So... I'm running an RTEK 1.8, 4 x 750cc injectors and my Neo MAXED, but, still lean over 50% throttle. (By lean I mean 13:1 AFRs at WOT)

It will hold mid-11s AFR up until than...

What you guys think? Time for larger secondary injectors?

Could it be that I'm using a stock s5 turbo?

For engine / exhaust info please see my signature below.

Thanks for your help guys,
-Chris

 

It's your port. You need a stage 2. Ports change midrange fueling requirements quite significantly and you get what you are experiencing, midrange lean. The Stock ECU cannot compensate and must be tuned.

 

Ugh.... Did you read anything? Lol
The ecu is a RTEK 1.8 and i have a APEXI AFC Neo before it.
It should be running VERY fat up top

 

Oh i read it. The AFC will only do so much. I'm just sharing the experience of what I've seen with customers cars.

What are the impedance of your injectors?

 

They are the correct high imp injectors... RC 750cc as primaries and Injector Dynamics 720cc secondaries

 

There is no way you are making out 4x750 w/ that setup so....

A) your fuel system has an obstruction
B) you are losing fuel pressure
C) your injectors are not firing
D) your wideband needs to recalibrated

When I was experiencing similar problems it turned out be sediment that had been picked up from an old fuel pump sock. and cycled through the system. Bear in mind I had already had the injectors cleaned, dropped and cleaned the tank, replaced the fuel filter, and flushed the lines with brake cleaner. The only thing that wasn't replaced (because the parts store was out) was the fuel pump sock.

 

I'm still running the GSL gas tank... no in-tank pump an option and no filter sock... yes, I know there is no sump in the GSL tank which is why I keep the tank full

My AEM UEGO does NOT preheat I've notice... but, thats resolved after the car's running a few minutes. My wideband DOES function in the "rich" range (mid -11s) as it stays there until I go over ~50% throttle where it starts to climb to ~13:1 at WOT

had to order a filter... none in stock at three stores... Will let you know tomorrow...

NOTE: filled up with different brand gas and no change... just ruling that out.

 

are any of your injectors low impedence? if you have resistors inline, they can reduce injector p/w by 20%, which would make it lean like you say. i was running into this problem with rtek, maxing the correction with 750cc/1000cc injectors at only 300whp

if you are running resistors, try replacing them with lower impedence. 10 ohms is way too high, factory resistors were 6 ohms. The injector drivers can actually handle up to 3A current, so you could use 3 ohm resistors inline

 

He said they were high impedance. So I assume the resistor blocks are not installed? Running high impedance injectors with resistor blocks will cause leaning.

 

People.... It's a complete s5 swap.. No resistors in the s5 wiring harness. I'll be changing out the filter today if it comes in and will let you know :-)
Im running 750D (denso) RC primaries and Injector Dynamics 725cc secondaries.. They're both HIGH IMPENDENCE

 

did you check the fuel pump voltage/rewire it? do you have an adjustable fuel pressure regulator?

i would for sure say 2.0 if your ported.... you have no control using a 1.8. it sounds like your trying to do something that the ecu can not support !

 

Have NOT done anything to wiring.. Still running stock FB pump wires... Guess i could jack it up and check voltage though...
Canister filter removed.. Stock turbo2 filter installed AFTER pump... Seems the richest i can get it to run is 11.7-12.2 at WOT

 

11.5 volts at pump... 13.9 volts at battery... Guess i'll be rewiring that.. Lol

 

Is that regardless of manifold pressure? TPS and/or MAP sensor issue?
Me would hook up the DVM to see if correct voltage output from both (and them voltages are seen by the ECU) to rule that out.
I run the 1.8 on 4x720cc, street port, moded turbo, FPR'd, FMIC'd S4-13B and runs absolutely flawless. By the color of the plugs, fuel mixture is spot on.
Per the DVM, the duty cycle always below 80% @12 psi boost @ 7K RPM.

 

TPS is brand new.. MAP is used.. MAF is used
... I can't believe you're running a modded turbo2 at higher than stock boost with NO wideband...

 

how can some one tune with out a wide band thats like.... pissing into the wind or something....

 

Well.. I suspect my secondaries.. Did a pull starting at 3k rpm with low-11s afr... Right at about 3600 rpm it starts going lean... U can just watch to numbers climp past 12.5
So, i guess i need to check my secondaries wiring as I know the injectors themselves are golden... Ignition on > gound out secondary signal wires a ECU > listen for injector "CLICK"?? .. Or do i supply 12v?

 

As far as i know, the injectors have constant 12v, and the ecu supplies the ground. Also, after seeing my own results, i would highly reccomend having your injectors cleaned and flowed. Cheap insurance.

 

I hope yall realize that when these cars were first being modded past stock boost levels in the early 90s, a wideband was a super $$$ commodity that No Body had them...

I first ran my 9.7 ratio rotors, on 87 octane, at around 7-8 psi(10th ae), WITH NO wideband. yes, it wasn't at it's full potential, and a wideband gets it there. However, tuning without a wideband is an art that can have the same results, good or bad.

 

"...higher than stock boost with NO wideband"! C'mon, w/the "fuel cutoff" disabled the stock fuel system address boost up to 1 atm. Anyways, I use my nose, ear, g-forces, and exhaust gas temps.

1st after seeing if fuel pressure drops to zero quickly when grounding the 2nds I'd use a DVM to see if they cycle when supposed to.
My DVM:
http://www.harborfreight.com/5-in-1-...ter-98674.html
xcellent DVM.

 

I'll check for "click" this afternoon by grounding injector signal wires at ECU w/ ignition on. I just want to rule that out before i start "chasing my tail"... I even left Rx7 at home so i'm not working over hot engine this afternoon... I should be able to get right on it after work.
Same wiring harness -> previous engine died from front apex seal failure... REALLY curious about front secondary injector activation... Will let you know

 

Tested all injectors at ECU with key on... All same voltage... Primary Injector Dynamic (modified Bosch) injectors make loud "click" when grounded that i could easily hear while probing the ECU... Secondary RC injectors make much quieter "click" that i had to run a jumper wire under the hood from the ECU to hear the injectors while grounding.
So.... Yeah.
.... I guess i need to fake a load now, rev to 4k rpm while probing the ECU and look for a voltage drop in the secondaries with my DVM??? *Confirm signal leaving ECU to fire them? *Or, how do i do that?*

 

... Is my wideband dieing? I have an AEM UEGO wideband.. It does NOT preheat i've notived and rarely reads FULL lean when decelling... THESE NUMBERS ARE ONLY WHILE DECELLING... Will read mid to high 16s until it warms up (five minutes maybe) than will usually read 17.7-18.0 until it gets REALLY warmed up (hard driving) when it will read --- (full lean)... Prob just need replacement o2 sensor? I really doubt the controller went bad

 

.. I have an old Sun dwell tach i could wire into secondary injector wires... It would output in a 0-90 scale (which can closely represent duty cycle)... Hmmm

Here's how you do it...*http://www.gassavers.org/showthread.php?t=7714

 

... Confirmed primary & secondary injector signal out of ECU using dwell meter.. Simulated load by disconnecting TPS and plugging pressure sensor vacuum line than reving to 4k rpm.. Secondaries started firing a little over 3500 rpm

Anyone actually running some similar to my setup WITH a wideband?