In my last post, I detailed how the relays in the ECU system allow the system to flip to a default engine map. This lets the team keep running, even when something fails, and it decreases the chances of the ECU doing something that blows up the engine. Here’s a short explanation of what exactly an ‘engine map’ is and what it does.
Cautions
Do Cautions Breed Cautions?
There are a lot of NASCAR sayings. You know them: one announcer starts and the others all join in. Last weekend at Martinsville, with three cautions in the last 50 laps, it was “cautions breed […]
Cautions
Will the Gen-6 Car Affect the Number of Cautions?
I love the Gen-6 car. Not as much as I love the Nationwide cars (but that’s got more to do with what I drive than it does the cars). The big question is whether the decrease in cautions is going to be changed because of the new car.Let’s start (as we usually do) with the new car. […]
Allmendinger, A.J.
Drug Testing FAQ
Some clarifications to clean up the incorrect information circulating around in the wake of A.J. Allmendinger’s failed drugs test. More questions – send them to admin(at)buildingspeed(dot)org and I’ll add them […]
Good basic explanation. The ECU runs in either closed loop or open loop mode. In closed loop it is receiving info from all inputs (sensors) within correct parameters, and so follows the closed loop map.
If some sensors fail, or go outside the normal operational data parameters, such as a temperature, oxygen sensor, or air flow sensor (MAF) the ECU goes into open loop mode, ensuring the engine wont go way too lean or way too rich, for example, but follows a “limp home” mode for ignition timing, and injector pulse width..
There however is nothing it can do if a cam sensor or crank sensor goes bad, it will lose all timing reference for injector PW and ignition spark events and the engine will not run.
And if the TPS,( throttle position sensor) fails completely, the engine will either die or remain at idle only,, depending on the ECU programming.