88 Ciera Strange Starting Problem

[phillyeve]

If I attempt to start the car, it cranks without starting. If I turn the key to the "on " position only, without cranking it, and leave it in the "on" position for around 5 or 10 seconds, and then crank it, it turns right over. This happens everytime I try to start it. Whether the engine is cold or warm. Been to numerous mechanics and nobody can diagnose it. Thanks

[Ian Szgatti]

One possibility would be a thermotime switch for the cold start injector, or a cold start valve, coupled with an innacurate coolant temp sensor... The thermo-time switch consists of a contact to ground for the cold start valve and a bimetallic strip surrounded by a heater winding. When the engine is cold and the key is turned to "start," the bimetallic strip contacts the ground contact and allows the cold start injector to inject fuel. When the key is turned to "on," that powers the heating element inside the thermo-time switch. As the heater warms the bimetallic strip, it eventually bends away and stops grounding the cold start valve.
This all happens in 10 seconds or less. This is to keep the cold start valve from injecting too much fuel and flooding the engine. So if the engine doesn't start within the 10 seconds, the thermo-time switch will shut off the cold start valve to keep the engine from flooding for future starting attempts. When the engine is already hot, the contact in the thermo-time switch is open, preventing the cold start valve from operating. A stuck closed thermo-time switch could allow the cold start valve to operate too long during starting, causing engine flooding (but regardless, the cold start valve will still only operate when the starter is operating). If the thermo-time switch sticks open, it could keep the cold start valve from operating and cause hard cold starting.
The thermo-time switch can be tested electrically. The temperature at which the switch activates is stamped on the switch housing. You can install a test lamp in series with the wire to the thermo-time switch, disable the ignition, and crank the starter. The lamp should light but then go out in a few seconds of cranking.
Can you tell us what tests these shops have performed? It would really help myself or others give you some answers.

[maxwedge]

Originally Posted by phillyeve

If I attempt to start the car, it cranks without starting. If I turn the key to the "on " position only, without cranking it, and leave it in the "on" position for around 5 or 10 seconds, and then crank it, it turns right over. This happens everytime I try to start it. Whether the engine is cold or warm. Been to numerous mechanics and nobody can diagnose it. Thanks

Welcome to AF. You should have the fuel pressure checked under the no start conditions to start the diagnostic process, , also post the engine and mileage and related service history, in the future.