Corner Wrench: Don’t get fuelled again
|driving.ca 12 Oct 2021 at 16:56|
It never fails; when a tech (whether a seasoned and licensed pro, or a veteran DIYer) is faced with a head-scratcher of an engine performance problem, one of the last things they check is fuel quality and flow. They can spend hours scanning for trouble codes, running wiring harness tests, activating and exercising various components, checking injectors (or carburetors); all of which pass every test and sometimes even two tests for good measure. Then finally, someone suggests checking fuel quality and/or pressure and flow.
We’ve talked about gasoline degradation before and how quickly even the best-quality fuel can go bad. It can cause rough idles, stalling, poor acceleration, jerky operation, and no-start conditions. But even bad fuel has to get to the engine first, and fortunately carbed and injected engines can exhibit the same symptom when fuel is actually getting into the engine’s intake; it creates an unmistakable odour. With carbed or throttle-body injected engines, you should actually be able to see liquid fuel spray when cranking the engine with the air intake hose or carb-mounted air cleaner removed. Taking a fuel sample doesn’t have to be an onerous job, but it is extremely necessary to check fuel quality. An easy way to siphon out a sample from the tank is with a hose of course. But if you don’t want to risk a taste of aged unleaded, cut a small hole in the side of the hose near the output end and use a blow-gun air tool to create enough air flow to get the fuel moving. If it’s immediately darker than normal (with or without an unusually bad smell), you don’t have to wait to let it settle to know that the fuel is bad and that a tank and lines cleaning is needed.