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Hot engine won't start


zigen9

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I have a question about my Nissan rb25det.  It starts good when the engine is cold. But when the engine is hot. It cranks but won't start. Here is what I've done so far.

 

-I have changed all my spark plugs.still no help.

 

-When my engine is cold, I turn my key I can hear the pump is on (because there is a noise from the fuel pump)even I switch my fan on to level 3 I can still hear the noise from the pump. 

 

-When hot engine, car is off. I've tried to turn my car on. I can hear the pump if my fan is off or in level 1. If I turn my fan on to level 3 and then turn on my car, then I cannot hear the pump. I have to turn the fan off and then try to crank my car. But still it won't start when engine is hot.

 

- Put starting fluid in to intake manifold. success. it starts when Hot!!. But if I turn off the engine and try again. It won't.  I have to put starting fluid again. I don't want to try too many times with this starting fluid. Because it's harmful to my engine.

 

My conclusion is the fuel pump might be bad, fuel filter maybe?.  Any other method to do more diagnosis.  I really want to fix this part, and I fixed all mechanical of the ride. 

 

 

Please let me know, if there are any solution. Would be much appreciated. 

 

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I have a feeling is the fuel pump. It's the MSD 2225. I believe it was changed probably 2.5-3 years ago. Yes it's wired with relay, but the that hot wire for the fuel pump does underneath the car (the guy who did the swap, put this hot wire underneath, which it needs to be re-wired). Do you think that will be a problem of the wiring?

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You could try swaping the relay out for a new one. I would just make sure the wire is fused so it it grounds out it pops a fuse first. I would prefer the wire be inside for as long as it could be but, no huge issue. 

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The fuel should recirculate and maintain an ambiant temperature because it recirculates back to the tank and cools.  It will have a rise in temperature as it approaches the heated fuel rail of a hot engine but it is moving at such a high velocity it should not rise too high.  A faulty or cavetating pump will also cause an abnormal fuel temp rise.  Also the act of the pump compressing will rise fuel temp but under normal operation not to the point of vaporazation.  

 

The reason I suggested a pressure guage is that when I was having motor issues it provided instant feedback as to what was going on with the fuel system.  I had issues with the tank pickup, the lift pump, multiple clogged fuel filters and the surge tank.  These issues were more quickly isolated because as I saw a rise to high RPM the fuel pressure would drop off to nothing and the motor would fall on its face.

Edited by dwarlick
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Thanks for the advise dwarlick. I brought a jaguar bosch external pump, one part I'm not to sure is which side is the fuel tank hose. Let me attach a picture of the pump. I'll look into the fuel pressure guage also. I don't think is too hard to install it correct??

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