Hi I am new here!
I have a big problem with my Volvo s40 2001 so when I start it and it's cold then need long time to start but when it's hot everything is fine! I recently replace new battery and also fuel pump. I clean injections fuel pressure regulators and throttle. Nobody can't find what's wrong with this and I am asking for some help if someone has the same problem!

 

did you replace the fuel pressure regulator - the part that sits on the end of the fuel rail? Long cranking when cold suggests either an issue with the idle air valve (works as a choke) or the fuel pressure regulator (pressure is slowly bleeding off when the engine is off leading to low pressure at start up) or a fuel pump issue (not enough pressure). I had long cranking on my '00 (like 30 or more seconds) at cold start and replaced the pressure regulator (Volvo PN 8658092) which cured my car.

 

I have replace only the fuel pump sometimes cracking long 15 seconds and sometimes more that 30 I think that it's fuel pressure regulator but as my mechanic check that he told me that it's seems to work well!!

 

Take out the idle control valve and try cleaning it with brake cleaner. Let it dry off then reinstall. Worst case you've wasted 15 minutes. Best case it solves your issue altogether.

 

I clean it all yesterday but it doing the same !

 

the FPR has a diaphram in it that can tear - not sure how your mechanic determined its working fine. Bad news is the FPR is expensive ($200+). good news is that you can install in about 15 minutes (two torx screws and you need a pick/flat blade to pop off the fuel line fitting. plyers help with the on/off of the vacuum line).

 

Yes i already know that is expensive that'swhy i want to know if it is the fault and car needs more time on cold start. I don't know what can i do now. I know how to change it but i need to be sure causing that the problem!

 

try this... start the car to get the fuel pressure back up. turn off the car and pull off the S shaped vacuum line to the regulator to see if you see any fuel weeping out of the vacuum line.

 

I start the car and then I turn it off after this I pull off th S and the regulator was leaking gas so I need to replace it?

 

Yes. That vacuum hose should never ever have fuel in it.