slight mod.

take some quick start
spray it around your intake manifold and then around your TB, if your rpm raises then you found the leak

 

vacuum leak is usually associated w/ surging idle, and sometimes stalling. i wouldnt guess vacuum leak, but a quick check never hurts.

 

If it was stock, the two common things that cause premature injector cut-off is TPS, and an unplugged/fucked IACV.
On a non-stock MAP sensor car, (assuming the previous 2 are known good) it comes down to the rom editor that you are using.
Ive worked on 3-4 2.5bar cars so far running CROME, and the decel injector cut-off was very very smooth. The latest versions of CROME are pretty freaking good in this area; 2.5bar, and GM 2&3 bar.
You using Uber or CROME? If CROME, what version? Post your bin if you want, Im bored.

Dave

Also, is this intermittent or 100% repeatable everytime you drive the car?
Ive noticed that a loose dizzy wire (CYP, TDC, or CPK) seemed to cause this condition until you reset the ECU.
Also, a loosely/shitty socketed chip can cause intermittent premature cutoff. (Ive noticed this first hand on my own car. Once I changed to a machine hole socket from a dual-wipe type socket, the problem did not occur again.)

 

good info, storing that in the memory bank.

 

i love how this thread was dead for a week, and now all this useful info pops up


i switched from uber to crome shortly after the manifold swap. It did it with uber too though.

i have one of those rubber cookies on an angle die grinder that i use to get old gasket material off. You'll never use anything better in your life

it doesnt pull much vacuum (10-13"), but there is no leak anymore. at least i cant find it. I had a problem at first because of the air injection holes in the y8 mani, but i plugged them all up with the jb.


leed- my iacv just started making some crazy noise yesterday. I believe it be fucked as of now. when i turn to key on, it makes this rrrrrweeeeee sound. Its kinda hard to type but kinda sounds like a fuel pump thats going bad.

im using crome 1.1.8, i kept ------- with the bin because it wont even start now. I'll have to see if i can find the origional.

 

how do i attach my bin anyway?

 

ZIP it and attach a ZIP file...I dont think the forum allows .BIN attachments

As far as your vacuum, 10-13 is VERY low...you could have a map sensor issue.

Go back to your BIN before you swapped intake manifolds...see if it does it on that BIN still when it didnt do it before. If it still does this wacky thing...then its mechanical and happened somewhere in the swap. If it DOESNT happen...chances are its something in the BIN file or tune...

 

so it actually stopped starting a few days ago too. Turns out the two problems were unrelated. I switched the fuel pump with a walboro 255 because i didnt hear it priming anymore. still didnt work.. i put a chip backwards in my ecu but didnt start the car. I figured my ecu might be beat. Swapped with a known good one. Still no priming action. So i check the service manual, and i dont know why i didnt think of it sooner.. main fuel pump relay. i heard they go bad all the time on eg's.

as for the bucking... the supra 440's fit fine in the z6 intake manifold because of how the injector bosses are made. The thinner shallower or whatever the ---- they are on the y8 dont like them. They actually dont even fit with my new str fuel rail. My assumption was that the injectors were either spraying at the intake or the head under low throttle, thus causing the engine to get a healthy dose when you step on it more. RC550's are on the way and i should have a fuel system good to 400+

 

^^^

 

good deal, thanks for updating.