How does that work?

Crash Lander · 16-04-2007, 10:03 PM

I've had an 'untidy' idle in my AU S1 since I got it last October. Did the leads and plugs, and throttle body and all that. The last 2,000km has seen the 'untidy' idle become a little bothersome, as it would occasionally take a larger drop in revs, or hesitate for a second on take off etc. I've been thinking maybe some injector cleaner could help. I normally fill my fuel tank at about 1/4 full or slightly under. However! Last week, I forgot to buy fuel on the way home, and the DTE got as low as 66km by the time I got home. (I'd done 670km on the tank since the last fill, so my fuel economy is fine), and I noticed the idle had improved qute a bit. I put $20 worth from a different to normal servo in it, and noticed the idle still remained improved, and could now even be described as smooth 99% of the time.
How does that work? Is it possible an injector was partially blocked, and because I ran the tank so low, more crap went through, and actually pushed through the original crap that was partially blocking the injector? It's not making any real sense to me. Comments?

maestrobmw · 17-04-2007, 10:59 AM

Sounds like it could have been running rich previously, possibly due to a blocked fuel pressure regulator. When you ran the fuel low, it may have partially blocked the fuel pump and/or filter, lowering the fuel pressure being supplied. This could cause one to cancel out the other. Does it go hard at full throttle, or is it capable of chirping the tyres front a standing start/full throttle application?

Crash Lander · 17-04-2007, 12:15 PM

Yes, it certainly goes when I put my foot down. Chirping on take off? Well, the cop that pulled me over about 3 weeks ago for squeeling the tyres on leaving an intersection seems to think so. LOL!

**Mechan1k** · 17-04-2007, 04:05 PM

I can't see how it was running rich though as his fuel economy seems to be VERY good.