Problem On Boost

[rhys5169]

ok so it was noticable tonight to post up on here, at around 4000rpm its almost like the car takes the accelerator off, cause i get a drop in revs and a back fire noise. i originally thought it was the back wheels spinning cause it was a simmilar feeling but the revs where dropping, not picking up, almost as if it was traction control?

it only does it every now and then, but it shouldnt be doing it......

the car is stock, apart from 4inch hks dragger cat back exhaust, pod filter, super spark coil pack, nismo S-tune sparkplugs and supposedly a bigger fuel pump?

is it just a case of maybe running too rich? overflowing the car with fuel and choking it??? injectors? spark plugs? im new to the whole skyling thing so any advice much appreciated

if youy need any more info please let me know

cheers

rhys

[rad100]

the forced induction section answers alot of questions i have learnt!

maybe have a search?

[Deluxe]

Have you checked cooler pipes and vacum hoses?? Just make sure they are all connected to something and dont have holes or splits!!

[4door_Sleeper]

Could it be a boost cut?

I am guessing you have a boost controler or bleed valve (but not listed in your mods). If you have increased the boost and havent got an aftermarket ECU or similar the could cause the problem. The cooler and more dence air in winter will make this more obvious than in summer.

[DSTROY]

my car did the same sort of thing, ended up being a bad fuel pump, then not long after that the motor died, so get it checked out before something bad happens.

[rhys5169]

the forced induction section answers alot of questions i have learnt!

maybe have a search?

ive got more replies and looks here than there, im not too sure on what to search tho???

Have you checked cooler pipes and vacum hoses?? Just make sure they are all connected to something and dont have holes or splits!!

i'll have a dig around and see if any are loose

Could it be a boost cut?

I am guessing you have a boost controler or bleed valve (but not listed in your mods). If you have increased the boost and havent got an aftermarket ECU or similar the could cause the problem. The cooler and more dence air in winter will make this more obvious than in summer.

no such mods have been done, everything else is factory, running factory boost. i think you may be onto sumthing with the colder air???? it has only done it at night, and this afternoon when it is freezing cold, whats the go with this?

my car did the same sort of thing, ended up being a bad fuel pump, then not long after that the motor died, so get it checked out before something bad happens.

ahh ok, in that case would you recomend getting it booked into a mechanic/dyno asap??

cheers for the help guys

[DSTROY]

When the air is colder, it has more oxygen in it, so therefore you also need more fuel, so maybe your running out of fuel, i would get a dyno and get the air/fuel ratio checked out.

[rhys5169]

ok will do, can you guys recomend anywhere other than boostworx? (long story, not going there)

i have a dent in the bottom of my intercooler, could this be effecting it at all?

Edited July 15, 2008 by rhys5169

[Dohmar]

ok will do, can you guys recomend anywhere other than boostworx? (long story, not going there)

i have a dent in the bottom of my intercooler, could this be effecting it at all?

if the dent has pierced the core of the intercooler, then most definately. and it'd be letting unfiltered air into your engine. not good. thats a worst case scenario but if i were you i wouldnt screw around, go to yr fave mechanic or mark at exhaust tech to check it out

-D

[rhys5169]

if the dent has pierced the core of the intercooler, then most definately. and it'd be letting unfiltered air into your engine. not good. thats a worst case scenario but if i were you i wouldnt screw around, go to yr fave mechanic or mark at exhaust tech to check it out

-D

exhaust tech it is, will call them first thing in the morning. so a dent in the front mount if it has pierced the core would explain my current problem?

[Dohmar]

exhaust tech it is, will call them first thing in the morning. so a dent in the front mount if it has pierced the core would explain my current problem?

its a >very< long shot that it is to do with your current proble (lack of boost at certain RPM). I would recommend it get checked for the simple fact that any sort of air intake, be it turbo or otherwise, needs a filter to stop particulate matter screwing up the internal mechanics of the engine. Imagine getting a single grain of sand underneath your eye for a day. I'm sure it'd cause some wear/irritation issues before too long. Same goes with engines.

Your current problem for lack of boose could be a number of things, but I'd be suspecing an individually anomalous map at that particular rev range. For some single problem at a specific rev range, there would have to be a particular corresponding map that calculates the mix.

Having said that, you say its around 4000rpm? This is just over the 3500rpm boost kick in of most std ecu maps....could perhaps be worth checking the vacuum/control pipes to EBC or ECU stock actuators.. the aftermarket coilpacks are a variable but if you're not having serious problems, they'd be the last thing i'd look at. ** bear in mind im not a mechanic **

I get a drop in power a couple of minute after driving, but thats normal...after the engine warms up it switches to the ecu's map instead of relying on some other sensor/valve (i cant remember what its called cause im tired as hell, can some smart bugger please tell me what its called... AAC valve perhaps? Dunno)

Anyhow, it sounds like a pain in the arse to diagnose for a layman. I'd gladly palm it off to an expert and pay them for it. Lifes to short to chase leaky hose.

-D

[rhys5169]

i wish it was more regular so i could get a grip of when and how it comes in, so i could better explain it....i just feel like an idiot walking into a workshop and trying to explain the problem..... cause there is such a vast aray of possible issues....

cause its not like i can take a mechanic for a test drive cause the problem only arises at night when its freezing cold

[DSTROY]

If i was rich, i would put money on it being a fuel or spark issue.

[rhys5169]

If i was rich, i would put money on it being a fuel or spark issue.

how would they correlate to a drop in temperature? im leaning on boost (piping) or fuel :s

[DSTROY]

how would they correlate to a drop in temperature? im leaning on boost (piping) or fuel :s

well i had the same problem, loss of power with very loud bangs from exhaust, but it happen'd all the time, not just with cold air temps like yours, and it was diagnosed on a dyno by my mechanic with air/fuel ratio's.

just take it to a good mechanic with a dyno, its not worth risking.

[rhys5169]

yeh i rekn i will cruise into MRE and have a chat to the boys and see what they say, theyve been good to me to date so try my luck again

cheers

rhys

[Krishy]

that actually sounds like a bosst cut to me.....i had that similar problem a while back when my vaccum hose came off.....so checking all your vaccum lines could sort that out....

if not then also take your cooler core and get it pressure tested as a dent could have punched the core and now its either leaking air or leting in unfiltered air....

if you say you have a aftermarket fuel pump then fuel shouldnt be an issue but get that checked as well.....most of the time a good dyno tuner will be able to pin point where the problem is arising from and should be a easy fix at times....

good luck with it all mate and let us know how you go

[rhys5169]

thanks for the reply, im just hoping a dyno tuner will know whats wrong from my description cause to date its only done it at night and there not open then

anyways thursday after work i'll putter around the corner to Mildren and see what they have to say

[Deluxe]

Could even be Air Flow Meter, would explain the colder air going thru it!!

[rhys5169]

just did a search in the SA thread and "diggity" can fix AFM's?

Edited July 16, 2008 by rhys5169