Mechanics

WARM START HESITATION

Toyota Camry

My 1993 Camry V6 3.0L, 205,000 km is having difficulty starting after being fully warmed-up. When I try to re-start the engine after it is warmed up there is starting hesitation and it sounds like the cylinders are firing sporadically as the engine stutters until it fires strongly after repeated engine turning/attempts. Cold starts work perfectly and the car never has problems with idling or stalling (engine & car as whole runs like new otherwise). It starts NORMALLY up to ~30 min after sitting warm, then begins to stutter when a start is attempted and the hesitation reaches its worst point at about 2 hours. After 4 (now cold) it starts again perfectly. I have recently done a fuel injector flush, replaced the plugs (NGK iridium), dist. Cap & rotor, ignition coil and cleaned the throttle body & IAC valve which improved cold starts, but the warm start problem continues. My fuel & air filter and battery are relatively new. I am trying to find the source of this problem but it will cost me plenty to replace unnecessary parts. Could you please give any Recommendations? Thanks!
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Ultros
March 30, 2007.




When you say you have trouble starting the car when warm I'am assumming the car cranks over normally. If this is the case the first thing that comes to mind is the engine coolant sensor since the car starts fine when the the car is cold. This sensor regulates the air/fuel mixture in relationship to the engines temperature. More fuel when the car is cold and less when the car is hot. Because an ignition problem could give similar symptoms, (defective electronic equipment is effected by heat) you can test the sensor with a ohm meter. Disconnect the sensor and make the reading across the sensor. With the engine at normal operating temp you should have.02 -.06 ohms. With the engine cold 1000-2000 ohms If out of specs the sensor is probably bad. Good luck

Tiny
Backyardmechanic
Apr 11, 2007.


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