Fuel starvation at start up.

[Rick]

If my car has been sitting for abit and I try to start it, it will only start when the fuel pressure is built up enough during cranking. My car has a fuel surge tank setup and aftermarket fuel regulator.

I think whats happening is the fuel is draining back into the tank when the car is turned off.

I thought about simply installing a switch to prime the fuel pumps before start up?

Has anybody had this problem or is this normal?


Cheers

[jakesae101]

wondering the same thing with my 4agze standard just the first start of the morning takes a bit to crank over then starts up no problems rest of the day just

[l1ttle_d3vil]

wondering the same thing with my 4agze standard just the first start of the morning takes a bit to crank over then starts up no problems rest of the day just

could be your cold start injector and/or cold start injector timer that's shagged?
mine used to take a fair bit of cranking to start and needed throttle.
have adjusted the cold start and now starts alot quicker with no gas...

[jakesae101]

hmm interesting was thinking cold start injector how do i ajust it?

[finx]

you cant adjust the cold start injector itself. the ecu controls that via the thermo time switch which adds extra fuel when cranking over on cold start up.
this could be either stuffed or it isnt connected.

[l1ttle_d3vil]

how do i ajust it?

get a link g3

you can check the resistances of the injector and timer to see if they are within the right specs, have a search on the net - i've got them somewhere so i'll have a look and post them up if i find them.

[MAGN1T]

It's more than likely one of the aftermarket parts that's not performing.

Some aftermarket FPRs seem to leak and drop pressure over time. Maybe hook up a pressure gauge to see what's happening.

Steve

[NZ_AE86]

If my car has been sitting for abit and I try to start it, it will only start when the fuel pressure is built up enough during cranking. My car has a fuel surge tank setup and aftermarket fuel regulator.

I think whats happening is the fuel is draining back into the tank when the car is turned off.

I thought about simply installing a switch to prime the fuel pumps before start up?

Has anybody had this problem or is this normal?


Cheers

Does the fuel pump 'prime' when you turn the ign on?

You should have full fuel pressure when you begin to crank if everything is working as it should.

[Rick]

Does the fuel pump 'prime' when you turn the ign on?

You should have full fuel pressure when you begin to crank if everything is working as it should.

Pumps only turn on when you start to crank the engine over.

[RomanV]

Perhaps hardwire the fuel pump to be on before you crank, and see if it cranks over any quicker that way?

I know that with distributorless cars they can potentially need to do up to a full 360 or 720 degrees of engine cranking before it knows when/where to fire a spark plug? What setup does the GZE have, dont they run coilpacks or something, or still dizzy?

[jakesae101]

they run coilpacks normaly there should be a prime singnal to the fuel pump before the car is cranked over

[rollaholic]

yeah the pumps should be running on IGN

i would have thought your surge tank overflow would be at the top (ie shouldnt be draining back into tank while its sitting)

[Rick]

No prime signal, I just followed the factory wiring diagram, fuel pumps are off the "open circuit relay"

i would have thought your surge tank overflow would be at the top (ie shouldnt be draining back into tank while its sitting)

The surge tank overflow returns back into the main tank but Iam talking about the return from the fuel regulator near the fuel rail, which also returns back to the main tank.

[escortman]

would have thought it would have wanted the pumps run on ign

[cedwards]

I may be reading the wiring diagram wrong but the way I interpret it they are connected to the ignition.?
The fuel pump relay is triggered through the efi main relay and G-R wire which I assume goes to ground?
Therefore should prime when you turn ignition on.
What keeps the pumps running when you are not cranking ie: when engine is running if not so?

[gepsk8]

escortman- would have thought it would have wanted the pumps run on ign
no, so if u crash and have a fire the pump will keep fueling it, not gud idea.

finx- you cant adjust the cold start injector itself. the ecu controls that via the thermo time switch which adds extra fuel when cranking over on cold start up.
this could be either stuffed or it isnt connected.
no, the cold start injector get signal via start circuit, and the big gay brown plug at back of head(when cold).

MAGN1T- Some aftermarket FPRs seem to leak and drop pressure over time. Maybe hook up a pressure gauge to see what's happening.
all fuel system drop pressure when pump arent running

Rick- u run a surge tank setup, when u dont drive the car offen the fuel will return to main tank, so ur high pressure pump is running dry as low pressure pump has topped up surge tank yet

i suggest put a spung return switch so u can prime the surge tank first before starting

[escortman]

escortman- would have thought it would have wanted the pumps run on ign
no, so if u crash and have a fire the pump will keep fueling it, not gud idea.

o i meant like wen 1st goes to ign for 3secs or something, thats how my stinger works

[NZ_AE86]

The GR (Green with red trace) wire on the relay goes to the ecu and goes to ground through the ecu - it will prime when the ign is first switched on and will then run again when the ecu sees the expected RPM signal.

Your fuel pressure reg. might bleed a little but if you prime system is working then you should have no problem.

You do not need a prime switch unless something is wrong with your wiring as it will only do what Mr Toyota decided to have the factory ECU do.

You should put a gauge on to confirm that fuel pressure is you issue but either way you should ensure your wiring is right.

[cedwards]

NZ_AE86-The GR (Green with red trace) wire on the relay goes to the ecu and goes to ground through the ecu - it will prime when the ign is first switched on and will then run again when the ecu sees the expected RPM signal.

Is your ecu then sending the appropriate ground "signal" on first ign on? should be easy to test. I assume it is working fine once running (seeing expected RPM signal) otherwise you'd stall.


Otherwise why not move your reg return and plumb it into surge tank? Then if Both your low pressure IN and fuel return are plumbed at the top of the surge tank (eliminates either siphoning the surge dry) you should always have a full surge tank which should give your low pressure plenty of time to catch up once engine is idiling. And your high pressure should always have fuel to start.

[rollaholic]

escortman- would have thought it would have wanted the pumps run on ign
no, so if u crash and have a fire the pump will keep fueling it, not gud idea.

just about every car i have ever driven primes the pump on IGN as mentioned