stalling when idling down?

[Guest]

ive just flipped manifold and twisted turbo on v5 wrx. stalls when you do a sharp blip on throttle as it idles down. fuel pressure is set to 43.5psi with vac off as per the thread on here. no vacuum leaks and was running fine before i started the flip. only thing that isnt finished is theres no bov as i cant weld aluminum got to wait till tuesday to get it done. its just sitting on driveway atm till thats done. it idles fine if you slowly come off the throttle and idles regular on start up everything else is fine.

im guessing it builds up the air back to turbo without bov and stalls it? any ideas?

[Timmah]

Yeah slap a BoV on there before you try diagnose.. They're there for a reason

[Guest]

pretty sure thats the problem just figured somebody would know if that would cause it not really trying to diagnose anything till after bov is on. ill know on tuesday anyway

[B4 2000]

it shouldn't stall even with no BOV (if there's no vacuum leaks)

the air will simply go back to escape thru the turbo and you might hear some fluttering noises

check the idler? the idle adjusting thingy

[johnny5]

Mates v7 runs no bov so cant be that

[Guest]

 B4 2000 said:

it shouldn't stall even with no BOV (if there's no vacuum leaks)

the air will simply go back to escape thru the turbo and you might hear some fluttering noises

check the idler? the idle adjusting thingy

i havent changed anything that would effect the idle. it still sounds like it has bov its just like it overfuels when throttling down revs drop right off. idle is fine and throttle cable isnt sticking or anything. if you slowly let throttle off its fine it only does it when you drop the throttle.

does the bov open when engine returns to idle? i thought it did so air didnt back up to the turbo? i will have bov on tomorrow so shall find out.

[pl0x]

wheres the vac line which goes to the bov? blocked off?

[Guest]

yea no vacuum leaks anywhere and not idling funny vacuum leak style ive checked all lines too

[B4 2000]

 evowrx said:

does the bov open when engine returns to idle? i thought it did so air didnt back up to the turbo? i will have bov on tomorrow so shall find out.

when the car is idleing the BOV should be closed, otherwise that would be the same as a vacuum leak.

But you not having a BOV at this point, the air will escape out one way or another when you release the throttle.

some leaks you don't notice when releasing throttle slowly but would stall the car with the sudden release.

i'd suspect a leak somewhere, like plox said, what did you do to the vacuum nipple that's for the bov?

[B4 2000]

 evowrx said:

yea no vacuum leaks anywhere and not idling funny vacuum leak style ive checked all lines too

hmm. i guess just wait till tomorrow and see how things go?

[Guest]

yea bov line is all blocked off. just noticed the rev guage flutters all over the place sort of like a narrowband air/fuel gauge fluctuates within a 1000 rpm of what it should be. also drops right off at idle even when the idle is still. catch is i installed a greddy speed cut controller yesterday but triple checked the wires before i cut them and only used speed sensor and signal. any ideas? maybe a slight break in the loom to icv? which one sensor should i look at lol?

car info and engine pics here

http://www.clubsub.org.nz/forum/index.php/topic,28448.msg403914.html#msg403914

[boon]

Check your throttle adjustment. My V7 has (I think) a dirty throttle body meaning the butterfly doesn't close all the way and I get really wierd hunting idle.

[Pappu1]

 johnny5 said:

Mates v7 runs no bov so cant be that

hahaha that guy is a lucky guy - turbo still holding sweet on him after all the fluttering hahaha

[Guest]

 boon said:

Check your throttle adjustment. My V7 has (I think) a dirty throttle body meaning the butterfly doesn't close all the way and I get really wierd hunting idle.

idle is fine holds steady as its just as you come up a stop sign and lift off throttle quickly if you know what i mean. gonna play with wires and see if it fixes it just waiting on the bov being welded up as we speak.

[funkytown]

you must have a leak somewhere id swear it. did you clean the head/manifolds inlets and replace the gaskets on the change over, made sure all the plumbing lines up, and everything is plugged back in.

no Bov shouldnt cause it to stall

[Guest]

 funkytown said:

you must have a leak somewhere id swear it. did you clean the head/manifolds inlets and replace the gaskets on the change over, made sure all the plumbing lines up, and everything is plugged back in.

no Bov shouldnt cause it to stall

sure did the only thing not plummed up is the breather off one of the solenoids in front of the drivers strut. it used to breath to intake. unplugging it pulls cel but it shouldnt matter whether it breathes to atmo or intake.

cleaned intake and head surfaces and new gaskets...only thing different is no pressure exchange solenoid to carbon canister but no cel and vacuum lines are plugged up. its driving me crazy and i really want to drive it lol.

i did set up the fuel reg with vacuum off that is correct ae?

[funkytown]

#1 - if you're running a factory ecu, you want it breathing to intake, not atmo - its important the ecu (via the MAF) is registering all air. and where it was plumbed to the intake - is that hole currently blocked or what.

those sorts of leaks will cause surgy idle.

#2- what did you change when doing the FPR, rails and injector change at the same time correct?

I think there are you're two obviously places to look.

[Guest]

 funkytown said:

#1 - if you're running a factory ecu, you want it breathing to intake, not atmo - its important the ecu (via the MAF) is registering all air. and where it was plumbed to the intake - is that hole currently blocked or what.

those sorts of leaks will cause surgy idle.

#2- what did you change when doing the FPR, rails and injector change at the same time correct?

I think there are you're two obviously places to look.

not running the standard intake anymore, no leaks in intake or intercooler pipes. no surge in the idle. the breathers arent running to intake either now but thats unmetered air right?

only changed fpr and split the rails. tbh it seems like it overfuels as you come to a stop like when you have a bov set up wrong to atmo instead of plum back. its set to 43.5psi with out vacuum on it.

pics as below.

before

after

[funkytown]

oh my.. thats fruity. give me time to study the pictures.

for #1 your AFM wont like being inline like that (no bends) and that close to your turbo.... heres one guess. your turbo with no bov is surging and becuase your AFM is so close and inline its causing air to run backwards through it and messes up what the factory ECU knows about air taken in - so it miscalculates and stalls.

#2 explain exactly what's changed in doing the rails / FPR.

[ADIKT]

Tried re-setting your ecu?

[pl0x]

 funkytown said:

for #1 your AFM wont like being inline like that (no bends) and that close to your turbo.... heres one guess. your turbo with no bov is surging and becuase your AFM is so close and inline its causing air to run backwards through it and messes up what the factory ECU knows about air taken in - so it miscalculates and stalls.

+1, seen this on multiple cars

A lot of work to go through just for factory comp?

[Guest]

 funkytown said:

oh my.. thats fruity. give me time to study the pictures.

for #1 your AFM wont like being inline like that (no bends) and that close to your turbo.... heres one guess. your turbo with no bov is surging and becuase your AFM is so close and inline its causing air to run backwards through it and messes up what the factory ECU knows about air taken in - so it miscalculates and stalls.

#2 explain exactly what's changed in doing the rails / FPR.

#1 could be a good point i just figured the turbo would get a hard time and mess up the airflow and cause it to stall. ran my first libero without bov till it ran a beb. didnt think about the afm though.

#2 set up just like yours funky set up in parallel with tees both sides to a fpr set at 43.5psi with the vacuum off. the tank breather/emissions line is poked down the side of the gearbox.

i will reset ecu tonight when bov is on not driving it too far at the moment.

[Guest]

 pl0x']

[quote name='funkytown said:

for #1 your AFM wont like being inline like that (no bends) and that close to your turbo.... heres one guess. your turbo with no bov is surging and becuase your AFM is so close and inline its causing air to run backwards through it and messes up what the factory ECU knows about air taken in - so it miscalculates and stalls.

/quote]

+1, seen this on multiple cars

A lot of work to go through just for factory comp?

did they have the same problem? its common for bov to cause this issue but it didnt have one ;D

how so? heaps of people front mount and i got it new and cheap so i just made the piping shorter and twisted turbo to fit the flipped manifold. splitting the rails was just common sense.

[funkytown]

#1 the afm straight off the turbo like that makes them go haywire in the first place, its been well documented that the MAF throws a hissy. - least of all with no BOV..

#2 - so you run no factory FPR on either rail, but tee a pair of inputs and outputs on each rail together, and use the aftermarket FPR now? Did the injectors come out of the rails during the swap?

[Guest]

 funkytown said:

#1 the afm straight off the turbo like that makes them go haywire in the first place, its been well documented that the MAF throws a hissy. - least of all with no BOV..

#2 - so you run no factory FPR on either rail, but tee a pair of inputs and outputs on each rail together, and use the aftermarket FPR now? Did the injectors come out of the rails during the swap?

#1 yea i researched it heaps a lot of mixed opinions on it its not how it was in my mind to tell the truth it was meant to have 2 45deg bends.

#2 correct the rails never came off the manifold i used a copper pipe cutter so no filings and an adaptor for the factory reg end.

cant see any fuel leaks anywhere either