modifying GTR fuel map

[GTaaargh]

My R32 GTR has a standard ECU that has been modified by garage SAURUS. For one thing, it stays in closed loop until 4,000 rpm.

It has a nasty flat spot between around 2,000 to 4,000. We hooked it up to a Lambda meter and took it for a drive. Each time I felt the flat spot problem the mechanic saw the air/fuel ratio go up to around 16 or 17:1.

I thought about using the JAYCAR kit to modify the output of the AFM, but the construction notes say that there is no point modifying outputs for the loads when it is in closed loop. Then again, while I am accelerating lightly, I would have thought that I was not in closed loop.

So, my questions:

Will I be in closed loop if I am accelerating lightly?

If so, is the JAYCAR kit likely to be able to make the fuel mix richer at set load points?

If not, is reburning the EPROM with an upgraded fuel map my cheapest option?

I'm also putting up a thread about the causes of the flat spot.

[GeeTR]

GTaaargh,

Any luck with finding your flat spot?

- M

[itbmils]

Hey GTaaargh

I have a BLITZ Access ECU up for grabs - out of my R32 GTR

it was mildly modified with HKS pods, bigger exhaust and R32 N1 Turbos

ran sweet as – and I'm open to offers at this stage

Upgraded to PFC – now getting 300awkw

[GTaaargh]

It's strange. I can't identify when it went away, but I took the car to Ed at Advantra in Queanbeyan, and the problem was still there, then shortly afterwards it went away. Ed was only checking bits, so maybe he tightened something and stopped a leak. Maybe it was the coils. Who knows. I certainly don't - unless it's the vacuum assist for the clutch. It's stuffed, so maybe there was an intermittent vacuum leak, which would fit the symptoms.

However, I took the car to the dyno tune shop on Monday and he pointed out that my closed loop was going until 4,200 rpm, and it didn't matter if if was full or partial throttle. Normally it would cut out at around 3,000. His theory was that I have 80mm AFMs. Maybe the voltage for 80mm AFMs at 4,200 was the same as standard AFMs at 3,000 rpm.

GTaaargh,  

Any luck with finding your flat spot?

- M