QuestionQUESTION: I have a 2000 S10, 2.2.L with 104,000 miles. Truck starts fine when completely cold or hot, but cranks for seconds before starting during the time engine is cooling down. Recently replaced spark plugs (not wires), have tried turning key to allow fuel pump to pressurize, before cranking and no check engine light is on. Could it be coolant temp sensor, or some other sensor?
ANSWER: Offhand it would be hard to diagnose this problem without looking at the vehicle. I haven't ever seen this complaint on this vehicle before.
You have not stated how many seconds the engine cranks before starting.
I would check fuel pressure when problem acts up.
Possibly one or more of the fuel injectors may be leaking fuel while the vehicle is sitting causing extended crank time.
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QUESTION: If one or more injectors were leaking, wouldn't turning the key to the last position before starting, then wait a few seconds for prime solve the problem? I have tried that and it doesn't help. During the engine cool down phase, it can take 2 to 5 seconds of cranking before it starts. Remember that when truck has cooled off over night, the truck will start instantly.
ANSWER: I mean fuel injectors are dripping into cylinders causing too much fuel when starting...flooding the engine.
When trying to start the vehicle hold the gas pedal to the floor. This puts the system in Clear Flood Mode reducing the amount of fuel delivered to the injectors. If it starts better when doing this the engine may be getting flooded by one or more leaking injectors.
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QUESTION: I have tried holding the gas pedal to the floor when starting during cool down phase, and while the engine didn't start instantly it started much quicker (almost instantly). Does this support your theory that 1 or more injectors are leaking? I also got engine up to operating temperature, turned off engine and relieved fuel pressure via inline valve, tried starting 1 hr later and engine fired right up.
AnswerI believe you have narrowed it down. When relieving the fuel pressure the injectors will not drip in to the cylinders. You stated that the engine does start better in clear flood mode and when relieving the pressure.
The only way to know for sure is to pull the fuel rail & injectors off the manifold, pressurize the system and keep watching.
Before doing that take a good look at the fuel pressure regulator. Pull of the vacuum hose and inspect it for signs of gas. It could be leaking through the pressure regulator into the vacuum circuit too.
