AzurePearlTC

When I start up my TC for the first time each day, I let it idle for a few minutes and let the RPMS settle down before I drive, but the RPMS don't go steady. The pointer moves up and down every split second at a particular RPM, and I don't even have the AC on. It surges up then drops down, surges, drops down, and then the pointer keeps jumping.

But after I do a little driving, turn off the car and turn it back on after a while, I let it idle and it doesn't surge anymore and stays steady.

Is this normal for a brand new car, particulalry the TC, to act this way?

xnevergiveinx

yep, thats how it is...do a search and you'll find numerous threads about this.

if it's really bad, bring it to the dealer

Casus_Belli

If your check engine light isn't comming on, then I'd say it's normal. But I haven't tested under those conditions. That is, I start the thing and go. Especially in the summer; no use waisting gas.

There are a number of sensors that control the accelerated warm-up on most cars. Engine temp, air temp. throttle position, O2, etc. I haven't gotten a shop manual yet, so I don't know which come into play on the tC - or which will throw an error code if faulty. However, I have seen an RX-7 that acted that way; and, it was producing an engine temp sensor error code, which turned out to be the fix. Computer thought the engine was colder than it was, added fuel, then O2 said enough already, and so on.

OK - I just checked mine and it does hunt a little during AW. But that's normal. The O2 needs a while to heat up to operating temp. So the computer has no idea what the A/F ratio is.

BTW, you aren't pressing the gas when you start, are you? That will mess up a fuel injected car's warm up. Let the computer control the fuel.

Bottom line is to learn not to sweat the small stuff. Unless it's really racing or wants to stall, then you're better off not staring at the tach.

JasonH

A) You don't need to "let the RPMs settle down" before you drive. In the time it takes you to buckle your seatbelt, check your mirrors, etc. it's ready to go (say 30-60 sec.) The car is made to warm up as you drive, even if it's numbingly cold out.

B) All the sensors (O2, airflow, numerous temperature sensors) report back to the ECU which determines how much fuel and air to give the engine. This happens whether the engine is warm or cold, so it's not uncommon for the engine to vary its RPM even when it's fully warm in neutral with no drag on the engine. The effect is magnified when the engine is cold, so what you're reporting doesn't surprise me. Welcome to the world ort modern car engines!

C) If you don't have a check engine light, it's probably a non-issue.

AzurePearlTC

No check engine light and I don't press on the gas pedal. I guess there's no problem and I shouldn't sweat it. Thanks for the feedback.

bubblemyster

not sure but my idle was fixed after a grounding wire install.

heyitznosaj

the idle in my tC seems to be lower than most cars which is about 850rpm. The tC is at 500rpm and the idle is very rough. It is also very loud when idling especially for a car that uses a camry engine.

rabberflatch

is it better to have a lower idle speed? my engine idle's around 600 rpm. whats urs usually? i think i wud want mine to idle around 850, i would probably have less of a chance at lugging my engine at 1st gear.

emiller

My car does this too. No CEL and doesnt drive any different so its probably just the car warming up and no big deal. You can adjust the idle and if its rough it might be a little low but every engine is slightly different. My old Saturn was about 500 but smooth. Just slow it down to its rough then speed it back up a little and its good.

rabberflatch

really? are u sure you can adjust the idle?

emiller

never looked on this car but you could somewhere on older cars.

jct

i think the idle is on the ecu i could be wrong

emiller

electronics suck. just more things you cant do yourself or need special tools for.

Rivulent

Yeah, everything is controlled via ecu so don't expect to be able to change it yourself with a reader/flasher.

My ground wiring kit seemed to help idling a good bit. It fluctuates < 100 rpms now in either direction now, I believe before it was a 200-300 rpm change. That review I promised is coming, about to get the real proof of the grounding kits worth tomorrow.

SassyScion

500 RPM is too low. I think the tC's idle is supposed to be at 750 RPM.

ScionTCizzle

lol im laughing at this whole thread because the idle problem has been the only headache since i picked up my car in early october of last year. My idle completely sucks when i am driving and rolling though. i took it to the dealership and they tell me they cant duplicate the issue! i dont know if anyone has the problem i have but everytime i put the clutch in when i am rolling the rpms drop lower then idle and then surge up as if the car was trying to not shut off. i dont knwo why it doesw this even though the car runs like a champ in ever other category