Perkins 404c-22g ElectroPak Diesel Engine
aka: HP35105U, 5H3XL2-22 NLC, HP29-1800C, 400 series
 Wiring required to get it running with either Manual or AutoStart
by Joe Mehaffey
3/18/2006 Release 3

I received a Perkins 404c-22g diesel engine from Hardy Diesel to replace my old worn out (200 hours of service) ChangChai Chinese built diesel engine.  Yes.. I know.. 200 hours life for ANY diesel engine is unheard of.  But.. For the ChangChai SAGA, click HERE.  After getting the Perkins engine connected to my MECC-ALTE EC0-28-L2 (rated 21KW prime, 24KW standby) alternator, I can say that the two engines are as different as to sound  and vibration as a hammer drill is to a sewing machine!  I used the same muffler (Volkswagen diesel car muffler) as with my old engine.  While the Perkins engine is MUCH quieter, it, too, is far from "silent".  However, the Perkins engine has very modest vibration and it does not sound like it is going to shake itself apart like the ChangChai engine did.   The 29HP (at 1800RPM) engine is a much better match to the MECC-ALTE EC0-28-L2 alternator than was the ChangChai. With the two cylinder ChangChai 17HP rated engine, the maximum output was about 13.5KW.  I am expecting about 24KW maximum output with the new engine.   I bought the oversize alternator when the original DADI alternator failed on the ChangChai system several years ago.  Only a single alternator connector casting (alternator fan housing) and four spring steel flywheel connecting plates are needed to mate the alternator to the Perkins engine.  The Perkins machine came equipped with a standard "SAE 4 Long" flywheel and bell housing.  (I have an extra  alternator fan housing casting  if anyone needs one.)  One other item of note is that the 30hz "flickering light" phenomenon I experienced with the 2 cylinder engine is gone with the 4 cylinder engine.  One power stroke per revolution instead of one power stroke per two revolutions makes a much bigger difference than I expected  in cycle to cycle voltage stability..

The Perkins engine came to me with no documentation whatsoever.  While the mechanical connection of the alternator and engine was fairly straightforward (Use lots of Locktite!),  I had considerable problems getting even basic information on  electrical component connections for the engine.  How our Perkins friends expect anyone to properly wire the engine controls without Perkins providing even basic information on what the connections are and specifications on component function and electrical terminal identification is beyond my understanding.   I decided to write up the essential information so that others would have an easier time of wiring up these Perkins engines.   If anyone has any additional  information, let me know and I will add such to the list below.  

For wiring, be sure to use #16 or #18 wire (except as noted otherwise)  for all connections to minimize voltage drops in the wire and maximize  the ability to start the engine under less than optimum battery conditions.  The wiring from the glow plug relay to the glow plugs should be #12  wire.  The wire from the battery post (or from the battery cable  connection on the starter solenoid) to the glow plug relay and starter solenoid relay (or ignition switch if used in manual switch mode)  should be #10 or #12  gauge.  This wire should be fused by a 30 amp "inline" automotive fuse at the starter solenoid take off point.   Use proper through hole (not spade) lugs and lock washers on all screw terminals for maximum reliability.  To reduce wiring voltage drop to the starter solenoid and to the glow plugs, wire size should be increased or an additional relay installed  near the engine should be used if wire runs from the engine to the controller/ignition switch panel exceed perhaps 10 feet.

1) The Engine  has a 12vdc fuel control solenoid that must be activated for engine run and DEactivated for engine stop.  This solenoid is attached to the rear of the injector pump. The pigtail connector cable out of the solenoid has a two pin connector, female socket with male pins. All three of the Perkins connectors are keyed the same so be SURE to harness them  on the engine so they cannot get interchanged.  There are two wires to the solenoid coil.  You must ground one wire and connect the other wire to +12vdc power to energize the solenoid and allow fuel to reach the cylinders.  The wires are not polarity sensitive. See image below.  In my installation, I used a common ground wire for the fuel solenoid and for the oil pressure switch and grounded the common connection.  Then the ungrounded fuel solenoid connection is powered by +12vdc for engine run.   Oil pressure switch details are in item #4 below.


2) The engine has a starter solenoid and switch mounted on top of the starter motor as is conventional.  At first glance, you will see only two terminals on the starter solenoid.  The first goes to the starter motor and the second is to be connected to the battery.  A third "slide on" terminal is semi-hidden behind the starter solenoid body.  This "tongue" terminal is to be connected to a female slide on socket (furnished in the parts kit) and is to be connected to the "crank" terminal on the ignition switch or engine controller.  See Image below.
3) This engine is equipped with a glow plug starting system, one glow plug for each cylinder. The glow plugs are mounted vertically and are located  just above and behind the four fuel injectors.  A sheet metal interconnection bar joins the four glow plug power terminals.   The attachment point for the glow plug power wire is on the left end of the  stamped sheet metal connecting bar.    It is best to feed this glow plug system with #10 (smallest #12) wire as the buss draws about 40 amps DC when energized.  Normally you turn on the glow plugs for about 7 to 10 seconds before cranking to allow the glow plugs to assist in starting.  To maximize power available for the starter, the glow plug power is often turned off immediately before cranking is commenced.  It is not normally  necessary (but it is OK and the engine will start faster)  to use the glow plugs above about 60F.  I note that my engine will not start at 50F and lower without the use of the glow plugs.
4) The engine oil pressure and temperature sensors are SWITCHES and not analog sensors.  The switches CLOSE on out of tolerance conditions.  The temp switch closes at about 205 degrees F signaling engine overheat and the oil pressure switch closes on low oil pressure. Both switches are two terminal SPST  isolated switches  with Perkin's unique two pin connector.  The oil pressure switch is closed when the engine is stopped and the water temperature switch is open when the temperature is below 205F.   It is intended that these signals be interconnected with a suitable relay or other circuit to shut off the fuel solenoid should the engine have either low oil pressure or an overtemperature condition.  See the  image below for the location of the WATER TEMPERATURE switch and the image in item #1 above for the location of the OIL PRESSURE switch.
5) Connector pins and fittings for Perkins two pin connectors are furnished in the kit with the ignition switch, air heater and other fittings.  These pins are designed to be crimped onto  #16 to #18 gauge wire but you can solder them onto the wires (carefully with a 47 watt iron) if you do not have the proper crimp tool. If you solder, you must be careful not to get solder on the outside of the pin body, else the pin may not fit properly in the connector body.  Use of a crimp tool that FLATTENS the connector pins is NOT advised as it can prevent the connector pin from entering the connector body and seating properly.  The proper crimp tool is a "mil-spec" tool that crimps the pin on all four sides in the area where the wire enters the pin.

6)  The 12 volt automotive generator supplied with this machine is a six terminal unit but only TWO terminals are used.  The FIELD regulator input (A) and OUTPUT terminal(B) are the only terminals used and are shown in the image below.     The FIELD terminal (A) is the topmost slide on connection terminal.  See picture below for locations.  The mating "slide on" female connector  and plastic cover kit is furnished as part of the hardware which includes the ignition switch assembly. Note: The Perkins wiring diagrams  below show A tied to B and directly to the battery.  However, I note that there are TWO design defects present  on my 12volt DC Perkins engine alternator  a) The FIELD REGULATOR (terminal A) draws 2.3amps from the battery when the engine is stopped if pin B is connected to the battery.  This will run down the battery quickly if wired in accord with the Perkins diagram which they tell me is actually  for some other model 12vdc alternator.  b) There is a "sneak electrical path" such that when the engine is running, voltage is fed OUT the field regulator terminal.  If you hook up the alternator regulator pin to the fuel solenoid, so as to prevent the sneak path,  then it is essential to have a diode in series with the regulator input pin otherwise, the engine will not stop when you turn off power to the fuel solenoid.    No other 12VDC engine alternator I have seen has this last problem.

An easy way to prevent the sneak path AND at the same time provide a flyback diode for both the fuel solenoid and the starter solenoid is to employ a full wave bride rectifier with slide on termials.  The diode unit I used is the Motorola MDA800 with 1.4" slide on terminals. An alternative is the MB1505-ND from DigiKey for about $2.50.   With this diode bridge, you wire the MINUS terminal to ground, one of the AC pins goes to the fuel solenoid and the other AC pin goes to the starter solenoid.  The 12VDC alternator regulator pin is powered from the PLUS diode bridge pin.  This provides diodes for flyback voltage supression (lengthens relay/switch life) and it also prevents the alternator regulator's sneak path from keeping the fuel solenoid energized when you turn off the power to the fuel solenoid.    Other alternator connections are (C) for the "not generating" light if used and connections E, and F are tied to B and connection D is not used.  Pin D has about 7 volts on it when the engine is running and the 12volt alternator is connected.  If anyone knows the purpose of pin D, let me know. Slide on connector pins can also be found at any automobile parts store though the ones for pins B and C are about 3/8" and not the standard 1/4" size..  
7) A suitable wiring diagram for the MANUAL ignition switch (furnished with the kit) is shown below.  This is a four position switch.  The positions starting from left are HEAT, OFF, RUN, and spring return START position.  Basically, the switch is wired so that when the switch is turned to the LEFT, the glow plug heat is turned ON.  When you turn the switch to the far right both the generator fuel solenoid and the starter solenoid are energized.  When you release the key, the key springs back counterclockwise to the RUN position where only the fuel solenoid is energized.   Note that with this manual switch system, if you leave the switch in the LEFT (HEAT) position for a long time you will probably burn out your glow plugs plus you will definitely run down your battery.  If you leave the switch in the RUN position with the engine stopped,  you will also eventually run down your battery. NOTE: If you use this method, check to be sure YOUR alternator regulator is not drawing power from the battery when the engine is not running.   Because of these problems with the manual ignition switch method, I think you will be a lot better off to have some automatic start/run/stop system which will automatically start and  stop your engine and not accidentally leave the system in a state to run down the battery.  Four such appliances are listed below in item #8..

Below are several schematic wiring diagrams for this engine.  
The first is a MANUAL START/STOP (using ignition switch) arrangement.  This design is totally manual and has no automatic shutdown if anything goes wrong.  The first two drawings are courtesy of Perkins.  Note: In the manual start drawing below, there was a GROUND wire connected from the fuel solenoid to ground.  This is an error. I made the change in the upper right corner of the drawing to show the diode D2 (flyback catcher diode) in its proper place.  Also listed are some part numbers for diodes suitable for this application.  For the diode shown in series with the alternator annunciator lamp, a 1N5000 or similar should be fine.  A 1N4004 will be OK for the alternator lamp diode if it draws less than a half amp or so.

Figure 8A)




The second schematic below  is for a Manual Start/Stop (using ignition switch) arrangement but with automatic shutoff of the engine in case of low oil pressure or overtemperature condition.  This requires an accessory relay and diode to detect the low oil/over temp condition and shut off.  This drawing shows an indicator lamp for low oil pressure, water overtemperature, and alternator not charging the battery.

Figure 8B)
8) Automatic Engine Starters suitable for use with the Perkins 404c-22g ElectroPak engine (and similar small diesel and gasoline engines) are the DynaGen GSC300 and GSC400 controllers and the FW Murphy ASM-170 and Cascade models.  The GSC300 model is sold direct by DynaGen/Canada  for about US$190 plus shipping.  A wiring diagram to connect the GSC300 model to the Perkins ElectroPak is shown below.  The other controllers are wired similarly.  Controller setup involves selection of such parameters as start motor run time, restart holdoff time,  glow plug operate time before start,  run time after switch off signal, and other parameters depending on controller model.

The following schematic is for the DynaGen GSC300 automatic engine starter/controller.  This configuration provides complete control and monitoring of the Perkins 404c-22g engine with few additional components.  The drawing shows wiring for external-to-the-controller indicator lamps, but there are also indicator lamps built into the control panel itself on the front side with the push buttons.  The GSC300 can detect frequency from input voltages of about 1 volt AC to 300 volts AC.  Engine started is usually selected to be when the engine is turning at about 800 RPM or about 26hz out of the main alternator.   This and other parameters are user adjustable.   The complete manual  is found here.

Figure 8C)
9)  The item below is a "Glow Plug Indicator".  It is a heating element that shows when the glow plugs are "ready".  It is only needed on the MANUALLY controlled circuits and not when one of the automatic engine starters is used.  It is wired between two connections on the ignition switch when used.  It is normally mounted near the ignition switch in easy view as it indicates when to turn the preheat to OFF and begin cranking.




10) If desired,  tapped holes are available on the engine for separate analog water temperature  sensor installation.  You can purchase such auxiliary sensors from almost any automobile parts store but if you use one of the automatic engine controllers make sure it is compatible with the controller.

Below is a picture of the overall engine/generator system with the enclosure side panels removed.


PS> My cellphone camera is not very good, but for something like this, it gets the job done quick and easy.

The information in this document is believed to be accurate, but there is no warranty express or implied.  Checking the data and connections independently is highly recommended as Perkins (apparently) frequently changes such things as alternators and the actual connections on your particular unit may be different from those on the above.

This Document Copyright 2006 by Joe Mehaffey. All rights reserved.