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-   -   Engine won't idle after ID1050's installed (https://www.miataturbo.net/megasquirt-18/engine-wont-idle-after-id1050s-installed-98734/)

Gregor 12-08-2018 08:13 AM

Engine won't idle after ID1050's installed
 
1 Attachment(s)
I have a 95 1.8 running: DIYPNP MS with MS2/Extra release 3.3.3 and I was running RX7 550's.

I just changed to ID1050x, now the car starts, runs for a few seconds and dies. I changed my Req Fuel to 3.0, my injector size to 1065cc, and injector deadtime to .995ms at 13.2V

Have I missed a setting?

Thanks in advance.

irodd 12-08-2018 11:23 AM

batt correction 0.105ms/V
multuply ve idle cells by 2

curly 12-08-2018 11:34 AM

Not sure what irodd is saying, but if it keeps running if you feather the throttle a little, try to keep it running in idle valve test mode, and slowly draw the idle down, looking at your AFR. More than likely these injectors require a different warm up curve or idle VE than your last injectors. You could also band aid it by selecting all those 3X cells in the idle range and making them 40 or 45, seeing if that works. Just hit the back button a few times if it doesn't.

Also, your idle voltage correction curve is really weird. Nothing except a 5% gain at 14 volts, which is where you should normally sit, so you're really just always adding 5% to your idle valve duty cycle. Fix your idling issue first, since it supposedly used to run well on this tune, then look into changing your idle voltage correction to more reasonable values.

irodd 12-08-2018 11:38 AM

Sorry, typo batt corr 0.105

https://cimg6.ibsrv.net/gimg/www.mia...a8b6513095.jpg

irodd 12-08-2018 11:55 AM


Originally Posted by curly (Post 1514028)
Not sure what irodd is saying, but if it keeps running if you feather the throttle a little, try to keep it running in idle valve test mode, and slowly draw the idle down, looking at your AFR. More than likely these injectors require a different warm up curve or idle VE than your last injectors. You could also band aid it by selecting all those 3X cells in the idle range and making them 40 or 45, seeing if that works. Just hit the back button a few times if it doesn't.
Also, your idle voltage correction curve is really weird. Nothing except a 5% gain at 14 volts, which is where you should normally sit, so you're really just always adding 5% to your idle valve duty cycle. Fix your idling issue first, since it supposedly used to run well on this tune, then look into changing your idle voltage correction to more reasonable values.

I am saying: change injector battery voltage correction from 0.2ms/v to 0.105ms/V and multiply idle cells by 2 (you suggested multiply it by 1.2) and seeing if that works.

curly 12-08-2018 12:45 PM

10-20% is a big change, and will tell him if he's stalling because of a lean condition, or if it's something else.

A 200% change is most likely going to flood the engine, causing a different problem. I'd be surprised if a well running car required not only the proper change in required fuel, but also 200% more VE.

Gregor 12-08-2018 07:15 PM

Thank you for the responses.

I tried changing the battery correction voltage first, then dividing my VE idle cells by two. Same condition.

I also noticed the tuner studio software reads my battery voltage at 11.90V, but with a voltmeter, I am confirming 12.7V(whenever the car sits for a while, I put a battery tender on it.)

I will try to play with the idle valve next. I can't keep the car running by feathering the throttle, but I can rev it up if I step harder on the throttle, but then it leans out and stalls.
I can bounce the rpms from 900(about to stall) to 4500rpms, but the engine sounds like it is missing.

Gregor 12-08-2018 07:56 PM

Ok, new development, now the car idles longer, at 17-18.5 AFR. Both ASE and WUE are on, no idea why it is so lean.

curly 12-08-2018 08:27 PM

First off, he said multiply by 2, not divide. Hopefully that was just a typo on your part.

If it's idling at 17-18, multiply the idle cells by 1.25, that's 17.5afr divided by 14afr, which is a good way to calculate how far off you are. Aka, you need 25% more fuel or there abouts.

irodd 12-08-2018 08:38 PM


Originally Posted by Gregor (Post 1514076)
Ok, new development, now the car idles longer, at 17-18.5 AFR. Both ASE and WUE are on, no idea why it is so lean.

plz post the tune and log files

Gregor 12-08-2018 09:06 PM

I wish, I misread(possibly due to sitting in exhaust filled garage). I thought when irodd said multiple cells, i thought he meant many cells. I have increase my VE table by 25% and it now idles very close to target. I will play with some more when I won't annoy the neighbors as much.

I was under the impression that since I nearly doubled the injector size, I would need to decrease my VE table values.

Thank you so much for helping me.

Any chance Curly could point me in the direction of how to tune my idle voltage correction curve?

irodd 12-08-2018 09:15 PM

https://cimg8.ibsrv.net/gimg/www.mia...8b4430d5f0.jpg

Gregor 12-09-2018 05:15 AM

Thank you!


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