Trouble starting when hot

Adam Vinnicombe

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Hi all I’m back with another problem with the new edge. Now when the engine is cold she will start as soon as the key is turned and runs great BUT if I pull in to a petrol garage turn the engine off when up to operating temperature wait for a few minutes and try to restart her she has trouble starting. The engine turns over just fine and turns over just a little bit faster than what the starter can do so she is trying to start but just spins over a lot longer than it should do before she finally starts. It feels the same as if you was to turn over the engine with the plugs out. She drives good the compressions are all good on all eight cylinders (I have the readings some where but just not to hand at the moment)
What could be the problem?
Thanks for your help all
 

ttocs

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it makes me wonder if its as simple as my problem last year when the motor got hot the tps sensor would start to show it had 4-7% on it when I was out of the car. I replaced the sensor and when it got hot it did the same thing. I replaced the harness to the sensor and that fixed it. If your tps is starting to drift if it works like my holley does when it sees you are giving it gas while cranking it actually shuts the injectors off at some point thinking you are trying to clear a flooded car. Next time it will not start go under the hood and just give the harnesses a jiggle and then push all the harnesses you can see together and try to start it again.
 

Adam Vinnicombe

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it makes me wonder if its as simple as my problem last year when the motor got hot the tps sensor would start to show it had 4-7% on it when I was out of the car. I replaced the sensor and when it got hot it did the same thing. I replaced the harness to the sensor and that fixed it. If your tps is starting to drift if it works like my holley does when it sees you are giving it gas while cranking it actually shuts the injectors off at some point thinking you are trying to clear a flooded car. Next time it will not start go under the hood and just give the harnesses a jiggle and then push all the harnesses you can see together and try to start it again.
I will give that a go mate
 

Adam Vinnicombe

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Does pressing the gas pedal while cranking change anything?
Does pressing the gas pedal while cranking change anything?

As a matter of fact yes it does. While it is just cranking over (although it is spinning over slightly faster than normal) I found that if I was to depress the accelerator at this point she would start to cough and splutter and it felt like she was only firing on a few cylinders. Unfortunately I didn’t continue to allow her to run for long like this and shut her down
 

Adam Vinnicombe

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Right. First thing this morning on a cold engine I turn the key and hear the fuel pump priming for a second or two max, I then pushed the accelerator pedal down to the floor tried to start the engine but it would just crank over and wouldn’t start. Took my foot of the pedal and tried again and it started first time. Got the engine hot, pulled over and turned it off. I then waited a few minutes and tried to start it but no joy it just cranked over , pushed the pedal to the floor and tried again and I got the same response it wouldn’t start. Also when I turned the key when the engine was hot I couldn’t here the fuel pump priming at all. At around ten minutes with the engine off I turned the key again and still I didn’t hear the fuel pump priming but this time she started the second the key was turned but was running very lumpy and uneven for around five seconds before the engine settled down and was running smooth again. Done a 50 mile drive back without any issues at all.
Any more ideas on what the issue could be ?
I could not smell and fuel at all in the engine bay
 

96blak54

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Im sorry...i stated leaky injectors but didnt give an idea of leak location. They will leak off into the cylinder when rail pressure is high and engine is off
 

Adam Vinnicombe

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Ok I ha e found a way to get her started every time first time when she is hot. All I have to do is depress the accelerator down just an inch or two max then turn the key and she starts instantly. Know for this can anyone pin point more on what’s gone wrong?
 

Adam Vinnicombe

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Guess what the idle has started bouncing around between 500 to 1200 rpm. When I come to a stop the idea falls very low and the engine almost stalls then revs up high
 

ttocs

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could be the IAC, could be the harness going to it, or it could be a vac leak. Jiggle the harness, try some technical taps on the IAC and buy a cigar
 

Boostr1

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Sounds like the same issue I have. Once I get everything back together I'm gonna replace the IAC.
 

Adam Vinnicombe

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Just to update you on the issue I had on the mustang not starting when hot. It turned out it had nothing to do with the temperature of the engine in the end, it was the micro switch on the clutch pedal that was at fault. One of my friends dad cane up with the idea so I bypassed the clutch switch and now she starts first time every time
 

ttocs

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Just to update you on the issue I had on the mustang not starting when hot. It turned out it had nothing to do with the temperature of the engine in the end, it was the micro switch on the clutch pedal that was at fault. One of my friends dad cane up with the idea so I bypassed the clutch switch and now she starts first time every time
as long as you don't have a remote start installed you should be ok but it would still be a good idea to get that replaced before someone that doesn't know cranks it with it in gear.
 

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