240Driver39

First off, i am runnin sr 370cc injectors, safcII, and a walbro 255 on my na ka currently, preparing to install a turbo soon. I installed this to work out bugs, and i have one so here is my issue/question

I installed the safc and ran it for about a week or so to make sure it was working correctly. And then I installed the 370cc injectors , made corrections of -27% across the board. The car will start fine at cold start in the morning after sittin all night, and will start up if it was just recently shut off. But in the period we'll call warm, it has trouble starting, 1/2 hour to a couple hours later, and needs help to start. Thinkin i may have had an injector leak, i picked up new orings from nissan pulled the rail again, installed the injectors, and then built fuel pressure to see of any leaks. None were seen. Put it all back together, same issue. Car starts right up when sittin for larger amounts of time (overnight or after a 9 hour shift of work) and when just shut off, but not after a bit of time. I have to essentially floor the pedal to start it (indicating to me that its flooded) The plugs were rich fouled and where switched to differnet plugs when the new orings were installed.

So, now im just tryin to figure it out, possibly a bad injector? When its tryin to start the motor shakes a bit, making me think a cylinder is flooded, but once it starts i get a lil smoke (smells like gas, goes away right away), then it idles and runs fine, with no smoke at all.

If so, any advice as to isolate a bad injector? Sorry bout the novel, just people like details on here so i figured id cover everything. Oh and this happened the same b4 and after the walbro install, so that is a null factor.

Thanks in advance

Adam

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1991 240sx SE, 5spd fastback

idlafie

From my understanding of what I've seen guys posting on here, isolating a bad injector should be as simple as disconnecting & reconnecting the injector plug wire from each injector as the engine is idling. There should be no change in idle when you pull the bad injector wire.

As for starting problems while the engine is in the warm stage, that's gonna be a tough one to figure out. Go thru the standard battery of tests....start at the beginning & work your way from there....battery, fuelpump, fuel pressure, starter, relays, spark, etc...Check everything, vacuum lines, sensors, etc. Try even cleaning out our IAV valve along with your Intake with carb cleaner. Do one step at a time & see if you notice any difference after you've completed each step.

Sorry I can't sugguest any more..problems like these are usually a bitch to figure out. All I can suggest is to make a checklist starting from the beginning...battery..then going from there. I know it sounds stupid, but most of the times by going thru the procedures you're able to trace down the problem & figure out what is was. And if you are able to isolate & figure out what the problem is, then feel free to share with the rest of the group. We all might learn something new from it.

Anyhow....Good luck!!

ID
95 SE

240Driver39

any more insight?

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1991 240sx SE, 5spd fastback

idlafie

Hmm...maybe a relay somewhere? Could possibly be stuck in an open or closed position when it's not supposed to be. Or maybe some sort of vacuum lock with the Carbon cannister system. Wish I knew what to recommend...this one's got me stumped!!
Oh..almost forgot...if your car is lowered..coilovers & wider tires, check your fender liners...your tires could have rubbed thru the plastic fenderwell liner & you could have shorted out an electrical line that runs thru there. Another Zilvia member had this problem with his car. It's a shot in the dark...but ya never know...
ID
'95 Se