Revised subject: 200 HPDI Bad ECU

[tkgjax]

My 200 HPDI keeps blowing the 20amp ECU/Ignition Coil/Fuel pump fuse when the keyswitch is turned on before engaging the starter. After the fuse blows the warning buzzer sounds until ignintion is turned back off. I am trying to determine if problem is in the motor or in the igntion switch itself. This started last Saturday when I noticed a strange smell coming from battery #2. I disconnected and switched to other battery while still running. I went from both to #2 instead of #1 and the motor died. I read that this will burn up the stator but I can't tell wether the symptoms I have could be caused by a bad stator. Any assitance would be greatly appreceated.

 

[Texasmark]

Re: Revised subject: 200 HPDI Bad ECU

Trying to help but know nothing.<br /><br />Most alarms are not in the engine; they are part of the wiring harness in the boat. The ignition switch is part of the same harness. The batteries are in the boat but most engines run power through the engine and there's the rub.....gotta have the engine hooked up to get power to the ignition switch.<br /><br />You need to get an electrical schematic of your engine which should show you all the electrical "loads" fed by this fuse (like ECU and coil and fuel pump). Find each and disconnect all of them except the switch it'self.<br /><br />Replace the fuse.<br /><br />Turn on the switch and go from there. If all are disconnected and it blows you have a short in your switch (unlikely unless to an aluminum boat dash or sideplate or something metal) or in your wiring harness. If in your harness probably a chafe point somewhere and the wire is "grounding" out. If a fiberglass or wood boat this is pretty unlikely.<br /><br />If the switch works (without blowing the fuse), turn it off and connect one of the loads. Turn it back on. If it blows, that load is shorted. Replace it.<br /><br />Continue till all loads are reconnected. You will find your problem.<br /><br />Mark

 

[rodbolt]

Re: Revised subject: 200 HPDI Bad ECU

your going to have to get the service manual and start tracing wires. the stator on that engine has nothing to do with the ign system other than keep the battery charged.<br /> the ign fuse should be different than the fuel pump.<br /> you will find there is a lot of wireing on that motor and the parts are very expensive. time spent with the harness diagram is money well spent, last ECU I looked at was almost 1500 dollars.<br />one fuse is for the relay for the injector driver, without it the engine stops, one fuse is for the main relay, if it blows the engine should quit unless the relay got smoked, the other 20 amp is for the fuel pump. any red/yellow wire will be 12V with key on power under the hood.<br /> all functions are controled in the ECU by the ECU making the ground curent path. the stator output is fed directly to the regulator and from there to the 80 amp fuses, one side is for the builtin battery isolator the other connects to the power tap on the starter solinoid. the 30 amp fuse is for the start solinoid circuit.

 

[grid]

Re: Revised subject: 200 HPDI Bad ECU

Gee, I don't know which "everyone" I am. Some things require cogitation. First, a blown fuse generally requires the bad timing of a ground to hot. Insofar as you "had a strange smell coming from #2 battery," and most strange smells incorporate burning (shorting out)I believe I'd look for melted wires around the 20A fuse area. Use a multimeter to locate a grounded positive wire. As far as switching the batteries, unless you passed OFF by going to #1, you may still be okay with the stator. Obviously, switching to a disconnected battery provided the elicited response.

 

[rodbolt]

Re: Revised subject: 200 HPDI Bad ECU

like I said the only thing the 20 amp fuse for the main and injector relays provides current for is the relay. something on the relay activate circuit is drawing excessive current.<br /> the wiring diagram bites but they are avalible in color now its just difficult to find them, the power supply side of the relay fuses are always hot, the ground path is activated by the ECU when the ECU recieves its key on 12V from the ign switch. without my magnifying lens I cant read the diagram. a friend loaded some from YDS and had Kinko's blow them up in color.<br /> this motor uses a 12V transistorized ign system very similar to the battery CD systems of the past. like I said the wiring on the HPDI and some of the EFI motors is rather complex.if the relay is not defective then you will have to trace the current path from the relay side of the fuse to the correct pin at the ECU connector. best I remember the two relays are identical and you can swap them to see if the other fuse blows. there is an inductor and a diode in parallel in the relay. so someplace between the input to the relay's activate circuit and the ECU something is drawing more than the designed 20 amps.

 

[tkgjax]

Re: Revised subject: 200 HPDI Bad ECU

Thanks for the responses. I took it to the shop and they indicated it was a bad ECU. Around $1800 for the ECU and labor. I like to troubleshoot myself if it something minor but this one is way over my head. It's going to take a while to recover this expense with the gas saving HPDI.