Aston Martin DB7 won't start

rugbyman

Hello All, I have had a 2001 DB7 for five years. it lives outside and has not yet done 1000 miles in my ownership. it has killed four new batteries. This is not unknown for that year and i can only blame myself for continuing this waste. So i have good experience of battery problems
The car was left unused, recently, for a while.then turned over quickly but would not start.

I should have mentioned that on four of five occasions over the years the car could cut out and stop while driving. A moment later I could restart it,instantly.

I replaced a Lambda sensor recently ,


Unsure of the petrol level we put two gallons in, the guage reads 1/4 full. The engine spins merrily, the fuel pump relays seem ok,i do not have a chart showing which fuses are relevant,and have not checked any of them yet.

Having read of the fuel valves at the ends of each fuel rail on top of the engine, i checked them today
The one on the N/S rail showed no fuel. The one on the O/S did spurt, and on several swithing on of the ignition key ,spurted(on pushing a match in) each time.

This suggests to me that one of my two fuel pumps works. Still the engine does not fire.
I propose to try some easy start to ascertain if the problem is ignition related.

I have a good mechanic ,who has a computer,compatable with the DB7, but he is unavailable

I am trying to educate myself in the meantime

Any suggestions, thanks in advance

Rugbyman

scannerd

The long term lack of use would make me worry about the fuel system, petrol goes off after a few months and it can then clog up the system, plus it will not burn. You have added new petrol but if the old as bad that could still effect starting. Pressure is also a good test, which you seem to have checked

After that you need spark, compression, then timing.

to test spark pull 1 plug, hold against the block and get someone to crank, and look for spark on that plug

turning over faster than normal, might just be from sitting, ie the oil needed for cylinders to make good compression has all dripped back to the pan, but that should resolve after a few times turning over, if not the could also be related to the fuel issue - washing the cylinders dry

classics need using regularly, even if just running parked for 30 min once a month

Bigus

Just to add to above , jaguars of this era and similar engine used to suffer terribly from non starting issues , particularly if they were moved a few feet when cold and shut down before they reached operating temperature.
Compression was lost across all cylinders from raw cold start enriched fuel washing the rings free of oil.
The official jaguar cure was to remove the plugs and squirt in a drop of engine oil to all cylinders, clean and heat plugs and refit and start on a newly charged battery at full throttle opening , and repeat if necessary, and if they did start, it was with clouds of smoke.
Once I got one to start that was parked in an awkward position by running two hairdryers in the engine bay for 40 mins and then one up the air intake (instead of changing plugs)along with a fullycharged battery and lots of turning over before it spluttered into life .

rugbyman

That's some story Bigus,strange thing is the engine whirrs fast when turning over,almost as if plugs were out. Hopefully my solution, when found, Will be simplr

tabby aspreme

rugbyman wrote: »

That's some story Bigus,strange thing is the engine whirrs fast when turning over,almost as if plugs were out. Hopefully my solution, when found, Will be simplr

If it's turning over that fast, it sounds like a lack of compression

johnayo

As Bigus has said.......



If started and stopped without running for a few minutes to warm up, the next time you try the engine may flood. You will then get petrol wash in the cylinders where the petrol washes the oil from the cylinder walls. With the oil washed away, you will lose compression hence the engine turning over quickly.
This can happen in any petrol engined vehicle.

Isambard

as for batteries, I have a solar trickle charger on my not in use vehicles which works very well (even under my carport and on the garage window respectively) and cost much less than a battery.

Bigus

rugbyman wrote: »

That's some story Bigus,strange thing is the engine whirrs fast when turning over,almost as if plugs were out. Hopefully my solution, when found, Will be simplr

It's a lot simpler then a holed piston/broken ring or bent valves.

That turning over fast is exactly the symptom , you'd swear all the valves were bent from a slipped timing chain, funnily enough I had a neighbour's 152 sport cross petrol Polo with the exact same issue( moved a few feet at Christmas and left for 10 days ) , except vigorous turning over eventually started it .

So in your case , plugs out , drop of oil ( not too much to cause hydraulic lock) , turn over with plugs out , plugs in and start. Repeat if necessary til you get compression, or starts.

rugbyman

Thanks all.... Bigus ,if thats the route to take, then even that will be some work, the plugs are not visible to me.!!!!. thanks again

Dades

Consider buying a lithium jump starter if you're doing a lot of cranking.

Will charge quicker and offer a lot of crank power. Might save you waiting a day a time to charge your battery every time you deplete it.

fancy pigeon

Does the DB7 have Nikasil coated cylinders?

rugbyman

Fancy pidgeon, i dont know, i assume(often a dangerous thing to do) that you are on the same track as several other people on here have suggested . on the Aston Martin owners forum Nikasil has not been mentioned

rugbyman

as part of my studies on this issue, i have found out that relays clicking does not neccessarily mean they are Ok

also i found that DB7 (ford parts) have lots of glitches

MercMad

There is some mis information here.and you haven't told us the exact engine type. The compression is.being list because the lifters have drained, squirting oil in does not help this. You have most likely flooded the engine by now. Charge the battery, remove the pump fuses or relays, and turn the engine over until it sounds normal, ie the lifters have re filled. This can only happen by turning the engine on the starter until oil is pumped back into the lifters.

Be careful not to overburden the starter, bursts of 15 seconds max and 30 seconds to cool

Now reconnect the fuel pump fuse or relays and try it. If you are lucky it will start eventually. If not you will need new plugs atbthe very least.

BTW the battery should be disconnected when not in use.

Bigus

MercMad wrote: »

There is some mis information here.and you haven't told us the exact engine type. The compression is.being list because the lifters have drained, squirting oil in does not help this. You have most likely flooded the engine by now. Charge the battery, remove the pump fuses or relays, and turn the engine over until it sounds normal, ie the lifters have re filled. This can only happen by turning the engine on the starter until oil is pumped back into the lifters.

Be careful not to overburden the starter, bursts of 15 seconds max and 30 seconds to cool

Now reconnect the fuel pump fuse or relays and try it. If you are lucky it will start eventually. If not you will need new plugs atbthe very least.



BTW the battery should be disconnected when not in use.

Unless it's a Virage V8 it has a Jaguar based engine as can be deduced from the op's description.
From wiki
"the car was designed by Ian Callum and Keith Helfet. The six-cylinder DB7 (based on the Jaguar non-supercharged engine AJ6"

Also the assertion that the lifters draining could cause a loss of compression is fundamentally wrong as the valves would be stuck closed in this case or at least not fully opening.

The above flooding advice is based on a Jaguar service bulletin , and it is a Jaguar based engine and fuelling system , therefore the advice holds.

Henry Ford III

1/. Check for spark.

2/. Check for fuel delivery.

rugbyman

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?

Kenny Logins

Can you bypass the fuel pump relay on that side? I had a similar issue on an old BMW and pulling the relay and connecting the terminals would allow the pump to run regardless.
Tapping the relay with a screwdriver handle also got the car going on more than one occasion.

Bigus

In fairness V 12 's sound like no compression even when 100% healthy as they are perfectly balanced, so the starter just give a constant sound.

TeaBagMania

there are many reasons for an engine to stop dead in its tracks like you described, my experience it has been the crank position sensor, just food for thought.

sounds like one of the fuel pumps isn't working, could be just a bad armature on the pump motor.
try knocking on the fuel tank a few times with a rubber mallet, sometimes its just enough vibration to get the motor to move a bit and make contact with the next armature, once running it will have enough momentum to spin past the bad one.

let us know how she does, and get some miles on that girl

rugbyman

Thanks all.any opinions on how magic the computer diagnosis will be

galwaytt

rugbyman wrote: »

Thanks all.any opinions on how magic the computer diagnosis will be

Very :pac:

beertons

Any pics?

scannerd

rugbyman wrote: »

Thanks all.any opinions on how magic the computer diagnosis will be

The magic computer give you about 20% of what you need to know most of the time, i'd bet it wouldn't show any fault in this case. It gives you a direction to go but you still need to know what your looking for.

rugbyman

hope to have talented computer user here next wed

rugbyman

TeaBagMania wrote: »

there are many reasons for an engine to stop dead in its tracks like you described, my experience it has been the crank position sensor, just food for thought.

sounds like one of the fuel pumps isn't working, could be just a bad armature on the pump motor.
try knocking on the fuel tank a few times with a rubber mallet, sometimes its just enough vibration to get the motor to move a bit and make contact with the next armature, once running it will have enough momentum to spin past the bad one.

let us know how she does, and get some miles on that girl

Tea bag (ex Prison Break?right?)
The computer man arrived today,unfortunately I was not there, my competent nephew was.his computer reading was "crank shaft sensor" he went on to say it could be OK but corrosion.he is too busy to sort it for me. Could you elaborate a bit on your theory, thanks

TeaBagMania

When someone describes an engine shutting off strait away, no hiccups, coughs, or sputtering. its more times than not the crank position sensor.

Just remember even though the scanner reads bad CPS it could be the sensor, wiring from ECM to the sensor, or the ECM itself not interpreting the CPS signals, again, more times than not its the sensor.

I think your Aston was from the Ford era so a CPS shouldn't be too expensive, you can try cleaning the one you have but they are usually buried between the engine and transmission, so might be less expensive labor wise to just replace it unless you are performing the work yourself.

rugbyman

Thank you for speedy reply
few questions
A if this is the problem ,cps or rust or wiring, does this shut off the sparks or the fuel

B What is the ECM, is it the ECU?


Having asked questions both here and on A.M. owners club, it was suggested I see if it will run on easy start (just a bit) to see if ignition is ok


Obviously if it is a CPS problem its better its a replace sensor than a wiring problem i.m.o.


I wont be beside the car for four days yet


Thanks

rugbyman

By the way, changing he plugs is a ten hour job, eight if the mechanic has done it before

TeaBagMania

A. it shuts off the spark as the ECM\ECU dosen't know where the crank is, and it seems since you have fuel pressure on one side of the motor at least one of the fuel pumps is working.
Given the age of your Aston, if i have to drop the tank both pumps would get replaced

B. ECM = Engine Control Module, ECU= Engine Control Unit. Both the same thing. I think the new one is PCM = Powertrain Control Module

you might ask the guys over in the A.M. club if this is the correct part...
http://www.astonmartincarparts.com/part/astonmartin/db7-vantage/39-85756/sensor-crank-timing/150-653-23764-649783-178827.html

Skatedude

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

rugbyman

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

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

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

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

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

yaeger

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

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

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

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

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

rugbyman

Got a ford ,prob escort pipe 13euro.

yaeger

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

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

www.andrewlindsayspecialistcars.com

It will be all worth when shes on the road .

unkel

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

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

rugbyman

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