2000 mustang issues

Avaliyn

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Nov 29, 2019
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Hello all!

I don't even know where to start in trying to fix my poor car. So any help would be a god send!

I have a 2000 manual v6 mustang.

Fun symptoms:

1. Occasionally when you try to start it, accessories will turn on, then when you go to turn it over, there is a loud click then nothing. If you try to turn it on again, there are no accessories and no click.

2. If you let it sit with the battery attached, after about 15/20 min you can get accessories back and get that single click again.

3. If you detach the battery and let it sit, you can usually reattach the battery after 15 min and it'll start. If it doesn't and you take the battery out to be charged at Auto zone, they will judge you cause it's already at 70/80% but if you get it back up to 100% then it will definitely start.

4. There is definitely stuff drawing power and I did a fuse test thingy. It's the Alternator, radio, and instrument cluster/pcm are the big ones, and the secondary air intake is drawing a little bit but I don't think that's anything.

Previously I have replaced the starter (actually twice this year) and the alternator and the fuse box.

I realize the pcm is probably the thing that's doing something funky here but I'm not sure what to look for or how to fix it. I'm not seeing anything grounding out.

If you have absolutely any suggestions I'll try it.

Thanks!
 
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MustangIIMatt

I need something stupid to play with
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Hello all!

I don't even know where to start in trying to fix my poor car. So any help would be a god send!

I have a 2000 manual v6 mustang.

Fun symptoms:

1. Occasionally when you try to start it, accessories will turn on, then when you go to turn it over, there is a loud click then nothing. If you try to turn it on again, there are no accessories and no click.

2. If you let it sit with the battery attached, after about 15/20 min you can get accessories back and get that single click again.

3. If you detach the battery and let it sit, you can usually reattach the battery after 15 min and it'll start. If it doesn't and you take the battery out to be charged at Auto zone, they will judge you cause it's already at 70/80% but if you get it back up to 100% then it will definitely start.

4. There is definitely stuff drawing power and I did a fuse test thingy. It's the Alternator, radio, and instrument cluster/pcm are the big ones, and the secondary air intake is drawing a little bit but I don't think that's anything.

Previously I have replaced the starter (actually twice this year) and the alternator and the fuse box.

I realize the pcm is probably the thing that's doing something funky here but I'm not sure what to look for or how to fix it. I'm not seeing anything grounding out.

If you have absolutely any suggestions I'll try it.

Thanks!
All of this points to a loose electrical connection or a missing ground strap. Check all of your connections to the starter, battery, alternator, and your grounds to make sure all are tight and free of corrosion.
 
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wmburns

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Aug 14, 2009
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It's not clear to me WHEN the loud click occurs. IE when the key is turned to "run" or when the key is turned to "crank". The trouble shooting is different for a "no crank" verses "crank with no start".

Can you post a video of the sequence?

Can you bar the motor over by hand? Trying to find out IF the motor is too hard for the starter to over come.

What is the voltage at the battery before the attempt is made. What happens to the voltage at the battery when the attempt is made. Does it change? If so, by how much?

IF the strength of the battery does make a difference, THEN this points to a voltage drop problem. Here is some information on voltage drop testing. The voltage drop test if done correctly can absolutely pinpoint or narrow down where the voltage drop is actually occurring.

Bottom line: High current electrical connections need to be CLEAN and TIGHT.

Howto perform charging system voltage drop test
 
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Avaliyn

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Nov 29, 2019
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The battery was at 11.9 then dropped to 11.4 during accessories in the video and now it's back up to 12v.

I'm still going through some other stuff you mentioned. I don't think I have the tools to try it by hand but I'll look around.

Video: View: https://youtu.be/BZXdWffMIQs


It wouldn't let me attach it to the post so I used good ole fashioned YouTube.

Thank you again for your help, seriously
 
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wmburns

SN Certified Technician
Aug 14, 2009
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The video points to a starter "issue". The starter's Bendix can clearly heard trying to engage. The trick is to figure out why the starter doesn't crank. We need to know IF
  • the starter is working but is unable to over come the resistance of the motor
  • the starter isn't getting enough power to do it's job.
  • The starter is bad. IE when the starter's Bendix engages (can be plainly heard) the starter motor itself isn't being powered.
To determine IF the starter is drawing current we need to know exactly what the battery voltage is doing when the key is turned to crank.

IF the battery voltage drops, THEN either the battery isn't holding voltage or the starter is drawing too much power.

IF the battery voltage does NOT drop, THEN the starter isn't really drawing any power.

A redneck method. Turn the head lights on. Attempt the crank the motor. IF the head lights do not dim this means no real current is being consumed.

Again. Don't cut corners on the quality of the electrical connections. Clean and tight should be the order of the day.
 
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Avaliyn

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Nov 29, 2019
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So if it's the starter then could you take a guess at why I've had to change it out 3 times in the past year? I'll look around as soon as I'm under there though to see if there's anything obvious.

And does that also mean that the alternator, pcm, and radio all drawing a whole bunch of power is a separate issue from the starter?
 

wmburns

SN Certified Technician
Aug 14, 2009
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As I stated in the opening reply, IF the condition of the battery's charge does indeed make a difference, THEN there is likely a high voltage drop SOMEWHERE in the system. The trick is to find it.

The starter needs a ton of power and will be disproportionality affected by any voltage drop. The voltage drop will add to the problem if the battery itself is weak.

But think about it. In general a battery that is 80% state of charge should be strong enough to crank a motor. The fact that it's not says to me there's something additional going on.

Sooooooooooooooo I'm not saying they are a separate issue for certain as this could all be caused by an underlying issue. What you need is someplace to start the trouble shooting process. A toe hold to begin work. That is why I gave you all of the tests.

Here's some more. Does it make a difference if the battery is jumped when the problem occurs?

What is the voltage at the starter when this problem occurs? What is the difference between battery voltage and starter voltage under load?

IMO you will be doing yourself a favor to trouble shoot the entire charging system. It's vital that the battery and alternator are working correctly. The alternator must fully charge the battery AND the battery must be able to hold a charge.

Have you looked through all of the voltage drop testing link? Many people get confused about how the test is done. They don't understand why the test is done with the VOM meter on the same side. IE positive to positive. Or negative to negative. So don't get caught up on the alternator test example but instead try to understand WHY the voltage drop test works in the first place. Then you will be able to perform your own voltage drop test say between battery negative and the starter case. Or between battery positive and the starter's main positive terminal.
 
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