So it appears the "box" is making it run leaner huh. Like maybe it's fooling the ECU into thinking you're too rich? Did you look at the fuel trims?

 

Well, I think it's just not faking out the ECU like it's marketed as being able to do - so the ECU is fighting me trying to force fuel. The _output_ A/FR is still 14.7:1 under boost, so the box is "working" in that regard, but it's obviously not enough.

The fuel trims were hugely negative, so it's taking out fuel. If I reset the ECU, then I get control back with the SMT. That makes sense based on the ECU having a fresh look and not having loaded huge numbers.

Gadget wrote me overnight to offer up phone support. Nice of him, but I'm past that. The box has had it's airflow killed, life is better, and I'll be ripping it out the first chance I get.

 

Update...

Gadget didn't give up, kudos to him, but it's driving me nuts. He strongly suggested that I replace the TPS. The one that's there is only a couple of months old, but as a pacifier, I replaced it yesterday.

The old one tested fine, and the new one dosn't change the behaviour at all. $45 down the tubes.

The box is getting ripped out. Gadget may still take it back, dunno.

 

Don't forget that the AFR only reads oxygen. So, if you add TOO MUCH fuel and you start getting rich misfires, more O2 will be in the exhaust stream and the AFR will indicate a lean running engine.

 

Valid point, but I can push the A/FR rich for a while until the ECU starts throwing large negative numbers into the trims. Alternatively, if I "take out" fuel, the engine will die.

 

This thread interested me cause it is related to some issues I have been experiencing with my setup. I too was confused about the ESC function; how it affects the ECU to permit user-selectable fuel trimming.

I wrote a very specific email to Split Second's tech staff detailing a problem and asking for a circuit level "theory of operation" to aid me in my understanding of the system. I also explained how much time Gadget has already spent with me - and my desire not to bother him further.

Their reply via email only said that they contacted Gadget and he would be in touch with me. So I am guessing that either they don't want to be directly involved with customers that purchase their devices through URD, or I just happened to contact someone too busy.

Anyway, since my 1998 setup uses the old Bank 1 dual O2 sensor scheme, I have played with the R4 "output b" settings to apply the "ECU trickery" at various boost/RPM triggering levels. I was also confused at first, thinking that it pushed the ECU into open loop when active. After I realized this was not correct, I then began to make progress.

I set my "output b" to 3 psi and 2800 RPM. I tune my fuel cells at 3 psi and 3K RPM accordingly. I am still working on dialing in my map, but I believe it is functioning. It is a tad more sensitive since I still have to deal with assuring the open-to-closed loop transition occurs smoothly. But I am glad you all posted your findings, since all related info is an education to me.

My REAL AFR problem is baffling me at the moment. I cannot tune around it and I am clueless as to the cause or even a way to progress with further troubleshooting.

My maps are fine, AFRs are as expected with one big acception. I have a freak LEAN condition that jumps in as a severe threat. When at WOT and progressing in the power band, the AFRs will suddenly go to LEAN, (above 20:1 on my PLX300 unit readout).

Realtime observation reveals nothing unusual in the maps for the corresponding cells during that moment. I of course let off of it immediately, and blip the throttle to check the AFRs once fuel is re-applied, and the readout is then "safe" as programmed by my map. I have created multiple tuning files to provide richer/leaner AFR's under WOT, (10.7 - 12:1 ranges). The bug still hits me regardless. It can happen at 4K or nearer to redline, usually when approaching 80 miles per hour. It is maddening.

The other condition which I suspect could be related occurs at idle. Mostly triggered after returning to closed loop and decelerating to the slow or stop scenarios. The AFRs will go into the 16 - 18:1 range and the engine will idle rough - like you would expect. Sometimes, it will correct itself after a few seconds. Other times I must blip the throttle and it will then "find itself".

The RPM range where this is prevailent is around 2K - 1500. Again, no map cells are rough in transition or of values that would seem to cause such. It may not happen one day, or in several. Outside temps of 40 - 50 degrees seem to make it more likely, particularly when damp. But it has also done it in the summer. Sorry for the lengthly post. But desperation is setting in.

EDIT/UPDATE: LEAN condition at WOT cured - (Yes, Thanks for the aid Gadget). Intermittent lean idle however, is a different story. It is worse than ever. It happens after enjoying a few good runs under boost. After letting off of it and coming to idle, AFR goes very lean, (just during idle, but stopping is not required to produce the problem). Absolute insanity. ANY constructive suggestions, PM welcomed.

'98 T-100 4x4 SR5. Gen IV TRD SC, 5VZ-FE, URD fuel kit/2.2" pulley. TRD ceramic coated SS headers, IPT trans VB mod, auto-trans cooler, Amsoil fluids, Iridiums, K&N air.

 

I had similar but worse symptoms with my ESC1 hooked up to the point of stalling. I have sinced ditched it and went instead with a MAPECU2 that uses a voltage based alteration of the 02 signal instead of a frequency based on like the split second box. I have had great driveablity with it and has proven to hold it "tune" without the stock ecu overriding it over time. Further, it is adjustable according to rpm and boost level for a more fine degree of tuning.

 

I worked with the guy with the T-100. The problem with his lean condition under power was a faulty wideband sensor on his PLX wideband unit. It was not accurately reporting the actual AFR. New sensor has been installed and all is well.

Gadget