Thread: O2 sensor
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Old 02-03-2003, 11:28 PM
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islandbrew islandbrew is offline
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Join Date: Jan 2003
Posts: 5
hot start problem

Thanks for your response to my question and sorry I'm late with my appreciation. I've spent the last month obtaining the CD Rom for my car and teaching myself about the fuel delivery system. What you say makes a lot more sense now. I've read through the fuel pressure check procedures. If I have it right, fuel pressure is maintained for about 30 minutes after engine is stopped at operating temperature thereby facilitating hot starts. I understand you to say that fuel is leaking back (pressure drops) during that period and a subsequent hot start requires the fuel pressure to be pumped back up during cranking (since that's when the fuel pump is activated). I guess this would this explain why I have to keep the starter motor engaged for so long, so the fuel is repressurized? I performed a hot start test and learned that the engine will start immediately within 5 minutes after the engine is stopped (at operating temp.), starts within 5 seconds of cranking after being stopped for 10 minutes, starts within 10 seconds of cranking after being stopped for 15 minutes, and starts within 15 seconds of cranking after being stopped for 20 minutes. To me this indicates the slow leak down of pressure over time as you mentioned. Knowing this additional info, can you further isolate/suggest the probable cause of the hot start problem? I understand the cold start hesitation problem is separate and I see where your suggestion that the warm-up compensator is the likely culprit. At this point, I only know and understand enough to be DANGEROUS !! I intend to have a mechanic look at the car but I would like to be educated enough to discuss the problem with him somewhat intelligently and be able to give him useful info to troubleshoot the problem effectively. I'll look you up next time I'm in Gainsville to repay your good karma and if you ever make it to Key West, please email me for a return favor. Thanks for the help. You're aces up.
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