Aston Martin DB7 won't start

rugbyman · 22-01-2019 8:09pm

Skatedude wrote: »

As mentioned, crank shaft position sensor, or possibly cam shaft position sensors.

Thanks Skatedude ,that's what the computer said,my technician says, as does Tea bag Mania that it may be dampness,wiring.he cannot look at it for three weeks.in the meantime car is moving into a heated shed

rugbyman · 03-03-2019 10:45am

car is now four weeks in a warm shed, now well dried out, awaiting attention by a competent person, by the way he told me to spin the engine over, if the rev counter did not show the revs of the turning over speed ,it was most likely CPS faulty than wiring, we will see

MercMad · 04-03-2019 9:58am

Of course you are correct regarding the compression. I had a brain lapse but also recall having rebuilt many engines that sometimes new lifters have to fill with oil and the engine does not achieve full compression because it hasnt inhaled enough.

Anyway what the other poster has said about V12's sounding like they have no compression is also true.

Sounds like multiple issues to me, CPS and bad pump.and or relay.

If no CPS signal most likely fuel is also shut off.

You should get someone to scope the CPS signal

rugbyman wrote: »

Thank you all for suggestions
The engine is a V12. I have done some reading on the A.M club page. these cars give quite a bit of bother with relays ,wiring,and fuel pumps(ford mondeo)
replacing the fuel pumps is a 12 hour job

Apparently each bank of six cylinders are fed by a seperate pump.

I have just gotten a fuse diagram and intend to check these today, the relays seem ok(they click)

on the advice of club members i uncovered the fuel rails running the length of the engine, at the end of each is a valve(schrader?) like a bicycle valve, pushing a match gets fuel from one of these but not the other, again i am told a pressure test here is a good idea

Regarding lack of compression, i have said that the engine whirrs over quickly ,but i cannot say this is not normal,because over four years the engine always started on the first push of the button, so I would not have heard it before ,as i now hear it.

Sorry ,I should have said that on a few occasions over the years the car stopped,while driving ,as suddenly as if the engine had been switched off. It immediately started when tried. On a run ,driven by a friend a few months ago it did this four or five times, the next day ,with me ,it drove 30 miles without fault

Last question chaps,,, when the expert mechanic with a suitable computer arrives next week, will his computer simply diagnose the issue, are computers that magic?

rugbyman · 30-06-2019 4:14pm

Right Chaps,

some progress. After several months in a dry shed, with heat ,all the moisture all gone.

I ordered two crankshaft position sensors from A.M. and they are in the post to me.

Among suggstions made to me ,either here or on the A.M.O.C. site ,I decidedto try easy start. The theory being ,that if it fired, then C.P. sensor and lack of sparks could be ruled out.

Thecar fired up, and ,not only that ,it kept running. Its only running on one bank of cylinders, buts that's all I expected, as one of the fuel supply lines does not emit fuel when pressed. My belief now is that the one which did emit fuel did not have enough pressure to start(I did not measure it), but the easy start encouraged it to run.
It now appears that I need to replace a pump,there are two. If this conclusion is verified ,then we will proceed. the job takes under ten hours, and the pumps ,from a Mondeo cost under 50 euro each.

As an Aston owner said to me, when its running, drive it like you just stole it!

Regards

Bigus · 30-06-2019 4:19pm

If the pumps are together, replace both for the sake of 50 euro.

yaeger · 02-07-2019 5:26pm

Hey Rugbyman, sorry to hear your troubles with that beaute of a car, it needs to be out on the road. I would not be as knowledgable about the DB7 as some on the amoc site but i gather the V12 can suffer from misfiring due dodgy coils and it can suffer from over fueling when driven at low speeds due faulty injectors.
When starting, My aston has a procedure which is gentle on the engine, so first crank after a few days sitting I fully depress clutch and accelator whilst firing engine which in effect dry cranks engine to circulate some oil and allows pump to build up some pressure prior to full start.
Are you a member of AMOC, is it worth it , is there meets or anything.
Lets see a pic of it 😀

rugbyman · 03-07-2019 10:59am

Thank you for your commi am not a paid up member of AMOC. just a free member of the site. I found it difficult at first to navigate. I found it somewhat useful, Perhaps I got better advice on here.

I am off on holiday, I intend to ask a few more questions on here before I start the pump change. the odd stop on road and immediately re start needs to be ruled out.

The CPS sensor arrived from Charles Hurst, perhaps now not neded

Regards

rugbyman · 19-02-2021 9:10pm

Right Chaps

The DB7 runs on all 12 cylinders.

After 18 months since last post I finally convinced my friendly old school mechanic to change the pumps.
I downloaded a very helpful step by step article on the process ,with pics from the A.M.O.C.

it took ten hours as predicted, two new mondeo pumps fitted. Inially it only ran on 6 cylinders but a swap of relays got it on 12 . Some beast.By the way one of the old pumps was knackered.

Next problem is that front brake was seizing, got it freed, seized again. The brainy mechanic showed me ,as he opened a valvy thing on the brakes, he said if fluid squirts out here , we have a master cylinder problem, ... it squirted
Then he concluded that if was only affecting one side ,it was more likely a flexible pipe problem. Apparently the inner rubbery stuff of the pipes can degrade inside. A new one from Hursts is almost 200 euro with vat and courier , so going to see if our local motor factor can suggest something similiar.

Failing that , we are told there is a chap who fabricates these things for rally cars.

Will keep ye posted

Regards

kadman · 19-02-2021 10:33pm

rugbyman wrote: »

Right Chaps

The DB7 runs on all 12 cylinders.

After 18 months since last post I finally convinced my friendly old school mechanic to change the pumps.
I downloaded a very helpful step by step article on the process ,with pics from the A.M.O.C.

it took ten hours as predicted, two new mondeo pumps fitted. Inially it only ran on 6 cylinders but a swap of relays got it on 12 . Some beast.By the way one of the old pumps was knackered.

Next problem is that front brake was seizing, got it freed, seized again. The brainy mechanic showed me ,as he opened a valvy thing on the brakes, he said if fluid squirts out here , we have a master cylinder problem, ... it squirted
Then he concluded that if was only affecting one side ,it was more likely a flexible pipe problem. Apparently the inner rubbery stuff of the pipes can degrade inside. A new one from Hursts is almost 200 euro with vat and courier , so going to see if our local motor factor can suggest something similiar.

Failing that , we are told there is a chap who fabricates these things for rally cars.

Will keep ye posted

Regards

Old school mechanic is way more savvy than a laptop jockey, well done.:):)

kev1.3s · 19-02-2021 10:42pm

I'm sure goodridge will knock you up a set of braded hoses for less that 100 quid.
Google goodridge hoses.

rugbyman · 07-03-2021 10:13pm

Got a ford ,prob escort pipe 13euro.

yaeger · 07-03-2021 10:45pm

Hey Rugbyman

Try astonmartinbits.com alternatively give andrew lindsey a call, he is based in county Down and would be the person to go yo if I were you.
Not sure who your specialist is down south but andrew would be dealing with these on a regular basis. Do we get to see any pics of this gorgeous V12 .

rugbyman · 14-03-2021 4:38pm

Thank you Yaeger
I would be most interested in an indy Aston Martin specialist, will try and Google Andrew,just did , no luck ,can you give me some more info

re photos ,my car looks well enough, we bought it ,damaged somewhat from England six or seven years ago. the all over paint job , tw grand at the time has a few inperfections now, will see how far to go with it.
some interesting points in its repair
A it needed a rear lamp. Cost new 250, one on e bay 125 , but my nephew in the motor trade said " let me look into this" result Mazda saloon lamp 15 quid

B Drivers side headlamp , 1,000 new , got one from e bay for 500, minor scratch

C as mentioned above ,fuel pumps from mondeo 40 quid each

D as mentioned above brake pipe 13 euro rather than 140

E Its a fine big beast, I think if i was buying one i would go for the 3 litre straight six

F This car deserves a trip to the Med, with deep pockets. I am working on that plan

Regards

p.s. needed to fit a Lambda sensor some time ago , luckily 50 euro from a local factor

yaeger · 14-03-2021 11:38pm

www.andrewlindsayspecialistcars.com

It will be all worth when shes on the road .

unkel · 16-03-2021 2:17pm

rugbyman wrote: »

A it needed a rear lamp. Cost new 250, one on e bay 125 , but my nephew in the motor trade said " let me look into this" result Mazda saloon lamp 15 quid

Love that, fair play to him

I knew there is some sort of connection with Aston Martins sharing parts with common as muck Ford Mondeos, but those are far newer generation cars

AMKC · 23-03-2021 1:17am

Any chance of a picture. Your car sounds lovely. Then again maybe you better not posting a picture of it here

rugbyman · 04-04-2021 9:28pm

AMKC wrote: »

Any chance of a picture. Your car sounds lovely. Then again maybe you better not posting a picture of it here

Funny you should say "maybe better not post picture"

I cannot imagine what you mean ,but you are quite right.
We bought it ,damaged from Uk seven years ago. To date I have not driven it 1,000 miles. We never got around to applying for a V5.
its a sort of "in limbo " car

Putting things on the long finger is a way of life with me

regards

Aston Martin DB7 won't start

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