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Discussion Starter #22
Gotta ask- did you replace the fuel pressure regulator (pictured above) that holds line pressure for quick starts?
I have looked online checked the Haynes Repair Manual and nowhere in the fuel system is there a FPR like the one you posted the only regulator in the system in my 2006 is in the fuel pump assembly.

If you could posted a picture of it/it's location on your car I will be more than willing to replace mine too lol I have almost replaced everything else at this point haha I appreciate al the time you have taken to help me out. But seriously if you can tell me exactly where that FPR is, ill give it a shot.
 

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OK- here's the FPR in my '03 track model. It's on the PS of the engine bay, next to the plenum with the battery to the left.
53315
 

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Discussion Starter #24 (Edited)
OK- here's the FPR in my '03 track model. It's on the PS of the engine bay, next to the plenum with the battery to the left.
View attachment 53315
ok so I did replace that as a damper or at least that's what i was told it was buy the parts store.

I did a fuel pressure test and it came back 51 psi with key in on position and 64ish while running both numbers stayed consistent thru never lost pressure.
 

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Discussion Starter #26
What was the fuel pressure reading after the engine was switched off?
I have a fuel pressure gauge on the motor now and its showing me 40-42 psi when I put the key in the on position.
While running it sits at 63psi and when I shut it off it sits at about 40-42psi.
 

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40-42 PSI is low for resting line pressure on a VQ35DE. 50-52 PSI usually guarantees a quick start, but you're building line pressure by starting the car several times. Since you've measured it a few times and not found any leakage, I suspect your fuel pump is defective. How many miles are on this Z?
 

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Discussion Starter #28
40-42 PSI is low for resting line pressure on a VQ35DE. 50-52 PSI usually guarantees a quick start, but you're building line pressure by starting the car several times. Since you've measured it a few times and not found any leakage, I suspect your fuel pump is defective. How many miles are on this Z?
I just replaced the fuel pump with a DW aftermarket pump and my Z currently has 47200 miles on it.

While cranking it isn't building pressure either like I thought it would just keeps at 42psi while the pump is priming it does go to 53psi but once it stops priming it dumps back down to 42psi
 

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Discussion Starter #29
FIXED I THINK!

So i was reading up on other post on the site and came across someone having the same issue. Someone suggested to do a key reset where i turn the key to the on position for 5 sec and the off for 10 sec and start the car. the car is going an hour now starting with no issues at all and on the first try every time.

I will be driving it tomorrow for about an hour to see if it sticks and the issue is solved so she can stay on the road.

Let you guys know tomorrow!
 

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So, the starting delay was caused by an electronic glitch? Have you changed keys at some point?
 

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Discussion Starter #32
Drove car this morning for about 35 minutes got home and had to do the key reset again but she starts every time at this point. I cleaned the throttle body and now it seems like I have to give a very small amount to start the car after it warms up but like I said I can actually drive it again!

I'll probably reconfigure the Throttle with the repair manual reset, maybe that will fix the need for throttle to start but overall, she's back!

Thanks to all you guys and especially dkmura. your the real mvp!
 

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You're welcome, but I remain puzzled by the fix on this problem. If these are the original keys, why would a key reset be needed?
 

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Discussion Starter #34
You're welcome, but I remain puzzled by the fix on this problem. If these are the original keys, why would a key reset be needed?
Short lived lol the car after being driven for about 2 hours decided to not want to start at all after it warmed up. waited til this morning and it took about 8 turns before it finally started. Im honestly puzzled at this point. Someone suggested to replaced the fuel pump assembly as it has a regulator that is known to go bad. In other words the pump works but it doesn't hold pressure in the line and after it works for a while (gets hot) it quits working properly making it hard to build any pressure and start the car.... IDK where to go from here.
 

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I think you should change out the throttle body. Probably will be the best $150 you ever spent.


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Discussion Starter #36
I think you should change out the throttle body. Probably will be the best $150 you ever spent.


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i have an extra upper intake plenum that still has the throttle body from a g35 with a DE in it, it should work right?
 

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Discussion Starter #38
Well I have swapped out the throttle body and still having the same issue. Im going to have to change the cam sensors again, they guy who sold them to me let me know a few days ago that he has had them in his tool box for over 5 years so it might be possible that they are actually bad. they seem to work when cool but once they do some work/reading and heat up they fail.
Really not too much left to change here im figuring either the sensors, FPR, or ECU at this point.

Anybody want to share an issue similar to mine that got it solved please lmk what you did cause im bummed out at this point. Havent been able to take my car out and enjoy it in months now.
 

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Based on my previous problems, I would check coil packs next. Perhaps they’re getting hot and failing on the restart. Perhaps you can just ohm them out before and after. Stick with the basics of air, fuel, and ignition. Good luck!


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Discussion Starter #40
Well today i replaced the cam sensors with new oem ones. still having the same issue tho. I did notice that if the car is running and I turn it off and immediately turn the key to start it, it starts everything. but if i wait more than 5-10 sec its take 5-7 trys to start again.

So my question is, does that sound like a fuel related issue? I changed all my coil packs my maf is new and works perfect, everything is showing signs of fuel being the issue. on crank my fuel pressure is only about 44-50psi while running it sits great at 62-64psi.
 
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