car wont start when hot

[dumbo]

Oh my....

No doubt.


A simple check for the FPU VSV, simply disconnect the vac line to your FPR and see if it makes a difference in hot starts, in you situation, i bet not.

Is your ECU a JDM ECU? And you let some coumputer store replace a resistor with some random one, your KIDDING ME right, ecu's work on like milli volts!!
You know what controls your fuel pressure, your fuel pressure regulator.


Reset your ecu, pull efi fuse for a min, check your codes again.


Is that fuel pressure reading with the vac line hooked up or not?

Everything you checked was it per TSRM?? AFM,ISC,TPS,COILS,CPS

ohh...have you done a compression test..?


Good Luck man

 

[SupaMan]

dude FPU VSV, mines being fussy off and on right now if the car heat soaks for a lil bit on a hot day itll idle like shit for a couple minutes and then be fine.

does it once in a blue moon.

 

[dumbo]

dude FPU VSV, mines being fussy off and on right now if the car heat soaks for a lil bit on a hot day itll idle like shit for a couple minutes and then be fine.

does it once in a blue moon.

I may be wrong but I think that VSV only ups fuel fressure for intial start up, then lets vacum act on the FPR again, I doubt thats your problem. And like I said, if you wanna test it simply unhook the vac line to your FPR and see if it changes your start.

 

[carfanatic89]

I thought of the fpr as well, I had another fuel rail laying around so I took the regulator off that one and tried it. Nothing, didn't change anything what so ever. I still wont hot start. I Checked the vacuum to it and it loses vacuum when I rev the motor, to up the pressure. I've unplugged the vacuum and drove around and it didn't make a difference. The fuel pump is a year and 1/2 old. and the fuel filter was replaced 6 months ago.

The only thing that will change how the car runs is if I play with the TPS but it doesnt help b/c Ill set it drive around come back and it will run just like it did before I messed with it. When I park the car I will try to Idle at 500 then start loping and die. Im gonna get my video camera out 2morrow and let yall see what im talking about.

 

[dumbo]

I thought of the fpr as well, I had another fuel rail laying around so I took the regulator off that one and tried it. Nothing, didn't change anything what so ever. I still wont hot start. I Checked the vacuum to it and it loses vacuum when I rev the motor, to up the pressure. I've unplugged the vacuum and drove around and it didn't make a difference. The fuel pump is a year and 1/2 old. and the fuel filter was replaced 6 months ago.

THATS SUPPOSE TO HAPPEN. That VSV vents your regulator to atmosphere on starting, allowing atmosphere 14.7PSI to act on it instead of vacum.

 

[carfanatic89]

Yeah I know I was just stating it was doing what its suppose, to do ruling out the vsv/vacuum as a part of the problem.

 

[SupaMan]

I may be wrong but I think that VSV only ups fuel fressure for intial start up, then lets vacum act on the FPR again, I doubt thats your problem. And like I said, if you wanna test it simply unhook the vac line to your FPR and see if it changes your start.

Sorry i guess i didnt add that mine only does it on start up.

itd be easy to test that if it did it all the time, it only does it every once in awhile randomly.

i was told by either jet jock or IJ cant remember which that the FPU VSV was the problem.

 

[amichie]

I chased this problem around for years and did all of the above.

One day I had to change the airflow meter for another reason and to my surprise my hot start problems were gone.

I think it must be the little fuel pump switch in the airflow meter stuffing up when hot.

My 2 bobs worth anyway.

 

[carfanatic89]

Thank yall for your input. My video camera broke so I cant video it. But I took it to the shop 2day and they told me they would look at it and get back at me in about 2-3 days so when I know something I will post it.

 

[carfanatic89]

Few months later ITS FIXED. The fuel pump was going out. The guy that put on a new fuel pump before I got it just cut the old wires in the tank and crimped new ones on and everything work for awhile, but the rivet that holds the wire to the fuel pump holder was loose and was causing the fuel pump to cut on and off at random times.

Which made the pump finally die at the shop, and thats how they finally found it because the first time he checked the fuel pump was working and had plenty of pressure. Well It finally died, they replaced it with all new rivets, and got it going for me.

The best part is shes FAST as hell. lol Ive already smoked a stock 5.0 mustang, and both of my buddies slightly modified tiberons, a v6 and a 4 cylinder. Thanks to all for your input. I really should have found this earlier:3d_frown:, but oh well. Im just glad I can drive to the store and back without it dieing and maybe smoking some cars on the way. I :love: my supra