1994 Saturn SL1 Choke?

FLUF

MEMBER
1994 SATURN SL1
4 CYL
FWD
AUTOMATIC
10,000 MILES

What would cause my car to have a problem when it first starts cold? After it is warm it starts like it should. When the engine has been sitting and it is cold, it seems like it is over choked and floods very easily. I can't give no gas to start it or it will flood it. Even after it starts it runs very rough for about the first 15 to 30 seconds. Like it is to rich. It has a computer, so it is all electronic controlled, I don't see anyway to make any adjustments. I have no check engine light that comes on, to lead me to believe that it might be a sensor.
Once it is running for about a minute, it seems to run fine. It still is getting 20 to 22 mpg. I tried spraying choke cleaner around the intake to look for a manifold leak, to no evail. Looked for any kind of vacumn leaks on hoses, changed plugs, changed idle control selonoid.
I'm stumped, and can't afford the car dealer, any suggestions?

3 Replies

DAVE H

MECHANIC
13,384 POSTS

Hello .. thanks for the doantion .. much apreciated

FUEL CONTROL
The PCM, using input signals, determines adjustments to the air/fuel mixture in order to provide the optimum ratio for proper combustion under all operating conditions. One of 2 types of fuel control systems are used: throttle body injection or port fuel injection. These systems can operate in the "open loop" or "closed loop" mode. Description of these modes is as follows:
Open Loop
When engine is cold and engine speed is greater than 400 RPM, PCM operates in "open loop" mode. In "open loop", PCM calculates air/fuel ratio based upon coolant temperature and Manifold Absolute Pressure (MAP) or Mass Airflow (MAF) sensor readings. Engine will remain in "open loop" operation until oxygen sensor reaches operating temperature, coolant temperature reaches preset temperature and a specific period of time has elapsed after engine start-up.
Closed Loop
When oxygen sensor has reached operating temperature, coolant temperature has reached a preset temperature and a specific period of time has passed since engine start-up, PCM operates in "closed loop". In "closed loop", PCM controls air/fuel ratio based upon oxygen sensor signals (in addition to other input parameters) to maintain as close to a 14.7:1 air/fuel mixture as possible. If oxygen sensor cools off (due to excessive idling) or a fault occurs in the oxygen sensor circuit, vehicle will once again enter "open loop" mode.

Hope this helps
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