RB25 acting like a dumb blonde!

[yanay]

I have the EXACT same problem right now and when the issue happens and the idle drops down its a 9.7 afr and when cruising and it starts cutting its around 10 afr on my car at least. I have swapped tps fpr o2 sensor maf iacv with no luck

[Skym]

My cars engine dropped below idle rpm and didn't want to recover when TPS was misadjusted (had to use throttle to compensate). You can tell TPS is misadjusted by turning aircon, light's, etc on and driving around on flat or up a fairly steep hill and back off throttle quickly and engine stalls or nearly does as ECU doesn't kick rpm up to compensate (wasn't touching idle contact).

TPS makes ECU switch to richer part of fuelmap when you step on throttle quickly to prevent engine going lean (MAF is too slow to react), same on ignition map to suit. So if TPS is misadjusted the TPS is telling ECU that it needs to run engine richer (higher voltage), hence the rich A/F ratio you are seeing on decel and if not touching idle contact inside TPS, ECU doesn't kick rpm up which means less air into engine and engine runs alot richer (o2 sensor would play a part in this).

Also cleaned, flow tested injectors??? I hear cleaning can stuff them, but also can find the faulty injectors (usually after reinstalling them the injector starts to leak).

[yanay]

When i replaced the TPS it shows proper voltage when the throttle plate is closed but it shows 3.5v at WOT. Tried swapping it with 2 different tps and same issue exact same voltages. When the idle does bog down the throttle is very very unresponsive. it will never stall it always catches itself. As i cruise (say 4th gear at 3000 rpm going with the flow of traffic) I watch my afr go from 14.7 slowly drop to 10.6. I need to get this fixed so i can sell it! haha have a couple people waiting on me fixing it

[l2u4k0assx]

my TPS is set at 0.45 and at WOT its at 5v so perfect


fuel pressure stays the same it is consistent

i did check the injector insulators and they are cracked so i flipped them and the car actually started running better... weird

It's easier if have Nistune, as it light's up the idle contact button in Nistune tuning software or Nissan's Consult which does similar. But it is lower than around 0.51V? or something like that which some use. On my cars TPS the idle contact is at 0.44V.



What's the fuel pressure doing when it does it????



Strange, I would have thought it was the MAF. It's common for injectors to playup when engine has done high km.



That's the best way to see what is happening with sensors in realtime. The other is oscillioscope (CAS, o2 sensor, ignition module, etc) multimeter at sensors.

[l2u4k0assx]

today i also noticed my brake booster hose and PCV hose collapse when running engine. so replacing those tonight.

[l2u4k0assx]

im gonna take the manifold off this weekend and rtv the manifold back on. so i can exclude that as a possibility.

[l2u4k0assx]

ok so update i made a leak tester and so far there was a huge leak coming from the injector insulators.

[yanay]

Have you had a chance to fix it? Has it cleaned up the problem? Keep going with the updates!

[l2u4k0assx]

no chance to fix just ordered the parts get 12 of them just in case. but when i was pushing air into the turbo from the maf side i could not only hear the leak but feel it. so try a leak test. like to make it simple you could no joke make a plug on your coupler where the maf would go and blow air in and you can hear the leak

[yanay]

I did a smoke test and fixed all my small little leaks. Still acting up

[l2u4k0assx]

well after i do the seals ill see if mine still acts up than i will do another update

[l2u4k0assx]

so after fixing the seals and still nothing...

[yanay]

**** man, ill let you know if i find anything.

[l2u4k0assx]

i hooked up a consult port to the car and ran it. Everything matches what the FSM says. Un less i have another leak hiding or my coils are taking a crap.

[l2u4k0assx]

Update did another smoke leak test and found the smoke coiming out of the turbo!!!