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Did I miss these battery-death hints? Battery spec for 300/24, please.


Hi Derek,

Thanks very much for going to so much trouble with the images.

Great advice, many thanks. I now have an action plan.

The running down of the battery is still a mystery, would it be linked to this fault, or have I been lucky and got two at once, perhaps?!

The battery does look new, but only 60 amps.

On Sunday the seat-belt p/t remained stuck-out at it’s fullest; I wonder if that would cause a drain?

Anyway, thanks again. I should be able to get to the car tomorrow morning.

Cheers,

Paul
 
Hi Paul ,

I'm guessing that the battery ran down as a combination of using seat heaters , HRW etc , then a prolonged starting attempt - there may still be a problem with the charging system , just possibly - but I'd start by replacing all those oxidised fuses and checking the relays first . Once you get the car running again give it a decent run and see what the battery voltage is showing - if upwards of about 13.5V all will be fine . A 60 Ah battery should be OK for the car .

I don't think the belt presenter would cause a drain unless stuck halfway and trying to push against some obstruction . Most likely a dodgy microswitch .

Lots of little niggles like this are amongst the joys of getting to know an older car that is new to you - most of them will be silly things that don't cost much but can be a pain to track down . Once you eliminate them you will have a good car . I usually reckon on about a year of working round things before I get a car to a condition I'm happy with ...

I hadn't seen the car on eBay , but a very nice example of a pre-facelift ( or Generation 1 ) W126 ; I have a similar car but mine is generation 2 .
 
The fact you are not smelling any fuel and not hearing the fuel pump on "switch on " points to fuel rather than ignition BUT difficult to judge without being there and as Derek says those distributor caps are notorious.
 
Thanks Graeme, looking forward to unravelling the mystery soon!
 
Hi All,

Well, after much not finding of the FPR, just as we were about to abandon the project when the, ‘one last turn’ produced a splutter.

Until then, there was without doubt no FP buzz/whir, and as I wasn’t ‘driving’, when it did start I can't testify to any noise. It was very much a last minute, ‘it’ll not start’ try.

After the first splutter, one or two more five second turns, then arrived a splutter about twice as long as the first, another few bursts, a more prolonged firing until eventually the car started. I might be wrong, but it seemed as if the cylinders were waking-up one by one.

I made it out of the car park and covered eventually about 100 yards before the motor simply stopped. No splutter, just stop. A quick restart – I can’t remember if I heard the pump – then about 250 yards and another abrupt stop, followed by around a mile without a stop.

Feeling confident, I advised Thunderbird Two that we’d let the car tick over for five minutes, and subject to, etc, whereupon it died before my very words.

Following on, it became harder to keep the engine running for anything more than a few seconds.

Whilst we tried, I could clearly hear the distinctive pump noise – certainly not heard earlier, at the start of the affair.

On hearing the pump the car would start for a short period, then die. Ignition off/on, no pump noise, but an occasional splutter.

Does the pump simply build up pressure, and not kick-in again until the pressure drops, or must I hear the pump every time I turn on the ignition?

I wonder, could someone give me directions to the FPR?

Could this be a dizzy problem, or would it have stuttered badly during running, which it certainly didn’t do – smooth as silk?

The fuses are really shot with oxy, so a change of all of them tomorrow, time permitting.

A trouble shared, etc!


Cheers,

Paul
 
Behind the battery there is a flexible black plastic shield. Its really just sits in place so just pull it out. Behind it you will see two large units with large plugs- one is the ABS control unit the other is the engine ECU. just beside them towards the centre of the car should be several relays one will be marked "kickdown" and "6zyl" like pontoneers picture--- thats the FPR The position of the OVP relay varies a bit but is in that region its easily identified by having 1/2 fuses mounted on top of it.
 
Is the dizzy-cap falling off the suspect list because of the smooth running - when it runs?

Thanks,

Paul
 
I would say so - sounds more like the FPR , definitely check that first .
 
Thanks Derek and Graeme,

I really appreciate your continued support.

Cheers,

Paul
 
Hi,

Progress Report.

Fuel Pump is priming, a very distinct buzz.

The car started on the second turn, and after a little splutter went straight up to 1100 revs, stayed there for a minute or two then stopped abruptly.

From then it would only start for a second or two at most, then die. I gave it a dozen or so tries, left it five minutes, turned it again and it ran for about ten seconds and stopped again.

If it has auto choke, then that’s all it seems to run on.

The only other thing I can report is that there is about 2/3 mm play in the ignition barrel.

Could that be something?

Cheers,

Paul
 
Hi,

Is the FPR visible on either of these images, please?

The car is now running on cold start, then dies on warming up.

abrlys.jpg


abatback.jpg


Cheers,

Paul
 
Hi
i know it was some time ago now but i may be able to help, ive got a r129 sl 300 24v and ive had all of your problems and i can tell you its all down to damp in the cap and electrics, you really need a proper bosch cap and rotor arm and good leads, i know its a bugger its runs very nice and then stalls and wont start but if you leave it for 24 hours it will start up again so it does not seem as if it could not be the cap as it dose run so well for the short time that it does run, these engines dont like damp conditions. i changed all of the above and it works fine now but i do keep it in a heated garage.
i do hope that helps, ps all these problems go away in the warmer months as the electrics dry-out.
 
Hi,

Thanks for the info.

I changed the dizzie and rotor a few months ago and everything is perfect.

I might change the leads as a precaution before winter, though!

Cheers,

Paul
 

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