Throttle Issue when cold: 00 civic auto

[Ryanabn82]

hello,
I own 00 automatic (for now) the AM and after work (cold starts) when I go into D or R or whatever the car moves by itself without throttle...I know its suppose to creep..but not move so fast it can shift into 2nd..??? hahah I was thinking throttle cable adjust? TB open? when it warms up everything seems ok...any ideas?

 

[daperez13]

Do you have a CEL?

Check TPS voltage. Unplug primary O2 sensor and see if that makes a difference.

 

[Ryanabn82]

In an automatic it shouldn't reach 20-25 just from releasing brake?

 

[Ryanabn82]

First pic is cold start idle...second was reverse with brake...could feel it wanting to move..

 

[Ryanabn82]

I guess what Im asking is why the car moves (faster than normal) when letting off the brake (auto) and when i hold the brake down i an feel the vehicle still wanting to move...CEL is for missing 02 sensor...4-1 header only had one opening

 

[XpL0d3r]

In an automatic it shouldn't reach 20-25 just from releasing brake?

It shouldn't be moving that fast though. Automatics don't hit 20mph without touching the gas.

Throttle plate might be sticking when it's cold.. pull the intake and look at the plate.. if it looks like it has a bunch of carbon deposits or is caked in black, especially around the edges of the plate, take off the entire TB and replace it.

You can also pull the intake, start the motor cold, and check to see if the throttle plate is open slightly.

Also, get an o2 sensor in there! Get a bung welded in by a shop. The o2 sensors won't affect cold engine idle though, as it will be open-loop (A/F ratio controlled only by ECU, not o2 sensor feedback) until the engine reaches normal operating temp.

 

[daperez13]

Cold engine - RPM's will be higher than normal, probably at or around 1,500-1600. Normal operating temperature - RPM's should probably be at or around 700-800.

When the engine is cold, you'll "feel" the car move (almost as if you were applying some gas) at the slightest release of the brakes. When the engine is warmed up to normal operating temperature, you'll still "feel" the car move but at a much slower pace.

You should fix that O2 sensor issue because it's affecting your performance and gas mileage. You should also check the ECU for any additional codes stored in it. Lastly, check your vacuum hoses, you may have a vacuum leak.

 

[daperez13]

Only if the code is for the primary O2 sensor.

The secondary O2 sensor is solely for emissions as opposed to fuel trim.

True, he didn't state which one was missing.

CEL is for missing 02 sensor...4-1 header only had one opening

Most headers will only have one O2 bung (primary), the secondary is normally on or close to the catalytic converter. Since he lives in CA, he should get it fixed either way.

 

[XpL0d3r]

Test your idea on a cold morning, if you own a similar Civic auto. You may get surprised.

I don't even own a Civic any more

But my Civic used to be automatic before I did an automatic to manual conversion on it. Never got up to 20mph without touching the gas. It would] go a bit quicker than the 3-5mph idle, but not almost road speed.

OP is also in bay area CA, where I guess it can get cold but definitely not like the lake effect or Berkshire snows / wind that we see up here. Unless he has an idle issue and it's idling very high, I would say 20mph without touching the gas is a bit fast (unless he is going down a hill lol)

The secondary O2 sensor is solely for emissions as opposed to fuel trim.

It also keeps the car in open-loop mode, I believe, essentially ignoring the primary o2 sensor and using fuel maps to control the A/F ratio. Likely close to what the sensors would read anyways, but OP may see some performance decreases or delays in performance in scenarios like going switching from driving downhill to immediately going uphill, etc. This may be negligible but, being in the bay area, OP may be affected more compared to those who drive mainly flat or small hills.