouldn't clear. Waited for 300 boats to come out the cut and then went back. Alban walks across the street, hooks up the laptop and it shows the primary and secondary sensors were bad. Replace both, take a sea trial all good. The next day same issue, this time while offshore, 1 reboot and all is good. Had Alban back to the boat almost everyday that week, they said they found a loose connection. Same thing happened on the way home, Ransome came, hooked up, guy said the ECM has to be bad, went to the truck, hooked up a new one, sea trialed the boat twice a day for the rest of the week with no issues.

The whole time I was in contact with our Ransome tech and he thought from day 1 it was the ECM, Alban refused to believe that, like I posted before, some are much better than others understanding what the laptop is telling them.
Don't know any independant CAT techs up on LI, You have to make sure the outfit you bring in has the ability to connect including the correct software. CAT doesn't make it easy for independents to function.

 

[JLR]

Thanks so much. The engine surveyor that was used when I just bought the boat did not have the correct software to access past codes. Live and learn. When I touched base with the PO, he said he had the same issue and replaced speed sensor number 2, believing he had cured thew problem. Guess not. So, I guess it will be a winter fix first winterizing the engine, then getting it fixed and then winterizing again ---unless I just wait until the Spring.

 

[JLR]

Cricket - just sent you a pm. Thanks.

 

[JLR]

Verdict is in. Bad ECM. Missed on the survey. Not very pleased. Although I did get a whopping 30 minutes of trouble free operation.

 

[Boatsb]

Nice Xmas present.



For caterpillar.

 

[JLR]

No kidding!

 

[doc g]

Hope it fixes the problem !

 

[Cricket]

That's sucks but at least you now know what the issue is. Sort of presented just like our bad ECM did with an intermittent issue, but the engine still would run. One would think the ECM would be all good or all bad.