Fellow Aston Martin Owners, my saga of misfires on my vehicle continues. Quick backstory, my vehicle is a 2005 DB9 with only 6000 original miles on it. I was seeing misfires on the vehicle and throwing many different codes, seen here. After replacing the upstream O2 sensors and battery without any improvement, I sent the car to Aston Martin.

Round One with AM:

The tech was very helpful and willing to talk, sharing his knowledge with me. After an hour of digging, he said he needed another 3.5 hours maximum to determine the cause of my misfires. I agreed to the work. He eventually found the misfires to be coming from coils 6 & 9. He stated that he found this after taking apart the manifold and testing the coils individually. So, I spent about $1600 in genuine AM parts and supplied them to the tech for the repair. He only charged me an extra hour of labor to put it all back together with the new parts, which I thought was nice. I asked him a few questions to make sure my intake, fuel delivery, vacuum, etc. all checked out fine, as those are supposed to be checked for misfires as well. He said all checked out normal during his diagnosis.

So I get my car back and about 10 miles down the road I have the same problems. Misfires, eventually throwing codes, etc. Eventually I get a red triangle which was thrown from a P0300 misfire code. Now my misfires are even worse than before although they are localized to only one bank side of the engine, cylinders 1-6. So, 4 hours of labor, $1600 in parts, and I have basically no improvement except for on one half of the engine, which was never truly bad to begin with (approx 30 misfires per 30 mile drive on those cylinders).

Round Two:

Car goes back to AM, the local tech who worked on my vehicle involves the remote AM tech in California for support. I am now being told I have abnormal ecu misfire corrections. Testing showed liquid fuel present in vapor management valve and lines, causing unmetered fuel to enter the intake manifold. Also, "Fuel present purge system due to malfunction or cracks in canister and/or lines located inside the fuel tank" whatever that means. I'm recommend to replace the charcoal canister and any worn or cracking lines inside fuel tank. All of this costing $3382 in labor and $1286 in parts.

Ultimately, I wonder if I paid all that money to fix the coils and plugs that never really were causing my issues, now being asked to fork out a lot more money. If you were in my position, what would you do here? Ask the dealer to comp some of this cost? Reach out to AM directly since my vehicle is such low mileage? Grit and just pay it? I've already invested a decent amount of money into the vehicle to get it running what I thought would be well and I can't in good conscience pass this onto someone else. Any advice is appreciated.

UPDATE: For any forum searchers, I am tentatively reporting that we found the issue, as the car seems to run fine now without misfires. Cause was a cracked evap line in the fuel tank, sending unmetered liquid fuel into the fuel tank. This flooded the carbon filter above the fuel tank as well, which needed to be replaced as well. Replaced both parts (among others in the fuel tank) and all appears to be well again.

 

Personally, I would raise hell. Now it could be that the coil was bad - or the symptom. I would certainly try to get a discount. Else, find an indy shop. The mileage wont matter - the car is 15 yrs old.

 

16.5 hours of labor to do this by the way, for anyone with experience on something like this. Does that seem high?

 

I'd take it to an indy shop for a second opinion before taking any next steps.

Did you replace all 12 coils or just those that tested bad?

 

Replaced all 12 coils and spark plugs, since he was already in there. Do you think it's safe to drive to an indy shop if it's misfiring this much?

Also, they're calling for me to replace (2) left hand side fuel filters, part #4G43-9155-BA. Isn't there just one left hand and one right hand filter? And my issues are all coming from bank 1, which would be the right hand side anyway.

 

I would say many problems with old low mileage cars are simply lack of use... most of the items you mentioned likely have problems related to age and not mileage... parts disintegrate, rubber and seals rot away, all sorts of issues happen because of non-use. Rich @ Redpants calls it garage rot.... my old Porsche mechanic said the best deal were Porsche's with an average of 4, 000 to 6,000 miles a year.

you can try to seek some recourse with dealer but given age, doubt you'd get much success

 

I definitely understand. I'm less upset about the early failure (mileage, not age) but more upset about the idea that I spent $2500 chasing a fix that may have never been an issue to begin with. Sure my car will run better but if something isn't broken, there's no sense spending money to fix it. I think that may have been what sliderule was getting at.

 

Did they not replace the PCV valves while they were in there? You didn’t say, but they are notorious for causing entire bank misfires.

 

Is "Garage Rot" real when a car is in the garage protected from the environment? I trust Rich/Redpants, but, Calicifer33's DB9 is 15 years old w/6,000 miles (400 miles/year av.). Not a lot. My 2005 DB9 has 16K miles and is a garage queen. I bought her 1.5 years ago with 9800 miles. Raging Bull did the service for the previous owner of 11 years and their PPI was a glowing endorsement. All belts, hoses and rubber are good visually and to the touch. I drive her weekly. I have several 3 hour week-end trips during my ownership. The most I've done is a 550 mile three day trip. The car was filthy when I got her back to the garage. Brake dust from the front calipers was half way down the doors. She was beautifully filthy! Am I missing something?

 

Thanks for chiming in. He did not. I actually brought it up several times but he told me that he checked my lines and saw no evidence that the PCV valves needed to be replaced because he saw no oil in the lines. I asked if he saw any oil in the intake and he said he saw a little, but that on these cars that's very normal and to be expected. I trusted his assessment after getting push-back on it two separate times.

If a pcv valve were to fail though, it would cause a bank to misfire due to too much oil ingestion into the intake, right? I think he's saying that somehow they were able to diagnose unmetered fuel into the manifold. That's what they're claiming, at least. Not sure how he missed it the first go-around though.

That's what he's saying, I think. Just sitting around allows bushings to stiffen, seals to dry out, etc. If the car were driven more, the thought is that I'd probably have less problems. I did the math and the previous owner drove the car about 500 miles in the previous three years, total! I WANT to drive mine, I just need it healthy again. Right now it's a darn near aesthetically flawless piece of art that doesn't drive.

 

If the tech is competent, you probably did need the new coils. And you do, indeed, have new coils. It's impossible to say that this was a misdiagnosis without the old parts and a second opinion. I'm surprised that they are letting you supply them with parts, BTW. If it were me, I'd try to get it looked at by an indy, even towed by AAA if necessary. Actually , if it were me, I'd never have been at the dealer in the first place. But you might also consider asking about a break on the cost of the first or second diagnostic at the dealer considering it was not complete. But as I see it, with the information I have, they haven't done anything wrong. It's entirely possible that you have two problems, or maybe even more.

 

Wow I'm currently dealing with some ASM issues on my 2009 V8 Vantage so i completely understand your frustration with this.

I'd deff recommend a 2nd opinion via a indy shop or a another dealership. In my quest to figure out my ASM issue i found 2 new resources through this forum.

Jordan @ Aston Martin Summit - Very knowledgable and direct. Took the time out to properly talk to me and go over my options and the issues the car was having. Took excellent care of my car while they had it.

Jon @ Steel Wings (Indy Shop) - Ive heard great things and will be bringing my v8 Vantage here for a couple of service items when things get better. He also pointed out some things and took the time to talk to me over the phone to make me understand. (Also in P.A.)

Hope your saga comes to an end soon. - Cheers

 

Ask for a discount on parts, or complete % off entire ticket. They want it fixed and gone as much as you do. It's not a common fault and it is a bad experience to go thru. It's the fuel system on a nice car have it fixed correctly.

 

I missed whether this is a volante or a coupe, but 16 hours is pretty quick to get into the tank and out in a volante. Granted it won't be his first trip in, but the tank is truly a PITA with access through the shelf behind the rear seat. IF, I ever have to go in, I will likely sawzall out the metal at the back of the trunk to create an access port, and then fabricate a hatch that bolts back in. If you want to see the top of the tank, remove the back of the trunk - there are 2 three inch diameter holes that you can look in and see a black plastic "frizzbee" that is glued atop of the tank access port. That is the entrance to the cave! At the bottom of the cave is where the pumps are mounted. A good mirror and lighting system will be useful.

In a coupe you basically remove the drivetrain and then drop the tank (or take a sawsall to the trunk). You could do a clutch job at the same time and combine some labor...

Dry rot comes from having an older car. Pump failures come from driving around with less than 1/2 a tank of fuel. The fuel is coolant for the pump. Drives me crazy that my family cruises around with the low fuel light on waiting for me to fill their car. Not because I mind paying for the fuel, but because I know how hard it is to get into the fuel tank!

 

when plugs and coils were replaced where injector O rings top and bottom replaced too, i remember having to replace those
when i did the plugs and coils in my old v12 db7. just wondering if it could be injector leaks or clogged giving the missfires
just a thought !