Volvo 5.0GXi Beeping Constantly despite pulling sensor wires

[mkap370]

I need some help. A friend asked me to look at his boat since the repair shop he usually goes to is booked out for weeks. I thought this would be pretty simple.

Sorry, I didn't think to write down the complete motor model and serial number but the boat is 2002 with 5.0GXi. I was hoping to get some suggestions of things to check before I go down there again- I'll get the complete numbers then.

He was at no wake speed and the audible alarm started. It's "beep beep", maybe a bit longer than it takes to say it out loud. Then quiet for a bit longer than the time of the beeps and then repeat... forever. All his gauges showed normal so he idled back to his slip. I went down the next day and it does it from a cold start and never stops.

At start, everything seems normal- the alarm gives two test beeps when the key is turned. Then nothing until the motor starts and immediately the beeping starts. I removed the wires to the exhaust risers and the oil pressure switch (spade connector, port, aft, over original oil filter location). I first disconnected one at a time and then all of them. I waited for over a minute. There's plenty of oil and the gauge shows pressure. Nothing felt unusually hot and the temp gauge shows normal and yet it continues to beep.

I checked for shorts and shorted sensors and didn't find any. I measured 5V at the sensor wires. The oil switch is working- goes from being grounded with the engine off to open once the motor is started and oil pressure opens it up. I don't know if the motor is in SLOW mode. I throttled up at the dock and it seemed to rev up but his tach isn't working (since well before this) so I can't swear I got it up over 2500 rpm.

I found a copy of the "7742218 Diagnostic Book" and went through as much of the troubleshooting on pages 252-255 that I understood. One of the later tests is to disconnect the J-1 connector at the ECM and turn the key; the horn should not sound. This one did. In that case, it said to check for another grounding source, possibly with the harness or Pin 4 in the 10 pin connector. I traced the wiring to the J connector and found no short in the sensor wires. I pulled the 10 pin connector and the wire to the alarm horn is not grounded.

I'm out of ideas. I can't check the ECM for codes and have no idea how to test the ECM itself. I'm not even clear on whether the alarm could mean something other than the overheat or oil pressure sensors grounding. The diagnostic book makes it sound like those sensors (or some unintentional short) are the only thing that could cause the beeping.

Any thoughts of what I'm missing or should try next?

Thanks in advance.
Mike

 

[dypcdiver]

I have no idea, but we have just had someone on here who eventually traced it down to his depth sounder!!!

 

[alldodge]

Being a GXI it should have exhaust temp switches

 

[mkap370]

I guess I left the word "sensors" out of my fourth paragraph; meant to say that I removed the wires from the sensors on the exhaust risers... Are there other temp switches somewhere? I found the sender for the temp gauge but didn't notice any other switches or see any on the wiring diagram.

 

[JustJason]

You are going about this the wrong way. Depending on exactly what sensors you are pulling wires off of, pulling wires off of certain sensors will cause an alarm. You need to get the engine scanned with a scan tool.

 

[Silverbullet555]

My VP engine has a sensor in the flame arrestor. I had a wire break on it and that sent my alarm going. I found it with a scanner to give me the code.

 

[Thalasso]

If it was your exhaust temp sensors there would be no beeping. It would be a constant alarm. When the engine is cold the alarm will not sound until temp comes up
You say he idled back. Was it because the engine went into limp mode (2000 RPM's) or because he wanted to just idle.
Did the engine shut down when he went into neutral?
Two beeps when starting is your fuel pump priming.
There is going to be a code stored. You need to get it scanned to find out what it is.

 

[mkap370]

Thanks for all the feedback.

I wondered about the beeping versus a constant sound. The diagnostic book says high riser temp will sound a "steady beeping tone". I actually tried to ground out the exhaust wire to see if the alarm would change; it doesn't.

To clarify the events when it started, he idled back to his slip because he was in a no wake zone. As far as I know, the boat never quit or acted unusual other than the beeping. I want to take the boat out with him to see if it's actually in SLOW mode or not.

He already has an appointment to take the boat in and they will scan it, but it's still 2 weeks out. I was hoping it was something simple so I could get he and his family back out on the water.

 

[alldodge]

Are there other temp switches somewhere?

There a temp gauge sensor and an ECT switch item 24

https://www.marinepartseurope.com/en/volvo-penta-explodedview-7744300-30-7516.aspx

 

[89retta]

I have no idea, but we have just had someone on here who eventually traced it down to his depth sounder!!!

I was thinking the same thing. If he has a Faria depth sounder in his boat check that first. Mine does this off and on through out the boating season.

 

[mkap370]

I wanted to follow up with the end of the story so that this thread may have some value for someone else someday.

We finally found a mobile mechanic that said he had the software on a laptop to read the DTC (error code) but when he came to the boat, he didn't bring it. He was very condescending and told us that he didn't need the computer yet. He spent an hour messing around and ended up telling us that it needed new plugs, cap, rotor and wires and that was the problem. He wrote up his bill and said if that didn't do it, he'd come back for free with the computer. We did all that but it made no difference.

A week later, he came with the computer and sure enough, the ECM (computer) was holding several error codes. Three different errors were called error #81. Two of the "81" errors were regarding the injectors and one was "cam signal fault". He told us that the motor didn't have a cam sensor. He made a call and confirmed with some Volvo "expert" that there was no cam sensor so it must mean the crank sensor. And he pointed out that junk like this is why he doesn't trust the computer stuff. So I ordered a new crank sensor and put it in. No difference.

After a few seconds of research, I found that the motor does in fact have a cam sensor mounted in the distributor under the rotor. I also found out that it doesn't really need the cam signal for the motor to run. It works in conjunction with the crank position sensor to tell the computer which stroke the engine is on and helps it start faster.

I was done with our mechanic at this point so I decided to try to read and reset the error codes with an LED and paper clip jumper; a DIY version of the CodeMate. It worked perfectly. Though as with the CodeMate, all you get is a series of flashes on the LED. After clearing and confirming that all the codes were gone, I started the motor and got the beep beep back immediately. I checked again for error codes and only had one this time, an 81. And therein is the shortcoming of the CodeMate; an error 81 can be about half a dozen things including the cam signal fault and the injectors. I followed the troubleshooting for the injectors as far as I could without a noid light set and it all checked out okay so we ordered a new cam sensor.

It finally came and I put it in yesterday. After six weeks of the motor beeping back at me every time I tried things, I truly did not expect it to stop this time. To my absolute amazement, the beep beep was gone.

To summarize, I should have trusted the DTC error codes (as suggested above!). If I'd have looked into the cam sensor first, this would have been solved weeks ago. I shouldn't have gotten distracted by our bad mechanic and his advice. I can also vouch for the paper clip and LED working, at least on this MEFI 4 ECM.

Lastly, I'd like to comment on the beeping. Nowhere in the manuals or the couple mechanics I talked to did I get a clear answer about the engine alarm beeper (or warning horn as it's called in the manual). Apparently, serious errors sound the solid beep as noted above by Thelasso. Our alarm for this error was the beep, beep I described in my original post so that's what you get when you have less serious errors.

And it took me a second to figure out the suggestion that the depth sounder might be the culprit. This motor has the alarm horn mounted on the engine and no beeper in the dash with the sounder.

Thanks for the help.

 

[alldodge]

Thanks for filling in the isuues

 

[Dave-R]

As ALLDodge said, thanks for telling us the conclusion. With all the electronics on the new boats, it's great to hear some of the problems the members have and how they fixed them. I caved in and bought a Rinda diacom. My language has improved and blood pressure decreased. With all the smart phone apps there are, why doesn't someone come up with one that can actually tell you what is wrong, instead of some stupid code. Never mind, then you wouldn't need to take it the dealer. Okay I get it. Dave-R

 

[Thalasso]

As ALLDodge said, thanks for telling us the conclusion. With all the electronics on the new boats, it's great to hear some of the problems the members have and how they fixed them. I caved in and bought a Rinda diacom. My language has improved and blood pressure decreased. With all the smart phone apps there are, why doesn't someone come up with one that can actually tell you what is wrong, instead of some stupid code. Never mind, then you wouldn't need to take it the dealer. Okay I get it. Dave-R

Did you get the standard kit? Is the Volvo Penta workshop manual in the program?

 

[Dave-R]

I got the standard kit, and I had to get a special extra adapter for the 2011 Volvo Penta EGC. It came with all the service manuals for Volvo and Mercruiser, and a lot the the inboard engines. I think there are manuals for outboards on it also. It has a great test section, for testing throttle operation, each fuel injector, each spark plug, and o2 sensor operation. It also calibrated my trim gauge. It displays every engine parameter you could think of. I think it was around 700.00$ They will update it for free if needed. Where my engine was under water over a month, most of the electronics were shot. I had the boat into a dealer for about 90 days and they could not fix it. I figured buying the Diacom was my only way to diagnose the engine. The tech at the dealer had a small hand held device that they used to read codes. The Diacom looks to be much more advanced. I put the program on my desktop, and the laptop which I take out to the boat and actually use. Dave-R

 

[Thalasso]

What is diff between the (can kit $699.00) that you apparently got compared to the standard kit.($579.00). Is it just the diff adapters?