hi, I have a stock 91 miata with a speeduino PNP i got it to start up but wont' idle, I have to hold the throttle to keep it running and once I let go it just dies. I left the stock afm installed and pluged in. I'm going to link a copy of my tune and a data log. can anyone help me understand whats wrong?

 

Variable TPS installed? Wideband?

Read this too: https://www.miataturbo.net/ecus-tuni...2/#post1484735

 

I don't have either currently, I have already tried the afm connection mentioned in that thread. it was to my understanding that you didn't need a wideband or variable tps to get a car running on speeduino, and I was hoping to figure out why it won't idle before I got my wideband.

 

As a starting point, try turning off the idle control. In your log I can see the idle value being around 28%, which will fully close the valve (These valves aren't linear in operation). With it turned off, the valve will default to about 25% open, which generally gives a stable idle, though a little higher than normal.
Was that log taken when the car was warm?

P.S. You also have your idle direction set to reverse, which is going to cause all sorts of confusion when you try to tune the idle control.

 

I tried turning off idle control and it still dies immediately, although in comparison restarting it is almost instant now. I will try to data log it tomorrow when I have a little more time.

 

You need a wideband NOW.

 

You can't make it run properly without a wideband.

 

This is correct, the starting procedure isn't really calibratable with a wideband and doesn't rely on the TPS at all. But you've already got it started, now you need to tune it. How would you now if your idle VE is accurate without a wideband? I would take a step back and do some research on standalone ECU's before you do any damage while tuning.

 

I understand that I need a wideband to get the car running properly, but would a lack of a wideband really be reason for the car to not idle? the seller for my kit seemed pretty confident that the car will run and drive without a wideband installed. I'm gonna stop messing with it for now until I can get a wideband into the car.

 

anyone who advises another to run a standalone without a wideband, should no longer be considered trustworthy.

 

You can idle without a wideband, sure. You can even drive the car without a wideband.

But it's going to be a looonnngggggg, shitty, and dangerous road to get to that point. Or you can spend $150 on a wideband and get there quickly and safely.

 

Would a car idle at 30 AFR? Would a car idle at 5 AFR? How do you know that you are injecting the proper amount of fuel? Your issue may be fuel, it may not. Who the hell knows.

 

take out 20% from the whole VE table and try again.

then don't drive anywhere, get a WB and get it tuned :P

 

Did you get any further on the logging?

With the last one you posted, was that in a warm engine? The log indicated it was cold, but the warmup enrichment was off and the pulse width was far too low for a cold start (assuming stock injectors etc). Leave the idle control off for now and then start.

Is the car otherwise stock? If so, did you start with the PNP base tune? There's a LOT thatst a little bit off in your tune is all.

 

Hadn't been getting emails from this since my last post, I have gotten a wideband in the car now. I still cant seem to idle, I was working off the tune that came with my pnp. the car runs around 16-18 afr while driving which is quite close to the14.5 I'm looking for. But looks like its leaning out at idle. I'm all stock except for a test pipe and a catback. I'm gonna put in my lastest data logging which my laptop died during.

 

That's not what I'm seeing in your log at all. According to that it's going VERY rich at idle as far as I can see. Which wideband are you using and have you calibrated it in TS?

If you're seeing lean on a wideband gauge, the I'd say your calibration is out as the log is reporting it as being very rich at idle.
I'm guessing you don't have VTPS on yet?

 

I found that later on, I have tried connecting the ecu connection to the same as my gauge but will have to check it later.

 

ok update I now have my wideband sending the proper signal to my ecu. been trying to get it to idle but car runs lean, and stalls out the second I take my foot off the pedal. this is what my tune looks like and my latest datalog. I have tried turning idle control off, and nothing as well. if possible it would be nice to see another 1.6 tune as something to compare too.

 

The log and tune both look reasonably OK. Your idle is a little lean, but nothing too crazy and definitely should idle by itself at that. Your AFR reported in TS now matches your gauge I'm guessing?

Definitely leave the idle control off for now until you find the stalling problem. It looks like it's on in your latest tune/log.

In terms of the hardware setup, I'm guessing you still don't have a VTPS (As there's no TPS movement showing in the log)? If so and you've still got the original switching TPS on, have you disconnected the plug for this (and preferably wired it with a resistor per the manual)? Obviously a VTPS is the better way to go, but you can still run with the original, however it must be disconnected.

 

I have not gotten a vtps I was hoping to get one from a auto but every person parting out a auto has chosen not to reponre. I still have the stock tps in place without the resistor. I have gotten the car to idle but I can't get it above 500rpm. I'm going to try the resitore hopefully I can acquire one tomorrow.