KA24de Starts right up and then dies...

[subwayguy4]

Got a KA24de that starts but then dies instantly.

I had it idle for over 4 seconds once when I was lightly spraying brake cleaner into the intake it stayed on as long as that was going...

I've see numerous threads on different forums about this, but none of them were ever answered....so any idea's is appreciated.

this is in a datsun 510 btw and yes the motor and everything previously ran good in the 240.

It has a walboro fuel pump that clearly works well I unhooked the injectors from the manifold and cranked, but I didn't see fuel spray. I'm not sure if it had to be seated to spray or needed vacuum to open up the regulator...so I bolted it back on and it just does the same start and dies

[speedeast]

Test the injectors and check all of your wiring...

[Klits562]

i believe the injectors should still squirt fuel even when unbolted.
but if none of your injectors sprayed i dont see how you could even start the car in the first place

[speedeast]

you can just check the impedance and make sure they're all good electrically

[subwayguy4]

i believe the injectors should still squirt fuel even when unbolted.
but if none of your injectors sprayed i dont see how you could even start the car in the first place

Yeah I remember them squirting before....

I grabbed another rail/regulator and cranked again just to see if they'd shoot out into the air, but nothing came out. I even tried taking the regulator out of rail hooking it straight to fuel line and this is where I found the fuel was not getting through...but on both fuel regulators? Should I be trying for a 3rd one? or possibly aftermarket?

fuel passes through the entire system except the fuel pressure regulator, Should it be like that? does it need vacuum to open or extreme pressure build up to be opened? I'm not exactly sure, but maybe I just grabbed another crap fpr...

[speedeast]

FPR needs vacuum...

"Most modern fuel injected cars run a fuel pump in the tank and run much more fuel than is needed to the fuel rail. A regulator keeps a certain amount of fuel pressure in the rail and then sends the rest back to the tank.

Your car as well as most fuel injected cars have a one to one fuel regulator. It varies the fuel pressure by 'watching' manifold pressure. It uses a diaphragm to control pressure. Most Nissans at idle (vacuum) fuel pressure is 34psi and at full throttle (No vacuum in theory) 43psi. If you further put pressure (turbo or super charger) to the manifold, it further increased fuel pressure. In factory regulators, for every pound of boost, it adds a pound of fuel psi. Hence 1 to 1.

Most adjustable regulators are still one to one or close to that, however you can adjust the pressure at idle or full throttle for fine tuning. There is one other type of regulator that is used with aftermarket forced induction. These are rising rate regulators commonly called FMU's (fuel management unit). These regulators increase fuel pressure at a multiplication factor of boost. So instead of messing with complicated computers and injection duty cycles, these systems just increase fuel pressure to add fuel. They go inline down from the factory regulators and only start to add pressure under boost. So when you are off boost, you maintain factory tuning and drivability. Only as you get boost does the FMU begin to increase fuel pressure."
-compliments of Mike Lee

"To check:

Release the fuel pressure in the system by removing the Fuel Pump fuse and start the engine. After it stalls, crank it a few more times to release the fuel pressure.

Install the fuel pressure gauge on the inlet side of the pressure regulator, start the car and check for fuel leaks.

At idle, the pressure should be approximately:

235kPa / 2.4 kg/cm2 / 34 psi.

Disconnecting the vacuum hose, you should see:

294 kPa / 3.0 kg/cm2 / 43 psi.

After getting your yah-yahs out over that test, connect a hand vacuum pump to the regulator and start the engine. As the vacuum INCREASES, the fuel pressure should DECREASE. If this is not the case, time for a new pressure regulator. "
-compliments of somebody else

It wasn't mentioned above, but I'm pretty sure you need to put the fuel pump fuse back in after you hook up the fuel pressure gauge.

Good luck!

[djidentity]

Hmmm... I had a similar issue with my sx. I had to check the vaccum lines. Turned out I had a kink in one of my lines, and it was not getting enough air. This was after I installed my aftermarket intake also.
Def check that, and your pressure... as mentioned above it could be your pressure and you need a new reg.

[subwayguy4]

Well It turned out to be the common problem of the fuel lines being reversed.........good old confusion.

It turned on but it has problems idling and well if you don't give it gas it dies. But main problem solved thanks everyone!