Nistune Forums

Recently put nismo 740cc injectors on my TT. Besides a bunch of deletes and a lightened flywheel, I'm mostly stock. From what I've noticed with Nistune, when I adjust TP Min and latency to get AFRs around 14.7:1 at idle, I start getting popping in the exhaust. AFR's also become much more unstable.

If I pull back to the high 13s, idle and afr's seem much more stable. Is this pretty typical of our Z's? Do they not like to idle at stoich?


-baggar11
1990 300zx Twin Turbo
AEM UEGO Wideband
Nismo 740cc Injectors
brullen 3 inch Cat Back
SouthBend TZ series Clutch
Megan Racing split down pipes
AIV's removed
Carbon Canister removed
EGR removed
PRVR removed
Throttle body coolant bypass

I've noticed my S14 doesnt like to idle at 14.7:1 either so I do have it running around 13s for a decent idle

With popping at the exhaust, what happens is that when the ECU does a fuel cut it uses the latency value. So if you increase latency there is more fuel injected than factory on deceleration

You can try lowering TP max table in the areas affected (making sure it does not limit load on acceleration) to cut the fuel earlier where possible

Thanks for the reply. Just when I thought I was getting the idle problem solved, I pulled the Z out of the garage on it's maiden voyage since installing the 740cc injectors and Nistune. The test drive didn't go so well. Lots of popping and surging during 2k low load driving. Played around with Nistune for a while trying to add fuel and still couldn't get any richer than 16;1. Looks like I may need to double check for vacuum leaks at this point.

Matt wrote:I've noticed my S14 doesnt like to idle at 14.7:1 either so I do have it running around 13s for a decent idle

With popping at the exhaust, what happens is that when the ECU does a fuel cut it uses the latency value. So if you increase latency there is more fuel injected than factory on deceleration

You can try lowering TP max table in the areas affected (making sure it does not limit load on acceleration) to cut the fuel earlier where possible