Thoughts on R5 EVC error w/odd engine behavior

[jeffpr]

Hi all,

We took our R5 w/Volvo 350 (Surf, but otherwise same as regular R5) out for first time this season after 100 hour service + winterization last fall, and now de-winterized and ran into an issue:

The engine started, warmed and ran normally as we idled out in the marina. I put the engine/drive in neutral to wait for a boat ahead. I heard a chirp from the EVC and saw the indicator with the exclamation inside the triangle on the front of the shift lever housing. While in neutral, the engine RPMs surged quickly up and down with no throttle input. The RPMs returned to normal idle and I put the boat in fwd gear - it chirped again, showed the error indicator and the RPMs surged. Since I was in tight space in the channel, I put it back in neutral and shut the engine down - worried that I didn't have control over RPMs. Back in our slip, I started the engine and it ran normally with no errs - but I didn't put it in gear. I couldn't see any err msgs on the Garmin - and I forgot to check the Volvo Connect app to see if there were any messages logged (I will do that).

Any thoughts on what this could be would be greatly appreciated. Techs can't look at it until end of next week - so I figured I'd try any investigation/troubleshooting you'd suggest.

Thanks!

Jeff

[jhnmdahl]

It makes sense that it would be something they tinkered with during winterization or bringing it back out, but I can't think of what that would be unless they were fiddling with the throttle controls or the engagement clutch on the sterndrive. I'm sure others will chime in shortly.

[stifflkd]

You will not see the error on the Garmins but it is reported on the EVC display. You will have to do this procedure at the time of the event. It is lost once you turn off power

[jeffpr]

Thanks for the information jhnmdahl and stifflkd - I appreciate it. I was able to use the Volvo Easy Connect app yesterday to get some info while I reproduced the problem.

I ran the engine in idle for 5-10 mins until the same error occurred:
Exhaust temperature too high
Engine power is reduced. Acknowledge fault by pressing the OK button. Contact a Volvo Penta workshop.
Driveline: Port
Status: active
Occurrences: 255
Engine hours: 97 h
FMI: 14
DiagCodeNr: 12
TypeOfDC: PSID
MID: 128

After the chirp and error exclamation mark appeared, the engine RPMS surged from 700 to 1,700, and then up and down from 1,400 to 1,700 maybe ten times, then chirp again and returned to idle (then I shut it down).

During this behavior, the engine values were:
Coolant temp: 167 degrees F
Oil temp: 78.6 F, then 96.4 F, then 117 F
Oil pressure: 432 kPa
Exhaust temp: 1330 F. (never seemed to vary)

So, perhaps something is interfering with exhaust cooling water on one or both manifolds, and/or the temp sensor(s) went bad?

[billk2632]

I would check two things:

Raw water pump impeller. When was it last changed?

Make sure the cap on your flush hoses is tight. If not tight the pump can suck air and not cool properly. This was probably used during the 100hr service.

[jeffpr]

Thank you - I will check these. I assume (but will check) that the impeller was changed at the 100hr service. And the water temp stayed at its normal 167 degrees the whole time - but I supposed the same system is supposed to be delivering cooling water to the exhaust manifolds and that might not be happening.

[billk2632]

Correct - the raw water pump could be pumping at reduced capacity for some reason - enough to keep the engine from overheating, but not enough flow. Quick things to check - the flush fitting can really be a problem - if you leave that off or loose and it sucks air it will reduce the cooling capacity - ask me how I know!

[NautiWeasel]

I agree, the seawater pump s/b checked. It could definitely cause the exhaust temp to be hot. And that temp is HOT. However I don't know that the seawater pump not cooling the exhaust would cause the engine running issues you're getting. A lean fuel condition will cause the running issues, and the high exhaust temps. Lean condition means hot exhaust. Usually the easiest way to diagnose a lean condition actually, without a computer telling you what's wrong. I'd still check all vacuum lines, connections, and fuel connections over very well. But look at the seawater pump (impeller) too. Can't hurt.

I'm very curious what the actual remedy will be on this one.

[jeffpr]

Hi all - a quick update: Given the feedback that the exhaust temp reading of 1330 degrees F was super high - I used the Volo Easy Connect app to check the exhaust temp reading prior to and just after starting the engine. Turns out - it reads 1330 degrees before even starting (and also just after) while the coolant temp was 73 degrees. So, my amateur guess is that it is the sensor that has failed.

I couldn't figure out the location (2021 Volvo Penta 350) of the sensor(s) - I assume each manifold has at least one. I did note that the "Exhaust temperature too high" alert said "Driveline: Port" and since I have just one engine, perhaps it is the port sensor (?).

If anyone could point me to the location of the sensors (I couldn't find a diagram online), I'd appreciate it. Plus any opinions on whether you think the theory of the sensor going bad could be valid.

Thanks.

Jeff

[jeffpr]

I found the Volvo service manuals site: https://www.volvopenta.com/your-engine/ ... handbooks/ as well as the parts site: https://www.volvopenta.com/shop/0 - so my next step will be to examine the two exhaust temp sensors, make sure they didn't get disconnected/broke somehow and perhaps pull them out to take a look. The part itself is inexpensive.

Thanks again for the ideas here.

Jeff

[stifflkd]

My exhaust temp has read 1330 since new. I do not believe it is due to a defective sensor, but that its just a dummy value from the EVC. Will be interested to see if new sensors make a difference. Exhaust temp is an extremely important parameter and it makes no sense why Volvo would not provide that info.

[jeffpr]

That is interesting that yours reads the same 1330 degrees - the value must mean something else or as you say, a dummy value from EVC. I checked the two sensors today and there were both plugged in securely (I had hoped for something simple). I removed both and checked with ohmmeter and they both behaved similarly - started at approx. 16 ohms and as I warmed them via body heat, they gradually moved to approx 12 ohms. Hopefully the dealer's tech can look into the situation this week.

[stifflkd]

Sounds like a restriction in the raw water flow. As mentioned earlier, it could be caused by air leakage from the fresh water flush. Did you check the flush port on the outside of the boat at the transom. If your dealer serviced the boat this winter he most likely connected the water hose to that port as opposed to the one inside the engine compartment. Much more convenient when the boat is on land.

[jeffpr]

Thanks - I will mention the flush port to the dealer. The boat is in the water, so I can't get to the port you mention.

[jeffpr]

Quick update: the dealer's tech took a look today and determined that "...the brain that's in your whole assembly is bad." (quote from their email). So, apparently not a cooling or exhaust temp issue (assuming they're right).

Shakes our confidence in the boat (our second new Cobalt) to have it fail twice (couple years back it was a failed engine coupler) to the extent it has to be towed back to our slip. Could have been tricky situations depending on location/weather when it failed - my family no longer feels comfortable taking the boat out without me (can't really blame them).