foreste1

Just some encouragement to anybody thinking about changing plugs. I recently changed plugs, replaced broken vacuum lines, cleaned throttle body, and replaced mass air flow sensor and just cant believe how much power I have now from a light!! I enjoyed my SC before, but now its even more fun to drive.
My car never kicked down like it does now and just winds out through the rpm's beautifully now!!
Word of advice, when you put the coil pack tube screws back in valve cover, barely turn by hand, and just tighten down slightly with socket, I broke one off in valve cover, what a mess on that.
Also pull battery cable for over 30 minutes and then reconnect so idle will adjust when done.
Also I cleaned my mass air flow and then car had a huge miss, and I tore apart 8-10 times looking to see if I missed something on a vac line and coil pack. I ended up replacing mass air flow sensor and the connector (rewired a new one on) and now its perfect. I dont think I will ever clean one again, just my input.
Good luck!!

alex2016g

Thanks for sharing. I changed my spark plugs last year and even that made a lot of difference.

Bgw70

Always snap pics with your phone as you go along and bag/tag all the bolts/screws from each area of the car.

Also, when disconnecting the battery for reset purposes, 30min is fine but 5min is sufficient to achieve the reset...

foreste1

On battery, I had first disconnected for only 5 minutes but idle was way high until I did it again for 30 minutes, not sure why the difference but it did make idle go back to normal.

Bgw70

that is an interesting result, I always thought five minutes should be enough. I wonder how the car could hold the voltage that long.
next time, after you disconnect the battery, turn the key to on position. That should get rid of any stored power in the system.

foreste1

Ok will do! I actually had the exact same issue with my GX last week and once I left off for 30 minutes the idle came back to normal. Getting ready to do my sons G35 coupe plugs and throttle body clean next, will see if it does same thing. I am on a spark plug replace kick.......

Bgw70

how about cleaning the fuel injectors!!!
i might do it again this weekend since it been well over a year!
i did my Trans Am injectors last weekend!
https://www.clublexus.com/forums/sc4...-on-sc430.html

Coleroad

Here, this is the relearn procedure. No need to wait to get it set, plus this will calibrate it to the current conditions. disconnect the battery. Remove the air inlet from the throttlebody. Push the throttle plate closed. Have someone else reconnect the battery while still pushing the throttle plate closed. Then have the other person put the key in the ignition and turn to the on position ( don't start) while you still held the throttle plate closed. Once the key is in the on position, reconnect the air inlet to the throttlebody (as soon as the key was turned on you can quit pushing the plate closed). Then start the car with everything turned off, radio, ac, lights. Let run for about 5 minutes at idle. Don't touch the accelerator. Shut the car off, you can restart and drive as normal.
__________________

Bgw70

Hey Cole, where did you pull this procedure?
service manual?

Coleroad

i don't remember, I used it on my sc430 after cleaning the throttle body to get the idle reset. Toyota has used this for awhile now on I know atleast several of its engines. It's just allows the ecm's to re acknowledge where closed throttle position is at. Atleast it isn't like Nissan has you do for the same thing. Wow, that one I have to have the instructions in front of me , because it has so much you have to do.

foreste1

Wow, wish I knew that a couple weeks back! So when you say close the throttle plate, it seems like it is closed normally and when you put a screw driver in to make it open up, that would be in open position, or is that closed you are talking about? Hope that makes sense

Bgw70

LoL, I just found the answer...see the following link for the relearn procedure!
https://www.clublexus.com/forums/sc4...procedure.html

Coleroad

it looks closed, but when you push it, It closes that last little bit.

Coleroad

[QUOTE=Bgw70;9876970]LoL, I just found the answer...see the following link for the relearn procedure!
https://www.clublexus.com/forums/sc4...procedure.html[/QUOTE

Sometimes when you manually open the throttle plate with the battery connected it reads where closed is wrongly. It thinks the plate is open more than it is. You could probably use the procedure you referenced, but this is a lot easier for this situation. The bottom screw for the tps sensor if I remember was a bit of a bear with the throttle body installed on the car. So in this situation you just need it to relearn closed position.

I had used this procedure when I had cleaned the plate. Later on when I changed the tps sensor, I used the procedure you referenced.

Bgw70

[QUOTE=Coleroad;9877267]i need to try out your procedure after I clean the throttle body and fuel injectors again!