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Cold start idle rpm's?

5825 Views 9 Replies 3 Participants Last post by  dmxsoulja3
In all of my previous cars you would crank them and it would sit at say 1800, solid. then down to 1500, then 1000, then to its final idle point, but at each point it would stay a solid rev.

With my tC when I first start it in the mornings, it kind of bounces from 1k to 1800, until it warms up, never really staying at one place. Is this typical, does everyone else see this as well? I basically start up, it starts at 2k, bounces down to about 1200 then a quick bounce close to 2k, then it is less of a bounce to any one rpm. finally resting at about 750 rpms once it makes to to the first 1/4 mark on the temp gauge. Am I going crazy or does your tC do this as well.


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It's typical, and I still haven't heard a good argument for why this is.
I recently added the K&N Cold air intake system without many ill nor improving effects to this idle situation, however, should I reset the ecu now, and what is the procedure, warm engine, idle for 15 mins with no loads? Obviously it did this stock and with the aftermarket system as well, but this is my first obd-II car.
Page 05-45 Volume 1 FSM:

3. CLEAR DTC (Without using a hand-held tester or OBDII scan tool)

(a) Perform either one of the following operations.

(1) Disconnect the negative battery cable for more than 1 minute.

(2) Remove the EFI and ETCS fuses from the Relay Block (R/B) located inside the engine compartment for more than 1 minute.

NOTICE: When disconnecting the battery cable, perform the INITIALIZE procedure (see page 05-1).
is the initialize procedure that which requires one to reset all the windows and such or is their something else they are hinting towards?

Thanks for the reply.

Also since I'm still in my break in period should I wait to reset it, obviously its only had about 500 miles worth of driving so far. I put the intake on but continue to drive it like a grandma
just a more pronounced whistle, a few times I heard that classic intake drone at about 3k, then it was on to the next gear. Again thanks for the help look forward to your response
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i believe you should wait to reset
Resetting is usually a good idea after any mod. It lets the engine start at factory base numbers and then it learns from there. Once you've given it a few key cycles to relearn what normal is, it's a good idea to use a scan tool and check for codes and any other information your tool provides. On the OBDI ECMs you check the Vf voltage to see how much the ECM trimmed your fuel to bring it into "normal". Some of the OBDII ECMs also have a Vf terminal, but I haven't looked on the tC. Then you've got some idea what really happened when you did the mod.
Thanks for the replies guys, I'm going out of town for 4 days, when I get back I will reset it and report back. Is it typical to do it cold or warm? I was thinking it would be best to learn how it is driven, obviously it starts cold first
Am I correct or should the car be warm when doing this whole reset procedure?

Thanks, Josh
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It doesn't matter. The ECM is smarter than you might like to think.
good glad to hear it, I will try it when I get back from vegas and let you guys know how it went.

Thanks, Josh
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