Guys I am in no way a tuner and do not wish to tune my car. After having a tuner screw up my CRX with a piss poor tune. I would like to learn a little more abour A/F ratios and whats safe whats rich or lean? Any info or links anyone can give would be great. I am wanting to start up my S2000 with the base Flashpro ID1000 basemap and would like to have the piece of mind knowing I would destory my motor just letting it idle.

 

You really won't find to much info online; at least I haven't. I ended up buying a couple EFI/tuning books.

 

"safe" and "s2000" doesn't go together in one sentence. =P

 

It is very difficult to destroy a motor while idling. There is no load on the motor so if you run it to rich or lean it will just stumble and die. The basemap is decent enough that you could start it and idle it to look for oil leaks check fittings and fuel leaks.

 

If a motor is running, their's a load. It might not be much, but their's a load non the less. The idle screw and IACV balance the air to this minimal load. The rest is just adjusting fuel and timing to make enough power from the air/fuel mixture to overcome, but not surpass this load.

 

The holly efi tuning manual has some good info. Read the manual for the tuning solution you are using over and over till you understand the concepts in there.

You may want to order a book but don't expect it to be directly applicable to the system you are using. Every system has slightly different ways to tune it.

 

When it's idling the ECU is running in closed loop, so it will adjust automatically to achieve circa 14.7:1 AFR. when you go into WOT the ECU will be running open loop in which you need to ensure your fuel table is tuned so that your hitting around 13.2:1 AFR (if your NA)or around 12:1 or lower if your running boost. Generally the higher the boost (especially if your turbo'd) the richer you go (within reason) as your using the additional fuel for cooling the pistons and cylinders to reduce the risk of detonation.

Dan

 

You're right, but you tune in open loop, no matter if your at WOT or idle. You do this for 2 reason's.

1. If you were in closed loop while tuning part throttle, the computer would be making extra adjustments on top of your own adjustments.
2. The computer can only compensate so much in closed loop. This is why you dial in everything in open loop, then switch it to closed loop when you're done.

 

My car is pretty much tuned (pretty much). But I have no idea of it is in closed or open loop (AEM 1052). I know running in open loop all the time is a bad idea, but I want to make sure it's not doing that. I am having it tuned in about a month by a pro. But it would be a nice to know kind of thing. One less thing on my mind.

Thanks,

-Josh