3\4 throtle pulls harder

[ka-t 300]

I have a jim wolf tune for n62 and 740cc inj. running 12 psi. on a stock block, with timing set at 21* btc and my wide band is reading 12.0 at wide open throtle and full boost every thing seems fine except for when i let out of the throtle to about 3/4 throtle i can feel it pull harder , about 30 hp stronger. i was thinking i could advance the timing a littlle more, but not sure . i don't want to detonate at 12 psi. i would think that it should pull it's hardest at full throtle. has any one experienced this or have any ideas ?

[ka-t 300]

any ideas ?

[240sxvaj]

Ivtec, heard they kick in only if you hold 3/4 of gas pedal down. LOL

j/m

Weird i want to know what can cause this too.

[ka-t 300]

Ivtec, heard they kick in only if you hold 3/4 of gas pedal down. LOL

j/m

Weird i want to know what can cause this too.

^ it don't have that. My theory is that there is not enough timing at wide open throtle , but when i let off to 3/4 throtle the ecu is seeing there is not as much load from the tps but the timing is still the same , so i need to add more timing, but not sure.

[ka-t 300]

any ideas ? also what is the cheapest way or what are all you obd II guys using to data log timing and such ?

[240sxvaj]

any ideas ? also what is the cheapest way or what are all you obd II guys using to data log timing and such ?

does this help????

zerosearch

[eazye2000]

My theory is that there is not enough timing at wide open throtle , but when i let off to 3/4 throtle the ecu is seeing there is not as much load from the tps but the timing is still the same , so i need to add more timing, but not sure.

That's what I was thinking when I read the topic, and then started reading your post. So yeah, that's what I think too. The timing is crazy pulled at WOT/100% load.

[DevilMB3017]

I forget which is which, but wide open/partial throttle runs open-loop or closed-loop fuel map. They use different sensors to determine fuel/timing.

While it could be the JWT ECU, it could be o2 sensor, MAF sensor, CTS...I forget which maps read which sensors, sorry.

[ka-t 300]

I forget which is which, but wide open/partial throttle runs open-loop or closed-loop fuel map. They use different sensors to determine fuel/timing.

While it could be the JWT ECU, it could be o2 sensor, MAF sensor, CTS...I forget which maps read which sensors, sorry.

thanks that is more of the info i was looking for, I'm pretty sure that when it is at idle it goes to closed loop (A set map) then goes to open loop in partial or wide open throttle so that it can make fuel and timing adjustments dedpending on the the load of the motor. I think i need some type of data loging device that plugs into my obd 2 port so that i can see what is going on but not sure what to get. I can see tps and msf readings on my apexi neo fuel controller. any ideas on what to use for data loging from the obd 2 port ?

[eazye2000]

Sometimes its a good idea to set your primary, and secondary maps to be the exact same, and disable the O2 sensor. That way your safe no matter what your pos O2 sensor does.Or not, but I've had good success doing it. Takes a bit of fine tuning, but generally works great.

[ka-t 300]

Sometimes its a good idea to set your primary, and secondary maps to be the exact same, and disable the O2 sensor. That way your safe no matter what your pos O2 sensor does.Or not, but I've had good success doing it. Takes a bit of fine tuning, but generally works great.

are you talking of setting the high and low throttle maps on the apexi fuel controller the same ? and then do away with all the factory o2 sensors.

[ka-t 300]

^^ bump ?

[DevilMB3017]

are you talking of setting the high and low throttle maps on the apexi fuel controller the same ? and then do away with all the factory o2 sensors.

I highly doubt that. The high and low throttle maps something like an SAFC system are just to add/decrease fuel based on sensor readings. easye2000 is refering to the timing as well as fuel.

[neverlift]

I highly doubt that. The high and low throttle maps something like an SAFC system are just to add/decrease fuel based on sensor readings. easye2000 is refering to the timing as well as fuel.

he is refering to the actual maps the ecu uses... an afc doesnt change the maps it lies to the ecu about actual reading, then changes where on those maps to read(good and bad, it advances timing when adding fuel, and retards timing when reducing fuel )

my timing/fuel high/low are tuned the same, and always will be

[ka-t 300]

an afc doesnt change the maps it lies to the ecu about actual reading, then changes where on those maps to read(good and bad, it advances timing when adding fuel, and retards timing when reducing fuel )

my timing/fuel high/low are tuned the same, and always will be

well right now i'm -7 % across the from 3000 rpm - 7000 rpm timing is set at 21* btdc, and afr are 12.0 with out fuel correction it's around afr is 11.0, so by what you are saying i have proly retarded timing? also what does the ecu do with the o2 reading it gets ?

[DevilMB3017]

Wait - you're taking away 7% of the fuel from 3-7K and your AFR is going more rich?

Something is very wrong with how this is working in my head. If you have a tuned ECU, I would remove the SAFC and see if that fixes your problem. You shouldn't *need* both...

Also, stock timing is 20* BTDC IIRC...

[ka-t 300]

Wait - you're taking away 7% of the fuel from 3-7K and your AFR is going more rich?

Something is very wrong with how this is working in my head. If you have a tuned ECU, I would remove the SAFC and see if that fixes your problem. You shouldn't *need* both...

Also, stock timing is 20* BTDC IIRC...

no with out the afc afr was 11.0 with the afc at -7 % afr went o 12.0

[DevilMB3017]

That sounds better, lol. JWT do tend to run on the rich side of things from what I've read of the internet. Maybe contact them about a re-tune or take the car onto a dyno to get some good SAFC settings? Sorry I can't help you too much more then that.

[klattr1]

every thing seems fine except for when i let out of the throtle to about 3/4 throtle i can feel it pull harder , about 30 hp stronger. has any one experienced this or have any ideas ?

I know the "feeling" you are describing...I used to think the same thing back in the day but the dyno will tell you the difference...I believe the feeling you are experiencing is a constant high amount of torque thats spread from like 4000-4500 rpms