Foxbody is possessed and will only fire up sometimes help

AJTunno · May 8, 2023

See video:
I have a 1992 5.0 that is having really weird issues. with the key in the run position it will do this sometimes and the fuel pump spazzes out you can hear it in the video and you can also hear a weird beeping type of noise. Car won't run anymore used to run fine, it sat for a while. Occasionally it will fire for a second but won't run there is no spark most of the time. Any idea what's going on here? And help is appreciated thanks

General karthief · May 8, 2023

Dead battery and/or bad connections?

AJTunno · May 8, 2023

General karthief said:
Dead battery and/or bad connections?

I don't think so it'll turn over fine I had it on a trickle charger

AeroCoupe · May 8, 2023

Sounds like the coil is shorting out. There is an adapter on the top of the coil, remove that and see if it makes the same sound.

General karthief · May 8, 2023

'don't think so' in the automotive world will get you stranded in a parking lot or at stop light. Clean the connections and have the battery tested.

AJTunno · May 8, 2023

AeroCoupe said:
Sounds like the coil is shorting out. There is an adapter on the top of the coil, remove that and see if it makes the same sound.

I removed the top part of the coil and still does the same thing. I also removed the spout connector and the coil seemed to stop sparking but it still made the same noise and sounds like there's a bunch of shorting out happening all over the engine and the fuel pump keeps priming. Then it'll stop spazzing out like this and when I turn the key to on position it primes like normal and stops after 3 seconds. No spark at all motor will just turn. The battery is fine and I cleaned the connections still the same thing

AeroCoupe · May 8, 2023

Do you have another coil you can try? That is just not normal for it to sound like that or at least neither of the MSD coils on my cars sound like that. Check all of your grounds like battery to frame and frame to engine block.

AJTunno · May 8, 2023

Thanks for the help. No I don't have any but I'll remove the coil completely and see if it does the same thing. I also pulled the computer and looked closely at the board nothing looks out of whack or burnt. Could it be my msd box or the distributor module maybe? I just went out again and turned the key on a few times and it primes normally but there's no spark just turns over. When it spazzes out like this (in the video) and makes the shorting out noises the car will fire sometimes. I'll check grounds tomorrow too

Noobz347 · May 8, 2023

AJTunno said:
Could it be my msd box

Yes.

Probably should have led with that

AJTunno · May 8, 2023

Yeah I had no idea where to start with this one. Is there a way to bypass the msd box or put it back to stock?

Noobz347 · May 8, 2023

Yes, there is and if it were me, I'd permanently remove it. I can't see what purpose it serves on our cars. The OEM ignition system is [hot] and produces a [fat] spark. My engine combo produces over 500 boosted FWHP on the stock ignition system.

Head over to MSD's website and download the installation instructions for your particular unit.

General karthief · May 9, 2023

It sounded like a solenoid buzzing to me from the video.

AJTunno · May 26, 2023

In order to bypass the msd box do I need a stock coil or can I use the msd coil that's in it now? I'm not sure If I did this correctly but I took the green/yellow wire and the red/green wire and hooked it up directly to the coil instead of them being connected to the msd box. Still the same thing it sounded like it wanted to fire for a second then nothing. Also replaced the ignition module and no change

foxbodyrobog · May 26, 2023

Seems like it's losing and regaining the ground

Noobz347 · May 26, 2023

You can use the stock coil assuming it's in working order.

AJTunno · May 26, 2023

Noobz347 said:
You can use the stock coil assuming it's in working order.

I don't have a stock one, is the stock ignition capable of sparking this msd coil or can only the msb box spark it? I think I read somewhere that msd fires the coil differently by grounding and the stock sends pulses or maybe its the other way around not sure

AJTunno · May 26, 2023

foxbodyrobog said:
Seems like it's losing and regaining the ground

Where should I check, I assume the msd box is shot but i re grounded it anyway

AJTunno · Jun 5, 2023

Alright so I looked at the computer again and this capacitor looks like it shorted out and fried one of the connections. Anyone know what could've caused this? Should I attempt to replace the cap or should I just get a whole new computer? I've tried a new coil and ignition module on the distributor and I also bypassed the msd and nothing changed so this is the only thing I can see is wrong at this point. Thanks

AeroCoupe · Jun 5, 2023

Looks like it burnt the trace so I would say send it off to ECU Exchange. Mustang5L5 may be able to tell you what that particular cap does so it would give a clue as to a possible reason it gave up the ghost but in all honesty the ECU's are 30 years old at best and the caps are just not meant to go much longer than that. Would not surprise me if the cap gave it up and burnt the trace.

rednotch · Jun 5, 2023

AJTunno said:
Alright so I looked at the computer again and this capacitor looks like it shorted out and fried one of the connections. Anyone know what could've caused this? Should I attempt to replace the cap or should I just get a whole new computer? I've tried a new coil and ignition module on the distributor and I also bypassed the msd and nothing changed so this is the only thing I can see is wrong at this point. Thanks

See the green fuzz, that's corrosion for the cap leaking, any where it leaked its going to start eating away at the trace. Need to clean it , remove the conformal coating, fix any damaged traces and pads and install new caps.

This is who I would suggest if your not comfortable doing that type of repair... This guy has done some repairs most places would tell you can't be fixed, he's out of VA.

Foxbody is possessed and will only fire up sometimes help

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wonder how much it would cost to ship you a pair

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lube between the nut and the face. I know my lubes

wonder how much it would cost to ship you a pair

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lube between the nut and the face. I know my lubes

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Stangnet Facilities Maint Tech... Er... Janitor

wonder how much it would cost to ship you a pair

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lube between the nut and the face. I know my lubes

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