Warning buzzer then engine shutdown

[maicoman]

Can anyone tell me the physical location of the oil pressure switch on the block of a 1998 305 TBI motor ?I am having the motor start and then a warning buzzer and then an engine shutdown.Do all or any warning signals(buzzer) automatically shut down the motor.Could a faulty distributor sensor turn on a warning buzzer.I am trying to open all of the warning switches one at a time to determine the cause,but am unsure of how many inputs there are to the buzzer.Thanks for any suggestions.

 

[Rocky_Road]

Re: Warning buzzer then engine shutdown

I believe that most electric fuel pumps will automatically shut off when low oil pressure is detected...it is a necessary safety feature. Is your pump electric?

If so...and you show decent oil pressure at the helm gauge...then you are probably needing to replace your oil pressure switch. Someone will probably jump in and tell you where to look, if you haven't already followed the wiring from your pump.

Happy boating!

 

[achris]

Re: Warning buzzer then engine shutdown

....I am trying to open all of the warning switches one at a time to determine the cause,but am unsure of how many inputs there are to the buzzer.Thanks for any suggestions.

ECU can also fire the warning buzzer, so if it's a sensor that the ECU is not getting a signal from, buzzer, and if it's critical, engine shutdown.

For a list of fault conditions and the particular buzzer sound they make, consult your owners handbook.... You know, the one you throw in the trash because "I'll never need THAT!!"! :facepalm:

Chris.........

 

[maicoman]

Re: Warning buzzer then engine shutdown

Here is the latest hope someone can help.Disconnected all sensors that get grounded when they are in err.(Oil pressure,oil lube res,etc.)Trying to get rid of the warning buzzer than engine shutdown problem.Achris and others had advised me to change IAC motor which my brother=in law supposedly did already.When I put the computer on the value it was 170 steps out,ignition on motor not running.Started the motor with computer still reading no change to 170 value,buzzer than motor shutdown.Bought another IAC connected all back together put computer and read 50 steps out.Started motor and no buzzer idled great for 5 minutes.Took lines off boat touched the throttle to reverse and the buzzer went off and the motor died.IAC value is now 110 and the motor only runs for 5 seconds again then shuts down.How can I test my ECU off the boat.Where do they sell and or test these computers.Help

 

[svxtech]

Re: Warning buzzer then engine shutdown

Here is the latest hope someone can help.Disconnected all sensors that get grounded when they are in err.(Oil pressure,oil lube res,etc.)Trying to get rid of the warning buzzer than engine shutdown problem.Achris and others had advised me to change IAC motor which my brother=in law supposedly did already.When I put the computer on the value it was 170 steps out,ignition on motor not running.Started the motor with computer still reading no change to 170 value,buzzer than motor shutdown.Bought another IAC connected all back together put computer and read 50 steps out.Started motor and no buzzer idled great for 5 minutes.Took lines off boat touched the throttle to reverse and the buzzer went off and the motor died.IAC value is now 110 and the motor only runs for 5 seconds again then shuts down.How can I test my ECU off the boat.Where do they sell and or test these computers.Help

TPS- Value will be all over the place and drop right before the motor dies. Check there.

 

[maicoman]

Re: Warning buzzer then engine shutdown

Thanks svxtech I assume you mean the computer will have all messed up numbers going to TPS if the ECM is fried ? Nice call ! Thanks again !

 

[Don S]

Re: Warning buzzer then engine shutdown

There are no sensors in the EFI system designed to kill the engine. There are some that will put it into slow mode (reduced rpm) but they will not stop the engine from running.
What is the serial number of your engine? Just because your boat is a 1998, doesn't mean the engine is.
Do you have the OEM service manual for your engine? Have you checked for codes set by the ECM?
The oil pressure switch controlling the fuel pump is ONLY on carbed engines.

EDIT: Did you actually download the oem manual I gave you a link to in your other thread, if so, did you actually read it?

 

[svxtech]

Re: Warning buzzer then engine shutdown

Thanks svxtech I assume you mean the computer will have all messed up numbers going to TPS if the ECM is fried ? Nice call ! Thanks again !

Not quite, numbers coming from the tps... ecm doesn't send info to the tps, other way around. Symptoms sound similar to those with a dead spot or faulty tps, look there before replacing an ecm.

 

[Don S]

Re: Warning buzzer then engine shutdown

I closed your other thread on the same subject. Here is a link to it for those that want to read it.
http://forums.iboats.com/showthread.php?t=518345

Please don't start multiple threads on the same subject, it gets to confusing

 

[svxtech]

Re: Warning buzzer then engine shutdown

I closed your other thread on the same subject. Here is a link to it for those that want to read it.
http://forums.iboats.com/showthread.php?t=518345

Please don't start multiple threads on the same subject, it gets to confusing

Thanks don, after reading the other post I have a Better understanding of whats going on.
Being a TBI it has a Map sensor, unplug it and see what happens...

 

[maicoman]

Re: Warning buzzer then engine shutdown

Thanks don for your help and sorry about the multiple post.I downloaded the manual and I have my own.Have read multiple times and have used a rinda computer all along.No codes are being sent.I disconnected map sensor and a code was set which I went back and erased.With the Map sensor unplugged the motor starts for 2 seconds then emits a continious buzzer and shuts down.Motor serial number is ol351438.In addition to the Knock Sensor located on the starboard block I have another sensor on the port block same local different side.Also another sensor is located just to port side of the distributor.I thought these were the Oil pressure and oil temp switch?My manuel and the one you sent me shows a oil pressure switch at j2-7 of the ECM(page 5G-19 in manuel)MEFI 3 ECM with a Mercury Distributor.Could the temp sensor go to J2-8.I bought a new IAC motor which was at 50 steps out that started the motor without buzzer coming on until I touched the throttle.I checked the shift interrupt switch also.Thanks again to everyone for your generous help.

 

[achris]

Re: Warning buzzer then engine shutdown

Engine temperature sensor goes to J2-11. Have you used a multimeter (digital is best because they have a high impedance) and check the resistances of the sensors, like the intake air temp, and engine coolant temp? Also check that the switches are operating correctly, like the oil pressure switch, the lube oil bottle switch and the shift interrupt switch.... J2-8 is for transmission temp and as you have a stern drive that wire will not be hooked up.

 

[maicoman]

Re: Warning buzzer then engine shutdown

Sent the ECM out to Cali. for a check-up.I hope I am the problem instead of the ECM,but now I will know.Thanks everyone for your help I have learned alot in a short time with your help.I will keep you informed on my progress.

 

[maicoman]

Re: Warning buzzer then engine shutdown

Update, ECM came back from Cali. and everything was fine.A code had been stored of low fuel pressure.Motor still starts and then the warning buzzer sounds and it dies.I can stop the buzzer and keep the motor running if I increase throttle quickly past 1200 rpm.It runs fine at this and all levels above this but when I try to come down to idle ,warning then engine shutdown.I took my cool fuel system out today and I am looking to replace fuel pressure regulator,fuel pressure sensor and possibly the fuel pump while I'm in there .Any suggestions ,comments would be appreciated.

 

[maicoman]

Re: Warning buzzer then engine shutdown

Here is the sorry solution for my sorry tech skills.The shift interrupter switch was bad and that was killing the motor.A friend of mine said that the switch rode open when in order to test the switch you short the 2 leads from the computer and the engine is happy.When the computer shuts the motor down there is a continious beep.When a guage is disturbed the buzzer beeps and as dON AND aCHRIS INFORMED ME those warnings do not shut the motor down.Hope someone will benefit from my ignorance.