Loss Of Power DB7 vantage

My 12 cylinder DB7 woke from its winter sleep with no power. Slow acceleration,no misfires.I changed the fuel filters, cleaned the air filters. No help. No check engine light on. Any ideas would help short of taking it to the dealer.

 

was it on a battery tender or disconnected while stored?

you could disconnect the battery - leave disco for 30 minutes - and try let the ECUs reset that way, after that, I'd say needs a code reader and to the shop

 

Does it have a misfire/rough idle? This engine should run so smoothly you can balance a coin on its side while it idles. Take the car to a local Autozone type store and ask them to plug in their OBDII reader and give you the code related to the check engine light. Look up the code online to see what it could be.

The Coil packs are a big issue on this engine due to susceptibility to water ingress. They usually start to die at 5 years old. If it's been stored and damp has got in then I'd suspect the coils. They are a real pain to get to as you have to remove all the top stuff/intake manifolds etc.

While you're there may as well do plugs as each coil sits on top of each plug.The coils are expensive it's about $1500 for the set and the plugs are a ridiculous $80 each if you buy from the dealer. I got aftermarket plugs and did the whole job myself, it's time consuming and you need double jointed kid hands to reach some of the fasteners. After I did mine the car ran completely differently.

Good luck

 

I did the coils and plugs last year. PITA to do but after car ran perfectly. Will try the battery disconnect this weekend and see what happens. Thanks for the help so far.Do these cars olug up their fuel pumps like the 550/456? I havent checked the fuel pressure yet. The car runs smoothly but feels like its dragging an anchor(No,the parking brake isnt on)

 

Hmm. OK I'd try the battery disconnect and see what happens. No history of pump fouling as far as I know on these, you could have bad gas I suppose but this would usually give rough running.

If the problem persists after the disconnect I'd drive a bit and then get out and test the wheel temperature with your hand to see if the rears are getting hotter than the front. The e-brake may be off but it doesn't mean you don't have stuck pads somewhere from sitting. You can also try coating and then take it out of gear and see if you feel any drag as it comes to a stop.

 

Found the problem. Just in case anyone is interested, it was a failure of one fuel pump. Engine doesn't miss ,just runs on 6 cylinders. Engine code comes up "lean",but not right away. Change both pumps as the other one will go soon and the its a PITA to remove the tank twice.