Hey guys my 3.1 mu seems to have develpoed a weird quirk, its only happened a couple of times, but when the vehicle is facing uphill the idle speed drops about 200rpm and if the fuel tank is low (fuel light on or close to coming on) then the engine starts to splutter. also if i am facing downhill with the same amount of fuel the idle speed goes up about 200.
The last time it was at an intersection at the top of a hill and as i stopped, it gave a big shudder, the battery light (charging system light?) on the dash flashed on then off, then it shuddered again, light flashed on then off and did it about half a dozen times before i pulled out and then stopped on the side of the road (on the level) by which time it was running fine again...... (!?)
i don't know much about engines or fuel pumps or anything but i drained the fuel pump in case it had any water bubbles in it, which there were none at all (i even tipped the fluid into some water to make sure it was actually fuel that was coming out and not just fuel flavoured water).
One of my mates suggested perhaps the fuel pump is stuffed/leaking so its fighting gravity when facing uphill or low fuel pressure from the tank and when downhill its got more pressure behind it so the pump doesn't have to work so hard, but he said he doesn't know how they work either so its just a pluck.
Any ideas?
- dunno if its related but it seems to take about 2-3 mins from startup to reach idle speed (720) when cold, and before it gets there it chugs up slowely from about 5-600rpm.