Salam all PWs
I read an article on TPS calibration of Honda on another site & experimented on my own civic. It did work as my TPS was out of calibration by just 0.02v but it made a big difference.
Its also useful for people whose TBs & Throttle Stop Screws r screwed up bu our CNG mechanics, Having Idling Issues, Or Throttle Body or IACV problems.
It will also rectify the problem of different rpm on petrol & CNG.
Here is the writeup:
To calibrate the voltage on the TPS Sensor, a sensor on the throttle body that tells the ECU where the throttle is positioned. Over time the Tps goes out of calibration and your car's performance suffers greatly for it.
I was VERY impressed with the difference this made to my car. It increased throttle response, smoothly revving across the whole rev range and makes for a far enjoyable car to drive.
If your car is around the 8 year old mark, you should DEFINATELY do this if you want better performance from your car and offcoarse, who dosen't?!
Again, I can't emphasize how effective this is, a must do!
THE TPS IS OVERLOOKED OR SHOULD I SAY NOT UNDERSTOOD BUT THE TPS HOLDS GREAT BENEFITS WHEN CALIBRATED.
This can be performed by yourself, without help, no problem.
This is being done on a d16y4.
-Remove the Throttle body - 4 bolts
-3 sensors that just unplug (TPS, Map and IACV)
-2 coolant hoses on the bottom, unclip the metal clamp and pull the hose off.
A little coolant will run out, perfectly fine. If you don't want to loose the coolant, plug the hoses up.
-Accelerator cable (and gearbox cable if an automatic)
Give it a clean
There She blows!
The Tps gasket is torn but it wont matter at all, so I will re-use it
Now, clean the whole Throttle body up, I only use Carb cleaner OR another product which I reckon.
Intake Air Control Valve (IACV), Clean that up real good!
Let it all dry out:
IMPORTANT: When U put it back together, make sure that little plastic doova on the tps goes between those 2 metal bits.
Put it all back together
Next, is to adjust the throttle cable. This is done by undoing these 2 nuts and tensioning the cable
At Closed Throttle (CT) the cable needs to be firm but not tight. At Wide Open Throttle (WOT) when the pedal hits the floor should be the same time as the Throttle body Wide Open Throttle stop (WOT) is contacted, therefore there is no significant load on the cable nor the WOT stop
The WOT stop varies in design but the exact same principle. I know on the b18c it's on the bottom.
The easiest way to achieve this is to put your foot to the floor (WOT) and check the above. If there is a gap, the cable needs to be tensioned to close the gap. If the TB WOT stop is contacted before the pedal hits the floor, you need to loosen the cable off a bit.
OK. Now the fun part. On the TPS sensor, there are 3 wires - Yellow, red and green (all with a black stripe)
Red is Positive and Green is Negative.
I inserted the pin through the wire but I have learnt that the better way to save damaging the wire is to stick the pin up into the plug where the wire connects to the plug, as so
Now, turn the car keys turned to the second click, so the lights on the dash come on. Then perform these tasks -
Set your multi meter to volts. We are looking for a range of 0-5 Volts, so the 20V setting is best
Positive probe to positive wire and negative probe to negative wire
Note: You can wedge the probes under something to stay on the pins, without the need to hold them. This will allow you to do this by your self.
[b]THESE VOLTAGES ARE THE SAME FOR ALL HONDA'S
0.48V @ CT (Closed Throttle)
4.5V @ WOT (Wide Open Throttle)
Now, hold the Throttle plate at WOT
And turn the TPS until you get 4.5V on the multi meter
Then tighten it back down
Re-check the setting haven't changed after tightening the TPS.
After you have done that, check the voltage at CT (Closed Throttle).This is where the TS screw (Throttle stop) will need to be adjusted to set the CT Voltage.
If you have a value greater than 0.48V, you will need to wind the TS screw out to open/increase the voltage range. If it's less, wind it in/up to close the gap/range.
Throttle Stop screw on the d16y4, from behind
Adjust it like this with an Allen key:
Firstly you will need to undo the nut on there to be able to turn the screw. Make sure the nut is tightened up when you set the values.
Undo/tighten the TS screw until you get a 0.48V Value for CT.
TIP: When you tighten the nut up with the ratchet, the voltage will increase slightly by 0.01V-0.02V.So, adjust the TS screw with the allen key to 0.46V-0.47V value and tighten the nut up good with your ratchet. This way you will get the required 0.48V and a tight nut on the TS screw!
Now, re-check the WOT value. I bet it has moved? It maybe at 4.52 for example. So CT is at 0.48 and WOT at 4.52,so the range is 0.02 too much. So we need to close the range in by 0.02.Do this via the TS screw. Turn it up to 0.50.Then set WOT again at 4.5V by turning the TPS until you see this value, tighten it back down. CT should now be 0.48V and WOT at 4.5V.
Note: If your car is an automatic and you cant get both value's, your gearbox cable maybe too tight and restricting movement, like mine was. I could get 0.48V but Wide Open Throttle was 4.33V.I loosened off the gearbox cable and I could get 0.48V and 4.5V easily. The cable was restricting movement.
You will need to loosen off the cable to free up some movement, it's the same set up as the accelerator cable:
If your automatic 'kicks' into gear, like too much then your gearbox cable is too tight, Loosen it off.
Also, be wary your carpet under the accelerator pedal may be restricting the pedal and may need to be removed like mine did to get a better pedal.
If U get WOT,4.5V and can only get say 0.52V for CT. This means U need to increase the range at which the throttle plate moves by 0.04V.To do this U can simply file a small amount off the throttle rotor, like this:
Then set the WOT again first, then the CT, done!
After your done, set the idle via the idle air adjust screw.
Make sure the car is fully warmed up and simply turn the screw until the idle is where you want it.For a manual car, set the idle when the car is in neutral and for a automatic car, set the idle with the car in 'D'. It's 'D' that you will be sitting in at lights, so that's where you want to set it, not Park, 'P'.
When you reset the ECU it will even the idle out.
Now we need to check that the values are the same at the ECU end. This will ensure the wires are fine and the ECU is seeing the same readings.
Remove the kick panel at the passengers feet to expose the ECU and wiring,1 clip and a bolt (How cool is the big march fly in the shot!):
Don't stab and ruin the wires like I did, stick the pins up into the connector, like this:
Wide Open Throttle (WOT):
Probe the Yellow and green wires to verify that you have 5v going to the TPS.
Check the reading starts at 0.48V and smoothly increase to 4.5V, showing you have nice smooth throttle increase/decrease coming from the TPS to the ECU. This will verify the wiring between the TPS and ECU is fine.
After you have completed that RESET THE ECU and bleed the air from your coolant lines. This can be done by parking your car on a hill so that the engine is the high point, this will allow the air to escape easier. Start the car up, pop the hood and undo the radiator cap, take it right off so you can watch the air escaping. Just let it idle for a few minutes (at least the fan comes on twice). Give the coolant hoses a squeeze to help the air escape.
Your car will run better with no air in the coolant system.
NOTE: If U experience a high idle that goes up to 2,000rpm and then drops off and keeps repeating this ,chances are the Throttle plate is a bit open and needs closing. First try screwing in the idle/air screw on the top, if that dosen't do the job, probably won't, you will need to screw the TS screw out to close the throttle plate. The CT voltage will read 0.44V or so when the idle stabilizes but don't worry it shouldn't affect the performance of the car as I am learning).