Tip & How-To about 2001 Acura 3.2CL
Let me share some information not found elsewhere about how to set your Throtle Position Sensor (TPS) and throtle plate after cleaning the throttle body. This article is about tuning your engine to get an happy ECM not race track nitrous tricks. The on-board OBDII ECM controls just about everything engine wise but for that it relies on a few bases set below. In OBDII era everything is controled with extrim acuracy. If a parameter is off you get bad driveability symptoms if the ECM can not detune the engine enough to compensate. We are not even talking engine code here. You'll get a CEL if something is busted not for driveability issues like misfirings induced by lean mixtures (no CEL but degraded driveability regardless - Trust me I design computers).
Set the throtle plate to be almost fully shut closed plus a quarter turn of the screw so it is not sticking ie. opened as little as possible. At this position you have base idle at which the TPS should read 0.6000 VDC (ie. 600.0 mV) in the car powered by the computer circuitry.
Note that at 610.0 mV you are off idle!! (ECM deactivates vacum engine mounts coil) So adjust acuratly to no more than 600mV +/- 2mV
Set the "Idle Air Mixture" screw to about 1/2 or 3/4 turn opened from fully seated. This is to provide idle air to the engine by bypassing the throttle plate.
More or less air is NOT better - There is an exact amount of air needed to mix with the exact amount of gaz injected at idle.
- Not enough air will give you a surge at pick-up and cause pinging and overall poor driveability at low speeds. The surge is caused by the computer jurking the Idle Air Valve opened to adjust the mixture.
- Too much air will keep the car moving when you let go the gaz pedal AND decrease the vacum available for your break booster.
So better not enough idle air than too idle much air.
By properly tuning the fuel injection you will increase the low-rpm power and you'll potentially save gas as well with increased power.
I find my engine drives around town about 1,100 rpm with amaising tork not always above 2,000 like before tuning!
I also have a TL'05 with the fancy throtle-by-wire, same thing is true. great tork when the idle mixture is set properly which no mecanics ever set. These setings are root to many poor driveability issues. It can not be acuratly factory set or should be retuned every 50,000Mi to match the engine conditions.
The acid test to know when your engine is well tuned: backup a 40% hill slowly. If it is smooth you have it. If the engine surges, misfires or hesitates you are off the chart by as little as 1/4 or 1/2 turn or more. The closer you are to the target mixture the better your engine runs. Aproach the IAM setting on the increasing side: from close to open.
Why backup a hill?? The reverse gear: is actually hard for the engine to drive because it is realy long. Up the hill: is to put the engine under load.
Love tuning these V6 3.2L and crusing around on tork alone while saving green house gases! Third gear WOT is really nice too.
Acura aluminum engines have some electrical ground issues because the ground straps and AL don't like each other (disimilar metals and AL forms an insulating oxide) - Tip: clean up all your ground straps connections including the ECM ground post directly on the thermostat housing and coat them with AL electrical wires compound from Lowes/HomeDepot. Well worth the trouble as well.
Posted by San_FranCA on
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