I’ve spent a frustrating few days trying to get to the bottom of why the Mercedes is running so badly. Progress has been pretty poor, hence not much in the way of updates. Sorry about that!

After two days of failing to improve things, I decided to take a break. After all, my trusty Citroen BX Turbo Diesel needed attention too. The hydraulic pump was running almost continuously. This means the clever hydraulic system was struggling to maintain the pressure needed to operate the suspension and brakes. An accumulator sphere holds the pressure, so when you hit the brakes, the power is already there, even if by some catastrophe, the engine isn’t running. It’s some pressure too – over 2000psi. That pressure can’t be maintained indefinitely, which is why a healthy Citroen will chirrup a few times a minute, as the pump quickly re-pressurises back to the maximum required. The BX was chirruping almost constantly, which suggested that either the pump was duff, or the accumulator sphere was unable to hold the pressure. Like anything, they age with time but replacement is pretty straight-forward. If you have the right tools.

A man with the right tool and plenty of BX know-how

I don’t, but I know a man who does, so I went to see him. Sure enough, the sphere was quickly changed and the chirruping (or tick time) occurred no more frequently than every 20 seconds. That’ll do. Generally, any tick-time below 10 seconds is considered poor. Mine went from about 10 seconds to constantly very quickly indeed. It was nice to have the BX back into full health. Especially as the rest of the fleet is not doing so well…

This morning, I got back onto Merc-fixing. Advice on a forum suggested tweaking the idle mixture – perhaps it was too rich, and was in effect flooding when I hit the throttle. Playing with the mixture is something that can go very wrong indeed, and is very rarely the fault. However, weaking the mixture by a touch has transformed the car. It still has a misfire, but it is now driveable and no longer bogs down when you’re trying to pull away. A fresh set of plugs and leads will be arriving before to long to try and transform things further.

Merc seems happy, even when stuck in traffic. Sheep traffic.

However, it is working well enough for me to actually undertake journeys in it, and what a delight it is. It’s a magnificent machine for wafting around in and while quick cornering makes it wallow like a hippo in a wheelbarrow, it actually feels much more nimble than my old W123 Mercedes. You can still corner quickly, as long as you don’t really push it. It’s quiet and refined, with excellent brakes should you need to call upon them. The BX wins hands down when it comes to handling, but these two cars are surprisingly close in terms of ride. Of course, the BX is uncannily smooth for a car in it’s class, so it’s a sign of how good it is that it compares with an equivalent executive car. The two cars may both be silver, but they’re very different to drive, and I like each of them a great deal.