marcucci

I'm not sure why they are having a hard time with a simulator... I've verified that a 10Mohm resistor inline with the sense wire on the O2 works, I am pretty sure it would work on the S2k as well. There's no need to "simulate" anything.

The ECU learns at part throttle, yes, but I'm not sure why you are worried about your VAFC and the learning. Whatever the ECU learns will be undone when you restart the car; what the VAFC does will not. I guess I don't understand what you're worried about, unless it's based on the fact that the VAFC was tuned with the ECU not reset, so you are dependent on some learned parameters for narrow throttle correction. But that's not a very good idea, since the ECU will learn what the VAFC has done and attempt to "correct" it. It should eventually tune out what the VAFC has done.

cbender

Marcucci: thanks for the note. I did pass your idea on to Justin at Caspers. I didn't fully follow his explanation, but he did have a reason why the 10Mohm resistor wouldn't work on the S2K. As for pulling the backup fuse, you've got it -- my tuning was done without first resetting the ECU, and I don't want to have to retune again (actually, that would be tuning it for a fourth time!) on narrow throttle with the ECU reset. And, besides, I like the "your headlight's on" warning buzzer. Plus, my hesitation to pull the backup fuse is, in part, pure stubbornness.... having bought the simulator, I want it to work... :-)

Ascended Sayian

cbender - thanks for keeping us all updated on the product - I for one am real anxious to hear whether Caspers will come out with a successful product. I've got a straight pipe waiting for install, but I'm waiting for something like the simulator - so I can do it all at once.

Again thanks cbender

AndyP

Ascended - What exhaust and test pipe do you have?

Ascended Sayian

Apexi WS Exhaust + Speed / Spoon stright pipe

sfphinkterMC

comptech has a simulator that works on their car and they are supposed to offer it as a retail product. i believe it takes feed off 1st o2 sensor so ECU doesn't see a disparity.

also i was told that even if the CEL is illuminated, if u were to throw a major code, the CEL is then designed to start flashing so it still warns for other serious malfunctions. anyone have experience or can test for this?

schwett

i'm a little confused by your references to the vafc narrow throttle settings.

the only purpose of narrow throttle tuning on a vafc is to prevent exactly the situation you've described, in which the ECU is forced to learn and hold a large LFT (long term fuel trim) in order to keep the car running properly. this is BAD because unlike short term fuel trim, which is based only on the primary O2 sensor values, LFT is applied EVEN IN CLOSED LOOP. this means at wide open throttle the computer is trimming the specified pulse width in the "map" to compensate for the long term changes it has observed.

the narrow throttle settings of the vafc should be adjusted so that the ECU does not require a large long term trim. if they are wrong, they should be changed. narrow throttle tuning is really easy, and does not require the use of a dyno. get yourself a datalogger and laptop, reset the ecu and zero out the vafc. cruise around for 10-15 minutes staying OUT of full throttle and boost, and observe the long term trim and short term trim on the datalogger. if the graph of the short term trim is shifted positive, and the long term is creeping positive, you are lean, and you should enter a positive correction across the board on the vafc in the narrow throttle tables. if the graph is shifted down, you're running rich (obviously much more likely in your case with (i assume) an fmu and fuel pump) and the narrow throttle settings on the vafc should be set to lean you out. essentially, you repeat this procedure over and over until the long term trim is zeroed, and the "average" of the reading from the primary O2 sensor over time is the ideal .5v that the ecu is looking for.

there are three benefits here - a) you can tune your high throttle settings without worry that the ecu is applying a large and inconsistent correction to it's stock maps, b) you won't have to worry about too rich/lean codes, which you will eventually get if your LFT is REALLY large, c) you can reset the ECU, unplug the battery, work on the car, whatever, and the car runs fine.

finally, it's also pretty easy to make a guess at what the settings should be. the formula for flow is rated injector size * sqrt (actual fuel pressure/43). e.g., the s2k was designed for

cbender

Schwett, thanks for the note. There's a lot here to digest. I may come back to you with a PM for some advice. I appreciate the help.

All, just fyi but Caspers sent a new simulator, which I'll probably install early next week. Stay tuned for an update mid to late next week.

AndyP

Pleeeeeease tell me it works. :fingers crossed:

cbender

The new part will be installed early this coming week, so expect an update in about a week.