View Full Version : RB25 acting like a dumb blonde
l2u4k0assx
01-19-2013, 08:33 PM
Ok so i have a RB25DET Series 2. Ran beautiful for months and then the alt. took a crap on me. So i had a brilliant idea to take everything out and do all the necessary things while i had the engine and tranny out. I had the regular side mount and stock exhaust from the ka single cam. After 5 months of getting everything together and ready to put back in. the CEL and the same lights indicating the alt is bad show up right before you turn the engine over. while the engine is running it idles right where it belongs vacuum is at -20. So here's where the problems start
Problems-
when revving the engine the idle starts to bog all the way down to the point of dyeing
while i drive it and keep it a 3000rpm it will bog down like some sort of fuel cut
After revving the idle is inconsistent.
when i touch the injector wiring idle becomes a little erratic
starting to backfire like crazy as well
Solutions i have tried- the unplug method
TPS
coils
injectors
MAF
Also sprayed brake cleaner around any spot for vacuum leaks no changes in idle
Parts upgraded-
nissan quest alternator
90mm throttle body
Sard FPR
gt30 turbo- possibly bad, oil comes out of exhaust yet still builds boost.
modified stock turbo manifold w/ tial wastegate 8.9lb spring
freddy intake manifold
custom downpipe
front mount added
here is video
Jan 8, 2013 7:11pm | Facebook (http://www.facebook.com/video/video.php?v=156087784539119)
Any help and i will greatly appreciate it. Thank you
l2u4k0assx
01-28-2013, 05:47 PM
so sprayed brake cleaner near the number 2 injector and idle change slightly. possible work injector insulator?
OrangeVirus1
01-28-2013, 06:23 PM
sounds like Vacuum LEAK! also if you are wiggling the injector wires and the idle changes, you could have crappy corroded wiring. but spraying brake cleaner near and injector and the engine changing tone/rpm is clear indication of a vacuum leak check your injector orings
steve shadows
01-29-2013, 07:09 PM
Check the seal from the fuel rail to the Intake Manifold.
Also put an exhaust on the car I hope you're not trying to figure out what's wrong with it with no exhaust. You need some back-pressure on any motor for it to idle and act properly. Especially at lower RPMs etc.
If worst comes to worst find someone you can borrow one of these from:
Pic of Smoke Base Vacuum leak Tester (http://tinyurl.com/aejgtqp)
Or make one lol DIY How-to: build a vacuum leak detection machine - Pennock's Fiero Forum (http://www.fiero.nl/forum/Forum1/HTML/081547.html)
l2u4k0assx
01-29-2013, 09:07 PM
im gonna check the injector insulators tomorrow wasnt able to work on the car today.
i do have an exhaust its just shortened up i have a stock cat. on it right now
smoked240
01-30-2013, 08:28 AM
First thing, do you have it tuned at all?
Second, rb's are picky little bastards!
Does it do it regardless of engine temp? My rb kinda did this but only when it was cold. Was the heating element in my o2.
Make sure you have the full length exhaust on, or whatever it was tuned for, if it was. That can mess with the tune.
l2u4k0assx
01-30-2013, 07:30 PM
@STEVE SHADOWS the injector insulators were all cracked at the top but not all the way through so i flipped them and the car started to run better after it driving for roughly 15 mins the car started to act up again.
@smoked240 no tune yet. i have the 300zx ecu and maf ready to be put in for the nistune but waiting to put it on. need it to drive right first
yes, yes they are mine is the biggest prick i know!!! it now only does this when warm.
the exauhst on my rb never mad a difference how much length was on it. i ran mine when i first had it with a stock ka exhaust with the stock cat. lol was very unfindable
l2u4k0assx
02-03-2013, 03:17 PM
found a huge leak in the injector insulators replacing part next week and going from there
funktown240
02-04-2013, 11:23 PM
I couldn't get my rb25det to idle correctly with a q45 TB either. You need a to install your Nistune to get it right, I bought a Haltech platinum pro and it purrs like a kitten.
smoked240
02-05-2013, 08:41 AM
I suggest a tune ASAP man, you'll love your car after. Mine had never ran so smooth after installing my AEM.
l2u4k0assx
02-05-2013, 05:57 PM
thats my next install after i fix the leak
thisisnotphil1
02-05-2013, 11:07 PM
Diagnosing RBs suck. When you say its back firing like crazy it makes me feel like the coils are pooping. Yes the injector seal is an issue but i dont think thats the main issue. The idle could be, but is not limited to, the injector seal, but is it missing at all? I had all the same symptoms youre explaining and it was my coils. For me it would rev perfectly fine but when i would put an actual load on the engine, it would bog. Around 3000-3500 rpm and sounded EXACTLY like a fuel cut. Smell rich, Spit flames the whole nine. hope this helps man. I was in the same boat 2 months ago. Good luck
l2u4k0assx
02-06-2013, 05:48 PM
so this is the update of my upcoming install
-injector seals
-wideband
-nistune
-ls2 conversion
will give update after these are installed
thanks everyone for the help
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