Hard Starting/ Possible glow plug problem?? M35 Engines & Fuel Pump Wiring

[Ed Shankle]

There must be variations of the ignition switch. On mine, when I click it on, it holds that position (key is at a diagonal), the fuel pump engages and I can go below to bleed the system. The glow plugs engage only when the key is turned all the way to horizontal, and must be held in that position. Releasing it, it goes back to the diagonal and then the starter button is pushed in to start the engine.

Ed

[John Sheehan]

Stu,

I have made up a jumper to run the fuel pump when changing the filters and it works quite well since I can control everything while at the engine.  Still not sure why in the C-34 application they think shutting the fuel pump off with low oil pressure would be a safety device if your fuel tank is over half full.  Probably just a generic system that may work for other boats or applications.

John

[Ron Hill]

John : You are correct as the Universal engines are made for many many differant boats. 
The C34 just happens to be one of the VERY few boats that has the fuel tank mounted higher than the engine!!   

[Stu Jackson]

Continuing from my reply #59 on page 4:

I was reading through some older boating magazines and came across a Cruising World June 2007 article by Steve D'Antonio, page 92, "Bleed Out the Air."

One excerpt: "On some engines, the electric pump only runs when the glow plugs are operated or when the engine is actually running, so in this case the pump may have be temporarily hot-wired."

This is nonsense, of course, because if that's what you have to do with your electric fuel pump to simply bleed the engine, you're really stuck when you have to do it and conditions aren't "favorable."  

If you have to do this, do it PERMANENTLY.

Which was the whole purpose of the earlier discussions about this subject on the last couple of pages of this topic.  What Universal has done is simply DUMB for bleeding engines.  I'll also bet their answer is the engines are self-bleeding.  If so, that's good.  If not...

Further, Steve's article goes on to discuss injection pumps, and "...Most are equipped with bleed screws, and thus the procedure is the same.  Then you must bleed the high pressure fuel system, which is done by loosening the union nuts between the top of the fuel injectors and the fuel line..."

DON'T DO THIS ON A UNIVERSAL ENGINE.  YOU DO NOT NEED TO DO THIS.

The amount of claptrap that comes with sailing rags gags me.

What you NEED to do is learn how to bleed YOUR engine.  I recognize that sail rags are "generic" but NOWHERE is there ANY need for our engines to have to crack the most basic connection (fuel lines at injectors) that should NEVER need to be touched for simple bleeding of the engine, which is linked in my Reply #59 above to Ken Heyman's excellent post (http://c34.org/bbs/index.php?topic=2884.0).

[Michael]

Stu, Ron, Steve, Tony, and others:

Many thanks for your follow-up posts on this topic, and my apologies for not responding earlier.  I've been out of the loop for more than a month and saw your postings for the first time only today.

By way of short update, I can say, with more relief than you can know, that Hali's engine has been starting first time every time since the first part of the fix, when we disconnected the oil low pressure switch electrical circuit from the starboard - on Hali anyway - side low power solenoid terminal and grounded that terminal.  And the engine has continued to start perfectly since we completed the fix (by connecting the oil low pressure switch electrical circuit, through a diode, to the port-side low power terminal on the solenoid).

You may recall that the diode (to prevent current from flowing from the oil low pressure switch electrical circuit to the solenoid terminal but not vice versa) was hit upon as a way to prevent the possibility of current from the oil low pressure switch electrical circuit from energizing the solenoid, and hence the glow plugs, during ordinary engine operation (instead of only when the keyswitch is turned past "on" so as specifically to energize the solenoid and glow plugs).

Although I am writing this without the benefit of a wiring diagram before me and from hazy memory, I think anyone reading this who might be thinking of attempting a similar fix -- and I note that some earlier postings suggest other, perhaps better, fixes - should ensure that they keep their diesel fuel tank topped up if they leave the oil low pressure switch electrical circuit detached as I did.  My recollection is that the fuel pump is wired into that circuit for ordinary operation (that is, for operation other than when the glow plugs are specifically energized by overturning the key switch), so without a fullish fuel tank there could be insufficient fuel pressure during ordinary operation to raise the fuel to the injector pump.  (I will correct this paragraph if, on revisiting Hali or the wiring diagram, it seems my memory has failed here.)

Thanks again.

Michael

[Stu Jackson]

More info on a similar problem is here: http://c34.org/bbs/index.php?topic=3925.0

Thanks, Mike & JoAnne and all of you for updating your experiences.

[Stu Jackson]

Found another post on a similar problem on a C310 with a M25XP.

The problem as described: 

Well Finally closed on our 2001 310 --  We’re very excited about it and this past weekend we brought it up from Mayo (South River) to the Elk River on the Chesapeake. For the most part, the 60mn trip went very smooth, with an overnight and sunset at Still Pond. We motored most of the way in almost no apparent wind conditions. The only thing that was not good was the engine (M25XP) after 2-3 hours of running great at 2500RPM, it started to loose RPM and power for a few seconds and then recovered. It did this 3 or 4 times dropping to about 1200 each time, then ran another couple of hours great.
The second day we sailed in a wonderful N15-18 knots for about 3 hours until we got to the head of the Elk, then motored into the N/E wind, and again after about 30 minutes it did the same thing a few more times, but recovered fine for the remaining hour. When we did the boat inspection I noticed some water in the bottom of the separator. The owner must have drained the water out of the separator, and filled the tank for our use (Nice Guy) after we complained about the fact that the fuel cap was not tight, because it was clean. Unfortunately I had planed to suck the bottom of the tank out, before our trip, but now that the tank was brim full I did not want to make a mess by gaining direct access by removing the sending unit. During the incidents I did not notice any more water in the bowl, just some residual sediment.
Both filters were replaced in the spring.
So, the question is; if there is still water in the fuel than why am I not seeing more in the separator? Could it get through with out settling out, or is this not a fuel problem at all, as I'm suspecting.
Any comments would be welcome,
Thanks,
Tom

************************************************************
The solution: 

What's wrong when the buzzer doesn't sound
Well, the problem was the fuel pump not getting power.
-Fact, the “P” terminal of the buzzer within the control panel senses the voltage at the fuel pump. When +12v is not present at the fuel pump the buzzer sounds. This is the case when you first turn on the key switch because the low impedance of the fuel pump is actually providing the ground for the buzzer circuit.

The Fuel pump receives its power through (2) different circuits:
1)When the key switch is turned all the way (in the spring loaded position) the “S” terminal provides current from the battery through the pre-heat solenoid coil to ground. As a result the contacts close on the solenoid and provide current to the glow plugs, and also provide current to the fuel pump. (thus the clicking sound)

When the key switch is then returned to the “on” position and the push button start switch is made which engages the starter and the engine starts the fuel pump get its power from a different circuit.

2)Once the engine has started the oil pressure switch closes (> 5psi) this now completes the circuit from the battery through the “I” terminal of the key switch (“on” position) through the oil pressure switch and then through the fuel pump to ground.

The source of the open circuit was a corroded shovel connector on top of the engine that supplies the current to the fuel pump from both sources. This is a stupid place to put a connector of this type. It is exposed to significant temperature flux and corrosive fumes. I cleaned up the terminal and all works fine. I will cut out this connector and solder for a permanent fix.

I sucked the tank out from the lower bottom corner, fuel was clean.
As long as the fuel tank is more than " full it will gravity feed and run fine with no fuel pump running, but when the level goes below that the fuel lift pump must do it’s job and push the fuel.
So, if your buzzer is weak or not sounding, than check this shovel connector, it is probably corroded and not conducting, or the circuit is open somewhere else.
Tech support @ Catalina did not have a clue about what the system was telling me when the buzzer doesn’t sound when it should!!! This is obviously a diagnostic feature that was designed in that they are not even aware of. Also the circuit diagram supplied in the original manual is incorrect. It has no connection to the “S” terminal of the key switch? The diagram is also labeled “Yanmar Trapezoid” at the bottom when a Universal engine was used? I will try to draw a composite circuit diagram, as currently only the separate panel and engine diagrams exist which doesn’t correlate properly.
Hopefully this lesson learned will help someone in the future.
Tom

The whole thread can be found here (don't know if it will always be there, hence the copying of the text above): http://www.sailboatowners.com/forums/pviewall.tpl?fno=499.154&uid=73200280089&sku=2008246194331.13

Tom's solution section reflects my earlier discussion of why it makes little sense to me to have the newer engine electrical wiring system turn the fuel pump off when the spring key switch goes back to its on position after the glow plugs warm up.  But. like almost everything else electrical, it's the connections.   

Tom's description of the operation is a bit off, since the fuel pump actually stops when the key is brought back from the spring (glow plug) position and only starts up again when the oil pressure sensor is satisfied, not just "when the engine starts."

The wiring diagrams discussed are linked to their sources in Reply #49 above in page 4 of this thread.

[Ron Hill]

Ed : Sorry I missed your post.  Your key switch is mounted "cockeyed".  
The normal mounting is:
In the OFF position the key should be straight up  In the ON position the key should point at
the 1 O'clock position.  In the SPRING loaded position (glow plugs) the key should point at the 2 O'clock position.
To change the mounting positions is easy - loosen the nut on the outside of the engine instrument panel that holds the key switch in place.  Turn the key switch until it's oriented correctly and re tighten that nut!  Be careful or you can scar the panel face.

Most all of the cylindrical electric fuel pumps have the case as the ground. 
If your pump (square or cylindrical) only has one wire the case is definitely the only ground. 
In another post I point out that if there is two wires the ground (- black wire) is then connected to the bolt that holds the pump case to the engine for ground - so the case is also actually grounded (but not for the pump actuation/operation).   

A few thoughts

[Stu Jackson]

This is one of my favorite "unforeseen consequences" topics, and I have listed it in the "Electrical Systems 101" thread.

I have seen, on many other boards, this acronym: RTFM.

It means: Read the Funny Manual.

The purpose of the earlier posts on this topic advise that the WIRING DIAGRAMS provided in the two DIFFERENT diagrams from the manufacturer, are questionable, because they really ARE different (Page 25 & Page 26).  And the cockpit panels and, perhaps, if not really, the key switches, on the Mark II boats are significantly different than those on our old Mark I boats.  I do NOT have a spring loaded key switch on my Mark I boat.  Period.

So, do yourself a favor, go look at them and see what you have on YOUR boat and simply work from there.  I'm not telling you what to do, and in this case not even what I've done on MY boat, since I don't have this "problem."  You may not even have this issue with your M35 engines.

But here's the "BUT":  You MAY sometime in the future, even tomorrow, and it would be helpful to you to have this information in your "back pocket" in case it ever comes up.

Indeed, Dave Spencer had JUST THIS PROBLEM on his boat, and we recorded it on "Critical Upgrades":  http://c34.org/bbs/index.php/topic,5078.msg41829.html#msg41829

[Ron Hill]

Guys : Stu is correct about RTFM!!!

The engine instrument panels regarding the glow plug switch's are differant on the 1986 and 1987 C34s as they have a push button switch and are not incorporated in the key switch (spring loaded) position as the later C34s have.  The 12 O'clock position on all C34s should be the OFF position and 1 O'clock should be the ON position.

There are numerous other changes in the engine instrument panels over the years, so that's why it's very important that you read your friggen instruction book.  The best example: is the time the glow plugs are engaged - keep the glow plugs ON for the amount of time specified for the M25/XP engine on a M35B engine and you'll burn them up!!

[added 5/10/2012 - Stu]  Ron's right.  See the Critical Upgrades topic, where Ray Irvine notes the difference between continuous and intermittent duty solenoids:  http://c34.org/bbs/index.php/topic,5078.msg41829.html#msg41829
  
That's why it's so important when you ask a question that you list your hull production year and engine model.  A few thoughts