Problem *cold start-ups*

[beyondpinoy]

hey guys i have a 1991 celica gt-s, and ive been having problems when i start my car.

this is what happends, when ever i start my car when it hasn't been running for a few hours (cold start), it starts fine, but for the first few mins, whenever i press on the gas, instead of rev'ing higher, like its suppose to, it revs lower to a point where the car stalls or shuts down.

*note this only happends on cold starts (when the engine has been off for about 4-6 hours or more*, not every time i start the car *

whats going on?

[westbeach]

Could be the automatic choke shutting it down.. ?? Not knowing do a search on google or something or look at a part source store where i used to work on their computers it will come up with " TSB's " ( technical service bullitens ) and it migth help ya out.. good luck.....

[BokCh0y]

i'm having similar problems with mr 91 MR2. I let the car sit like you said for 4-6 hours, go and start it....starts fine no problem but then when i go to drive it, it hesitates between 2000-3000 rpm. Once I get the revs up high then it's ok. After the car fully warms up the problem is gone.

I've already replaced the plugs, wires, distributor cap and rotor with no luck. Using Genuine Toyota Parts only as well. Another member here told me it cold be my O2 sensor....so that's the next thing to try on my list.

Have you replaced the plugs,wires, distributor cap and rotor as well? I noticed that once I changed those it did get a little better but then it went back to the hesitation.

[racin_jayson]

I had a similar problem on my old celica, I changed the MAF sensor and it went away

[beyondpinoy]

i think ima try replaceing plugs, wires, distributor caps too. i'll do that soon, and let you guys know how it goes

[kuks]

What spark plugs are you using ? Try to use the manufacturer specified plugs. Also try unplugging the MAF sensor and the coolant temp sensor - see if any of these help.

On the older cars a loss of fuel pressure through a worn fuel pressure regulator caused cold start hesitation also.

Good luck.

[BokCh0y]

Originally posted by racin_jayson
I had a similar problem on my old celica, I changed the MAF sensor and it went away

MAF sensor pretty pricey? Where is it located and how does it look?!?!?!?

[CelicaST-162]

check the MAF, TPS, Timing....

[beyondpinoy]

Originally posted by BokCh0y


MAF sensor pretty pricey? Where is it located and how does it look?!?!?!?

i wanna know too