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EMPIRE231

Wiring gremlins!!

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3 minutes ago, acefuture said:

Never really did. Talking with CBM and Mefiburn they both said sometimes it just happens. Usually not for no reason, but the main one is someone tries to jump the car with the mefi still plugged in. It'll burn it up quick. Second is a ground or strong arc that causes it to burn a pin up and fry the unit. In my research I found a couple guys who just mysteriously had one go out like mine did. 

Jump start the car?  Could you elaborate, last thing I want is a burned up MEFI.

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1 minute ago, rampster said:

Jump start the car?  Could you elaborate, last thing I want is a burned up MEFI.

I was told to never jump the car while having the mefi plugged in. So don't jump the car basically. Unhook your Mefi from the battery, charge the battery, then pull jumper cables, replug in mefi and start it. 

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45 minutes ago, acefuture said:

I was told to never jump the car while having the mefi plugged in. So don't jump the car basically. Unhook your Mefi from the battery, charge the battery, then pull jumper cables, replug in mefi and start it. 

Interesting  I would love to hear the logic behind this.  The alternator on the car can supply (in my case 160 amps).  This is no different than jumping it when it kicks on.

Now if the battery was REALLY dead say 8-9 volts I could see where that could cause a high amp situation that might fry the cpu but it should be fuse protected for this exact reason.  This is why Holley wants you to hook their computer + and - directly to the battery.  Acts as a buffer for voltage spikes and current.

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1 minute ago, r3meyer said:

Interesting  I would love to hear the logic behind this.  The alternator on the car can supply (in my case 160 amps).  This is no different than jumping it when it kicks on.

Now if the battery was REALLY dead say 8-9 volts I could see where that could cause a high amp situation that might fry the cpu but it should be fuse protected for this exact reason.  This is why Holley wants you to hook their computer + and - directly to the battery.  Acts as a buffer for voltage spikes and current.

I had the same thought, and my MEFI was/is protected by a fuse. It was just fine when I was doing the trouble shooting. I would think that they give that advice assuming many people don't have a fuse protected computer 

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If the car starts when the fuel pump is jumped, unplug the 2 connectors on the mefi and look to see if any of the terminals are missing. They should be evenly spaced across both sides no gaps should be 16 pins per connector

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2 hours ago, CBM said:

If the car starts when the fuel pump is jumped, unplug the 2 connectors on the mefi and look to see if any of the terminals are missing. They should be evenly spaced across both sides no gaps should be 16 pins per connector

Jumped fuel pump + to battery +, pump works and is right at 58 PSI. but car still will not start. 

Next step is to test continuity between the wire from the ignition to the ECM PIN. 

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Testing pins at the ECM plug. I’m getting 12+ volts to the battery feed pin.  The ground for ECM tested good for continuity. 

Now the pin that is for ignition feed is not zeroing out when I test for continuity. Close, but not zero. Should this pin test at 12+ volts when key is switched on? Or is this some sort of signal wire?

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19 hours ago, r3meyer said:

Interesting  I would love to hear the logic behind this.  The alternator on the car can supply (in my case 160 amps).  This is no different than jumping it when it kicks on.

Now if the battery was REALLY dead say 8-9 volts I could see where that could cause a high amp situation that might fry the cpu but it should be fuse protected for this exact reason.  This is why Holley wants you to hook their computer + and - directly to the battery.  Acts as a buffer for voltage spikes and current.

Yeah, this doesn't make any sense.  12VDC is 12VDC (or technically 13.2-14.4VDC).  It's not AC power with conflicting wave forms if you try to merge two power sources...  I'd understand if you tried hooking the jumper cables to the MEFI or went red to black on the cables, but if it's connected to the battery correctly, this is no different than if someone ran two batteries in their buggy...

As you say: only place this would matter is if you had a really flat battery  or too little alternator, and tried driving something directly from the MEFI like a fuel pump and tried to start it.  In this case, jumper cables would help, not hurt.  

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14 hours ago, EMPIRE231 said:

Testing pins at the ECM plug. I’m getting 12+ volts to the battery feed pin.  The ground for ECM tested good for continuity. 

Now the pin that is for ignition feed is not zeroing out when I test for continuity. Close, but not zero. Should this pin test at 12+ volts when key is switched on? Or is this some sort of signal wire?

Ignition should see 12v solid.  I suspect your key switch is bad or your wire feeding the ecu might have an issue.  Run a jump to the ignition and the battery inputs and see if it starts.

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1 hour ago, r3meyer said:

Ignition should see 12v solid.  I suspect your key switch is bad or your wire feeding the ecu might have an issue.  Run a jump to the ignition and the battery inputs and see if it starts.

I agree... switch is good, but pretty sure the wire is not.  Will know tonight after I drop the skid plate to gain access to the main loom that is running down the center console.

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Pretty sure I found my problem. 

Damn thing was corroded together, I had to break it apart to separate it   

5F1189D2-356B-4AC7-AA8A-F1EA26AE8A87.thumb.jpeg.4db2b9913ea1a64506181e9b4573e6aa.jpeg9056415D-77A5-4E04-B44E-DA13B3792D2A.thumb.jpeg.dd1be09bcbe37ca0bc785e1a418780be.jpeg0131729C-D71A-48E5-91FD-ADF0C46A8A00.thumb.jpeg.0ce5becb30ab3913bc8ec20038885627.jpeg

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Looks burnt.

But, that will do it...

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On 12/4/2019 at 10:19 PM, EMPIRE231 said:

Pretty sure I found my problem. 

Damn thing was corroded together, I had to break it apart to separate it   

5F1189D2-356B-4AC7-AA8A-F1EA26AE8A87.thumb.jpeg.4db2b9913ea1a64506181e9b4573e6aa.jpeg9056415D-77A5-4E04-B44E-DA13B3792D2A.thumb.jpeg.dd1be09bcbe37ca0bc785e1a418780be.jpeg0131729C-D71A-48E5-91FD-ADF0C46A8A00.thumb.jpeg.0ce5becb30ab3913bc8ec20038885627.jpeg

Dauuum it's time to change that out to a Weather Pak or ? those are the same types of connectors that come with the seat heater that fail most of the time I hate those things, your lucky that baby didn't short out smoke something else. 😮

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Wow. Good find! I changed all mine to K4 weather packs a couple years ago for similar problems, but they were just the seat heaters. The weather packs are holding up pretty good. 

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yeah definitely no good! keep in mind, it's all chewed up from me trying to pry it apart, wedging screw driver in there etc.  Still funky.  

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Update: problem solved! That connector was it. Reconnected the wires, car fired right up and is back to normal 😎

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