difficult to restart after engine is warm and 40 minutes elapses


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Old 03-01-14, 11:38 AM
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difficult to restart after engine is warm and 40 minutes elapses

My 1996 Toyota Tacoma, 3.4l engine, does not want to restart after the truck has been driven for several miles, then allowed to sit for 40 or so minutes. It cold starts fine, it restarts fine, if just a few minutes have past, but not if allowed to sit for awhile before the engine cools. The repair shops have done diagnostics, replaced the ox sensor, idle control, etc. etc. and tell me they can't duplicate the problem after $600. I can, every time I reclaim the vehicle and drive it myself. I'm just wondering if its a component that is getting hot and affecting resistance or something?. I don't think its a loss of fuel pressure since it starts every time when the engine is cold. The symptoms are that it cranks and cranks and almost starts then seems to start just as I'm letting off on the starter. I've tried no gas pedal, pumping the gas pedal, flooring the gas pedal. I'm afraid I'm going to burn up my starter, or wear down my battery and get stranded in the middle of nowhere. I've had the truck for 13 years and this problem is something new. Anyone have any thoughts?
 
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Old 03-03-14, 06:21 AM
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a coolant temperature sensor out of range could cause problems like this.check for spark next time it happens.
 
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Old 03-09-14, 05:39 PM
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What I have run into in past is an injector(s) leaking down and flooding . Leaking down at night for example, will evaporate some, but also supply needed rich mixture for cold start, so doesn't create start problem. Have that same thing happen to a hot or warmed up engine and you get a flooded condition, hard start. Have you pulled the plugs when no start condition occurs to inspect for wet condition from excess fuel? The other thing I would try is connecting a fuel pressure gauge and leave it attached for a while to see if pressure drops at all. Probably best to attach after a good run, warmed up and then shut off where no start would happen normally and see what happens to pressure.
 
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Old 03-10-14, 04:45 AM
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You said "shops" - plural - more than one shop has had a go at it and can't dupe the problem? If you can make it do it consistently I would say find another shop and drive it until you know it'll act up when you pull into there parking lot. From your description it sounds as though they are merely throwing parts at it rather than any deep troubleshooting/diagnostics. I second autojoe's suggestion to check for spark when it won't start. That at least would give you a possible starting point

Quick guess would be that you were on to the right track when you suggested an electronic component getting hot; that's not an uncommon situation for a crank/no-start condition.
 
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Old 03-26-14, 05:52 AM
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I would check the fuel pressure regulator and the fuel pressure at the schrader valve on the fuel rail.
The fuel pressure regulator holds the fuel pressure up so when you restart the fuel is there ready for the next restart, especially when warm.
When the vehicle is off for "x" amount of time the fuel pressure regulator opens/releases the fuel pressure and the fuel is returned to the gas tank.
On a cold start the fuel pump ramps up the fuel pressure in the gas lines and the fuel rail and the computer tells the vehicle to go into "cold start mode", which is why it starts fine later.
I have had similar issues on two vehicles, one was the fuel pump one was the fuel pressure regulator.

Good luck
 
 

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