Nistune Forums

Hey guys, i've got some trouble to do "easy" things on my car :

Nissan S13 SR20DET (50f00 ecu), (EDM S13 swap in fact)

-Stock cams and internals,
-Z32 MAF
-550cc injectors
-GT2871R (HKS evc-s BC)
-Tial 50 BOV
-FMIC

The thing is, if my MAF is plugged i cannot start the engine.

In Nistue i changed my injectors (370 to 550) and the Maf (S13 SR20DET 266hp to Z32 500hp), i upload the maf and burned it into the chip,

Everything seems normal, my o2 sensor read 1.1v, my timing is set to 15° and my tps at idle is at 0.48/0.5v.

Any advice ?

Does your MAF show 0.5V when car not started? If you blow through it, does the voltage increase?

In consult view when i don't run the engine, nistune show "0.380V":


But for some reason i managed to start it, it's run great if i play a lot with the throttle pedal, but with poor idle and at the end he stall.
Pictures when it run :



Tomorrow i will try to blow through the MAF, to see how the voltage increase.

MAF voltage seems to be okay, so 'works'

You need to adjust 'TIM' at cruise (2000rpm light load) until it runs stoich. Then adjust K constant until load is set correctly

Also read our tuning training notes and documents

Ok thanks Matt, i would read those documents,

Just a few questions,

It's normal to have 0V on the O2 sensor now ? I just figure out that after seeing the pictures above, that's wasn't the case before.

For a correct idle, do i need to change anything apart from K constant ?

If my car is too rich, i need to increase or decrease the K constant ?

Thanks,

O2 sensor should read above 0V when vehicle is at operating temp, and richer than 14.7:1

Idle can be adjusted using latency, once you have the K/TIM dialed in for correct load (on boost) and stoich mixtures at cruise

Decreasing K will reduce fuel and load indexing, decreasing TIM just fuel

At cold start i have 0v (25°C),

Is TIM a Feature pack only ? because i don't have (yet ?) a FP base map in my ECU.

I will try to play with the K otherwise.

TIM is only feature pack, so yes you only have K to work with (and rescale load scales on fuel and timing maps)

Okay so i tried multiple things :

Change my injectors latency (stock 580ms to 283ms, 550cc Deatschwerks)
Change the K constant from 27k to 22k slowly, and from 27k to 31k.

But still the same thing, my car run if i play on the throttle but eventually stall.
Also, if i don't press the throttle a bit when i crank it, the engine will never start.

My O2 sensor read 0v everytime, but on my AEM wideband i read things like 16 or 17 afr.

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Update

My car idle almost ok, but my AFR goes from 15 to 10 progressively, and goes directly to 17 and does the same thing again and again (recording attached).

stock 580ms to 283ms, 550cc

Too small value for 550CC. Try setting around 750uS

Ok thanks Matt,

I tried yesterday, it's clearly most smoother but she keep doing the same thing:
950 RPM, goes to 1200/1300 and become too rich progessivelly, nearly die at low RPM, recover, again and again.

But i noticed something: when i start the car my AFR is 15/15.3, if i open the throttle a bit my SR recover at idle and my AFR goes like 10 and will never go back to 15/15.3.

If your running STI Yellow Side Feed Injectors I found a latency of 1020uS works perfect when im tunning with those particular injectors

It's actually deatschwerks 550cc side feed. (The purple ones)

Ok i found it, that's was my BOV... I think i need a stronger spring (TIAL 50mm).

My AFR at idle is like 14.8/15.2 with my O2 sensor disable, 45 k in k constant. But if i enable my O2, my car will enrich a bit by it's own ?

O2 will adjust fuel trims. These should be around 0% at cruise. You should not rely on O2 if your tuning is 'off'