glow plugs

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    • #30556
      dogdoc
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        Got my Jinma 254 last fall and until today always needed to plug in the radiator hose heater to get it started, even with the glow plugs.  Did a little electrical check today and get 12.5v when I check the supply wire disconnected from the glow plugs, but when connected to glow plugs get 9.7v anywhere along the buss bar.  Should I get that much voltage drop??

      • #34537
        Bob Rooks
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          Voltage loss is because the high resistance of the glow plugs is drawing the battery down. Kinda like leaving your car lights on. Did you purchase the tractor new? How old is your battery? Sounds like it could be a little weak.

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        • #34538
          RichWaugh
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            Also, the wiring to the glow plugs is marginal on these tractors.  Better to install a relay and a heavier primary wire to the plugs.   Saves the switch contacts and gives the glow plugs full voltage.  I'd recommend nothing smaller than 10 gauge for the glow plugs – 8 gauge would be better.

          • #34541
            dogdoc
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              tractor is 2009, sat until i got it in fall2011, the battery was poor and i replaced it.  the primary wire does look wimpy, i will replace it.  can you be more specific about the relay

              thanks

            • #34498
              Bob Rooks
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                What Rich said is true, however nothing really needs to be re-wired. Simply remove the existing (blue?) wire from the bus bar and use it for the relay coil feed. Run a new 10 gauge wire from the battery terminal on the starter solenoid to one leg of the relay contacts, then run another new 10 gauge wire from the other relay contact leg back to the glow plug bus bar. I recommend using a 40 amp relay. This same mod is recommended for use in the starter solenoid circuit. I have done both mods and it makes a world of difference. Performing these mods prolongs the life of the key switch by keeping high amperage loads away from it.

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              • #34542
                Tinbender
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                  The blue wire comes up from the starter hot lug to the 40 amp relay. The black wire from the relay to the solenoid.Another black wire from the solenoid to the glow plug buss bar. The yellow wire is the original wire from the starter switch to the glowplugs, it’s now only energizing the solenoid which uses very little current saving the starter switch and giving you plenty of juice for the glow plugs. Same thing Bob said with a picture.

                • #34544
                  Tinbender
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                    What I called a 40 amp relay is in fact a circuit breaker, I can't seem to edit text, the text didn't show up when I hit edit, just the picturehmmm

                    Sorry for the confusionembarassed

                  • #34547
                    Bob Rooks
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                      Tinbender raises a good point, one which I forgot to mention. If/when you install a relay, it's a good idea to also install a 5 amp fuse or circuit breaker on the relay's contact coil feed wire.

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                    • #34548
                      dogdoc
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                        I get the picture literally and figuratively.  Just to clarify you are really using a solenoid though right?  All the relays I have looked at have dinky wires and connectors, where as the solenoid have post to bolt down a connection.  Whole thing makes sense, small wire to energize big switch and big wire.

                        Thanks

                      • #34549
                        Tinbender
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                          Yep, if you have a wrecking yard nearby just about any Ford truck will have one mounted up by the battery, mine came out of a Honda that was being junked at the time we were putting the tractor together. I used these for hot leads for trailers many times before too,with the energizing wire going to the ignition on circuit. That way if the trailer is hooked to a parked truck it can't run the trucks battery down.cool

                        • #34550
                          Bob Rooks
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                            To further clarify: A solenoid is an electro-mechanical actuator, usually mounted on the starter motor to pull out the Bendix drive, engaging the flywheel. A relay is a “switch”. The starter relay Tinbender was referring to will work just fine, the generic relay I was referring to is rated for 40 amps and will work just fine also – it's what I used for starter and glow plugs. You may use either. Your call. wink

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                          • #34558
                            dogdoc
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                              So I went to the auto store today and got a starter solenoid switch with adequate amp rating.  Speaking to the tech support guy at the manufacurer he said since this is not continuous rated that energizing for 20-30 seconds may burn it up, he suggested continuous duty model.  Any thoughts.

                              Thanks

                            • #34559
                              Tinbender
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                                I’ve had mine since 2008 without any problems, and it ran in a Honda for 20+ years before that. That’s a good sized switch for the amount of current going through it, Think about it, it's made for starter current, not a little 10 or 12 gauge wire for glow plugs, and sometimes folks crank on the starter for 20 seconds at a time. I wouldn't worry about it.

                              • #34560
                                Bob Rooks
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                                  Dogdoc,

                                  If you purchased a starter relay (no such thing as a “starter solenoid switch”) , your tech support guy isn't very knowledgeable. Typically, a starter relay is rated for well over 200 amps momentarily, and because their designed service is momentary they don't have a continuous rating. Your glow plugs are only going to draw 25 amps max. and that diminishes as they warm up. I assume you will only use your glow plugs momentarily anyway.

                                  If you want to get into continuous duty relays then you are talking latching relays, and I don't do those here.

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                                • #34561
                                  dogdoc
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                                    Seems like we have gotten down to semantics here, this is what I was looking at as a reference.  When I was a kid we had an old Saab that you pullled a lever on the dash which pulled a cable and manually closed the contacts on the starter selenoid energizing the starter and pinon gear.  Its all good, I will hook up what I got and see what happens.

                                    Thanks

                                     

                                    Automobile starter solenoid

                                    In a car or truck, the starter solenoid is part of an automobile starting system. The starter solenoid receives a large electric current from the car battery and a small electric current from the ignition switch. When the ignition switch is turned on (i.e. when the key is turned to start the car), the small electric current forces the starter solenoid to close a pair of heavy contacts, thus relaying the large electric current to the starter motor.

                                    Starter solenoids can also be built into the starter itself, often visible on the outside of the starter. If a starter solenoid receives insufficient power from the battery, it will fail to start the motor, and may produce a rapid 'clicking' or 'clacking' sound. This can be caused by a low or dead battery, by corroded or loose connections in the cable, or by a broken or damaged positive (red) cable from the battery. Any of these will results in some power to the solenoid, but not enough to hold the heavy contacts closed, so the starter motor itself never spins, and the engine does not start.

                                  • #34564
                                    Bob Rooks
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                                      Semantics are very important when it comes to understanding technical issues. Oftentimes meanings and descriptions get lost, bastardized, or clouded by using colloquial and slang iterations.

                                      Btw, all of those links are dead.

                                      It's all good. Good luck. wink

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                                    • #34565
                                      biggerten
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                                        Bob is right about the solenoid/relay thing. hailking All my Ford pickups (and my 72 Dodge, for that matter) had a relay on the fenderwell that energized starter and solenoid. The solenoid is actually a coil with an internal steel rod that gets pulled into the coil when current flows, throwing the starter gear into the flywheel. The coil energizes, creating a magnetic field. The steel rod distorts the magnetic lines of force, which like rubber bands want to be as short as possible, so the rod is pulled inside of the coil. When current stops, the lines of force go away, and there's a spring that pushes the rod out of the coil, waiting for the whole thing to happen again. readin The Chevys I remember (ain't had one in a long while) had an integrated relay and solenoid, just like the Jinma.

                                         

                                        There's plenty wrong in that quoted article, although it's good enough for the average Joe. It glosses over a whole lot of detail.

                                         

                                        Bob IS wrong in his post #2 where he talks about the high resistance of the glow plugs drawing down the voltage. It's the LOW resistance (and hence high current draw) that does that. I bit my tongue until now, 'cuz I know he knows what he's talking about and just mis-spoke. neener

                                         

                                        deadhorsedeadhorsedeadhorse

                                         

                                        Tom

                                      • #34567
                                        Bob Rooks
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                                          Biggerten wrote:

                                          “Bob IS wrong in his post #2 where he talks about the high resistance of the glow plugs drawing down the voltage. It's the LOW resistance (and hence high current draw) that does that. I bit my tongue until now, 'cuz I know he knows what he's talking about and just mis-spoke. neener

                                          Ur right Tom. I know I was thinking the right thing but it came out backwards somehow. Gad! I hope I don't do that at work.

                                          embarassed

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                                        • #34599
                                          dogdoc
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                                            Guys one last question.  I've everything ready to go but am wondering about a fuse.  The original primary wire to the glow plugs which will now activate the relay is fused in the fuse box with a 20 amp fuse.  Should I be putting one inline from the starter solenoid lug to the input of the relay?

                                            Thanks

                                          • #34602
                                            Tinbender
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                                              It wouldn't be a bad idea, I'd use a 40 amp. Something would have to short out to blow that, that's why I used a 40 amp circuit breaker (behind the switch/relay in the picture). I used this for if a momentary surge did require 40 amps (not at all likely) it will shut the relay, and when cool, it will reset. That and I have a catchall drawer in my toolbox with several of these laying around.cool

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