A4 Engine Won't Turn Over

[scspoon]

It has happened about 5-6 times in the last 5 weeks that when I go to crank my 2011 A4 Quattro it won't turn over. It's almost like it gets to the peak where it would crank and it just won't fully turn over. I replaced all 4 spark plugs thinking that could be the problem but the day after I did that it happened again. I had the battery tested and it checked out perfect. I took it to a local shop here in Charlotte, NC and they had it for 2 days and couldn't figure out what was going on. It happened where it wouldn't crank for them 1 time but didn't do it again so they couldn't pin point the problem. It doesn't happen every time I crank it and once it does crank it never shuts off. I have no idea what is going on. Any suggestions? The techs at the shop I took it to said one thing that it could be was the older software I had on it. They said they weren't certain but thought that might be the issue. However, they said I had to go to the dealer to get it updated. Really not in the mood to get bent over so was hoping someone could help. If it happens to be a software issue anyone in the Charlotte, NC area that can help me so I don't have to go to the dealership? Hopefully someone knows what the deal is. Anyway thanks everyone!

[treginginco]

Does this sound like the dreaded timing chain tensioner others have dealt with?

[oshwi]

Did you scan for any faults? That shouldve been the first step to diagnose it. And as treg said. It does sound like the dreaded timing chain failure. Dont crank the car anymore till you scan it!!

[Allowencer]

To be clear and on the same page, does the motor "spin" or is the issue that it isn't spinning/turning the motor over and you are getting multiple clicking sounds?

[scspoon]

There aren't any clicking sounds at all. It sounds like it is going to start like it normally would and it's almost as if it gets to the "peak" and then just stops. Not sure if that really makes much sense.

[Allowencer]

Ah, so the starter 'is' turning the motor over but it never 'starts'? If that's the case, yeah, more than likely good ole' timing tensioner failure.

[scspoon]

Yes. What's an estimated cost to have that fixed?

[Allowencer]

Ouch... hard to say. The first issue of concern is has any further damage occurred - you wont be able to know/tell unless it is taken apart. You can tell based on how many teeth timing has jumped. If you're 1-2 off, very good chance valves, head and pistons aren't damaged. If the count has jumped more than 2 teeth, the probably of further damage drastically rises.

With gaskets, hardware, etc. you're looking at a good $1300-1500 alone. That's not including labor.

Search for the DIY: motor repair thread I started to familiarize yourself with all the details.

[ak11214]

What's your mileage?

[scspoon]

120K drive a shit load for work

[Allowencer]

Yeah, you're up there for sure. Guys, you got to remember, it's not so much the mileage but the number of 'starts'.

[LINDW4LL]

Ah, so the starter 'is' turning the motor over but it never 'starts'? If that's the case, yeah, more than likely good ole' timing tensioner failure.

I think it's a little early to conclude that.

He said the no crank issue is intermittent.

[scspoon]

Exactly. There are times where I will crank it numerous times before it won't crank. Typically it will crank and run fine for a few days before it won't crank again. I had it at the shop and it cranked for them every time they tried to figure out what was wrong.

[Allowencer]

Not necessarily. That is a symptom; hard / no starts. It's because the chain jumps, like a bike chain and then it catches the sprockets again. It still stays in sync though.

This can be easily confirmed by popping off the top timing cover and rotating the motor over. If you see the chain jump, like a bike chain, well, there you have it [unfortunately].

There isn't much to 'start' a car. Compression, fuel, spark and a working ECU. You can check compression with a compression test. Fuel can be checked by checking the rail pressure (mind you it's a VERY high pressure, a normal fuel pressure gauge will not do).