Car not starting

[bcredliner]

Originally Posted by upallnight

More bad info being posted from the net. People should do more investigation about how our X work instead of posting bad info on top of bad info.

Here's a diagram of the power distribution from Bentley Manual.



If you can read a diagram you will see that the BST circuit is only for the starter. Once the BST is blown, there is no more power being supplied to the starter. Like I stated before because he is jumping the car from the jump terminal in the engine compartment so he is basically backfeeding power to the starter. All the other circuits are not on the BST circuit so they will still function.

For all the bad posts here, even some of yours, you choose this to take issue. I do my very best to provide constructive input. I won't always be right and when I am not I apologize. Everyone knows we have to be careful about believing what is on the internet I have no problem anyone challenging what I post, however, it is disrespectful, inconsiderate and uncalled for when it is done in this manner. I am fully aware you have an axe to grind with me. So say what you think of me and move on. Depending on how OPs no start problem is solved I will congratulate you for being correct and apologize to OP.

[80stech]

Originally Posted by SeattleBimmer

Update: Tested voltage drop under load.

3) Connected the leads of my DVOM to the positive battery terminal directly on the battery in the trunk to the positive terminal under the hood. Voltage read 0v (without load). Held the key in the ignition position and the voltage jumps to 11.10v for about 2 seconds then drops to 4.5v and continues to stay at 4.5v even after turning the key off. Can someone explain that???

Excellent, problem is somewhere between the positive battery terminal and the positive terminal under the hood. Rule out the battery clamp itself by testing from positive terminal to the clamp(under load). after that you you are going to have to prod the cable beyond the BST to isolate the problem.

[80stech]

So yes at this point it looks like it's a poor battery positive connection, BST, (most likely), or bulkhead splice. Awesome to have a diagram to work from! If you have test light it would work just as well and might be easier to prod with.

[upallnight]

Originally Posted by bcredliner

For all the bad posts here, even some of yours, you choose this to take issue. I do my very best to provide constructive input. I won't always be right and when I am not I apologize. Everyone knows we have to be careful about believing what is on the internet I have no problem anyone challenging what I post, however, it is disrespectful, inconsiderate and uncalled for when it is done in this manner. I am fully aware you have an axe to grind with me. So say what you think of me and move on. Depending on how OPs no start problem is solved I will congratulate you for being correct and apologize to OP.

Don't know why you think I have an axe to grind with you. I have call out other posters on this forum as well as other forums when they post miss leading.

http://www.xoutpost.com/1096504-post5.html

The post that you linked to also stated that if the BST blow you can still start the engine, but as you can see from the diagram that I posted shows that all power to the starter is cut off.

If people doesn't have any confident in my ability to help them with their problems then why are people constantly PM me? They read my postings and know that I am one of the few posters that can actually help them with their problem. Maybe it's because I am willing to post things that people would rather not hear. They will rather hear that the fixe is as simple as a fluid and filter change instead of you need to rebuild the trans, that is why the previous owner dumped the X on them.

No I don'the have an axe to grind with you . Just waiting for that info on the rear differential cover that you were suppose to get me.

Merry Christmas and if that is inappropriate Happy Holidays.

[SeattleBimmer]

Final Update (hopefully):

After identifying the problem was somewhere between the battery terminal to the engine bay terminal, I decided to inspect the engine bay terminal first since I recently did work there.

1) Disconnected the engine bay positive jump terminal, under the hood near the driver side firewall. This junction is essentially a stud that is threaded on both ends. One end (closer to the windshield) connects the cable that runs from the battery in the trunk. The other end (closer to the front bumper) connects the cable that goes to the starter.

2) Upon inspection of the junction, there was noticeable electrical arcing on the nut/cable joint on the the windshield side.

3) I decided to test this by simply removing the junction stud and clamping the 2 ends of the cables together. The car started perfectly! That was the problem.

4) Going to take some sand paper to the nut and junction stud and cable ends and clean it up really well.

I'm happy to say I have finally resolved the problem. I learned A LOT during this whole process. The whole process was invaluable but the most valuable take-away was probably a better understanding of performing a voltage drop test under load to properly diagnose (Thanks 80stech). If I did this from the start I would have saved myself from buying a new battery and a new ignition switch. Either way, the cost of the aforementioned was definitely worth the knowledge I gained.

Thanks guys for your help!

[80stech]

[bcredliner]

Originally Posted by upallnight

Don't know why you think I have an axe to grind with you. I have call out other posters on this forum as well as other forums when they post miss leading.

http://www.xoutpost.com/1096504-post5.html

The post that you linked to also stated that if the BST blow you can still start the engine, but as you can see from the diagram that I posted shows that all power to the starter is cut off.

If people doesn't have any confident in my ability to help them with their problems then why are people constantly PM me? They read my postings and know that I am one of the few posters that can actually help them with their problem. Maybe it's because I am willing to post things that people would rather not hear. They will rather hear that the fixe is as simple as a fluid and filter change instead of you need to rebuild the trans, that is why the previous owner dumped the X on them.

No I don'the have an axe to grind with you . Just waiting for that info on the rear differential cover that you were suppose to get me.

Merry Christmas and if that is inappropriate Happy Holidays.

As we know, many forum members are fairly new and don't know members enough to know the validity of posts and there are always several different solutions suggested. Some of them premature conclusions, some are right, some are wrong and some are way out there. I don't recall anything said about lack of confidence in your ability. It was my understanding from when I sent PM saying I hadn't forgotten about your inquiry you responded with something that led me to believe information was no longer needed. I did ask anyway when I had my diffs done because I was interested--they weren't sure. If you still need to know I have another source I can try. Hope your Holidays are all you would like them to be.

[jopecasa]

Originally Posted by SeattleBimmer

Final Update (hopefully):

After identifying the problem was somewhere between the battery terminal to the engine bay terminal, I decided to inspect the engine bay terminal first since I recently did work there.

1) Disconnected the engine bay positive jump terminal, under the hood near the driver side firewall. This junction is essentially a stud that is threaded on both ends. One end (closer to the windshield) connects the cable that runs from the battery in the trunk. The other end (closer to the front bumper) connects the cable that goes to the starter.

2) Upon inspection of the junction, there was noticeable electrical arcing on the nut/cable joint on the the windshield side.

3) I decided to test this by simply removing the junction stud and clamping the 2 ends of the cables together. The car started perfectly! That was the problem.

4) Going to take some sand paper to the nut and junction stud and cable ends and clean it up really well.

I'm happy to say I have finally resolved the problem. I learned A LOT during this whole process. The whole process was invaluable but the most valuable take-away was probably a better understanding of performing a voltage drop test under load to properly diagnose (Thanks 80stech). If I did this from the start I would have saved myself from buying a new battery and a new ignition switch. Either way, the cost of the aforementioned was definitely worth the knowledge I gained.

Thanks guys for your help!

Good to hear you found your problem!

Thanks for sharing and hopefully others can learn and fix similar symptoms.

[StephenVA]

Congrats on the solution and the need for only effort to resolve the issue.🤑