One of our classmate's Nissan Silvia RPS13 or 180SX has been very sick.......massive fuel unburned and wasted in the exhaust pipes, while the spark plug condition shows that the air fuel mixture, LEAN. What could possibly be happening?? As the Silvia has a Trust Greddy E-Manage in it, piggybacking its ECU, our teacher think that may be the main culprit.
Nowadays car has a inbuild computer call ECU (Engine or Electronic Control Unit), its basically a computer that takes input signal from different sensors in a car and outputs a signal to something to do the job...example Air Flow Sensor wil pick up how much air is coming in to the engine, translate it into a signal, sends it to this ECU, then this ECU will recalibrate the fuel injector's duty cycle to spray more fuel in it to cope with the incoming air........as in an engine, more air = more fuel^^
So what happen is if u wanna fine tune ur car u can choose to change the prefixed OEM settings. Original settings normally look after reliability, fuel consumption, and drivability (is it easy to drive or not) and then performance...Of course if its performance type vehicle they will look after for more performance thn maybe fuel consumption....anyway...the original ECU is prefixed, means u canot change them cuz only the manufacturer can do that....so what happen is the E-Manage has the ability to rewrite and correct the input signal as much as u want, meaning if u are a sporty person u like to drive ur car fast, u might want get more fuel into ur engine as early as possible...but we can't change that in a original ECU, so heres where the E-Manage does its stuff.
Well instead of the usual Input - ECU - Output, the E-Manage systems intercepts the Input signal first, while allowing u freedom of changing the value of the signal itself, and then put the signal back into the orignal ECU.....which will then reads to the 'modified' signal that we change and makes a different output signal according to that.....so in this case, is Input - E-Manage - ECU - Output ^^ so basically what is does is it bluffs the ECU, yup, its a liar~
So now the E-Manage has got some very wrong mapping going on and therefore make my friend's car has bad bad fuel consumption, and possibly, will ruined the engine as well...
So what we can do is, we hook the E-Manage with a laptop, put the car on a dyno machine to simulate driving conditions, then use the laptop to change the value itself again to get the base map running smoothly and properly first.....
We first do that by keeping a real time monitoring on all aspect we can, Air Flow Meter Voltage Output, RPM, Throttle Position, Ignition Timing and so on~, since we can't do real time adjusting because the E-Manage doesn't have live adjusting options, we gotta first extract the map out of the E-Manage, put in our specified value and thn sends it back again, we call this Import and Export, you Import the data to ur comp and you Export it back to the E-Manage. And if done, the engine will run according to the new map that we Exported it back, but unfortunately, somethings wrong with the version compatibility between the software and the hardware itself, so we can extract information, change it, but we can't put it back in.................which means we're good for nothing, since we can't make any changes, we call it a day~
Our teacher speculates that the massive amount of Hydrocarbon (HC) which is fuel in the engine oil (!) is the result of overflowing from the injectors into the cylinder, which leads to the HC dropping into the crankcase from the piston rings. The exact problem is still very much hard to understand as we'll get more into it on next class hopefully....but today i've learn quite alot on E-Manage and the importance of value adding or decreasing and the amount of choices and functions of a, be it a
Stand-alone ECU (Input - Standalone ECU - Output.)
(which unlike the E-Manage, piggybacking the original ECU, replaces THE original ECU to become the sole ECU in the car.)
Example, Apexi Power FC, MoTeC
or
Piggyback ECU (Input - Piggyback Device - original ECU - Output. )
(the one we work on today.)
Example, Trust Greddy E-Manage, HKS F-Con V Pro
actually matters alot, as today already we felt our hands tighten up due to the limitation of the info we can get....
The car itself on the dyno...
Hooking up the car to a safety belt..
Analyzing the exhaust gas...
Alrite, this is the result of the exhaust gas coming out of the car, 250 PPM (parts per million) means that in 1 million air, there are 250 of Hydrocarbon (HC) which is fuel or unburned fuel, and thats bad, really bad, optimum ratings should be at 50 PPM....while 2.231% of the gas is Carbon Monoxide....which is bad, we want that to be as low as possible...and 0.984 is the Lambda rating, with 1 being 14.7:1 air fuel mixture, 0.9 suggest slight rich condition, and which during testing the richness reach about 0.6-0.7, it should be LEAN which is approx 1 or 1.2 during cruising...
Put ur leg down, out comes minced meat ^^
Houston~We have a problem....
