2011 4.6L Sedan will not start

[bbhuey99]

I have searched the forums but have found nothing that applies in the searches...

I have a 2011 4.6L sedan with 77K miles on it. When I try to start the car it will not turn over at all. The dash lights come on and everything seems fine, it simply will not engage the engine. I tried jumping it but that did not help. I then checked the battery and it registered 12.78v at the battery. I followed up by checking fuses in the engine bay. Everything seemed fine (but I didn't check the relays...not sure how). What am I missing? The battery is only a year old and seems fine plus I had driven the car 2 days prior with no issues.

When I push the ignition button, the display goes blank, there's a slight click and then it does nothing. If I push it again, it goes through the shut down process. The battery just doesn't seem to be the issue.

 

[Genesisson87]

Did u press n hold the brake when pushing start? Cause it only goes into acc if you don't.

 

[mikec]

What the OP is describing sounds like loose/poor connections on any of the battery cables. At low loads - dash lights, door lights, etc. - they conduct well enough so things can function... but under starter motor loads those bad connections cause excessive voltage drops and thus everything downstream acts like the battery was disconnected. A very common issue is where the black lead from the battery connects to the bodywork in the trunk; that is the main ground for the car. Paint between the connection = problems. A toothed star washer helps a ton here. Star washers have spurs that are twisted a bit, the edges of the spurs dig into the connector and car sheet metal to make solid connections.

Another common issue is the battery connections themselves. The factory battery post connectors sometimes fail to grip tightly to aftermarket batteries, allowing corrosion and other contaminates to cause issues.

A test to try: without pressing the brake pedal, push the START button twice so the car is in the "ON" mode but not started. Turn on the headlights. Are they bright or not? If not, that indicates a weak/bad battery or lousy electrical connections. If they are bright, firmly stand on the brake pedal and pusht he START button again while the headlights are still on. They should dim a little when the starter motor engages but if they dim to almost nothing that too indicates a bad battery.

How firm is the brake pedal while trying to start? If it's rock-hard right as soon as you try to press it (which means the power assist vacuum has bled away) you may not be moving the pedal far enough to trigger the electrical switch that turns on the brake lights and confirms to the engine computer that you in fact are pressing the brake pedal. If the pedal barely moves, push hard and try starting. If that makes the car start, you'll feel the pedal sink under your foot as the power assist vacuum (created by a running engine) builds back up. The power assist vacuum should not bleed down by itself over a day or two; it will bleed down a little each time you use the brake pedal (with the car off) which is normal. Typically, you can apply the brakes 2 or 3 times on stored vacuum assist before the vacuum reservoir is empty.

Last, wiggle the shift lever or move it from Park into Neutral and try starting. A flaky sensor on the shift lever can make the car think you aren't in Park or Neutral when starting. This is a common failure on almost any car with an automatic transmission - the "Park/Neutral Safety Switch" on older cars. On the Genesis ZF 6-speed transmission (used on the early model year V8 cars) a position sensor, attached to the shift lever cable, sends computer signals to the rest of the car for Park/Neutral safety functions. Shift lever cable issues or problems with the sensor/switch, both on older car designs or on the Genesis, can make the engine starter circuit think the car is not in Park or Neutral which inhibits the starter.

mike c.

 

[bbhuey99]

Well, I tried each of these suggestions to no avail.... I live in a very dry climate so corrosion typically isn't an issue here but I double checked everything and all seem normal. I went so far as to measure the amps from the battery and at the starter. There was minimal loss (.34 amps loss). Any other suggestions before I put this thing on a trailer and haul it to the dealership 50 miles away?

 

[Qship]

It could just be the starter solenoid. The starter has a plunger that pushes the starting gear out to the engine. If the solenoid is stuck, all you'll hear is a click since it can't spin until its pushed out. The starter takes a ton of juice to run when it's functioning normally. If it's stuck, it'll take even more power. I had an Eagle Talon with the same symptoms and what I had to do was tap the starter with a hammer which would loosen the solenoid and the car would start. I ran like that for a year until some chick's started laughing about it in a parking lot. Then out of respect to myself, I got a new starter lol.

 

[chrev]

Try tapping the starter solenoid or pulling it off and testing it.