r32 GTR misfire

[mickr32gtr]

Got an r32 GTR with these mods:

PFC

AVCR @ 1 bar boost

HKS filters

3 inch exhaust from front pipe

Standard turbos, dynoed etc making 210 awkw. I noticed that after the PFC was installed that when im in 3rd @ about 3000 rpm on a mild load the engine misses for a fraction of a second. It doesnt do it all the time, maybe once every 5 occasions im at that rpm and load point.

Has anyone had anything similar? Any ideas on fault and repair necessary?

Cheers.

[The Alchemist]

gidday, Mike in NZ gere , i too have R 32 GTR with a PFC.....Has your one been "tuned" or is it just running on the base program that comes with the PFC?

I ask because when i brought my GTR the PFC was on its base program ( previous owner reset it by accident i think) and the PFC runs a bit lean just as you're coming on to boost at the point you describe. At least it did On mine anyway...around 14.3:1 I think it was. My car also had a slight pause or hesitation here...that was until I made a Techedge wideband AFR meter and did some adjustments

When it crossed over into boost it would get heaps of fuel and take off like a rocket giving the impression it was guttless off boost.

I richened up the 2500 to 3500 rpm at around load row 8,9, & 10 to give me an AFR of 13:1 or just under the the response of the engine was dramatic! The off then on feeling of the car disappeared now it just has a smooth power band up until you hit boost then its bye bye everyone

Hope this helps mate .

Mike

[mickr32gtr]

Thanks Mike. I did get the PFC dyno tuned, got the fuel maps leaned out. It all took about 15 mins and i was surprised how short it was. The guy used the Apexi Commander unit and im told he has done it 1000 times before so he was an expert. It was C & V here in NSW that did it. When i got the PFC installed i only had the full exhaust fitted and on std boost it gave me 180 awkw. After the AVCR was fitted and retuned for the higher loads, its pumped 210 awkw. Im not sure what to do next, whether to see another tuner and have the fuel & ignition maps checked or whatever. The car does feel off under 3500 and its unbelievable on boost and i would be happy if it felt alive all the way thru the rev range. I got the impression that i was being taken for a ride, so to speak, when the car goes into a tuner and i dont want to get ripped off.

[The Alchemist]

sorry for this question but why when you have a PFC did you install an AVC-R when its just a piggy back computor for fuel....the PFC can make all the changes you need can't it?

If you have a fully mappable computor like the PFC there is no need for an AVC-R???????

before I go any further I need to confirm why you installed this?

MIke

[The Alchemist]

I beg your pardon prime minister was thinking of the Afc... duh!

Ok ....

the PFC need to be leaned out in the top end over 4000rpm and load point 12,13,14 & 15 from the base PFC map. I guess this would be almost standard fare for an experienced tuner like the one you went to , so he/she would know this and do it automatically so to speak. Which explains why it was done so quickly

However,

like I said in my earlier post I found that the low midrange was very lean on the std map at 14.3:1 just coming on to boost. this made the car really soft off boost and I found myself having to floor it to get boost and hence power when going up even moderate inclines...

sound familar?

Richening this up did wonders! If you like you can send me the numbers off your fuel map in a grid arrangement from 2000 to 4500 rpm and from load point 5 through to 11. This is the critcal area when tuning for nice transitions between boost and off boost and hence overall drivability.. This type of tuning seems to be best done and the road with a wide band AFR meter so you can feel the effects of your changes, which is what I did.

MIke

[mickr32gtr]

Mike, is there any way to get the load-point numbers without the Commander Unit? I dont have one. Ive been thinking about buying one for a while.

[The Alchemist]

No I'm afraid not mate....see if you can borrow one from someone. rather than buy a commander save a bit extra and contact the people at FC-Datalogit. They have made a software interface that talks to the PFC just like the professional tuning software the Japs have...except you can read this one

Have a look at the site...

http://www.fc-datalogit.co.nz/

I got one and its the best thing I ever did!!!!! heaps easier and more practical than the commander to use and it does full datalogging similar a MOTEC...