Engine Air Temperature sensor

[Pilot]

Hi all:

Anyone have this alarm before? And, if so, what is the part #? The dealer parts guy can't seem to locate anything on it. Its been going off with 2 beeps when I first start it up and then after I clear it a couple times, it stops and goes away. it only happens when #2 engine is 1st started and of course is cold. It doesn't shut it down, just provides the warning. Not sure if its affecting idle performance or not. The engine is an 8.1 Horizon. Thx

 

[Korkie]

I have 496 mags (8.1s) and have been dealing with the same thing for 3 years. Mine comes up a [MAT ckt low] on my VV 703. Switched sensors on motors and no change. Put new sensor in, no change. Mine is intermittent as well. Sometimes on start up and others when coming off plain. Only thing several merc techs can come up with is poor connection/short on that circuit from computer or actual comp issue. The sensors on our motors work off of like 3.6v and are very sensitive to voltage changes. So when it does happen, I disconnect all the harness connections on that motor and reconnect them. Usually after I get done with the boat that day and while the engine is cool. Be sure to shut down all power to motors. Shutting everything down, keys off and breakers off for a while also seems to help. I am told the VV / SmartCraft is a computer and needs to be rebooted occasionally. Normally doesn't affect performance, just a pain to clear out every time. If you figure it out, please share. I will do the same.

 

[Pilot]

I have 496 mags (8.1s) and have been dealing with the same thing for 3 years. Mine comes up a [MAT ckt low] on my VV 703. Switched sensors on motors and no change. Put new sensor in, no change. Mine is intermittent as well. Sometimes on start up and others when coming off plain. Only thing several merc techs can come up with is poor connection/short on that circuit from computer or actual comp issue. The sensors on our motors work off of like 3.6v and are very sensitive to voltage changes. So when it does happen, I disconnect all the harness connections on that motor and reconnect them. Usually after I get done with the boat that day and while the engine is cool. Be sure to shut down all power to motors. Shutting everything down, keys off and breakers off for a while also seems to help. I am told the VV / SmartCraft is a computer and needs to be rebooted occasionally. Normally doesn't affect performance, just a pain to clear out every time. If you figure it out, please share. I will do the same.

Thanks, appreciate the reply and results of your efforts and workaround. I'm still exploring this with dealer and mechanics and will let you know what I find. I actually had one mechanic tell me there is no such air temp sensor installed on the 8.1 engines and that its a ghost alarm. You're right though, its a pain in the ass, but doesn't shut down or put engine in safe mode so,, thats a good thing. will keep you posted.

 

[Korkie]

Thanks, appreciate the reply and results of your efforts and workaround. I'm still exploring this with dealer and mechanics and will let you know what I find. I actually had one mechanic tell me there is no such air temp sensor installed on the 8.1 engines and that its a ghost alarm. You're right though, its a pain in the ass, but doesn't shut down or put engine in safe mode so,, thats a good thing. will keep you posted.

It is on the backside of the Intake Manifold, with you having V drives, it would be on the front as you are looking at your motor. If your mechanic thinks says it doesn't have them, then you may want to consider a second opinion.