[fchavez09]

Hi all i have been working on this issue for quite some time. I have a starting issue when the car is hot and in direct sunlight. As we all know the B15's have been plagued with a flawed fuel system. I have been doing some research and even took apart the fuel pump piece by piece to see where any issues could arise. Upon disassembling the fuel pump i noticed that Nissan integrated the fuel pressure regulator and the check valve into one unit. There is nothing "wrong" with this design but after age the spring that retains the digraph valve closed becomes weak and thus causes fuel pressure to leak when the car is off.

In most fuel injection applications there is a necessity to have existing fuel pressure to feed the injectors when starting so the fuel pump does not have to do all the work in filling the fuel line with gas. When the check valve is faulty fuel leaks out and replaces its volume with air. Air in an engine is like a stomach full of beer this can lead to starting issues upon your first crank of the engine.

I noticed that there was a post on the forum where someone put a check valve close to the injectors but there really i have not seen anyone say if it worked or not. So i decided to custom make a braided fuel line with an external check valve and place it closest to the fuel pump thinking it will allow more fuel to be pressurized in the line.

Below are some pictures of what i did...



The result from this repair made a small improvement in my particular case with the starting issues. Now with this device in place i can start ruling our issues in the fuel system. Putting a large check valve now rules out the fuel pump's check valve since it is isolated from the equation. The next step was to replace the fuel pump relay.

The fuel pump relay is activated by the ECM when the key is turned to ON for about 3 seconds to charge the fuel pump and then turns off. Then once the ECM receives a rotation signal from the crank position sensor the relay comes back on and stays on while the car is running.

Once i replaced this relay the car has been working allot better. I have to test more to see whats going on but this seems to have fixed the issue. Any feedback is welcomed. From what i see buying the fuel pump repair kit doesn't actually fix the problem sadly.

 

[i68k]

i just prime the fuel, keyON 2-3 seconds, start motor. starts everytime hot and when just turned off, 250,000+ miles.

 

[fchavez09]

i just prime the fuel, keyON 2-3 seconds, start motor. starts everytime hot and when just turned off, 250,000+ miles

Thank You. But i have always done that before i start the car ever since i have owned it but now with some of the replacements i have done the issue has basically gone away. Before this became an issue i was always priming the car before starting and then after a while it stopped working. Hopefully this is more of a long term solution. I am not as fortunate to have problem free miles :rambo: so i try my best to be one step ahead of the car.

 

[i68k]

just saying, cause most people dont, and then say wtf.

hopefully you solved your problem, i have read people saying a check valve worked using the previous write-up. i have yet to get there, so i pray thats the long-term solution is this simple

 

[fchavez09]

Haha your right about that. And just like you said i hope that the long term solution stays simple.

 

[ImJustMe555]

Good write up. What are the spec's on the check valve that you used?

 

[fchavez09]

Hi ImJustMe555,

The specs are...
- 5 PSI opening pressure
- Operating pressure range 5-1500 PSI
- Operating temperature -30° to 400° F

I made the whole setup with Russel High Pressure fuel line AN fittings and made an adapter to use the quick release so I can service the fuel pump if needed. the hardest part was removing the heat shrunk OEM fuel tube from the vehicles aluminum piping. it just takes some time and a sharp utility blade.

 

[ImJustMe555]

Cool. Thanks for the info.

 

[whocares9725]

I replaced the stock camshaft position sensor on my car(it went bad), car is alot more responsive to starting up now than it has been since I bought it. (Along with the walbro)

 

[ImJustMe555]

Hi ImJustMe555,

The specs are...
- 5 PSI opening pressure
- Operating pressure range 5-1500 PSI
- Operating temperature -30° to 400° F

I made the whole setup with Russel High Pressure fuel line AN fittings and made an adapter to use the quick release so I can service the fuel pump if needed. the hardest part was removing the heat shrunk OEM fuel tube from the vehicles aluminum piping. it just takes some time and a sharp utility blade.

What size AN fittings did you go with?

 

[fchavez09]

-6 AN it's the closest size to the stock fuel line so it doesn't restrict flow.

 

[ImJustMe555]

Hi ImJustMe555,

The specs are...
- 5 PSI opening pressure
- Operating pressure range 5-1500 PSI
- Operating temperature -30° to 400° F

I made the whole setup with Russel High Pressure fuel line AN fittings and made an adapter to use the quick release so I can service the fuel pump if needed. the hardest part was removing the heat shrunk OEM fuel tube from the vehicles aluminum piping. it just takes some time and a sharp utility blade.

Cool. Thanks.

Is the quick release the part the fuel line connector that attaches to the fuel pump canister? If so the what kind of adapter did you use? Do you have picks of how you did that part? Did you use the Earls Econ-O-Fit hose clamps there?

 

[fchavez09]

Sorry it took me so long to respond... i was out of town for a bit.

Yes, the quick connector is the one that connects the fuel line to the fuel pump canister. The nice thing about that connector is that the end is barbed so it just slips inside of the Russell fuel line. Unfortunately i don't have any pictures of how i did that part but all you need is to take the quick connector off of the OEM plastic line with a knife carefully down the middle to remove it and then take the connector and press it into your new fuel hose. then use clamps of your choice. a nice wide worm drive clamp will do. I used the Russell high pressure clamps to keep the look.

- I did do some research on using an AN style quick connector from Russell that is very nice but it started to make this whole setup a bit expensive that connector is for the 90's mustang's. The OEM connector is plenty good. I might just use the better connector for when i make a nice custom fuel line for the one that goes to the fuel rail. i don't like how the original one has that tamper cap and stuff on it.

 

[Jon]

You mentioned its worse when hot. Is there a possibility that the heat causes a pressure build up in tank that could be cause some problems?
I have noticed random ses codes relating to vapor recovery system when it gets hot out .
Great post you have put alot of work into solving the issue.

 

[fchavez09]

Jon,

Yes your right about the pressure build up in the tank and the vapor recovery system (If working properly) should allow the gases to escape at highway speeds. When i was researching this issue i took the whole pump apart and found that the weak point in the system is the check valve that causes most of the starting issues. The fuel pump motor is actually a great part but building a regulator and check valve into the same unit becomes problematic allowing fuel to drain back into the tank and replacing the space with air. The other part that i found was that because of the lack of a return system allows the fuel on a hot day to almost vaporize when its at the injectors. kind of like when you pour a little bit of water onto a hot pan... it turns to steam instantly piston=pan water=fuel.

I can't avoid a minor hard starting issue when the car is out in 110+ temperatures but for anything below that it has worked without any problem. its been in there for about a year now

Hope this helps...

 

[ImJustMe555]

Thanks for the info. I'm really considering doing this within the next few months, but I'll probably use Jegs fittings because they're cheaper.

Do you know if our quick disconnect is a 5/16" connector? I found some metal quick disconnects from Russell, Aeromotive, and Jegs, but for the most part they say that the rail that it clips to has to be 5/16" because they're made for either the LT1 or LT4 engines. Here's what I found:

Russell 640863 Russell Fuel Line Adapters GM LT1/LT4

Russell 640853 Russell Fuel Line Adapters GM LT1/LT4

Aeromotive 15117 Aeromotive OEM and Specialty Adapters

JEGS Performance Products 103100 JEGS Fuel Injection Fittings

If they fit I'll probably just get the Jegs one.

 

[fchavez09]

The one that should work for the car would be the 5/16 adapter. The ones you want are either 640863 from Russell or the Jegs 103100 because they go from 5/16 to -6 AN hose size. you only need on because the part that goes to the aluminum fuel line is barbed... meaning you just need to slip over the fuel horse.

Also the only way to do it is by dropping the tank a little bit. use a small jack placing it under the fuel tank and remove the bolts for the straps on the tank. Make sure you have a quarter of a tank or less so its easy for you to muscle the tank back into place since it has to fit right back on the rubber dampers.

Other than that... using russell braided fuel hose or jegs brand is very nice once you put the fittings on the end of it. no teflon tape just 2 wrenches.

 

[ImJustMe555]

I guess that's why most people put the check valve in the engine bay. Your setup looks really clean though although no one would ever see it, but it would be a great addition for anyone who was upgrading their fuel system.

 

[fchavez09]

I guess that's why most people put the check valve in the engine bay. Your setup looks really clean though although no one would ever see it, but it would be a great addition for anyone who was upgrading their fuel system.

Yah, your probably right about that. it took me about 2 hours to get it together but it payed off.

 

[Tyler Taz Milisits]

this forum is so awesome haha ive noticed since ive got my spec about 3 months ago or so that it does this and i just noticed its when it sits in the sun xD go worried today cuz it took 2 cranks.. ill try the 2-3 second deal and see if it does it anymore