Power Failure issue

[darreng505]

Hey guys,
Had a very scary problem occur at the track this past weekend, that I luckily caught in time. But need help diagnosing it.

So I'm on grid pulling out for first session of the day. As I'm turning I notice a momentary loss of power steering, but it comes back. Then again during warm up lap, loss of power steering for a second, so I'm pitting immediately.

Then, while driving slowly back to my station, complete loss of power. engine, lights, everything. Turn key....nothing...no lights...no chime...no life

Pushing car back.....then key chime comes back on...car starts...no engine codes...

What could be happening here? Some theories.

1. Loose ground wire somewhere?
2. Bad alternator?
3. Engine harness?
4. Loose tensioner/belt?
5. PCM/ECU?
6. Tune?

One other oddity, I did notice a strange sound while warming the engine up...kind of like a belt or something harmonic to the motor...but it faded and I didn't notice anything from it...could be related.

Help appreciated!

 

[el jefe 302]

Rule out the tune. check everything else on your list.

 

[_Snake_]

I keep thinking electrical. Like a ECU / PCM plug is loose or something.

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[svt1111]

Check the fusible link (200 amp) and the fuse for the electric power steering (100 amp) which is located right next to it on the same block.

 

[darreng505]

Thank you sirs. I will check these items.

 

[svt1111]

I just re-read your post. I stand corrected. If the car started back up, then neither thing I suggested is plausible.

Could be a hiccup in the tune maybe?

 

[darreng505]

Someone also suggested something with the key/ignition switch? Maybe loose wire or something? I know nothing about these electrical systems. But I did have a quick change steering wheel put in which may have affected wiring there. Seems unlikely to cause a catastrophic failure though.

I doubt (but not 100% sure) it can be tune related because I did not even get the key chime with the key inserted or any dash lights. The tune would need power to start affecting the ECU/PCM in weird ways.

 

[IamRacerX]

I wouldnt write off that noise you heard, could very well be related if its something you havent heard before. My gut says alternator/bad ground related.. good luck!

 

[MaximumVelocity]

Check the fusible link (200 amp) and the fuse for the electric power steering (100 amp) which is located right next to it on the same block.

^^^ This. You are right, the symptoms point to the positive battery cable / connections being loose (where the fusible link for the steering motor is).

 

[darreng505]

^^^ This. You are right, the symptoms point to the positive battery cable / connections being loose (where the fusible link for the steering motor is).

I will check this. Oddly enough I did zip tie the rubber cable cover over the positive battery connection before heading to the track. Maybe something jarred loose.

 

[RTD]

Turn key....nothing...no lights...no chime...no life

Loose battery cable or bad main ground. I can't think of anything else that would cause a complete loss of all electrical power to the car and then everything springs back to life perfectly a few minutes later.

 

[darreng505]

Loose battery cable or bad main ground. I can't think of anything else that would cause a complete loss of all electrical power to the car and then everything springs back to life perfectly a few minutes later.

But once the car is running, is the battery all that important electrically? (Forgive me if a dumb question).

It was running and then just went dark...so I guess main ground is more likely?

Where is the main ground located? I see a number of ground taps screwed to the inner engine compartment near the passenger strut top area.

Also, other oddity was the loss of power steering for a second, twice. Car was still running fine then, best as I can tell. Maybe an electrical surge so brief it didn't kill the PCM.

 

[RTD]

But once the car is running, is the battery all that important electrically? (Forgive me if a dumb question).

It was running and then just went dark...so I guess main ground is more likely?

Where is the main ground located? I see a number of ground taps screwed to the inner engine compartment near the passenger strut top area.

Also, other oddity was the loss of power steering for a second, twice. Car was still running fine then, best as I can tell. Maybe an electrical surge so brief it didn't kill the PCM.

A car SHOULD be able to run on alternator alone, and this was definitely the case in the old days of carbs and points ignition. I've seen weird things happen on newer cars though with the battery disconnected, in your case the EPAS steering failure could fall under that. Follow the negative battery cable to find ground. Have you checked both cables at the battery yet? That'd be the first thing I'd look at.

 

[darreng505]

A car SHOULD be able to run on alternator alone, and this was definitely the case in the old days of carbs and points ignition. I've seen weird things happen on newer cars though with the battery disconnected, in your case the EPAS steering failure could fall under that. Follow the negative battery cable to find ground. Have you checked both cables at the battery yet? That'd be the first thing I'd look at.

I did check them and they looked ok, but I didn't follow the negative cable. Will do that today.

 

[_Snake_]

Personally, I'd start my troubleshooting with the aftermarket, quick change steering wheel. Not the wheel itself, but everything that was touched during the install.

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[Brewmaster]

Personally, I'd start my troubleshooting with the aftermarket, quick change steering wheel. Not the wheel itself, but everything that was touched during the install.

.

I was thinking the same thing. Maybe installation resulted in a loose connection in the ignition wiring.

 

[draxxus131]

Were you ever able to find a solution to this?

 

[darreng505]

Dropping it off today. I told them they need to know for sure what caused it. So hopefully they will find a smoking gun.

 

[fredfred]

I have had a few fords come in my service department for the same concern. Ended finding the problem with the main fuse block on pass side below dash. Found main harness not locked all of the way in. Have to pull fuse block.

Hope this helps.

 

[darreng505]

Thanks. We'll check that too. As of now, things are pointing to a loose/faulty battery terminal, but it looks fine to the naked eye. Jiggling the terminal connections caused the key chime to come on or go off.
There could still be something else lurking, but hopefully its this simple.