Nistune Forums

Hey all.

Just wondering if anyone can shed some light on an issue I am currently having.
The car drives fine at low rpm but once i hit between 4-5ish k rpm it appears to go into R&R (Hesitates badly/stuttering and so on). If i push it past this (which i did once just to test) it finally moves on and keeps pulling without issue.

Attached is the log from a run i did yesterday, Firstly i thought maybe the AFM reading was too high causing it to hit R&R but it would appear (According to the logs) that this is incorrect.

Here is a link to what is is exactly doing (not filmed at the time of the log, but it was doing the exact same thing at the time of the log file being taken)
http://youtu.be/NtRSP0afE0E

So any other suggestions that can be made would be good. I am probably going to take it back to the tuner to get this resolved if I can't resolve it with much ease.

Cheers,
Brendan

Could be fuel related: what are your AFR's when it decides to start stuttering? Hows the fuel pressure/fuel pump?


Could also be a spark blowout issue. what is your plug gap set to?

Unfortunately I don't have a wide band so I can't really say on the afr side of things but that was a thought I had late last night as it only hesitates once it warms up (I recall reading that o2 input is ignored when it's cold?)
My plan for today was to do a few Cold runs and warm runs and compare the differences and also disable o2 input completely once stuttering occurs to see if it still does it.

Fuel pressure could be it too the reg was set by the tuner I can't remember what to off the top of my head (will look into this as well)
And plugs are all gapped to .8

Cheers

okay so the fpr is running at standard(ish) psi. hovering around 43-45psi and it still does it. Using 750cc injectors this pressure should be okay I think?
also using an intank walbro gss342 (genuine) which should also be ample.

After googling this issue people have suggested a few things which I might try out but later tonight im going to log a few runs and then disable 02 sensor input completely and see how that goes. if not ill move on to something else lol.

Hey All,

I went for a tune a while back and found my gate was leaking so it stayed untuned mostly (minor improvement on the stock tune)
Drove it for a while and cracked the exhaust manifold. anyway long story short.

Over the weekend just gone everything was fixed/replaced and AFM was relocated to cold side ready for a retune in a week or so!

Only issue is... AFM was moved to cold side... Right before throttle body (After the iacv hose comes off it) so would i be right in saying that this is a bad thing, unmetered air getting into the engine?
Or is this something I shouldn't worry so much about, something that should be able to be worked into the tune?

Please let me know asap so I can move the afm back before the IACV if need be before I get a tune

Thanks In Advance guys

I think it should be okay. Just check your AFRs are close to before moving the MAF