Fuel Pump Replacement

When the JDMny lost power and stalled close to home one evening it didn’t take long to identify the fuel pump as the cause of the problem – a buzzy old pump that ceases to buzz has not magically got better.

Initially it didn’t look like a particularly easy fix – there’s no inspection hole in the boot floor, meaning it’s necessary to drop the tank to change the pump, and the pump assembly itself is completely different between JDM and UK spec Jimnys. Oh, and I’d brimmed the tank only 21km before the failure, meaning the tank would be at its heaviest and the old pump assembly almost fully immersed in fuel. Yay.

Whilst I could’ve easily picked up a JDM pump via Jesse Streeter I was keen to get the JDMny back on the road as soon as possible – autumn is true Jimny season and the Wagon All-the-Rs’ insurance was also almost at an end. Thankfully on closer inspection of the parts catalogue it turned out that, whilst the pump assemblies are different, the pump itself is the same across all Jimny models. A secondhand (low mileage!) UK spec OEM pump assembly was duly sourced from eBay and when it arrived I gently extricated the pump out from the rest of the gubbins.

Lowering the tank was a pretty stressful experience requiring the removal of the rear propshaft, the rear centre-section of the exhaust, and the expert(!) use of two trolley jacks. The process was made slightly easier thanks to the use of flexible fuel lines – rather than the UK spec steel lines – which allowed me to pull the fuel pump assembly out of the tank without having to try to blindly undo the Rubiks-cube-like connectors with one hand and with no room to manoeuvre . Good luck to any UK Jimny owners attempting this…

With the new pump in the tank and everything back in position I turned the key to the “accessory” position, listened for the initial priming of the fuel system… and heard nothing. Rather despondently I decided to try and crank the engine over anyway and to my complete surprise it fired up immediately. Turns out my old fuel pump was so loud I’d completely missed the new one’s ultra-quiet hum ?