Vtps/AFR issues
 

Hi y'all

Im having a weird issue on my 91 miata so, i will try my best to give a lengthy explanation.
I've wired my DIYPNP up according to diyautotunes instructions for the vtps, and GM sensor. I loaded up braineack's basemap for a diypnp,set the timing correctly,rescaled the table to 100 kpa since i'm running NA, put in the correct injector size for my 1.6 and followed the guide on mx5nutz regarding the iac valve ( Tuning Idle Valve - Ms2 - Guides: Forced induction - MX5Nutz Forum) . Also,i've got the full version of Tunerstudio

So far so good.Once i calibrated the TPS ( which gave me a full sweep from 0 to 100% ) and wanted to start the car , it seemed like my TPS was grounding out. I tried this on both a Kia Tps and a Bmw one. Both gave the same problem.As you can see in the clip i uploaded,the car doesn't start with the vtps connected.As soon as i crank the car, the tps shoots up to 741. Without the tps connected, my car actually runs . My common sense tells me this has something to do with wiring.I'm aware that i didn't switch the TPS pins on the stock connector around, so my readings are backwards so to say


At first i thought it was a bad ground, so i connected my wideband (negative terminal)to the engine block ground bolt near the FPR instead of on the cigarette lighter. This seemed to help a bit. I also change the TPS lag factor.This also seemed to work, but as soon as i start the car again, the issue came back .
I'm considering putting the stock TPS back in and rewiring the diypnp to accept the stock Tps ( which isn't more than an on off switch).I've seen that a VTPS helps with accel enrichments and stuf, but i'm not on that level yet and try to do everything step by step, so i actually know which values im playing around with before asking questions

The car is running at 1500 rpm and going down to about 900 after warmup.My wideband is reading 10 AFR at startup,and increases when i give a small blip of throttle so i know my wideband works.At this point i'm not sure if it's a good idea to start autotuning so i didn't drive around the car yet.The car bucks after halfway throttle so i guess my VE table is not correct yet.

So in short i've got these questions

1: what could cause my VTPS to give such weird readings
2: could i run my diypnp without the stock TPS without any issues
3: how do i proceed from here making the car driveable? As far as iv'e seen,the lower idle cells should not be tuned with autotune and the car should be idling @14.7 AFR

With the key on and engine off, what voltage do you get on your TPS terminal at closed and at wide open throttle?

First of all happy newyears!

Well, i decided to resolder the connection between TPS SIG and 4L, and between VREF and 1N with a thinner wire . Now it reads correct after calibrating the tps about 3 times trough tunerstudio 😮I checked it again after leaving the car sitting for a while and the tps still reads correct.Seemed to be a bad solder joint.
That issue is now solved.

The next problem i seem to have now is tuning the acceleration enrichment.Car seems to ''buck'' (sometimes going full lean)when i stab the throttle.AFR goes rich for a second and then bounces back to normal.Google told me that it had something to do with the enrichments settings. I read the diyautotune article ( https://www.diyautotune.com/support/...el-enrichment/ ) .I don't really know where to start with the settings. I am still on Brain's basemap, which works pretty good.

Post up a data log of the AE issues and a copy of the tune that was in there when you took the log.