Suddenly Not starting 2.8... Solved...

[jpr1977]

Evening All

A very strange one for you...

Have finally recommisioned the Z after 7yrs in a garage... Got the MOT (no advisories I hasten to add) about to tax it and run it in and well its behaving like a petulant teenager, don't think it wants to leave its nice new warmer garage...

Started and ran fine on Saturday, Sunday comes, turned key nothing... if you lock and unlock the car before you try starting you get a click from the starter motor and can hear the fuel pump kick in to pressurise the system, however on second attempt nothing... (I hope that makes sense)

I have checked all the earths, the battery and starter are new (2 months old) and have worked fine until now and battery has been double checked (both voltage and ampage)

I have got the BMTechic software and there are no faults reporting at all ( I have triple checked before during and after attempts at starting)

I'm at a bit of a loose end tbh, going to try replacing the battery in the key tomorrow and see if that makes any difference, however the diagnosis software shows that the car can see the key and there are no faults/comments shown.

I do remember seeing a way of reprograming the key involving opening doors, disconecting battery etc, etc, but can't find it at the mo.

However any suggestions shall be very much greatfully recieved

Thanks in advance, help save this z'd from a firey end...

Jp

 

[jpr1977]

Mods

Please remove, i managed to post in wrong section...

 

[GazHyde]

Do you have the key with the separate 'brick' button fob? If so this is the reprogramming guide written by @jonco

http://zroadster.org/wiki/bmw-z3/guides-and-how-tos/bmw-z3-alarm-3g-ews-gemel-remote-programming/

 

[GazHyde]

Mods

Please remove, i managed to post in wrong section...

I've moved it for you rather than removing it

 

[jpr1977]

Thanks Gaz

Though you might have double post... As for the key its the other all in one type.(1998 car)


Jp

 

[zedonist]

It's not the immobiliser playing up is it?

 

[Rev]

This is just a thought, but there has been an awful lot written lately in the papers and magazines about classic cars and how leaving petrol in the tanks is a bad idea. It seems with the current additives it goes off and causes the cars to run terribly. Misfires bangs and pops. Untraceable causes that people cannot figure out. Draining the tanks changing any filters, and filling with new petrol resolves the issues.

It may just be worth looking at.

 

[jpr1977]

Afternoon, its not the petrol as that is new and the car isn't even trying to start to fire, I'm sure its the imboliser too but what is driving me to distraction is that there ar no fault codes occuring and so far none of the key reprograming tricks have worked....

 

[Aceman]

Does the starter motor turn the engine over, if turning over could be the crank sensor not detecting when to fire the plugs, fuel pump relay ?

From experience there is too much reliance on ECU error codes so I wouldn't play too much into the fact you are not getting any errors. Back to basics fault finding usually works.

 

[zedonist]

I don't know which alarm system you have, but the immobiliser is usually just a chip that gets detected when you place the key in the ignition, in mine it receives no power, and looks like a small black brick, so the battery in the fob may not be the answer. Alternatively it could be in the alarm itself, others may confirm, so you could have a duff alarm.

So if we assume it is not the immobiliser / alarm and you confirm the alternator and battery are ok and the connectors are not corroded and you have no blown fuses, then it could be the starter motor, when you turn the ignition do you get lights on the dash? If you get dash lights but the starter does not fire, you can remove it and try it off line by connecting momentarily to a battery, if it is ok it will spin up, if not it will just click, if it spins up then it may be a connection problem, if it doesn't, good chance it is broken.

If the engine does turn over and its not firing, then you could be looking at coil pack, leads or plugs

If it is a sensor (crank or cam) i would have expected an error code.

 

[jpr1977]

Delayed update...

Changed the starter under warrenty as the previous one was giving slightly strange results on cranking. New starter in place, exactly the same outcome, click and nothing... However did notice that normal dash check lights (oil and battery) now weren't lighting up,(well there was a very faint oil warning 'glow'). So checked the battery and it was sitting at 12.2, not low but not great, therefore assumed the car wouldn't start with the battery in the low 12's, so hooked up the jump leads to the diesel bus and hey presto it started... From a check of the alternator readings it didn't appear to be charging at all, therefore took the alternator off and took it to a mechanic friend who tested the unit and it worked perfectly... Put it back on the car and now works perfectly, readings show it is charging well and the car starts almost instantaneously...

So really no wiser if i have solved the issue or not... Think its just the car wanting to be used more often...

I'm away for a few days now, so we'll see what happens when i get back, but in the meantime thanks for all of the suggestions.

Jp

 

[Aceman]

It has been known for the connections on the battery to be the cause of non starting. The problem with the Z3 is that as the battery is in the boot if you do not have a very good connection on the battery posts you can drop a few volts across the cable run going to the front of the car. This might not show when checking the voltage unloaded but as soon as you try and draw a fair few amps you will reduce the voltage significantly. It is also worth checking the level of the battery too as some after market batteries are slightly shallower resulting in the earth connection being strained as it is a short wire and tries to pull off, some packing under the battery usually solves this.

 

[jpr1977]

Thanks Aceman, that does make sense, as I noticed that the negative connector took some extra 'fiddling' to get the cable to sit/connect properly. After the starter/alternator debarcle I did test the voltage from back to front and found nothing out of the ordinary but was considering that something maybe breaking down under load,

I'll double check that and the battery height when i get back and then I suppose we'll soon see if an auto electrician is required afterall..

 

[zedonist]

Good to see it is starting again, so cannot be anything major, you probably had a bad starter and several corroded connections, which you have fixed by taking the bits off and re-seating, fingers crossed now for you

 

[jpr1977]

Looking back on it I'm more inclined to think it was a combination of poor 'new' starter motor and connection issues related to the battery.

The first thing i tackled was all of the earths and major electrical connections, coming from a background of old VW's I have learnt the importance of Good Earths...

 

[FRANKIE]

I have just read this today and don't know if you have found the solution. If, on occasion, this happened to me, I would turn on the headlights before attempting to start the car. Normally, you shouldn't this in the event your battery might be low and the use of power for the lights might just be enough to prevent your car from starting. However, this case its used as a test. If you turn on your lights first and they go on normally, and then try to start the car and when doing so the lights suddenly go out, you have a poor electrical connection, usually at your battery. The connection is ample enough to give your headlights power but completely quits when the demand for the starter kicks in and completely stops all electrical flow turning out the lights. This is the fastest, quickest test I know to test the connection of your battery.

 

[Mint]

I have just read this today and don't know if you have found the solution. If, on occasion, this happened to me, I would turn on the headlights before attempting to start the car. Normally, you shouldn't this in the event your battery might be low and the use of power for the lights might just be enough to prevent your car from starting. However, this case its used as a test. If you turn on your lights first and they go on normally, and then try to start the car and when doing so the lights suddenly go out, you have a poor electrical connection, usually at your battery. The connection is ample enough to give your headlights power but completely quits when the demand for the starter kicks in and completely stops all electrical flow turning out the lights. This is the fastest, quickest test I know to test the connection of your battery.

Good tip Frankie - I'll remember it

 

[jpr1977]

Thanks Frankie, I've used that one in the past as well, but oddly the lights were staying on with this, which led to this merry go round... Honestly car electrics could drive me to the brink...

I got back last night and the car started after a couple of worrying clicks from the starter... Played around with the battery connections again (thanks again Aceman) and the car appears to start on the button now, so i'm going to leave it for a couple of days and try again at the weekend, fingers crossed...

 

[jpr1977]

Update time... The car continues to annoy... All connections /cables from the battery to the starter and all of the earths have been checked and double checked, (well apart from where I presume the +ve cable runs through the passenger comparment) there are no fault codes, no current drains and nothing else that would appear out of the ordinary. However it still is refusing to start on its own, a full charge of the battery or a jump and it starts spot on. The starter is fine so the only answer left that i can come to is that I have an alternator that is 'lazy' at best, however before i take the plunge and buy a new one can anyone confirm what their fully functioning alternators are charging at? i've been getting approx 12.7 at tick over to approx 13.5 at 1500rpm, which seem low values compared to other makes I have worked on but want to check before i spend my hard earned penny's.

Any help would be greatfully appreciated.

Jp

 

[Brian4]

As far as I know they are supposed to be between 13.8 and 14.8v and pretty much the same whatever the engine revs. Dynamo's used to vary a lot with revs which is why alternators became used.