Running lean??

[Raksj04]

I have a 87 base with a S4 JDM swap with a 2.1 rtek running 550/720 injectors, my wideband is a PLX with a multi gauge. It is After I wired in my narrow band output from my wideband contorler to the ECU I noticed the car would cruse with a really lean unstable afr. It would jump from 14.8 to 16 during a low load drive steady speed level driving. The would also feel like it would stumble a little. If I would accel more the AFRs stablize at about 13.4 under vaccumm. Under boost they would get close to 15.5 and would not get richer. Disconnecting the wire I wired into the ECU did NOT fix the issue. The rtek will log the narrow band signal. also the car will idle at about 10 to 11 AFR. Any help would be great, or a place to start. If you have any questions reading this ask or pm me for my phone number.

[Raksj04]

I have a little update. The car seems to be a little lean under boost but will start to come back down. AT curise around 20in/hg of vaccum the acts like my bike does when I need to switch to the lower part of the fuel tank. And the AFR are pretty erractic at this point. If the rpms are about 2k to about 4k. To me it seems like its not getting enough fuel at this point, I am not sure why. Under slight accel the AFR are richer about 13 or so. I know in the Mazda FSM there is a tool that is used to check fuel pressure of the pump and the FPR. It is basiclly a gauge with a ball vavle on it. Does anyone know where I can get one or how to make one?

[Whizbang]

if i recall, my cruise AFRs would run into the 16s on my 13b. I would verify with someone more knowledgeable. What are you seeing under boost?

Idle was a little unstable, closer to the 12s though. I had a megasquirt II running off the wideband (no autotune).

fuel pressure can be checked usually with an inline tee and a gauge. rather universal

[FerociousP]

my car likes low to mid 12s at idle (neg split)
under boost they should be no higher than 12ish
should be high 14s low 15s at cruise.

With your 2.0 you should be able to tune most of this. Make sure you didn't turn on weird settings on the rtek on accident.

doublecheck all of your wiring is to the correct pin placement, etc on the ECU and that you are using the wideband 0-5v output (not the narrow band 0-1v) of the PLX.

[Whizbang]

is the RTEK make the ecu understand a 5v signal for closed loop operation?

[Raksj04]

The PLX is sending a narrow band signal to the Rtek. I was told that you can only use the wideband for datalogging.

Under boost I will see about 14ish.

[88turboii]

i believe you are describing a problem a bunch of us had with rtek 2.x. Mine would idle in 12's AFR, cruise in closed loop (14/15 AFR), and 10/11's in boost. But if you cruise in very low vacuum like near 20in, it would lean out to 17/18 AFR and hesitate. a lot of guys are having this problem. i eventually upgraded to haltech, same setup, same injectors, same boost sensor but never saw the problem again. i suspect its an rtek programming problem, but never was able to prove it

http://www.rx7club.com/showthread.php?t=681555

[Raksj04]

So what I have read is getting an adjustable FPR and turning up the pressure may fix the issue?

[Raksj04]

Is it like a constant hesitation? My AFR will only spike at 17. they normally bounce from 13 to 15, like a ADHD kid on sugar.

[Whizbang]

When my cruise would lean out too far and hesitate, the hiccup is caused momentarily changes the vacuum which changes various other things going on causing the AFRs to bounce around

[Raksj04]

The also seems to hiccup sometimes. Mainly when it is cold. Like I need to push the pedal down harder to get the car to accel compared to when it is warmer. I really dont know how to describe it. Like something is holding the car back untill I give it more gas. If I accel hard there seems to be no problems.