Fuel flow alarm (Dutton EWDS) at idle -causes?

[Antipodean]

I am struggling to understand my current situation. Given that my Ericson 35-2 and I are now in New Zealand (no, unfortunately I didn't sail her all that way) where the A4 is not known to the locals I would love to pick the collective wisdom.

As a preventative measure given the problems of ordering parts from the US I installed the EWDS/Dutton diagnostic system last year and it all seemed fine until a few weeks ago. Now when I idle while picking up the mooring or slowing down in traffic the fuel light/buzzer on the EWDS goes off. Increasing rev's silences it, idle back again and after a few mins it returns. There has been no noticeable change in engine performance and there is no missing even while the alarm is sounding. Obviously the simple thing to do is to just remove the alarm wire. But that would defeat the purpose...

Does anyone have any idea of what I can/should check before I start ordering parts from the US/replacing things?

-The fuel hose is Type A1 USCG ethanol resistant 3-4y old and for the last 2y here in NZ has only had pure petrol through it (Ethanol is only in Premium grade Gas in 2 markets here and then only 2 of the 5 main suppliers use it).
-I am using a Facet electric fuel pump that was installed about 6-7y ago.
-The Racor primary and the Moyer in-line secondary filters were replaced when the EDSS was installed.

Thanks for the help
Rob

[ndutton]

I'm thinking four things:

1. A fuel pressure gauge will be helpful in chasing this down.
2. Oil pressure may be dropping low enough at idle to cut out the fuel pump's Oil Pressure Safety Switch (OPSS) which stops fuel pump operation but not low enough to trip the alarm system oil pressure switch. At idle the engine will continue to run for a minute or so on fuel in the carburetor bowl without the pump running. One way to test this is to bypass the OPSS with a jumper wire between the terminals and see if the alarm repeats while keeping an eye on the oil pressure gauge.
3. The OPSS may be faulty. Same test as above but the oil pressure gauge does not drop below 6 PSI.
4. The EWDS fuel pressure sensor may be faulty. This is where a fuel pressure gauge is helpful. The pressure sensor comes from its manufacturer preset at 3 PSI and is recalibrated to approximately 1 PSI on a pressure testing apparatus. The gauge will show if the EWDS fuel pressure switch is operating within the designed range.

[joe_db]

I would strongly second the suggestion to get a fuel pressure gauge.
BTW - what is your oil pressure at idle?

[thatch]

"Oil temp?"

One clue in helping to determine if oil pressure is involved in this puzzle has to do with the oil temp. You mentioned that the problem shows up while returning to your mooring, and I'll assume at this point that your engine is fully warmed up and your oil is at it's thinnest, resulting normally in lower oil pressure, particularly at idle.
Tom

[joe_db]

Here is an idea:
Connect a 12 volt light to the pump side of the OPSS. If the light goes out at idle, there is your problem

[Antipodean]

Thank you for all chiming in. Please bear with me as I try to work my mind around each of your suggestions.

Neil,
1, Fuel Pr gauge
This would obviously be ideal but unfortunately here in NZ finding an 1/8" NPT threaded anything is proving impossible. A1/8 BSP is available but given the age of the engine (1976), difficulty in finding parts etc I really don't want to bugger any existing threads or run the risk of damage. For that reason I need to try the other ideas.

2, Oil Pr dec to point OPSS trips & stops pump
My gut tells me this is not the story as the motor will idle away with the alarm sounding for several minutes -at least longer than I have felt OK leaving the alarm sounding. I will get back to the boat later this week on my own and see if it does finally die. I have a jumper on board and will also test that way if it solves the problem. Should also be identified using Joe's light suggestion

3, Bad OPSS (not bad oil Pr but bad OPSS trips early/inappropriate time)
Check as for #2

4, bad fuel Pr sensor
As for #1 this is not something I can test at present so it will need to be last on the list.



Joe,
-Pr gauge
As explained above that is not an option right now.

-Oil Pr when happens
Actually that is a problem that I haven't solved. My gauge is 'flakey' and doesn't always read. I have replaced the wire back to the cockpit, and the cockpit gauge previously but it still comes and goes. I have been monitoring the input/output temps on the hose to the external filter, filter bowl and cooler and they have not shown a change in time to rise (good old hand test), or absolute value (IR thermometer). Solving this little dilemia has been a long-term issue.

Thatch
-Oil temp -happens when I return to mooring
I was a little simple in my description as it actually happened at any point. When I start the engine I have choke on and a little throttle applied. If I drop straight down to an idle it will happen then also (cold oil at that point). Note also that I actually have an in-line oil cooler installed so temp is going to be close to engine temp. Oil is changed at min once per 6 months or every 50h -weather here is like Southern CA so all year round sailing (a real change after 2 decades in the NE).

Joe,
12V light on pump side OPSS
A nice simple idea that avoids me having to hold the meter to the terminals. I will give this a shot. Thanks

[ndutton]

Oil Pressure decreases to point OPSS trips & stops pump
My gut tells me this is not the story as the motor will idle away with the alarm sounding for several minutes -at least longer than I have felt OK leaving the alarm sounding. I will get back to the boat later this week on my own and see if it does finally die. I have a jumper on board and will also test that way if it solves the problem. Should also be identified using Joe's light suggestion

There's every chance you continue to receive fuel via a gravity feed or siphon if the OPSS is stopping the fuel pump and Joe's test light may point you in that direction. The more you report, the more concern I have with your oil pressure at idle. The ultimate solution may be as simple as tweaking the oil pressure adjustment screw.

edit:

My [oil pressure] gauge is 'flakey' and doesn't always read. I have replaced the wire back to the cockpit, and the cockpit gauge previously but it still comes and goes.

Can you correlate the coming and going with engine RPM? Does it appear to work at higher RPM and not at lower RPM or is it totally random?

[Antipodean]

Thanks Neil. I will test the suggestions and try a tweak to the Oil Pr later in the week and report back then.

Currently all batteries are off and in the shop getting appropriate slow discharge/cranking capacity tests -Another thing that is expensive here! Last Gp27 Deep Cycle marine batteries I bought were at Costco for USD$70 each (Boston, 2011, ~NZD$100). Here in NZ $350-$800 per battery depending on the brand.

[JOHN COOKSON]

WOW!

The more you report, the more concern I have with your oil pressure at idle.(+1) The ultimate solution may be as simple as tweaking the oil pressure adjustment screw. (+1again)

I could never tolerate squirrelly OP readings. How does one know what the OP really is?
I would get a mechanical gauge and get correct OP readings before doing anything else. In my neck of the woods of you can buy mechanical OP gauges at any "boutique" auto parts store.
Good OP readings are ~40 PSI at cruise RPMs engine warmed up and 1\2 that at idle. Engine cold OP readings will be a bit higher.

TRUE GRIT

[joe_db]

Do we need to mail a care package of plumbing parts to NZ?

[Antipodean]

Neil,
I reread your response and realised I had not responded to the rpm question. Yes it is 100% related to low rpm.

Joe,
I might come back to you on that offer.


As an FYI I wrote to the manufacturer of the Facet pumps and got a response within hours. It looks as if I can go ahead and swap out the new for old pump and with some preventative steps be able to keep the old as a spare (assuming it isn't the problem)

Hi Rob
Storing the old pump should be fine and I would try and put some light oil in the pump and cap the fuel fitting with the caps from the new pump and clean the fuel filter. This will help prevent the internals of the pump from corroding. <NZ contact for deleted>

Paul Puleo
Motor Components, LLC
National Sales Manager

www.facet-purolator.com

[ndutton]

Don't assume you have an oil pressure gauge problem. You might, I'm not saying for sure you don't but everything thus far points to alarming oil pressure at low RPM and your gauge may be trying to tell you exactly that. Waiting for the test light on the fuel pump circuit results.

[Antipodean]

Neil,
If the oil pressure was low wouldn't the EWDS Oil warning light be coming on also? What I am seeing is that the only light that shows under the low rpm situation is the Fuel warning lamp. The Oil lamp does light up, as expected, prior to starting and goes off after the engine fires. Maybe naively, I thought that as the Oil Pr lamp does not light under the low rpm fuel alarming situation then oil Pr couldn't be the root cause -now that is in no way saying I might not have an improperly set oil Pr situation.

For those commenting on the flakey oil Pr readings I have taken your concern on board and will try to resolve asap. In my defence I have been pegging hope on the fact that until this flakey guage response started the Pr readings had always been within the preferred ranges.

Hmmm

Rob

[ndutton]

The oil pressure sensor (actually a pressure activated switch) for the EWDS is a completely different device than the OPSS and the trip points may be (read: are likely) different. The EWDS oil pressure switch comes from Cole-Hersee in their basic alarm kit and its trip point is preset. I'm pretty certain the Cole-Hersee switch is not user adjustable. The OPSS comes from an entirely different source and its trip point is preset as well. Looking at the picture in the MMI catalog, it's possible the OPSS is adjustable but I cannot say for certain. I have never heard of anyone adjusting their OPSS trip point and I'm not so sure we should.

It sounds to me like your OPSS is tripping at a higher pressure than the Cole-Hersee alarm switch causing the OPSS to stop the fuel pump thereby causing a fuel system EWDS alarm but the oil pressure isn't quite low enough to trip the oil pressure alarm.

I'm very interested in your results as this proceeds. If we are correct, the EWDS alerted you to a problem you would have never known otherwise.

[JOHN COOKSON]

It sounds to me like your OPSS is tripping at a higher pressure than the Cole-Hersee alarm switch causing the OPSS to stop the fuel pump thereby causing a fuel system EWDS alarm but the oil pressure isn't quite low enough to trip the oil pressure alarm.
.

I'd bypass or short across the OPSS until this situation is resolved. This would get one possibility out of the picture while you are looking for a solution.
When I want to bypass the OPSS I pull the push on fitting off the OPSS and insert a small piece of metal, cut to size, between the two wire push on fittings and wrap it with tape.


TRUE GRIT