1g-gte misfiring on first few seconds of startup - common?

[Z2TT]

I think cylinder 1 had some oil or something in there too, just looked a bit moist in there but I'm not certain, cylinder 3 was definitely leaking. Guess I'll have to take the injectors out. Another problem I have which might be related, is that sometimes after a drive, when i leave at and go back to turn it on later like in 15 minutes it would start up straight away, then stutter real badly and turn off.

[pandaah]

have you taken out the ISCV and made sure water flows thru it properly?

[Z2TT]

I have taken it out, but haven't tried flowing water through it.

[JoJo]

I just found this thread now. My Celsior (1UZ) does the exact same thing. I know EXACTLY what your talking about. It has done it for more than a year and the car is fine.

It is a fuel thing. When you first turn the key, it will start up with a rough idle for about 3-7 seconds and then instantly turns good.
During this time, lets say 3 seconds in, if you touch the accelerator, it will instantly come good as well.

I looked on some forums and found it is common. From memory, the problem (in Celsiors/LS400) was deemed to be worn o-rings inside the fuel pump, which affects holding fuel pressure when the car is off. There are NO O-rings availiable as a replacement and you have to buy a new pump.

But you said you changed the fuel pump so this may not be applicable to your car.
I got no idea now.....

Could it be the fuel pressure regulator?

JoJo

[Z2TT]

How could a bad fuel pressure reg cause that problem?

[Z2TT]

Checked all the spark plugs today, all good and none were fouled.

[sleepy1g]

mine does this as well have replaced nearly everything still does it.
i'm running a walbro pump, aftermarket fpr made no difference,

even with these still drops pressure over night as they should the fpr slowly bleed back to the tank.
also hard wired the pump still hasnt helped.

i'll be watching on with interest to see the results of this

[timbosaurus]

I don't see why the FPR should bleed back into the tank overnight. You want pressure in the lines when you go to start, so the FPR should hold, and a one way valve in or around the pump should too.

Mine struggles to start sometimes, needing an extended crank. I suspect this is fuel pressure related, but have not had a chance to hook up a pressure sensor yet.

Kind regards,
Tim

[sleepy1g]

no doubt an arguement will follow ......
but of the 5000+ cars i have worked on they all prime first before the car starts.
stick your head near the pump and have someone flick the key to the start position and it will come on to prime.
from commodores to ferrari's the all prime first. even the dirty ole rt142 primed first

[Z2TT]

Well Fuel Pressure problems I'd say would either be caused by the pump or the FPR, Sleepy1g has replaced both and still has the problem, unless his aftermarket FPR was bad?

I thought it was the check valve in my fuel pump gone bad, replaced the fuel pump and nothing.

Sleepy1g maybe get your injectors cleaned, so far I've narrowed it down to my injectors.

Maybe It's an ECU Problem.

[sleepy1g]

changed injectors also tried a different ecu also neither have helped its down to the temp senders for me

[auto351]

mine does this as well have replaced nearly everything still does it.
i'm running a walbro pump, aftermarket fpr made no difference,

even with these still drops pressure over night as they should the fpr slowly bleed back to the tank.
also hard wired the pump still hasnt helped.

i'll be watching on with interest to see the results of this

When you say to have hard wired the pump what have you done here (just to clear my confusion)

is the pump comming on with the ignition key ?
if so are you waiting a while from ignition to starting the car ?

[sleepy1g]

Auto351 yes it is wired off the key. means once the key is in the on position it runs constantly.

used a relay running off battery power switched by the key. gives the pump cleaner power

[timbosaurus]

no doubt an arguement will follow ......
but of the 5000+ cars i have worked on they all prime first before the car starts.
stick your head near the pump and have someone flick the key to the start position and it will come on to prime.
from commodores to ferrari's the all prime first. even the dirty ole rt142 primed first

Yeah, no arguments about cars priming for a few seconds on key on. But that's to compensate for leaky injectors, one way valves, and any other wear that means you lose pressure overnight. The FPR is not *supposed* to bleed fuel back into the tank...it would only do that if it's worn. Maybe that's what you're saying though, and I've read your post incorrectly?

[sleepy1g]

even when i worked at ford, brand new cars slowly bleed off, not a huge amount but becuase the fpr is designed to allow fuel through they "dribble" some pressure. can be anywhere from 1psi through to all.
but getting past this.

sometimes and i have tried it on mine and it changed the way it starts, was to disconnect the cold start injector to see the difference the miss was gone but was sluggish reconnected miss came back.

another thing i've on the list is replacing the factory earth with a good quality setup and also to add sevral more earths at several diferent points.