going SUPER lean from 2850 to 3050 rpm

[thesupragod]

I just got back from the shop, i installed an AEM Tru Boost and and AEM UEGO gauge in the car today...

Since the single swap i have noticed a "dead spot" in the rpm range, from `2850 to about 3100 rpm, the car will barely accelerate through this range.

After installing The wideband i can see why, It goes full lean in this rev range???? What the Hell???

Is there anything that changes at this rpm that would make the fuel just dissappear?

On another note, untuned with no provisions for tuning i had inadvertently installed Aristo injectors in the rail as well, though it should run PIG rich with those in.

And it does, on boost the wideband stays pegged at 10.1:1, i gotta get this thing tuned!

Mod List:
1jz
USDM 2JZ Cams- re-shimmed to perfect tolerance
Aristo 440cc Injectors
Aeromotive FPR - Base fuel pressure was set at 45, decrease to 35 today
Walbro pump
Masterpower t70 single .68 Hotside
Tubular china manifold
HKS SSQV
Tial 38mm Wastegate
3" Turbo back Exhaust
FMIC
AEM UEGO
AEM TruBoost
DEFI: EGT, ect... gauges


Any Input would be AWESOME!!!

Thanks in advance!

 

[Bigzavs]

the decrease in pressure on the FPR is most likely the culprit

set the base pressure w/no vacuum to 43psi (factory)

we had a local car at 37psi base pressure, and his car had the same thing, we couldnt tune it out or anything. upped it to factory pressure, tuned it and his car was good to go.

try doing that before anything

 

[86_sports_1jz]

^^agreed

 

[thesupragod]

Im going to bring the fuel pressure up to 44lbs, between what Bigzavs and gotturbos recommended, ill report results later today!

 

[thesupragod]

cranked the FP back up, no progress... Im installing the NEO today and am getting it tuned tomorrow, hopefully they will be able to tune it out!

THanks for the input!

 

[Cya]

wow, I have the same problem! Please do report back.

 

[thesupragod]

Ok, apparently i didnt update this thread.

I have not gotten the problem resolved, The guys at IPS Tuning were not able to tune the lean spot out, even addin 50% fuel at 3000 rpm didnt resolve the issue. Im Really stumped now.

Any suggestions?

 

[shaeff]

How's the fuel pump wiring? Pump?

 

[SupraClaou]

Ok, apparently i didnt update this thread.

I have not gotten the problem resolved, The guys at IPS Tuning were not able to tune the lean spot out, even addin 50% fuel at 3000 rpm didnt resolve the issue. Im Really stumped now.

Any suggestions?

Have you got the fuel pump on direct +12V ?
Or you still have it on the stock oem setup...through the fuel pump
resistor / relay? Check the fuel pump resistor / relay. This unit adjusts
the voltage on the fuel pump depending on the rpm range...

The fuel relay / resistor unit is located near the ABS unit.

 

[thesupragod]

Sorry for the lack of clarification... The fuel pump is a Real Walboro 255, it is 12 volt modded directly from the battery and wired by a relay that i installed. There is no dip in fuel pressure throughout the rev range, even while boosting the pressure will just increase.

 

[nytefire]

I'm having the same problem at near the same spot, I'm close to 3000-3200rpm.
The only change I did was install the Driftmotion AFPR kit for the 1j. With the stock FPR I did not have this problem, so it really doesnt make sense why it came up just now.

Walbro in tank
Did the 12v mod and without (Same issue)
AEM UEGO Wideband
Basic mods, intake/exhaust

 

[dslocal]

well do you still have the fuel pressure dampener?

 

[nytefire]

No that was done long ago.

well do you still have the fuel pressure dampener?

 

[dslocal]

ok I was just thinking, you said it didn't happen until you installed the afpr and a lot of people delete the fpd at the same time.
How is your fuel filter? Last time you changed it?

 

[Cya]

What ecu are you running? Supra, Chaser/Soarer? Im leaning toward this issue being ecu related.

I am running a chaser ecu and have the same problem.

 

[charlesshen]

you think it might be a faulty cps? it might cause this to happen not sure but i think it send a signal witch lets the ecu know when to fire the injectors i beleave maybe your getting no injector pulse at some point between those 200 revolutions its so short of a period the ecu doesn't recognize the fault in the sensor.

just a wild guess:crazy1:

 

[nytefire]

What ecu are you running? Supra, Chaser/Soarer? Im leaning toward this issue being ecu related.

I am running a chaser ecu and have the same problem.

If I can find another ECU anywhere, I'll swap it see if I'm getting the same thing

I have a Supra ECU

 

[nytefire]

Not sure, just find it funny that the only thing changed was mechanical and not an electrical thing. Think I'll switch back over to the stock fpr this weekend see if it goes away, I still dont see how it would be the aeromotive afpr

you think it might be a faulty cps? it might cause this to happen not sure but i think it send a signal witch lets the ecu know when to fire the injectors i beleave maybe your getting no injector pulse at some point between those 200 revolutions its so short of a period the ecu doesn't recognize the fault in the sensor.

just a wild guess:crazy1:

 

[dslocal]

you think it might be a faulty cps? it might cause this to happen not sure but i think it send a signal witch lets the ecu know when to fire the injectors i beleave maybe your getting no injector pulse at some point between those 200 revolutions its so short of a period the ecu doesn't recognize the fault in the sensor.

just a wild guess:crazy1:

I don't think so because it would cause the spark to get messed up too.

And nobody answered me, Fuel Filter?

 

[nytefire]

Same filter, didnt touch it or change it.

I don't think so because it would cause the spark to get messed up too.

And nobody answered me, Fuel Filter?