ThunderbaySr20

Ive been on nico for a couple years and have almost 1k posts. I have asked many a question and no one over there will help. Unless of course your asking if your wheel sit flush enough, or your car is slammed enough or something stupid like that.

anyway i have a retarded problem >> My SR has been running great all summer. the problems started around september. I just installed a AEM wideband to see what it was really doing. Mind you, it still pulls like a mother just hesitates pretty good before it hits boost, like before i would hit full boost by 3200-3500, now its almost 4k

my setup is REDTOP SR
Greddy FMIC
Adjustable FPR
GT2865R turbo
KA24E MAFS
BC 264 Cams
Greddy Type RS BOV re-circ'd
Autometer boost gauge
AEM Uego Wideband

I have a AFR of 10.1:1 at idle. thats friggen rich. I have a vaccuum reading of 10InHg. I used to get 19-20 all the time no problem. I have NO trouble codes on my 62 ECU.

I have built a boost leak tester and i think i found something that i doubt it causing it, but it might be.

The IACV pipe, when i do a boost leak test i pull it off and block it on the FMIC side. with the throttle body closed I pressurize the system from where the MAFS is. however, air comes back out the brass pipe for the IACV... ive been told that this isnt supposed to happen...
where am i looking for the problem? should i check the IACV? or the TB? i know my throttle plate is closed. i can see that it is, with or without the piping off.

Ive tested everything else that i think could be making the car run rich. the TPS is within spec, the O2 sensor is good, (all these are tested as per the FSM) the KS wiring (lower harness) was done, but i changed that out and got rid of the code.

I live in the great white north, it hasnt snowed here yet, so i can still drive my car. and i want to but the stupid thing is giving me issues againe

Heres some pics of my car,

louisdaboois

the best way to do a boost leak test is to go through the intake side of the turbo and leave everything the way it would be as if you were driving it. That way you can pressurize the entire system. Try spraying some soapy water around every joint that may be a potential leak, so when you put pressure through the system, it'll bubble up and you can pin point it on the spot.

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ThunderbaySr20

i know my actual charge piping system is sealed. but what bout the throttle body...should i be getting air back from it? like back out the IACV?

sillyvia13

Like dude above said... from intake of turbby...
gl bro...
try a good ole seafoaming too... maybe its gunked up... you can also remove iacv and clean it up they often get dirty

ThunderbaySr20

yeah im already thinking about pulling off the IACV and givin er a good cleaning.

and when i do my boost leak test i do the whole intake to hairdryer thing, and even when the throttle body is closed air is still getting past it

ThunderbaySr20

but seriously wtf could be causing my vac reading to be so damn low.

sillyvia13

while you have it all apart clean piping too...
old oil in pipes will gunk system up...

you should also take the lil filter from valve cover and send into a can... or some shit...

I had mine like your is now...and oil would drip on my mani... no good.

louisdaboois

air would still get past the throttle body even when its closed because theres a little weep hole that lets a little air pass through so your car can idle. when you pressurize the system, it should fill up the intake mani and if the valves are open it'd go through the combustion chamber and everything else. You should lose 1 psi for every 3-5 seconds. any faster, then you obviously have a leak somewhere.

clean out your iacv and use some seafoam through the brake booster to clean out any junk. also, when did you upgrade cams and what are you running to tune it? idk a lot about cam profile and duration, but i know your vacuum will be a little lower with bigger profile cams opposed to factory cams. (just trying to throw out another solution)

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fliprayzin240sx

Trust me, when you pressurize the system and you have a leak, YOU WILL HEAR IT.

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duffman1278

^^ Exactly what he said. I've done this 3 times. I suggest when your doing it to do it in a garage and close the door so that its nice and quiet. But even outdoors you should be able to hear it and pin point the source(s) without soap and water.

ThunderbaySr20

Sorry, one other thing i absolutley hate about nico is no one ever updates their post to say what was or wasnt the problem. i know it wasnt my throttle body. because i poured a bunch of water in my tb (with the intake off) and i let it sit for a couple hours full of water, nothing got passed. so it does seal, thats what im thinking, the only thing that hasnt changed is the IACV, will know what happens when i change that one

KA-T_240

I pressure test my system to 30psi. I know its high, but I find all the leaks. I ended up replacing my IAVC cause it leaked externaly. I normally start by leaving the throttle closed and fixing those leaks then opening it fully to find leaks after the TB.


Your poor idle can be caused by other things besides your boost leak. Your A/F ratio and timing could be causing it. I'm not a tuner but 10.1 seams a bit rich for idle. Also could be cause by something on the internals of the motor(compression, valve seals or other things.)

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ThunderbaySr20

the compression etc is all spot on changing the IACV soon, im thinking going with a calum tune. i see your running one, i know with a daughter board i just switch the jumper right?

jakerps13

Things I would check for is ect, tps, compression, fuel pressure at idle/vac and re-check ign timing. Gotta start with the basics bro.

So it was running fine WITH cams, then later it pooped with them installed?

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ThunderbaySr20

got the AFR thing figured out, now when i fire up the car i get a high idle condition, it instantly shoots to 2k -2.5k rpm and holds it...no vac leaks?

crzycav86

blow into your intake pipe. if it comes out then you have a boost leak.

ThunderbaySr20

lol i know how to do a boost leak test, and i dont have any boost leaks lol...i just have a surging idle

Johny5

you won't necessarily always hear a boost leak, 9/10 soap finds leaks that your ear can't.

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sbanzer123

turn your car on and spray brake clean around all the areas that could possibly be leaking. if you hear your idle change when you know you have a leak.

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ThunderbaySr20

turns out the whole problem was the gasket between my IACV and lower intake