Codes

I seen a lot of threads regarding people asking if anyone has access to the EFI codes, however, I don't believe I have seen one response.

I have a 2000 Mercruiser 5.7 MPI/Horizon. I take it, it must be coding as it appears to be in the "guard" position as one engine will not rev above 2500 or 3000 rpms. Not sure how long it's been that way, however, I do have an idea what may have caused it.

I ran the boat for about 15 or so minutes on 6 cylinders. I had changed my plugs, wires, cap, etc....However, I guess I didn't secure two spark plug wires; they fell off causing the engine to only fire on 6 of the 8 cylinders. I think that may have caused it to go into the "guard" position.

Either way, I found the link to test my system using the LED light. However, once I do find any faults, I need to know what they mean.

Does anyone have a link to the codes or can scan and fax/email me a copy of them?

I wish to thank everyone in advance for your help on this issue.

Re: Codes

It has probably stored the code...
Look at this thread and see if it helps,

http://forums.iboats.com/showthread.php?t=384536

Re: General Information About Mercruisers Warning System Horns On EFI Engines.

Re: General Information About Mercruisers Warning System Horns On EFI Engines.

Here is a link to the oem service manual, now you will know exactly what is what,
http://www.4shared.com/document/Pss92fbC/Service_Manual_24.html

it looks like a lot of the above information is for the 555 ECM, and you don't have that on a 2000 model.
Your best bet when asking questions is to post your engine SN, your boat may be a 2000 model, but your engine could be older or even newer.

Re: Codes

If you have a MEFI-3 ECM, here are the codes:

MEFI-3 Diagnostic Trouble Codes and Audio Warning
System
Models
MCM/MIE Sterndrive, Ski and Inboard EFI and MPI Models with MEFI-3.
MEFI-3 Diagnostic Trouble Codes (DTC)
The version 2.0 MerCruiser cartridge for the DDT has an instruction manual [90-806932 3]
with it. On page 62 of this manual, an MEFI-3 Diagnostic Trouble Codes [99 GM ECM] chart
is shown. MerCruiser does not use all the codes listed on that chart.
The six codes that MerCruiser does not use.
1. Code 13 Oxygen Sensor.
2. Code 24 Vessel Speed Sensor.
3. Code 31 Governor Not Tracking.
4. Code 32 EGR Valve
5. Code 54 Oxygen Sensor.
6. Code 55 Oxygen Sensor.
The following two codes are used only on the V8 454/502 cid MPI engines.
1. Code 41 EST/Bypass Failure Type 1.
2. Code 42 EST/Bypass Failure Type 2.
The following three codes are used only on V6 and 305/350 cid EFI and MPI engines.
1. Code 45 Coil Driver Fault.
2. Code 61 Fuel Pressure Sensor [High].
3. Code 62 Fuel Pressure Sensor [Low].

Page 2 of 2 JUNE 2000 99-3
MEFI-3 and Audio Warning
The MEFI-3 engine?s Audio Warning system will sound the alarm differently and it has more
items that will cause it to sound.
There is what is called a ?soft? and a ?hard? alarm.
1. Soft Alarm = Below 3000 rpm. Horn on for 1 second, off for 3 seconds, on for 1 second,
off for 3 seconds, etc.
2. Hard Alarm = Above 3000 rpm. Horn sounds all the time.
Audio alarm sounds for the same malfunctions as MEFI-1 and -2;
1.
MCM - Low lube level in Gear Lube Bottle. [General 1] or MIE - High Transmission
fluid temperature [General 2].
2. MCM/MIE - Low engine oil pressure.
3. MCM/MIE - Too high engine coolant temperature.

Early production and service ECMs had the following items that will sound the alarm;
1. MCM/MIE ? Horn will sound if there is an active engine Diagnostic Trouble Code [DTC]
that is occurring while the engine is running. The horn will not sound a stored DTC.
Correcting the DTC malfunction will stop the horn.
2. MCM/MIE ? Horn will sound if the battery voltage to the ECM is low, [less than 9v for at
least 5 seconds]. Using the throttle lever to increase engine rpm to get the alternator to
put out more voltage will correct most low voltage problems.
3. MCM/MIE ? V6 and V8 305/350 cid engines only. Horn will sound if there is low fuel
pressure [for at least 5 seconds]. These engines have a fuel pressure sensor. The EFI
engines have the sensor in the throttle body unit and the MPI engines have the sensor
located in the port fuel rail toward the rear of the engine. Correcting the cause of the low
fuel pressure will stop the horn.

The ECM checksums listed below have these additional alarms turned ON in them.
NOTE: Later production and service replacement ECMs have these extra alarms turned off.
If the ECM checksum is different from the ones listed below, the extra alarms in that ECM
is turned OFF.
MCM 4.3L EFI: ECM never had these extra alarms turned on.
MCM 5.0L EFI: With D04B or D074 checksum.
MCM 5.7L EFI: With D7ED or D798 checksum.
MCM 350 MPI, MCM 350 MPI Horizon, MIE 350 MPI Ski, MIE 350 MPI Inboard or MIE 350
MPI Horizon Inboard: With E60D or EAED checksum.
MIE Black Scorpion: With BB98 or BB42 checksum.
MCM 7.4L MPI or MIE 7.4L MPI Inboard: With FE28.checksum.
MCM 454 MPI, MCM 454 MPI Horizon or MIE 454 MPI Horizon Inboard: With EBC4
checksum.
MCM 502 MPI or MIE 8.2L MPI Inboard: With F02D checksum.

Re: Codes

Your right, I am sorry. My serial numbers are: OL 397915 and OL 397917

Re: Codes

two serial numbers = two engines??

seeing as how you probably fouled out the two plugs that weren't connected, did you install new plugs and run the engine??

its possible that with the voltage on two plug wires going essentially nowhere the wires are shot, the cap/rotor are now faulty, the coil has an issue, or other ignition related parts are malfunctioning

if you do have a dual engine setup, and the other engine is running correctly, you are in luck because you have a parts room right in your bilge - you can try swapping parts to see if the problem goes away

Re: Codes

Yes, two engines. The plugs, wires, cap, rotor are all good. I use to be a mechanic 30 years ago. Basic are still basics. you can leave a plug wire off for a short time without ruining it or the cap and rotor. It was only off for about a 5-8 mile run. Also, no rotor per sae...2000 350 MPI/Horizon has electonic ignition, this has what is called a "wheel" and rotor sits on it.

Anyways, the engines run good. No skip, no rough running. Only have one engine that appears to be set in the "guarded" position. This prevents the engine from reving high and protecting it when it senses something wrong. I am only guessing running it on 6 of the 8 cylinders may have set it in the "guarded" position.

The only way I can find out for sure what's wrong is to view the codes. I did find the link on making up my own EFI code tool using a 12v resistor LED light. However, once I try it, none of the flashes or codes will do me any good unless I know what the codes stand for.

I was hoping someone had a EFI code manual for a 2000 Mercruiser 350 MPI/Horizon with the engine numbers starting at OL3979........

Thank you. I

Re: Codes

I was hoping someone had a EFI code manual for a 2000 Mercruiser 350 MPI/Horizon

Click to expand...

I gave you a link to the OEM service manual in reply #4 of this thread. That is where the codes are. There is no stand alone "Code Manual" as such. Just the information in the manual.