Need help with Electrical Gremlin
12-10-2008, 03:42 PM
#1
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Need help with Electrical Gremlin
I have a brand new electrical gremlin I need some help killing. For some reason, my car keeps blowing the 30A INJ fuse under the hood. It happened the first time last Friday while driving. I wasn't doing anything crazy and we had been driving for about 20 minutes, when it just quit. I still had power and the engine would crank, but the fuel pump wasn't running. Replaced the fuse this weekend and drove it to/from work on Monday just fine. Went to drive it this morning and the fuse was blown again.
The only thing I can think of is I recently (last month) replaced my fuel pump with the walbro 255. The car has run great since that installation with the exception of this new problem.
Called FM support today and they suggested I run the power to the fuel pump off a switch directly from the battery to see if it keeps popping the fuse. I am looking for something a bit more analytical. I have the wiring diagrams for the car, but I was wondering if any of you have some ideas on where I should start.
The only thing I can think of is I recently (last month) replaced my fuel pump with the walbro 255. The car has run great since that installation with the exception of this new problem.
Called FM support today and they suggested I run the power to the fuel pump off a switch directly from the battery to see if it keeps popping the fuse. I am looking for something a bit more analytical. I have the wiring diagrams for the car, but I was wondering if any of you have some ideas on where I should start.
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12-10-2008, 03:58 PM
#2
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Unless you happen to own a DC ammeter with logging capabilities, moving one device at a time off of the circuit in question is a pretty good troubleshooting strategy.
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12-10-2008, 09:56 PM
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No, the wires are fine and there is no shorting that I could see. I have an ok multimeter, but it doesn't have an ammeter built in. Perhaps this is time for an upgrade 
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12-12-2008, 11:24 AM
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Looks like I need to do some more work on this. I tried a brand new fuse today and it blew as soon as I turned it over. Is there any chance the pump died? It is only a month old... 
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12-12-2008, 10:39 PM
#9
Look in the area behind the driver's seat.
Meanwhile, save some money by not using new 30A links, get a fuse holder and a couple female spade connectors and pop blade fuses instead. Then, once you're sure the problem's gone you can put the link back in.
miataunderhood003.jpg
Meanwhile, save some money by not using new 30A links, get a fuse holder and a couple female spade connectors and pop blade fuses instead. Then, once you're sure the problem's gone you can put the link back in.
miataunderhood003.jpg
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12-13-2008, 09:33 PM
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Yeah, 5 pack of blade style was $3. The normal ones are $4.15 and I have already gone through two of those :( I just had some of my neighbors help me push the car into the garage so I can work on it tonight. I really hope it is something simple.
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12-14-2008, 07:11 PM
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Solved my problem and it turns out I was the failure point... again. Not sure how it happened, but I failed to follow the first rule of soldering. Never have two joints at the same place in the loom. Apparently the heatshrink I used was not solvent safe and swelled. When this happened, the solder joints rubbed on each other until they shorted inside my tank 
Took them off, resoldered them to different positions, and the car jumped to life! Anyway, maybe someone else will learn from my mistake
Took them off, resoldered them to different positions, and the car jumped to life! Anyway, maybe someone else will learn from my mistake
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12-14-2008, 09:16 PM
#15
Solved my problem and it turns out I was the failure point... again. Not sure how it happened, but I failed to follow the first rule of soldering. Never have two joints at the same place in the loom. Apparently the heatshrink I used was not solvent safe and swelled. When this happened, the solder joints rubbed on each other until they shorted inside my tank Took them off, resoldered them to different positions, and the car jumped to life! Anyway, maybe someone else will learn from my mistake
Took them off, resoldered them to different positions, and the car jumped to life! Anyway, maybe someone else will learn from my mistake
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