Topic

When I first started building engines I was cool has cucumber...after a while your brain gets overloaded with large amounts of info...and you drive down the road in a different manner....hearing turbos and picturing camshafts and followers..bigend bearings and the like...my blood smells of diesel ...but worst of all you start looking for problems has your knoledge is there to find them...take today I cured a small oil leak and opened a can of lager has a little thankyou to myself..on going out of the garage I thought hey I haven't checked the ecu for faults...so I did and found this..

I should of just gone in the house and chilled with some more beers or read a book like this one!

thanks just thought it was only me, if only i drank beer there would be an answer then,love the pic tho.nice one, hope to see you out and about throughout the coming summer,

Graham.
It might be worth checking if you have a bad earth on the engine bulk head . Take a voltage reading from the battery +ve to a clean earth point under the bonnet and compare it to the voltage from the main starter lead to the earth lead in the engine bay . The point you raised about the boot hinge wiring is always worth consideration bearing in mind that it's a source multiple problems on these cars .
John

Ps apologies for my previous.

all sorrys taken . i will have another look tomorrow and let you know how i got on, thanks john.

thanks John bad earth from battery terminal . all ok now, started to worry there,

Good job we got john..

Following on from my post in what ya been doing thread, regarding my flat battery and the speed it drains down at - most of us are experiencing this kind of issue come this time of year, I have been doing some of my own checks, similar to Mr Bluestreak, but thought this thread a better place to record my findings!
As some of you may have read, my battery drains down while standing and has now been fully drained three times since I bought it about 9 months ago. I find that I am needing to start my car every 3 or four days and run it for 10 mins at least to maintain a healthy charge in my battery.

So out with my trusty Fluke multimeter and Clip on ammeter and see what is happening to my battery and why it seems to be going flat so quickly.
First up, its a voltage check, and this is after the car has been standing overnight - I did a short run of about 12 miles last night. At least it started ok this morning, anyhow heres what the Multimeter showed when I checked the Voltage first thing.


As you see, its alarmingly low at under 12 volts - a good healthy battery should really be up to 13 volts or so....maybe I need to call a warranty claim on this one...

Now with the engine started, good news my Alternator brings the system voltage up to a nice and healthy 14.2 volts. Once the engine is turned off, the battery voltage slowly falls and holds, for now at about 12.4 volts, however this will drop with the car standing at about 0.1 volt per hour.



Now lets see how much load there is on the battery....here is a current reading with the bonnet open - note my TF has a bonnet courtesy light fitted, so this is on during this test. A current drain of 0.3 A is noted.



Now with the bonnet closed (simulated by pressing the bonnet switch) ..



And the load drops to 0.2 A, much as is to be expected.

Finally lets see what happens when we lock the car and set the immobiliser....



The current drain leaps to a whopping 0.8 A !

Now I am understanding why the battery is draining after such a short time. A bit of simple maths tells us that a 63 A/h battery having a drain of 0.8 A should maintain its charge for about 79 hours or 3 1/4 days. This is what I am seeing when my battery is failing after 3 or four days!
It now makes sense to me to fit a larger capacity battery, as there is room for it in the bay, so maybe a 80 or even 100 A/h battery will be fitted when I replace it.

Sundance

Just had ago on mine with the multimeter...not 100% if I've got meter set up correct..here is what I got.I have no light on my bonnet.

ALARM SET.

Pause for short period and drops to this.

If using a multimeter to check the current, you have to disconnect one of the battery terminals and connect the multimeter in series with the battery and the disconnected lead.
My clip on ammeter is different as you can just clip the sensing coil over the cable that is to be measured.
If you disconnected one side of the battery and dropped your meter in series, then you have got it right Mark.
I would be testing the current on the 10A setting, as it seems like you will be far surpassing the 20 milliamps maximum measurement that you have set your meter to.

Note how the circuit needs to be broken and then re-connected with the ammeter in series. Also you have to be careful to get the settings right or you could at best blow the internal fuse in the leads (if they have any) or inside the meter itself, at worst you could burn out the multimeter.
Thats why the clip or clamp on ammeter is a great tool, you do not need to break any circuits and cannot damage it with excessive current. Ones that measure DC current are very expensive to buy and I am lucky to have one. I do have a spare AC one I am looking to move on if anyone is looking for a cheap AC clamp meter!
Sundance

Yes I disconnected the earth lead to the battery...noticed you had one of those posh meters with the hook around cable..cool...I just have 2 cheap meters has they get lent out a lot at work...hence why my other meter at work as blown fuses...something to do with my boss testing 3 phase.....he gave it me back set at 1000vdc...both fuses blown the main fuse and the spare that's clipped in the case....the meter in the picture was only about £3 off ebay...I think the duracell 9v battery in it has more value...The other I have is one of those with a funny name I call it my f**k you meter.

Ok looks like you are using the ammeter ok, but your reading is 10 times lower than mine....this needs further investigation. I will see what my Fluke multimeter says tomorrow and connect like yours.
My Clip on should be accurate enough and has been calibrated in the past, so will double check with the Multimeter and repeat the exercise again.
Good to know the fuses protected your boss if not the meter, Mark. If you ever decide to buy another, I would always recommend an auto ranging one, which helps as you do not have to select any ranges, just what you want to measure. Your other meter still may work if you put a new fuse in it, If you struggle to find one, I may have spares.
Let you know how it goes. Happy new year by the way!

Sundance