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

[Michael]

John, thank you.

I wish I had got your posting last night instead of tonight!

Puzzling over the wiring diagram this morning, I realized that the low oil pressure switch (which I presume is "off" when the engine is stopped or if oil pressure fails) controls the fuel pump electrical circuit in ordinary operation (keyswitch merely at "on" between B and I) and the low oil pressure switch would need to be "on" for the fuel pump to operate in that case.

To test the theory (and perhaps figure out how low oil pressure switches work!) I jumpered around the low oil pressure switch and so got the new-new fuel pump to work. (The old new fuel pump really was dead on arrival.)

Unfortunately, the problem of lack of heat from the glow plugs continues, despite new glow plugs.  I am assuming and checking for the electrical gremlin.  Today's question is, "Why would glow plugs that work fine when wired directly to the battery not produce much or any heat when wired in place in the engine block even when, to test them, they are powered directly from the battery and not through the preheat solenoid?" [Modified posting: Electrical troubleshooter Jim, referred to in a later post, says that there may not be much heat perceptible on the engine block near the glow plugs or on the glow plug terminals or other parts of the glow plugs you can touch when then glow plugs are in the engine block. Since the "fix" referred to later in these postings, I have not checked to ascertain whether the now correctly operating glow plugs do produce much perceptible heat.]   I suppose either the glow plugs collectively need more power than is reaching them (I am wondering whether the house and starting battery used to be used and are not now or if the house bank is low or...) or there is a short somewhere in the system that provides a better path for the electricity than through the glow plugs. I feel like a bloody Don Quixote chasing these gremlins...which will probably turn out to have been brought to life by something I did.  Oh, well, one or two more windmills.  Thanks for your help and that of everyone who has contributed to this thread.

[Mike and Joanne Stimmler]

Michael,
So sad to be reading of you're problems and I hope I can help.

First, if you haven't tried this already, try a longer glow time, even as much as 45 seconds, just to prove if the plugs are getting anything at all.

Also notice on the volt meter while you are holding the glow plug button to see if you are seeing a noticeable voltage drop of 2 or 3 volts. I you don't see a voltage drop, then nothing is getting to the plugs, if it drops WAY down, you have a dead short on the circuit.

Then I would re-verify if you have voltage at the top of each plug and depending on what you have found from the above paragraph, you may want to disconnect them one at a time and try starting the engine after each disconnect.

Lastly, even after I changed my plugs and everything was working good, I never felt a major amount of heat at the top of the plugs, just a slight warming, as you did, so that may not be an accurate test.

Best of Luck.
Mike Stimmler

[Craig Illman]

Michael - Do you hear the solenoid "click" when you engage the glow plug position on the key? (you may have covered this before). One project I did over the winter was copy Mark Elkin's secondary starter switch project. http://www.c34.org/projects/projects-secondary-starter-switch.html

It's helpfull for bleeding injectors and other "cranking while solo" needs. Possibly, there's an inline fuse between the battery and solenoid that's blown.

Craig

[Footloose]

Michael,

I am lead to believe that you have a poor or high resistance connection somewhere in your starting circuit.  You need to follow it from the batteries to the engine.

A simple test is to disconnect the batteries and place one end of an ohm meter on the engine and the other on the ground wire in the battery box.  If it reads more that 0.5 ohms start looking at those connections.  Do the same thing on the positive side but the pos lead is on the starter or alternator.  Many of us have cut off the original ring terminals on the battery cables and replaced them with good results.  I said this before, a small amount of resistance result in a large power drop at large current draws.  I have to admit that I thought you had found the problem when your glow plugs were reading out of spec. 

[Michael]

Mike, Craig, David:

Thank you for your advice.  I'll check through the things you mentioned.

Dave, I was getting about a 1 ohm resistance between the starter battery negative and the engine block...but I am doubting my multimeter now as it gave me 1.9-2.2 ohms as the resistance between the terminals and the body of Hali's old NGK Y103V glow plugs and not much better for the new NGK Y103V glow plugs.  A new multimeter is in order although I am afraid this is the bad workman blaming...

The weather is good now and my co-owners are concerned (rightly!) that I will soon have the boat entirely in pieces.  After I removed all the electrical connections to the engine last night - testing the new glow plugs each step of the way (without success) - and two of us replaced all the connections afterwards, we couldn't get the starter motor to crank.  So my co-owners are calling in the cavalry (experienced big diesel engine mechanic who works with one of them) to rescue their boat from me.  We are going to put our brains together aboard Hali tomorrow night.

I will produce the bodies of the dead gremlins if we kill them.

Thanks again.

[tonywright]

If you can't get the starter motor to crank, then your battery terminal connections need radical tightening. Use a wrench to tighten them as much as you can without breaking anything. You will be amazed at the results.

Tony

[Footloose]

Michael,

What reading do you get if you touch the leads of the ohm meter together?  That should be zero.  If it isn't, there is an adjustment for that on the meter.

If you have one ohm of resistance you loose 3600 watts of power at 60 amps (about what my glow plugs draw).  That is a lot of heat that isn't going to the glow plugs.  At 200 amps, the starter motor, you are losing 40,000 watts, which is not only a lot more heat but also about 50 horse power which could make your starter crank slowly or not at all.

Getting another opinion is never a bad idea.  We can become blinded to something very obvious after we have started chasing a red herring.

Hang in there.  I had similar problems when I first bought my boat but all is well now.

[Michael]

Eureka!

A great gremlin hunter, Jim, a troubleshooter from co-owner Lionel's stationary diesel electric company, has driven a stake through the heart of the electrical gremlin aboard Hali.

Jim may have exposed problems C34 owners can create for themselves when they replace old electric fuel lift pumps with new "electronic" fuel pumps like the popular inexpensive Facet Purolator "Posi-Flo".

Later, I may write this up more succinctly and accurately.  Meanwhile, brick bats are invited.

The theory -- possibly somewhat proven by the fact that Hali now starts "first time every time" -- is that a gremlin lives in the intermittent making and breaking of the electrical circuit through the "electronic" fuel pump but that this gremlin expresses itself in the rather inscrutable way of interfering with the energizing of the preheat solenoid that completes the glow plug circuit.

To paraphrase partly John's post above of June 19: on the M-35B engine wiring diagram [see your Catalina owner's manual] and in the actual wiring of the M-35B engine, when the engine is not running the electric lift fuel pump will only operate when the keyswitch is in the "glow plugs on" position.  Put another way, the electric lift fuel pump on the M-35B will operate (a) when the keyswitch is in the "glow plugs on" position (which of course it only should be before the engine is cranked) or (b) when the low pressure oil switch is closed (as it usually is once the engine is running). The fuel pump is wired simultaneously into two circuits - this is much clearer on the wiring diagram which unfortunately I do not have before me at the moment.  One of these circuits is completed only when the keyswitch is turned to the "glow plugs on" position and one is completed when the low pressure oil switch is closed. If the keyswitch is at the "on" position but not at the "glow plugs on" position, and the engine is not running (and therefore the low oil pressure switch is not closed), the fuel pump will not be energized. (I say energized rather than operating because there will be cases when the pump is receiving an electrical current but is not operating because the fuel line pressure is such that no demand for fuel is being made - that is, I guess, above about 4 pounds per square inch gauge pressure on these Posi-Flo pumps which are rated for 1.5 to 4 PSI.)  In other words, when the M-35B engine is off, don't expect to hear the fuel pump clacking away when the keyswitch is only at "on".

Now the problem as it is theorized to be is that because the electrical circuit ("preheat solenoid activating circuit") that energizes the preheat solenoid (which acts as a switch to close the glow plugs circuit) runs through the electric lift fuel pump (a clever way to make sure that when the glow plugs are energizing fuel is also being delivered by the lift pump to the fuel injection pump for onward delivery to the cylinders when the engine cranks), if the lift pump electronics are making and breaking they make and break the preheat solenoid activating circuit with the result that the preheat solenoid does not close - or closes intermittently - and the further results that the glow plugs do not energize sufficiently to heat the cylinders and compression ignition is not achieved.

Without the benefit of investigation, the speculation is that the old electric lift fuel pumps operated without making and breaking the electrical circuit and so did not interrupt the preheat solenoid activating circuit -- but the new "electronic" pumps do or can in some cases (Hali's apparently being one).

At first blush, Jim thought there was an easy complete fix: ground the preheat solenoid energizing circuit immediately after it passed across the preheat solenoid low power terminals -- that is, ground one of the preheat low power terminals and terminate the "glow plugs on" circuit from the keyswitch and the 10 amp circuit breaker/fuel pump/low pressure oil switch circuit on the other preheat solenoid low power terminal. However, on further thought, he realized that if this were done, there was a possibility, when the engine is running and the low oil pressure switch has closed its circuit to the electric fuel pump, that that circuit would activate the preheat solenoid and cause the glow plugs to energize.  His more complete solution is to re-wire as indicated but with a diode (one way electrical current flow device) in the fuel pump/low pressure oil switch circuit just before it connects to the preheat solenoid low power terminal.  The diode would prevent electrical energy from flowing from the fuel pump/low presure oil switch circuit to energize the preheat solenoid and glow plugs when the engine is running - something that could cause the glow plugs to crack and shed material into the engine cylinders.

Jim is going to wire the diode and send it along for installation in the circuit.

Here lies a dead gremlin (?) and maybe a stillborn one.

My many thanks to all of you who helped along this path.

[tonywright]

Great news.  Seems a good rational explanation.

This also explains one of my earlier questions. I wondered why the Universal manual required continued application of glow plug until after the oil pressure alarm switches off. Now it is clear that it is not so much to keep the plugs glowing, but to keep fuel pumping until the oil pressure sensor stops blocking the circuit to the pump. Conclusion: I will continue to follow the manual's recommended procedure. It hasn't let me down so far.

I just realized that I am in your direct vicinity this weekend. My daughter is appearing in "Bard on the Beach". if I am not mistaken, that is pretty much next to your marina?

Tony

[Stu Jackson]

Sometimes engineering "improvements" screw things up!  The older boats had a very simple solution:  engine on, pump runs, no solenoid unless an owner installed one.  It would be quite easy for your mechanic to simplify the wiring and avoid the inherent dependencies of one upon the other -- of course, there is a good reason for the way the boat is wired, but sometimes complications are involved.  Congratulations on your research and problem solving, and your updates and report.

[Michael]

Tony - Lucky you having a daughter playing in Bard on the Beach.  Yes, that is very close to the marina where we keep Hali. If you have a minute this weekend, will you call me on 604-970-9345?  That's a cellphone that doesn't take messages so you might have to try a few times.  I would be delighted to show you the boat.  Cheers. Michael

[sedelange]

Micheal:

The fuel pump is connected to the Indicator terminal of the glow plug relay and therefore should not affect the glowplugs as it is energised only when the relay is activated.  The relay should be grounded through the base.  If there is nothing wrong with the relay, the small current drawn by the fuel pump (old or new style) should present no problem.  Many people confuse this style relay it the ones where the two small terminal posts are for the coil when, in fact, the coil is connected to one terminal and the base.

[Michael]

Steve - Thank you for your note.  Before I concede that the gremlin was killed by luck (which is entirely possible), I wonder whether the solenoid we are using - a Cole Hersee 12v continuous (Part Number 24059) - is wired as you mention.  The wiring diagram is at http://www.colehersee.com/resource/index.htm and while it does not appear to be wired with the solenoid activation circuit the way you mention I cannot conclude that for certain.  You have raised an interesting point that I will try to get to the bottom of. 

[Ron Hill]

Michael : Why don't you call Joe Joyce (the Westerbeke Service manager @508-588-7700) and ask him if you an just run a separate wire from the "on" pole of the key switch to the fuel pump and another separate wire from the "spring loaded" pole of the key switch to the glow plug solenoid.  Then you could bypass all of the "automatic" relay stuff and have both the glow plugs and the fuel pump operate when YOU want them to! 
A thought.     

[Michael]

Hello, Ron.

Jim (troubleshooter) and I had a discussion about doing almost what you suggest.  If the boat were mine alone I might do it: it  would be nice to control the fuel pump/low oil pressure circuit and glow plugs separately.  However, two considerations weighed against it.  The more important was that we have four families in Hali and want to keep things simple, meaning in this case not having to make a conscious choice to turn more things on or off (and know why you are doing it).  The other was the nuisance of having to pull the wire.  (In fact, we were also thinking of putting the fuel pump on a separate switch as we hadn't come exactly to your idea of adding the fuel pump circuit to the "on" switch.  So that was another factor.)  Anyway, we decided to leave the glow plugs/fuel pump/low oil pressure switch circuits together but with the re-wiring and diode mentioned above.

The theory of failure mentioned previously - although it seems to be supported by the result - does depend upon an assumption about the different nature of the new "electronic" fuel pumps as compared to the old electric fuel pumps that I am not sure will be found to be true.  Perhaps Steve has somewhat similar misgivings about the analysis although he comes at it from the point of view of the solenoid.

In the circumstances, I am not sure whether I will call Joe Joyce at Westerbeke although I appreciate your suggestion and it would be interesting to know whether he knows of others having similar issues with new electric fuel pumps.

As ever, thanks for your input.