2010 A8 crank, no start
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AudiWorld Newcomer
Joined: Nov 2024
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From: Cincinnati, OH
2010 A8 crank, no start
I have a 2010 A8L with 4.2 with 120k miles, i bought from a customer that originally brought it in for the issue I'm having, on initial diagnosis i found an injector on cyl. 3 to be cracked and leaking an excessive amount of fuel and the intake runner on the same bank to be cracked. figured the issue was because of the injector leaking all the fuel pressure out was causing it not to start. after i bought the car, because the customer declined all the work and wanted to get rid of it, i did all the repairs and was meet with the same issue. tried scanning car with ODIS but ODIS couldn't communicate with the gateway so i thought the gateway was bad and the ecu runs through that. attempted to scan with VCDS and was able to communicate with everything, i was able to clear all the faults and try again. sounded like it got so close to starting but just couldn't turn over. don't have access to my log at the moment and will upload when i can. i also replaced a bunch of vacuum lines, pcv valve, and the coolant bypass valve on the back of the intake manifold. i don't know where else to go. I'm a certified Audi tech and I can't even figure it out so any help would be appreciated.
AudiWorld Wiseguy
Joined: Aug 2012
Posts: 4,071
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From: Chicago
Way too much noise due to low battery voltage in that scan to be useful. Charge the battery, clear all the codes then try and start it, see what codes come back and go from there.
Either way, sounds like a fuel supply issue so check both low and high side fuel pressures are within spec. Cam timing error is a worry though. Could just be low voltage noise, or an actual timing error. Have you verified that you’re getting spark?
Either way, sounds like a fuel supply issue so check both low and high side fuel pressures are within spec. Cam timing error is a worry though. Could just be low voltage noise, or an actual timing error. Have you verified that you’re getting spark?
AudiWorld Member
Joined: Jun 2019
Posts: 439
Likes: 43
From: Houston, TX
That crank shaft position sensor, when it goes bad (perhaps maybe just dirty) it does look scary because that starter would not even engage.
I think the Crankshaft Position Sensor should be on the top of your list if your A8 does not even turn over. (It is not that hard to check)
For other Cars, do they present the same symptom when this part goes bad? (no crank, it's as if you have a dead battery)
I believe there is posting of a guy here in Audi world who took the part out, cleaned it put it back. After that he was good to go.
If that part has not been replaced after those many years and miles.... Take the part out and take a picture.
I think the Crankshaft Position Sensor should be on the top of your list if your A8 does not even turn over. (It is not that hard to check)
For other Cars, do they present the same symptom when this part goes bad? (no crank, it's as if you have a dead battery)
I believe there is posting of a guy here in Audi world who took the part out, cleaned it put it back. After that he was good to go.
If that part has not been replaced after those many years and miles.... Take the part out and take a picture.
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