# won't start when engine is hot



## cpparent (Apr 29, 2010)

HI I have a starting issue with my Ga16de B13 but only when its hot the car will start just fine when its cold and then as soon as the engine is hot as long as I dont stop the car its fine but if I turn it off and try to restart it is hard to start eventually I can get it to start. It crank strong so I dont think the starter is the issue, changed the O2 sensor cleaned out the idle air control valve and intake manifold changed fuel pump relay pulled out the codes from the ecu : code55 No errors. I am planning on changing the fuel filter and pressure regulator this weekend any other ideas? or people how had similar probles this use to happen with my honda accord but I can hear the fuel pump priming so I dont know what else to look at
thanks


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## PhantomSunny (Apr 22, 2007)

There is temperature sensor that the ECU uses to adjust air fuel mixture. It's just to the back right side of the engine just below the intake manifold near the water pump. On some of the cars there are actually 2 sensors one on the thermostat cover which controls the fans and the other sends the ECU signals. The one you probably need to change has a coloured square connector built right into the switch. That may be part of the problem.


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## Asleep (Jan 19, 2003)

why do people always take the starter into consideration when a car wont start but is cranking? always baffled me. of course its good - its cranking.
sounds like an ignition problem to me. ignition coils will do exactly this as theyre very temperature sensitive. do a resistance check on your ignition coil and see what you get.


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## cpparent (Apr 29, 2010)

update I have a strong feeling Asleep is leading me in the good direction changed out the temp sensor fuel filter and pressure regulator and cleaned out the distributor cap and rotor seems to be a little better it is still hard to start but it starts after 2 or three tries compared to 10 ish before thanks guy I have ordered the ignition coil therefore I will be changing that out shortly
cheers


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## krislou80 (Apr 6, 2010)

if it is a multipoint injection system (has multiple injectors instead of one) then the fuel rail is sitting just above the engine which would cause fuel to vaporize when engine is worm and fuel is not flowing (turned off)

to combat this the fuel pressure should stay at 1 to 2 bar (14 to 28psi) for at least half an hour after the engine is turned off

this is facilitated using a one way valve which is usually situated in the electric fuel pump and can be tested by rigging a pressure gauge to the fuel rail and turning the ignition on to prime it and then off to monitor the pressure drop.

if it is an older vehicle with carburetors we used to have a problem with the base of the carb distorting in the heat of a turned off engine (no air flow) which was rectified using a thick rubber base gasket 

______________________________________________________________
Actron ignition tester,can perform all types of electrical tests for your car.


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