Electrical Issue-SOLVED

[Buldawg76]

What do you mean by tt car. was it a track car put back on the street. Sounds like with relocation of alternator and fuse box it's an electrical gremlin nightmare unless it was done very professionally.

BD

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[Skye]

Relocating the items you mentioned, unless part of a professionally-made kit...I'm afraid all I can offer is to seek out someone who is good with electronics and electrical wiring itself. Someone who can wire an entire car. Individual physical connections, types of connectors used, additional length of wires impacting voltage and resistance, tunes, securing all these items against heat and vibration, etc, etc, induces complications a pro might be able to assist with. If these mods were part of a kit, maybe the supplier could provide some t-shooting insight and diagrams.

 

[ttyoye]

Relocating the items you mentioned, unless part of a professionally-made kit...I'm afraid all I can offer is to seek out someone who is good with electronics and electrical wiring itself. Someone who can wire an entire car. Individual physical connections, types of connectors used, additional length of wires impacting voltage and resistance, tunes, securing all these items against heat and vibration, etc, etc, induces complications a pro might be able to assist with. If these mods were part of a kit, maybe the supplier could provide some t-shooting insight and diagrams.

We traced down every wire and figured out where everything went, wasnt that complicated. Every wire was tested along with the grounds, relays and fuses, also all the dtc's have gone away except the 2 evap ones. Tried reflashing the car again and it is still losing communication in the process.

 

[Cobra Jet]

When you bought the car, was it private sale or dealer? If private, can you contact the seller and ask questions?

I'm wondering if the last owner dumped it because of these very issues? Could be coincidental but kind of strange it's having the issues after driving it such distance.

Have you been able to pull any codes at all?

Here's some links to help you pull codes using Engineering Test Mode from the dash cluster. Now I can't guarantee it will work because it seems someone really did some mods to your car but you can at least try to see if there's any stored codes.

If you have a 2015-2020+ with the ANALOG gauge cluster, you should be able to enter the “Engineer Test Mode”.

Follow this link:
https://www.mustang6g.com/forums/threads/engineering-test-mode.27581/

If you you have a 2018-2020+ with the DIGITAL cluster, you should be able to access the same test mode found here:
https://www.mustang6g.com/forums/th...n-18-digital-dash-old-way-doesnt-work.115231/

---
There is also this thread where a GT350 owner had a similar non-start issue and could not get the car to start, it ended up being a 125A fuse:
https://www.mustang6g.com/forums/threads/car-is-dead-need-help.137125/

 

[Skye]

OK. Physical is the best place to start. Sounds like you covered that. Cobra Jet gave some insight on the logical; hopefully some tells will display which lead to the problem.

 

[ttyoye]

When you bought the car, was it private sale or dealer? If private, can you contact the seller and ask questions?

I'm wondering if the last owner dumped it because of these very issues? Could be coincidental but kind of strange it's having the issues after driving it such distance.

Have you been able to pull any codes at all?

Here's some links to help you pull codes using Engineering Test Mode from the dash cluster. Now I can't guarantee it will work because it seems someone really did some mods to your car but you can at least try to see if there's any stored codes.

If you have a 2015-2020+ with the ANALOG gauge cluster, you should be able to enter the “Engineer Test Mode”.

Follow this link:
https://www.mustang6g.com/forums/threads/engineering-test-mode.27581/

If you you have a 2018-2020+ with the DIGITAL cluster, you should be able to access the same test mode found here:
https://www.mustang6g.com/forums/th...n-18-digital-dash-old-way-doesnt-work.115231/

---
There is also this thread where a GT350 owner had a similar non-start issue and could not get the car to start, it ended up being a 125A fuse:
https://www.mustang6g.com/forums/threads/car-is-dead-need-help.137125/

When you bought the car, was it private sale or dealer? If private, can you contact the seller and ask questions?

I'm wondering if the last owner dumped it because of these very issues? Could be coincidental but kind of strange it's having the issues after driving it such distance.

Have you been able to pull any codes at all?

Here's some links to help you pull codes using Engineering Test Mode from the dash cluster. Now I can't guarantee it will work because it seems someone really did some mods to your car but you can at least try to see if there's any stored codes.

If you have a 2015-2020+ with the ANALOG gauge cluster, you should be able to enter the “Engineer Test Mode”.

Follow this link:
https://www.mustang6g.com/forums/threads/engineering-test-mode.27581/

If you you have a 2018-2020+ with the DIGITAL cluster, you should be able to access the same test mode found here:
https://www.mustang6g.com/forums/th...n-18-digital-dash-old-way-doesnt-work.115231/

---
There is also this thread where a GT350 owner had a similar non-start issue and could not get the car to start, it ended up being a 125A fuse:
https://www.mustang6g.com/forums/threads/car-is-dead-need-help.137125/

Fuse looks good, can it still be bad?

 

[Buldawg76]

Check continuity between bottom plate and top threaded studs to be sure it's good.

BD

 

[ttyoye]

So looks like I can have figured something else out. When I try to connect any device to the obd2, I see the lights coming from the device but it’s not connecting to any device. Did some Google searching on “no communication to obd and no crank” couldn’t find anything on s550’s but found a bunch of threads of other cars with similar issues. One guy had to replace his whole engine bay fuse box (mine had some corrosion on some relays possibly dude to not being waterproofed and water slowly getting in there) another guy had the same issue with a fuel sensor causing his car not to crank and no connection with ecu and throwing every possible light and his issue was a faulty fuel sensor. Upon further inspection it looks as if my oil pressure sensor is leaking a tad and can be possibly causing the car go into some safe mode if the sensor is bad. I also read a thread on a s550 where a guys bcm ground was lose causing the car to spaz out and not cranking but too many electronics in my car work to make me thing something with the bcm but I’ll check it out anyway. This is my first coyote I’ve owned so bare with me if any of this sounds dumb lol.

 

[Brokestang]

No it's not dumb but these kinda talks help dumb folks like me learn!

 

[Cobra Jet]

So looks like I can have figured something else out. When I try to connect any device to the obd2, I see the lights coming from the device but it’s not connecting to any device. Did some Google searching on “no communication to obd and no crank” couldn’t find anything on s550’s but found a bunch of threads of other cars with similar issues. One guy had to replace his whole engine bay fuse box (mine had some corrosion on some relays possibly dude to not being waterproofed and water slowly getting in there) another guy had the same issue with a fuel sensor causing his car not to crank and no connection with ecu and throwing every possible light and his issue was a faulty fuel sensor. Upon further inspection it looks as if my oil pressure sensor is leaking a tad and can be possibly causing the car go into some safe mode if the sensor is bad. I also read a thread on a s550 where a guys bcm ground was lose causing the car to spaz out and not cranking but too many electronics in my car work to make me thing something with the bcm but I’ll check it out anyway. This is my first coyote I’ve owned so bare with me if any of this sounds dumb lol.

The oil sensor above the oil filter - the "seepage" or "leak" is very common across the whole S550 platform. That little bit of seepage should not prevent the car from starting or running at all. If the harness to the sensor is loose, possibly - but many on here have had the seepage and it didn't stop the car from starting or driving. These sensors have been found leaking right off the showroom floor. Get yourself some carb cleaner, spray down around the sensor and oil filter area, clean and wipe dry. Then tighten the oil sensor just a tad. Some have pulled it out and used a bit of Teflon tape on the threads, shouldn't have to but it will work.


This is the proper oil sensor socket:
https://www.lislecorp.com/specialty-tools/13900-oil-pressure-switch-socket-for-ford

The oil psi sensor should be 13/16”.

Usually the local parts stores sell Lisle tools. Also Auto Zone or Advance Auto may have an oil psi socket for rent too… ask them, as they both rent out a variety of tools.

 

[ttyoye]

The oil sensor above the oil filter - the "seepage" or "leak" is very common across the whole S550 platform. That little bit of seepage should not prevent the car from starting or running at all. If the harness to the sensor is loose, possibly - but many on here have had the seepage and it didn't stop the car from starting or driving. These sensors have been found leaking right off the showroom floor. Get yourself some carb cleaner, spray down around the sensor and oil filter area, clean and wipe dry. Then tighten the oil sensor just a tad. Some have pulled it out and used a bit of Teflon tape on the threads, shouldn't have to but it will work.


This is the proper oil sensor socket:
https://www.lislecorp.com/specialty-tools/13900-oil-pressure-switch-socket-for-ford

The oil psi sensor should be 13/16”.

Usually the local parts stores sell Lisle tools. Also Auto Zone or Advance Auto may have an oil psi socket for rent too… ask them, as they both rent out a variety of tools.

Since we have checked all the grounds and everything looks fine. Now it’s sounding like a possible sensor or bad module issue somewhere or maybe even the pcm. Tried plugging in forscan and it won’t even connect to the car. Saw some other posts about obd2 having communication issues but having power and that’s exactly what’s going on here.

 

[ttyoye]

https://www.mustang6g.com/forums/threads/no-power-at-obdii.144876/

https://www.mustang6g.com/forums/threads/no-power-to-obd-ii.53049/

https://www.mustang6g.com/forums/threads/obd-port-aint-getting-power.31053/

https://www.mustang6g.com/forums/th...ble-service-advancetrac-dash-messages.110170/

 

[sstone]

Lots of folks have had issues with the BCM ground. Under the rear seat, driver side.

 

[ttyoye]

Used pcm (same p/n) now has connection to obd and fuel pressure is back. Plugged ids in and would still lose communication when trying to connect with the pcm.

 

[Cobra Jet]

Have you reached out to prior owner of the vehicle to ask if he deleted or cut any wires out of harnesses? Or has the prior owner pretty much been non-responsive?

Check all grounds in engine bay, make sure they are making proper contact. Even if they "look good", remove them, get some Emory paper or sandpaper and clean both the connector and the surface to which it is being secured to - even if it means to scrape a little paint to get a true metal to metal contact.

Check all routing of the harnesses under the dash and look for any cut wires, grounds that may be disconnected or loose.

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