Fuel pump could be the culprit

On my 2014 Chev Utility 1.8, which has now done 135,000km, it happens occasionally that while I’m driving, the bakkie loses power and refuses to accelerate. After pulling over for about 15 to 30 minutes, everything goes back to normal. The engine becomes lame. It does not misfire or jerk, nor does it cut out. When I stop, it still idles, albeit at a lower than normal idling speed. No fault messages or codes appear on the dashboard. The only discernible pattern to the incidents is that they only occur once the engine has reached normal operating temperature. I have taken the bakkie to the dealership, but they failed to pick up a fault. I have also taken it to an independent service centre, and it came back with a clean report. I have now taken it back so they can drive it in the hope of identifying the problem. What could be the cause? — Ernest Ernest, intermittent problems are always the most difficult to trace, because you can only investigate them once the vehicle is in fault mode, and you have no way of triggering fault mode. Nevertheless the details in this case suggest you occasionally experience a sudden drop in fuel pressure at the injectors. Not a complete interruption in the fuel supply, because the engine still idles, but a drop in pressure sufficient to reduce the power. This would seem to indicate a problem in the high-pressure fuel pump which feeds the injectors. When I discussed the symptoms with the owner of a workshop, he confirmed my suspicions by stating that those pumps are prone to failure at around your bakkie's mileage and the problem usually surfaces when the engine has reached normal operating temperature. A fuel pressure test will confirm or refute this theory, but of course, such a test can only be conclusive if done while the vehicle is in fault mode. There’s a chance it is a clogged fuel filter which sometimes becomes so badly blocked it restricts fuel flow to a trickle. When the engine is switched off, some of the dirt disperses from the filter inlet, allowing enough fuel through for normal operation (for a while). Unless the filter has been changed recently, you may want to first replace that.