500efi troubles
09-15-2003, 08:54 AM
#1
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500efi troubles
Have a friend with twin 500efi's in a 02, 35 Sonic. The warning buzzers go of usually above 4000rpm. All temps, pressures are normal according to guages. A marine tech replaced a couple of sensors, checked and cleared the codes, and the buzzers still go off. Now apparently they go off above 3000 now on occassion. Again everything shows fine on guages.
Marine Tech also ran new wire for a suspected wiring problem with one of the sensors. The engine in question
also after comming down off plane idled at 1200 rpm and would not come down. Had to shut off the engine then restart it. A map sensor was recently replaced as a suspected cause and the TPS sensor also checked. All appeared to be fine. All wiring connections were checked, cleaned, etc, and appeared to be ok.
Any idea guys as to why the alarms keep goin off........
Marine Tech also ran new wire for a suspected wiring problem with one of the sensors. The engine in question
also after comming down off plane idled at 1200 rpm and would not come down. Had to shut off the engine then restart it. A map sensor was recently replaced as a suspected cause and the TPS sensor also checked. All appeared to be fine. All wiring connections were checked, cleaned, etc, and appeared to be ok.
Any idea guys as to why the alarms keep goin off........
09-15-2003, 09:05 AM
#2
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The alarms with the 500efi are water temperature, oil pressure, and drive fluid level and are controlled through the ECU (ie. not the same sensor as used by the gauges). Without knowing the trouble codes that the tech has been dealing with, any comments would be a guess at best. I would double check all three sending units, especially the oil pressure and drive fluid level.
09-15-2003, 11:20 AM
#5
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The Audio Warning System IS NOT controlled by the computer. Its wiring is part of the engine wiring harness and is simple to troubleshoot. Did you check the alarm and wiring behind the dash? Mine was just dangling in there.
Last edited by MAG502NUM; 09-15-2003 at 11:26 AM.
09-15-2003, 12:36 PM
#6
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Check your facts...
Mag502num,
If that is the case, somebody had better tell Mercury Racing because they have wired the HP500 EFI with a "Discrete Switches (Audio Warning)" Input to the ECM and an "Audio Warning Buzzer" output from the same ECM (page 5A-20 of Service Manual Number 6). You should check your facts before posting, especially if you are going to SHOUT incorrect information. You are correct, however, that the wire for the warning buzzer is part of the engine wiring harness.
If that is the case, somebody had better tell Mercury Racing because they have wired the HP500 EFI with a "Discrete Switches (Audio Warning)" Input to the ECM and an "Audio Warning Buzzer" output from the same ECM (page 5A-20 of Service Manual Number 6). You should check your facts before posting, especially if you are going to SHOUT incorrect information. You are correct, however, that the wire for the warning buzzer is part of the engine wiring harness.
Last edited by Adivanman; 09-15-2003 at 12:41 PM.
09-15-2003, 01:05 PM
#7
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Thanks guys for the mpute. However it is not my boat that is doing this stuff, although it is another Sonic. From what I understand, the mechanic working on the boat is a very knowledgable guy.
He told my friend that sometimes the sensors in the fluid get gummed up ? And removing the bottles and cleaning them out, corrects this sensor problem.
Does or will the warning buzzers go off if there is a problem with fuel pressure ? I was wondering if he may have a problem with the fule pump or sensor.
Dont have a clue what the codes/if any where in the computer.
Any other idea's ? Again thanks !!!
He told my friend that sometimes the sensors in the fluid get gummed up ? And removing the bottles and cleaning them out, corrects this sensor problem.
Does or will the warning buzzers go off if there is a problem with fuel pressure ? I was wondering if he may have a problem with the fule pump or sensor.
Dont have a clue what the codes/if any where in the computer.
Any other idea's ? Again thanks !!!
09-15-2003, 02:01 PM
#8
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Advanman- No ego here dude....I dont own a service manual, but I have recently worked on my audio warning system and all three sendors are mechanical auxiliaries...I found the system in no way conected to the computer. I could be wrong. How does the computer control this system? Every thing on my 99 502 is electro /mech.
09-15-2003, 02:21 PM
#9
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TeamSonic42 - The most likely candidate is the drive fluid (or sendor) and, although I would doubt that it is a dirty sensor it is possible. There is no warning buzzer for fuel pressure.
Magnum - TeamSonic42 asked a question about HP500 EFI's. On the 500 EFI's "several discrete switch inputs are utilized to identify abnormal conditions tha may affect engine operation. These switches are used in conjunction with the ECM to detect critical conditions to engine operation." WIth the 500 EFI's there are external switches for oil pressure, gear oil, and transmission temperature while coolant temperature is read from the same ECT sensor used by the ECM for the fuel injection system.
Magnum - TeamSonic42 asked a question about HP500 EFI's. On the 500 EFI's "several discrete switch inputs are utilized to identify abnormal conditions tha may affect engine operation. These switches are used in conjunction with the ECM to detect critical conditions to engine operation." WIth the 500 EFI's there are external switches for oil pressure, gear oil, and transmission temperature while coolant temperature is read from the same ECT sensor used by the ECM for the fuel injection system.
