Start very rough for about 5 or 10 seconds and stall and not start again?

Tiny
SHAREELEE18
  • MEMBER
  • 2005 AUDI A6
  • 3.2L
  • V6
  • AUTOMATIC
  • 155,000 MILES
I bought the vehicle listed above at auction and when we try to start the car it will turn over and start very rough for about 5 or 10 seconds and shut off and then it will just turn over and not start again. When putting a scanner on it the fault codes came back as cam shaft position sensor and crankshaft sensor so we replaced the 2 top ones and the crankshaft but then realized there were 4 camshaft sensors we could only find 1 more sensor in town so we bought that one and changed one sensor on the bottom bank b I believe. Although the scanner only identified 2 camshaft sensors as being faulty. The car is still doing the same thing no change we did notice the car is leaking oil and the light on the dashboard is saying low oil pressure when it does start for a couple seconds. What do you think is the problem?
Sunday, March 26th, 2023 AT 10:19 PM

5 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,520 POSTS
It sounds like the oil pressure problem could be causing all of these issues. I would remove the oil pan to check the gunk build up inside and around the oil pump pick up. If the oil pump pick up is clogged due to low maintenance, I would clean the pan and replace the pick-up. Here is how to remove the oil pan in the images below. Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.
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Monday, March 27th, 2023 AT 10:19 AM
Tiny
SHAREELEE18
  • MEMBER
  • 3 POSTS
Okay, we are going to try the suggestions above. But one more thing I wanted to add from this morning scan code reading when working on it, it spit back a code that said misfire on piston 4 piston 5 and piston 6 and then the codes never have shown up again yet this morning. And not prior could this mean anything?
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Monday, March 27th, 2023 AT 10:28 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,520 POSTS
If you did not clear the codes, you could have a bad PCM. You should do a CAN scan to confirm. You can get a good CAN scanner (Controller Area Network) from Amazon.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

and

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Here is one for about $99.00 if you need it:

https://amzn.to/3ZixY4v
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Tuesday, March 28th, 2023 AT 8:53 AM
Tiny
SHAREELEE18
  • MEMBER
  • 3 POSTS
Okay, so, we have this tool right here. I think it does everything. We did what you suggested with the oil pan yesterday and still nothing. We did go buy a new battery and installed that and now the car is decrecting zero voltage even though it tries to turn over so it’s getting some kind of power could this be an alternator issue? Or what would make the car detect zero voltage with brand new battery?
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Tuesday, March 28th, 2023 AT 7:30 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,520 POSTS
Let's check the battery voltage manually. Here is a guide to help with the test. It is for the alternator, but it shows how to test the surface voltage.

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Please go over this guide and report back.
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Thursday, March 30th, 2023 AT 1:05 PM

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