C5 X7 various problems fixed - I hope

[Peter.N.]

Intermittent wipers had been an ongoing problem with the red one, sometimes they would work perfectly and at others they wouldn't. Recently the engine was not always starting first time but usually on the second, the starter didn't seem to be all that energetic so firstly I checked the battery, it read OK on the load tester with 11 volts on a 100 amp draw, so I dismissed that and overhauled the starter, still not much better so I fitted a new one which wasn't much better - from that time on I had no turbo boost.

I recently tested the battery again and it read slightly lower but still within the yellow section, it always started eventually and never went flat even though it has not been used much lately. However I decided to fit a new one which immediately cured the starting problem and also appears to have also cured the intermittent wipers.

I can only theorize that as the battery wasn't delivering enough current to turn the starter quickly enough that every time I started the voltage dropped lower than the electronics would tolerate, anyway the wipers work every time now.

I solved the turbo problem yesterday, there seem to be a mass of vacuum pipes all over the front of the engine, I gently pulled on them all until one appeared with nothing on the end of it, couldn't see where it came from, eventually almost standing on my head and using a bright light I found a little metal block with two very small pipes attached, or at least, one at the time, I refitted the loose one and eureka! The seem to be a very loose fit, but then I suppose if you are not poking about in there they will stay on.

I have read all the warnings about low battery voltage but have had other cars cope with much poorer battery.

Peter

[white exec]

They do seem very intolerant of slightly low battery voltage.
Worth investing in a CTEK MXS3.8 ? Have one here on the XM. They are really good at maintaining battery condition.

[Peter.N.]

Hi Chris

The battery voltage was always good under running conditions, about 14.4 or so and a good 12+v even when it had been standing for some time. I suspect that the battery had lost capacity and wasn't capable of supplying the full starting current. Anyway, I think the new one would drive the car on the starter.

Peter

[GiveMeABreak]

That is very likely Peter - I've seen it again and again - the measured charging rate and standing voltage can't account for the underlying battery capacity of an older battery to hold a charge. With the number of electronic systems - and specifically those that remain live (RCD / remote locking circuit) and those that are intermittently polling systems on the car (like the TPMS and BCSU) and the head units that stay live for a while after ignition off etc., all of which are a drain over time.

It's why during lockdown, I've recharged the battery several times and now put the car into Park Mode to disable some of those power consuming functions.

[Peter.N.]

Yes, good idea. Strangely mine had been standing for weeks on end without being used and the battery didn't go flat, what was left of it must have been in good condition.

I must admit I was suspicious when I took the battery off and put it on trickle charger and it was fully charged by the following morning, did smack of low capacity.

Peter

[GiveMeABreak]

Yes, that a clue....

I have a smart charger and that can desulphate a battery and condition it (as much as is possible) and can be left on in maintenance mode automatically. Since putting it in Park Mode, I left the car for 4 weeks and it started instantly and quickly.

To recover the battery and desulphate it properly though does take time as it depends on very low trickle charging over a long period of time (7-10 days), so a smart charger is great for this assuming you have a spare battery or don;t need the car!