Mustang Failsafe Engine temp

[lyndenbouws197]

I'm experiencing a really strange issue with my Mustang.
I recently installed a new performance radiator, and now I'm having a major problem. Before I even start the car—just by turning the key to the "on" position—the engine temperature gauge instantly spikes to overheating, and the car goes into failsafe mode. I can't even start the engine.


To make things weirder, when I try to connect my BAMA tuner, it won't connect at all. It just throws a "general error" message.


Has anyone seen anything like this before or have any idea what could be causing it?

 

[SVT Rider]

Sounds almost like a ground or short issue. Did a wire possibly get pinched when installing the radiator?

Have you tried disconnecting the battery for 30mins and then reconnecting to reset the PCM?

 

[86GT351]

Go back over everything you did. I have never seen a radiator create an overheating with the car NOT running.

 

[lyndenbouws197]

I have tried disconnecting the battery, but not for 30 mins; I will give that a shot. I'm also guessing a grounding issue if that doesn't work. Cuss, the problem is forsure not actually overheating; it has to be something electrical.

 

[86GT351]

ON the Passenger side of the radiator support, isn't there a ground wire that screws in with a 7 or 8MM screw?

 

[Juice]

ON the Passenger side of the radiator support, isn't there a ground wire that screws in with a 7 or 8MM screw?

Two actually. One is pcm ground.
Temp guage pegging, I bet odometer is dashes.

 

[lyndenbouws197]

Yes there was the two, they were good when I check them. And I reset the battery for 30 mins. Think I just have to hook up a scanner to it and see what codes it giving me

 

[lyndenbouws197]

I'm experiencing a really strange issue with my Mustang.
I recently installed a new performance radiator, and now I'm having a major problem. Before I even start the car—just by turning the key to the "on" position—the engine temperature gauge instantly spikes to overheating, and the car goes into failsafe mode. I can't even start the engine.


To make things weirder, when I try to connect my BAMA tuner, it won't connect at all. It just throws a "general error" message.


Has anyone seen anything like this before or have any idea what could be causing it?

I have even disconnect the battery for over an hour, hooked up a scanner and nothing, checked the grounds they were working. what was weird is when i disconnected my coolant temp sensor it would crank but wouldnt start and it was loose so i may need a new one, but i should still be able to start the car tho atleast.

 

[lyndenbouws197]

oh and also important detail which i cant figure out when i try and start it my thorttle body starts spamming opening and closing.

 

[DieHarder]

I'd recommend rechecking everything you touched (especially electrical) when you replaced the radiator including the crankshaft position sensor down by the crank pulley. If you damaged it the car won't start. Also sounds like you have a short somewhere.

Here's some troubleshooting steps:

No DTC's present:

Ford Workshop Service & Repair Manuals - fordrepair.info - 2005 Mustang Powertrain Control And Emissions Diagnosis Step 2- no diagnostic trouble codes (dtcs) present symptom chart index

Ford Workshop Service and Repair Manuals, 2005 Mustang Powertrain Control and Emissions Diagnosis SECTION 3 Symptom Charts Step No Diagnostic Trouble Codes DTCs Present Symptom Chart Index

iihs.net

Chart 23: https://iihs.net/fsm/?d=9&f=Step 3-...e Codes (DTCs) Present Symptom Charts.pdf&p=9

Chart 23 (cont): https://iihs.net/fsm/?d=9&f=Step 3-... Codes (DTCs) Present Symptom Charts.pdf&p=10

Starting system: https://iihs.net/fsm/?d=204

 

[Autokyrios]

Something's shorted. Did you pinch a wire when slotting the new radiator into place? Go through everything in the bay, not just what you think you might have touched.

Only other thing I can think of (in my state of coffee-less sleep depravity) is the ECM is knackered...but that's only for worry when everything else is ruled out.

 

[DieHarder]

At some point might be worth taking it to a dealer to get it hooked up to one of their diagnostic analyzers. Diagnostic costs around $200 - $220.

 

[Juice]

Sounds to me the pcm plug got messed, is right there next to the radiator. Temp guage pegged - I do believe it pegs without the pcm plugged in. Plus the tuner cant comm either.