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Really Weird Problem...any Help?

heyhey!

By heyhey!,
in Engines & Forced Induction

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heyhey! Rising Star

heyhey!

Posted
Posted

ive been around skylines for years...but this one was a little weird

r33 rb25det

SOUNDS like its running on 5 cylinders on idle

SOUNDS like its running on 5 cylinders when you go to take off and let the clutch out

at about 1500rpm BAM dissapears!!! and runs PEFECTLY

can run as much boost as you want ...rev to any limit or do anything you want

its like under 1000rpm to 1500rpm it sounds like its running on 5???

o2 sensor?

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blind_elk Grand Master

blind_elk

Posted
Posted

See what you've done, God! I warned you this would happen when you invented the O2 sensor - now the O2 sensor is the cause of every single problem in the modern EFI engine!

heyhey! - have you bothered to analyse which - if any - cylinder is misbehaving at low rpms? Have you checked that the VVT solenoid is working?

heyhey! Rising Star

heyhey!

Posted
  • Author
Posted (edited)

it used to run fine...but just sort of happened

i thought if it were plugs or coils...wouldnt it be doing it all the time?

BLIND ELK---- havnt found which cylinder...as it only runs on 5 when letting the clutch out... that tiny moment of initial take off

havnt checked the vvt solinoid will do that today

Edited by heyhey!
heyhey! Rising Star

heyhey!

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Posted (edited)
well until you workout which cyclinder is missing - no-one can help

Even then, once you FIX the once that is causing the problem, you'll find you dont have one anymore...

if i knew which cylinder was playing up IF ANY do u think id be posting here asking for anyones help???

i ask the question incase anyone else had been througha similar problem....

or for help from people that had ideas... not useless comments

as i said above....it SOUNDS like its running on 5 cylinders very breifly on take off...very very breifly though ( it may not even be running on 5 but sounds that way)

then runs unbelievably well for the rest of it

constructive ideas or people that have had a similar problem would be a great help

3lit3 32 ill look into this

.

Edited by heyhey!
R31Nismoid Grand Master

R31Nismoid

Posted
Posted
if i knew which cylinder was playing up IF ANY do u think id be posting here asking for anyones help???

i ask the question incase anyone else had been througha similar problem....

Well how about you go and find out? Like i said...

heyhey! Rising Star

heyhey!

Posted
  • Author
Posted
Well how about you go and find out? Like i said...

your amazing...i went out and found it was cylinder 1....and now just like you said...its FIXED!!!... i didnt even have to touch anything!

NOT

what im getitng at if it is cylinder 1 ,2 ,3,4,5,6, what difference does it make if i have no idea what causing the problems

HENCE why i ask for opinions on THE problem...not which cylinder it is

for example ...oh that sound like an injector sticking problem i had in my old r32

example 2 ...oh that sounds like a dirty 02 sensor problem i had in my silvia

etc

Punk72 Community Regular

Punk72

Posted
Posted
well until you workout which cyclinder is missing - no-one can help

Even then, once you FIX the once that is causing the problem, you'll find you dont have one anymore...

Yeah you need to chill out a bit!!, hey hey!? is having a bit of trouble and is simply asking around for some advice and isn't that what this forum

is for!! yes maybe it is hard to give advise to hey hey, as there could be a number of reason for what it is doing but maybe some where to start would help instead of being a smart ass

nIsMo86 Experienced

nIsMo86

Posted
Posted

+2 I'm with Punk72...

R31Nismoid, You usually have contructive ideas...bad day? :blink:

In regards to the problem, i'd suggest check your plugs first as it sounds like they may be fouling on idle then cleaning themselves as the revs go up. Also you may have the wrong heatrange...what plugs you using?

BensDR30 Experienced

BensDR30

Posted
Posted

We can suggest generic solutions all day, but knowing which cylinder is important.

See if you can get access to someone with DataScan or equivalent & do a software-based power balance test at idle.

It may just be a dud plug, but do you really want to pull them all out, change them and still be wondering what the problem was?

Where are you located?

The Dan Grand Master

The Dan

Posted
Posted

Hey let's not beat up on Nismoid here.

It is extremely important to know what cylinder a missfire is on. You simply cannot diagnose a missfire unless you know this.

It's a very valid statement to make as we are all here offering advice for days and days, using our own time, and after 5 days of rigorous testing you turn around and say 'oh I found the problem fellas, it was missfiring on cylinder one because there was a slightly broken wire in the injector plug at the terminal'

FUUUUUUUCK!!! - is what everyone says

If you are talking about some kind of shudder when you take off, could it be something silly like clutch shudder?

Also, if you have a valve seating problem, it will only be present at idle and the beginning of throttle (if the leak is tiny) but the missfire will definitely be there at idle.

Is it there from idle all the way up to 1000rpm? or is it fine at idle and just there once you try to take off?

heyhey! Rising Star

heyhey!

Posted
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see everyone is split

im saying if i knew which cylinder it is i wouldnt be posting ...i would have found the problem and fixed it the second it happened

you guys are saying find the cylinder and then u'll find the problem

im saying...ok its cylinder one! to solve this issue

now what would cause a car to miss under 1000rpm on cylinder one.....any ideas?

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