Let the smoke out of a mini starter this morning
#2656707
05/18/19 10:27 PM
05/18/19 10:27 PM
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Joined: Jul 2007
Posts: 1,682 Philadelphia
radar
OP
top fuel
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OP
top fuel
Joined: Jul 2007
Posts: 1,682
Philadelphia
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I have my wiring harness including charging system all attached to a remote insulated positive stud under my hood which is fed from the big hot lug on my mini starter which is fed by a 0g cable to the battery under my truck bed. The only things attached directly to the battery are grounds, the cable to the starter, and the constant power to my sniper EFI.
When I started and warmed up the truck this morning I thought I heard an extra whirring sound but I wasn’t sure- it’s a little loud with 3.5” exhaust. Everything seemed normal until I went to leave I noticed that my sniper dashboard was flashing yellow on battery voltage and it was down to 10v. Huh that’s wierd I thought- my autometer voltage gauge in the dash is reading 13.5 like my charging system is healthy and it sure cranked fast when I started it. Then the sniper battery volt gauge went down to 9.9, 9.8, 9.7, then smoke started pouring out from underneath with electrical fire smells!
I successfully shut off the motor with the key and unplugged the sniper main harness connector, negative battery cables, then positive cables, and the smoke from my starter tapered off. My engine bay is tight so I had the starter wrapped in a dei blanket held on with two neatly twisted shut loops of bailing wire. I think the fiberglass and foil blanket contained any fire if there was one. I suspected that I had wired the blanket on too tight or somehow crossed or shorted my 0g cable but at the time I just wanted to make it safe and get to work ten mins late and smelling like an electrical fire.
I just got home and started investigating, expecting to find my heavy cable all melted to hell. To my surprise it was the cable that’s part of the starter on the bottom that melted! If my trigger wire had shorted it would have stayed on and cranking despite removing the key and if the jackshaft had stayed popped out into the converter ring gear I expect I would have heard more mechanical racket?
What’s y’all’s guess on cause of death on this POS? Did I do something wrong that needs fixin on version II? I have another mini starter here so I guess I’ll just throw it in but wow this was a scary morning for a minute!
Last edited by radar; 05/18/19 10:28 PM.
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Re: Let the smoke out of a mini starter this morning
[Re: radar]
#2656893
05/19/19 02:10 PM
05/19/19 02:10 PM
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Joined: Jan 2003
Posts: 15,348 Omaha Ne
TJP
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 15,348
Omaha Ne
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I just wonder if the solenoid stuck then why didn’t the starter continue to crank when I turned off the ignition? Maybe the motor was already fried and making a dead short instead of cranking power? Then why don’t I see more ring gear damage?
When I started and warmed up the truck this morning I thought I heard an extra whirring sound but I wasn't sure A starter motor that stays engaged with the ring gear will become a generator at a given RPM. This in turn fried the wire from the motor to the solenoid which likely led to a dead short and caused you voltage readings to drop I suspect your solenoid stuck on, or the 12v signal from the ignition switch did not switch off thereby keeping the solenoid engaged. You got very lucky. There would be no ring gear damage as the ring gear was driving the starter instead of the other way around. And yes you probably correct that in the process the starter motor fried itself BTW your starter cable lug needs to be properly crimped / soldered and should have shrink tube sealing the connection.
Last edited by TJP; 05/19/19 02:13 PM.
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Re: Let the smoke out of a mini starter this morning
[Re: radar]
#2657093
05/20/19 12:18 AM
05/20/19 12:18 AM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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I'm thinking you are set (just a starter issue).
live every 24 hour block of time like it's your last day on earth
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Re: Let the smoke out of a mini starter this morning
[Re: RapidRobert]
#2657098
05/20/19 01:11 AM
05/20/19 01:11 AM
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Joined: Jul 2007
Posts: 1,682 Philadelphia
radar
OP
top fuel
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OP
top fuel
Joined: Jul 2007
Posts: 1,682
Philadelphia
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Thanks Robert
Holley wants the EFI constant power direct to the battery but I have a master disconnect on the negative cable from the battery (big nhra style switch but on neg not +) that I used while building and shaking down the truck before welding or letting it sit for a few days. Using it with the sniper constant ground still hooked to the battery side post led to wierd ground loop problems- the IAC was ticking like a clock and hunting around and the fuel pumps had a wierd low voltage ghost. I swapped all the chassis grounds to the same side of the switch and was using it only to lift the grounds on the fuel pumps in case of emergency (never needed it but the battery is somewhat tucked away and that makes me nervous).
Well this episode made me want to use it as a master disconnect again so now one side has my - battery cable and the other side of the disconnect switch has the fat grounds to the frame & block, the fuel pump grounds, and the EFI constant ground. Hopefully it won’t be too noisy.
I agree I was lucky but my system actually worked exactly as intended. The battery acted as a damper so the sniper only saw a slow voltage drop, and my secondary main cable (4g) from the fat starter lug (0g to batt + from there) has a 50 amp maxi fuse that blew when things got wierd. That’s why my autometer gauge read steady 13.5 while the battery was draining and the starter was waging war on itself. The front half of my harness was disconnected from the battery and perfectly happy to run off my ‘89 dakota alternator and brand new regulator.
It was a busy day- Atco in the AM then dinner guests, then the game of thrones finale, but I got the new starter in this afternoon and finished the wiring after the show. First I left the sniper harness disconnected and tried my key. All my lights and gauges are working and the starter hits and turns over the motor nicely. It disengages quickly with the cranking pressure off the key left in the run position. I crossed my fingers and plugged in the sniper main harness. No wierd noises with the master disconnect off so I turned it on and still good. I turned the key to run and the sniper dash came to life and I heard the fuel pumps come on then off like normal, the injectors priming, and the IAC valve parking. So hopefully that’s all good too. I didn’t want to wake up the neighbors so I’ll test it out for real tomorrow.
Thanks for all the helpful responses fellas!
Radar
Last edited by radar; 05/20/19 01:12 AM. Reason: Typo
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Re: Let the smoke out of a mini starter this morning
[Re: radar]
#2657187
05/20/19 10:58 AM
05/20/19 10:58 AM
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Joined: Jan 2003
Posts: 15,348 Omaha Ne
TJP
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 15,348
Omaha Ne
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My keyswitch gets fused power from the fusebox and a single run of wire straight through the firewall down to the trigger post on the starter for cranking. You may need a relay in the circuit depending on how much current the starter solenoid draws and what your ignition switch contacts are rated for. This may or may not be the root cause of the problem. Also as previously mentioned you cable crimps look a bit suspicious. They appear to have been just flattened rather that crimped with a proper tool and / or soldered.
Last edited by TJP; 05/20/19 11:03 AM.
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