Glow Plug Heater Circuit Issue M18 Diesel

markwesti · Jun 18, 2018

My friend had this problem with his C320 . When we were looking at it we determined there was power to the switch but no power at the glow plugs . He bought a new switch still no power to plugs , at that point I said just call the guy . Problem turned out to be simple the wires going to the engine were connected to a terminal block and then went to the engine . The mechanic put on a new block , clipped back the wires to new , wired it all back up and it was fixed .

markwesti · Jun 18, 2018

That sounds good Mr. End , my friend discovered that if you blow hot air from a hair dryer into the air filter the engine starts right up .

Stu Jackson · Jun 18, 2018

Loose Ends said:
I am wondering if the Teleflex amp meter in the panel may be going bad.

Loose Ends said:
I am aware of the Wiring Harness/Trailer Plug/Battery Charging circuit mods and they are currently in the works.

Your problem IS the ammeter in the cockpit, regardless of whether it is working or not.

Replace the ammeter in the cockpit with a voltmeter. Install a glow plug solenoid.

Ammeters & Shunts 101: http://c34.org/bbs/index.php/topic,6032.0.html

http://c34.org/wikiwp/?rdp_we_resource=http://c34.org/wiki/index.php?title=Faster,_More_Efficient_Glow_Plug_Heating_with_a_Solenoid

http://c34.org/wikiwp/?rdp_we_resource=http://c34.org/wiki/index.php?title=Engine_Harness_Upgrade

LeslieTroyer · Jun 18, 2018

You glowplug amps are down but if you haven’t done ampmeter, glowplug relay or the trailer plugs it may be ok. Your glowplugs should draw 12A each plug.

Als read about the alternator mount upgrade. It’s on Stu’sC34 site and on Marinehowto.com. If you have the old style and don’t want to repower in the next few years - move that onto the todo list just below trailer plugs and Ampmeter.

I did trailer plugs and alternator mount last winter, trailer plug mod took ~3hours
The alternator took 2-3 weekends as I had to wait for manifold gaskets, and fix some previously broken bolts. Pulling the exhaust off the back of the manifold was the worst part of the job and that wasn’t bad. Be sure and seal the studs to block threads (I use permitex #2 ) as they are “wet” and could leak.

Les

Bill Roosa · Jun 18, 2018

If you apply power to the glow plug switch it works!!!! so why is the switch not getting power? Assuming you have an off-run-start and not a preheat-off-run-start ignition switch.
the glow plug switch should not be hot all the time. it should only be hot when the ignition is in the run position. I've seen them wires several different ways. In all cases you have to have power to the switch so figure out why it is not getting power. Take off the glow plug hot terminal and stick a volt meter + prob in the wire. ground the other probe. There should be 12 volts if it is hot all the time,
OR
0 volts (start, and off) or 12 volts (run or preheat) if it is connected to the ignition switch

jviss · Jun 19, 2018

Loose Ends said:
Not connected to the ignition switch. Look at the attached drawing.

The drawing is great. Could you please reduce the ambiguity a bit by telling when you say

Loose Ends said:
If I apply power directly to the switch and depress it,

which terminal of the switch are you talking about? I assume it's the leftmost one - let's call it terminal #1.
There is one node you don't mention in the drawing which is node 9, which is the +12V rail, connecting the ignition switch "A" terminal, alternator field, Ammeter, tach, and temp gauge lights, oil light, starter switch, glow switch ,and fuel pump.
Based on your report, I suspect a bad connection from that node to terminal #1 of the glow switch.
When the key is in "run," is there 12V at terminal #1?

jviss · Jun 19, 2018

O.K., gotcha. It certainly seems you are dropping all of your voltage across the Ammeter when you depress the glow switch; except you didn't note the voltage at "A" when the switch is depressed. It could be a bad connection at the 30A fuse, or in the wire somewhere, but it's most likely the Ammeter.

When you measure the resistance of the Ammeter, was it completely disconnected from the circuit? These should read nearly 0 Ω when good, and usually fail open (∞ Ω). You might be measuring the DC resistance of part of the stator in the alternator.

Why don't you remove the wires from the Ammeter and measure the resistance with nothing else connected except your Ohmmeter.

For now, for operation, you can just move the "A" wire to the "B" terminal and ignore the Ammeter.

LeslieTroyer · Jun 19, 2018

All this trouble shooting is wasted time. 1st make the mods @Stu Jackson recommended, and your problem has a 90% chance of being fixed. Your boat will be safer and more reliable. Don’t buy the CD kit, just buy a terminal block and ring connectors for the engine side - I like weatherpak connectors for the panel side. I used two 5 pin connectors and altered the sex so you can’t plug them in backwards. You can also group the wires as inputs on one connector and outputs on the other, that way power is on the female portion.

Les

jviss · Jun 19, 2018

LeslieTroyer said:
All this trouble shooting is wasted time.

I beg your pardon. Troubleshooting is extremely valuable, not only in providing an understanding of why something is not working, but as a learning tool as well. Finally, this level of understanding will help if you have to make an emergency modification.

I agree with the recommendation of eliminating the Ammeter, maybe filling the hole with a Voltmeter; it perhaps does not go without saying that it is wired differently. I also agree with the recommendation of a terminal block for the engine side, and a glow plug solenoid.

LeslieTroyer · Jun 19, 2018

You troubleshooting a system that should be replaced ASAP how is that not a waste of time. Your going to “learn” what 100’s of folks already know, it’s a horrid design prone to failing and starting fires.

Head Sail · Jun 19, 2018

Your problem is most likely a connection issue. You just need to troubleshoot it or clean up all the connections. I don't see the point of the glow plug solenoid. I never needed one and don't need any clap trap on board.

Stu Jackson · Jun 19, 2018

Head Sail said:
I don't see the point of the glow plug solenoid. I never needed one and don't need any clap trap on board.

His problem IS the ammeter.
Re the solenoid, I learned that when sailing on SF Bay when I needed the engine to start, I found that there is a HUGE difference between 30 seconds and 12 seconds. I don't think it's claptrap at all. It was ans remains a simple Ford solenoid, quietly sitting in the engine compartment doing its job when called upon.

But it's always:
Your boat, your choice.

The recommendations were based on 30 years of Catalina 34 experiences. I'm sure you're familiar with our trove of information.

Head Sail · Jun 19, 2018

Stu Jackson said:
His problem IS the ammeter.
Re the solenoid, I learned that when sailing on SF Bay when I needed the engine to start, I found that there is a HUGE difference between 30 seconds and 12 seconds.

Stu: Love the information trove on the C34 site but I've found that when I sitting out on Commencement Bay my engine is usually warm enough from the trip out that I don't even need glow plugs. Zero seconds is much faster than 12. When at the dock and cold, I count 20 one thousands and usually starts on first try. I do concede that shorter and heavier wire runs are better than longer smaller runs but is it really worth the effort and additional failure points?

Stu Jackson · Jun 19, 2018

I agree that if the engine is warm then 0 seconds is a SURE winner!!! But I've found that after two or more hours I still need more than a warm engine and use the GPs.
Glad you enjoy the C34 site.
I simply don't think of it as more failure points, I think of it as a safety improvement because the whole GP electrical load, which is substantial, doesn't have to run up to the cockpit and back down to the engine in (TINY UNDERSIZED) #10 wire. My solenoid has been in since the late 90s and is still working fine. Probably because I do have a spare!

Head Sail said:
Love the information trove on the C34 site but I've found that when I sitting out on Commencement Bay my engine is usually warm enough from the trip out that I don't even need glow plugs. Zero seconds is much faster than 12. When at the dock and cold, I count 20 one thousands and usually starts on first try. I do concede that shorter and heavier wire runs are better than longer smaller runs but is it really worth the effort and additional failure points?

Head Sail · Jun 19, 2018

Stu Jackson said:
I agree that if the engine is warm then 0 seconds is a SURE winner!!! But I've found that after two or more hours I still need more than a warm engine and use the GPs.
Glad you enjoy the C34 site.
I simply don't think of it as more failure points, I think of it as a safety improvement because the whole GP electrical load, which is substantial, doesn't have to run up to the cockpit and back down to the engine in (TINY UNDERSIZED) #10 wire. My solenoid has been in since the late 90s and is still working fine. Probably because I do have a spare!

It sounds like the OP doesn't have a start battery which could be part of the problem. That long wire run from the house bank and up to the cockpit may be part of the problem. Put in a start battery with short cables to the starter and you will substantially reduce voltage drop not just for the starter but for the glow plugs as well.

Glow Plug Heater Circuit Issue M18 Diesel

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