Hi,

I'm a new DB9 owner. Took delivery a week ago of a 2009MY with 81,000 km on it (50K miles).

When I went to pick up the car, the MIL was on. Salesperson said to not worry about it and that it would go off (mentioned gas cap issue). I've since purchased an OBD-II scanner and learned that several cylinders are misfiring. Simplified data is below.

Is this a significant number, and should I insist on having coils and plugs replaced? Dealer says I shouldn't worry about it, and it's okay to drive. He'll look at it next week. How many misfires before I should start getting concerned?

Any help is appreciated.

Thanks

Trouble Codes
P0300 $07EE
Random/Multiple Cylinder Misfire Detected
P0311 $07EE
Cylinder 11 Misfire Detected
P0316 $07EE
Engine Misfire Detected on Startup (First 1000 Revolutions)

----------------------------------------------------------------

Mis-Fire Monitor Data
$80 Test Status: OK
$81 Test Status: Fail
$82 Test Status: Fail
$83 Test Status: Fail
$84 Test Status: Fail

Mis-Fire Cylinder 5 Data
EWMA Misfire Count 44
Misfire counts Last 262

Mis-Fire Cylinder 6 Data
EWMA Misfire Count 10
Misfire counts Last 100

Mis-Fire Cylinder 10 Data
EWMA Misfire Count 66
Misfire counts Last 114

Mis-Fire Cylinder 11 Data
EWMA Misfire Count 487
Misfire counts Last 994

Mis-Fire Cylinder 12 Data
EWMA Misfire Count 100
Misfire counts Last 198

 

50K is a lot of miles. You for sure need coils/plugs. Too many misfires and you could end up fraging your cats and then, if really unlucky, ingest the material and destroy the motor. I'd reset the MIL and drive it until the dealer sees it, but I wouldn't let them get away w/o replacing the coils/plugs.

 

That is lot of misfires on 5 of 12 cylinders. You basically shouldn't have any. Did you buy it from an Aston dealer? They should change out each coil pack and I would also change all plugs.

 

Any number of misfire is NOT good. They should never let you drive it before they fix the problem. Could be coils, plugs, injector or vacuum leaks. I suggest you don't drive it until they look at it. You could easily damage your cat converters.

 

Coilpacks, plugs, gaskets & labour on a DB9 will run somewhere around $5-6K CAD at the dealer. Insist that they do it.

 

So guessing your dealer wasn't AM. If it was an AM I'm shocked they'd let a vehicle out the door with any codes at all.

 

That was an unprofessional way to handle your concern. As the other guys already said, misfires are bed, period. Aside from the obvious concerns, a secondary is that the raw fuel making it's way into the exhaust after the misfire can cause the exhaust catalysts to overheat, damaging the core and causing you additional CEL and catalyst failure issues sooner than later.

Because of the amount fo work required to do plugs and coils, it is advised to replace them all "while you're in there". It will also be prudent to take note if engine oil is weeping through the cam cover seals around the plug wells, and filling them. This means the cam covers will need to be resealed as well.

 

Thanks all for your comments. A brief update....
When I sent my data to the AM dealer, they told me they did a 7 year service just prior to my taking delivery. During that service, I was told they replaced all plugs, but did not do any coils. I asked why they would do all that work and not replace the coils while they had the whole thing open, and the response was it cost another $2K. Ridiculous that they did not do this work, I know!!

Mechanic told me he drove the car prior to delivery and did not find any mis-fires. I don't know if they even checked the OBD status at that point, but as I said, the car didn't have the MIL on until I picked it up about 3 weeks after my test drive. I asked if I could drive it and he said it was okay to drive until I brought it back to them next week, and that if the situation became really bad, MIL would go solid red and the car would go into 'limp home' mode. I told him I was planning on taking a 4 hour drive on the weekend and he advised against it.

They're taking it in next week. I'll insist they replace all coils and check the cam covers and throttle bodies for oil. Anything else? PCV valves?

 

Yes to PCV valves. At 50K miles they're probably not doing the job. It's a cheap and easy maintenance item while everything is apart.

 

So here's an update on my situation:

Dealer testing confirmed misfires on Cyl 10 & 11, so they replaced coils on those two. I complained that I found more than just two cylinders at issue and wanted them all replaced. After replacing coils on those two cylinders, they found they were still misfiring. Next they checked wiring (confirmed OKAY) and compression (also confirmed OKAY). Dealer has now contacted AM Headquarters for assistance in diagnosing the problem.

I've told the dealer that I'm considering walking away from the car, as I don't want to be into a vehicle that will cost thousands of dollars to make right, even though I'm not paying for this current work. To be fair, the dealer is trying to make the car right (at no cost to me), however the point I made is that if this event had occurred a month from now instead of the day I picked up the car, I'd likely be into $5k to $10k worth of time and repairs. While I technically own the car, I contend that what I purchased is not what was delivered to me. In other words, the car I test drove did not exhibit any check engine light, and as far as I knew was in 'decent' shape. I did not have a PPI done on the vehicle, which was probably a mistake, however I trusted the dealer (another mistake??).

So far the dealer has been helpful, is working towards fixing the issue, and has agreed that if more than two coils need to be replaced they'll do them all. My options as I see them are as follows:

1. Wait to see what the problem with the car is and ensure it gets fixed fully, otherwise I walk.

2. Wait to see what the problem with the car is and, depending on the severity, decide on my next steps. If the car has such a significant issue now, what other problems might be just around the corner?

3. Get a full inspection from the dealer, or potentially the AM dealer in Montreal, now. I could do this before more work gets put into fixing the car, to minimize the dealer's expenses. Potentially they could say that when they've fixed the problem, I'm obligated to keep the car.

4. Have the dealer fix the car then get an inspection, and assuming all is well, an Extended Service Contract (ESC). The dealer quoted these costs at $7,100 (1 yr) and $12,150 (2 yrs.) including inspection, plus taxes. A lot of money!!

As always, your experience and knowledgeable comments/suggestions are valued.

 

All cars have misfires, that is a given.
How many are to many is easy, when you have a constant smell of raw gas out your tail pipes it is to much.
Coils while labor intensive are not hard to replace, but if you are DIYer, fix the car and have them give you a rebate.
Most state have lemon laws, even on used cars and have laws against false advertisements, so you can go down that road.
You should back out of the sale and if you want to buy the car, have the dealer replace all coils, cause if one or two is bad, the rest are sure to follow.

 

Thanks for your comments Randy. For me the question has changed from:
to
If I have an inspection done after it's fixed, what's the likelihood I'll be able to walk away from the car or renegotiate some price reduction?

 

There is no way that I know of to tell if the cats are going bad, now once they are bad that is pretty easy to tell and as far as what misfires do to the engine, I do not know these engines well, so I would ask Irish07, he would know more about this than anybody else I can think of.

 

Hi Toronto DB9. It is sad you had a bad experience with GTA. I used them before and was also not impressed. Lack of communication.

But your car is very nice! All the right specs! I think walking away you will regret it. Not manny DB9 in Canada for sale. I would let them fix it what they will. And enjoy it. It's a fantastic car.
Cheers from the West Coast

 

Thanks for the words of encouragement Skeena... I don't want to diss GTA at this point. I think they're doing their best to make things right, which I appreciate.

I do love the car, but don't want to get stuck with a lemon. Any thoughts about the options re: inspection (after the fact) or the Extended Service Contract option?