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Discussion Starter #1
Okay, so I have read the tsrm for the calibration method and was wondering how exactly to apply that to an aftermarket ffim with an RMR 90mm throttle body. Am I even using the right TPS sensor? I have the factory 2jzge (cali spec) TPS sensor on the car. The issue I'm having is uncontrollable idle within the AEM v2. My options at the moment are IACV, vacuum, or TPS? Any ideas?

I'm about to be fed up with this car. It fires up and runs great but the idle just keeps getting higher and higher as the temperature warms up and nothing I do in the AEM makes a difference unless I pull or add fuel. I'm lost
 

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You can adjust idle control duty in the software or just cap IACV off temporarily to see if you’re dealing with an idle valve that’s just stuck open. What is your throttle % reading in the V2 software? Did you go to the wizard and calibrate low and high voltage of TPS? If your throttle percentage is pinned at like 100% you probably have the pins in the TPS backwards. Also check for vacuum leaks.
 

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Discussion Starter #3
I have done the calibration wizard and while the car is idling the throttle reads 1.2%. I have the entire Idle Target Base map set to a flat 1200 at all temperatures but when I try to control the Idle % vs Target it does nothing at all, even if I take it all the way to zero. When I first cold start the idle is at about 1400 and it steadily climbs with the temperature of the car up until I shut the car off around 200 F with the idle at about 2400.

So if I have the throttle percentage set in the AEM then I don't need to worry about the manual calibration following the tsrm methods? That would at least eliminate the TPS as a culprit.
 

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the calibration of the tps with the stock ecu is used to set the IDL pin, so it knows when you are off idle or on idle, you use feeler gauges etc...
With the aem, it does not work that way and doesn't matter where it is set because you do the tps calibration so it knows the min and max.
you don't want your min to be 0, so at 1.2% sounds good.
If you are familiar with how to do it in the software and its still not responding, based on what you said last I would look at a stuck open iacv or a cracked connector/broken wires on the iacv.
I know I have replaced several of those connectors over the years. good luck!

edit* Did you just install the FFIM? an air leak would also raise the idle just like the iacv would, and if you had enough air leaking in you wouldn't be able to bring the idle down with the IACV. I would take another look over the install and maybe some shots of carb cleaner to spot any potential leaks etc..
 

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Discussion Starter #5
Thanks for the response @Ali_SC3, I was actually kind of hoping you would chime in as every time I've searched a question I always end up in a thread where you provide the most logical answer.

I didn't just install the FFIM and the car has been tuned around the IACV (broken at the time) before but the tuner said he never felt he could get the car "to run like a Supra". I have since made a couple changes and want to retune the car but that shop went under and I couldn't find the tuners info to unlock my AEM, so I had to wipe it to get access to be able to tune. So I'm starting from scratch on my own for now.

So Im kind of thinking either I'm having a wiring issue with the IACV or a vacuum leak around the injectors. Since it sounds like my TPS isn't the issue. (Now I need to change the title of this thread)

I just came across a thread last night about the difference in the cali spec and regular lower runners and the way the injectors seat differently. I'll have to try some carb cleaner around the whole intake side and see if I can pinpoint a leak. Would a vacuum leak from an open IACV or injectors cause the RPM to climb steadily like that as the temperature goes up? Thats what seemed weird to me about the issue, I assumed a big vacuum leak would just cause the car to stay at a steady high RPM and not one that climbs with temperature.
 

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Well if the FFIM isn't new and it wasn't doing it before the software wipe, it could be in the settings, the aem is a little confusing for idle setup if you haven't done it before.

I used to tweak mine all the time and some starts it would run away exactly like that until you mess with the settings.
If you have a screen shot of your settings or something post them up and I can take a look at it.
one of them if i remember right is idle correction below rpm and above rpm.
If your idle control below rpm is less than 1400, and your cold start shoots to 1400, you wont ever get idle control and it'll increase idle as it warms till like 2000 rpm.
happened all the time on the aem... depended how well it started and if the rpms shot up too fast it wouldn't ever be under the range for correction.
try raising the idle correction below rpm to like 1600 or 1800 and it'll work if that is the issue.
only thing is it can be annoying to have idle control at that high of an rpm, so you have to tweak the other settings like load etc..
I also usually zero out the timing correction vs idle error, or i reduce the timing swing amount alot.
If you do it right you can do idle correction just via the IACV without swinging the timing.

Generally, If you have X amount of air coming into the engine when cold, as the engine warms up the idle will go up with the same X amount of air.
That is why you usually have the IACV open when cold to add more air to keep an idle, and then close off the IACV to maintain the idle when warm.

for example, when I had no iacv on one of my turbo setups with a FFIM, I would cold start the car using my foot on the throttle and it would want to idle around 4-600 rpms without any throttle input.
by the time it was warmed up with no iacv my idle would be at 1000-1200. With no iacv I had to strike a balance by cracking open the throttle body some, cause if I lowered warm idle to 800, then cold start would not stay running without my foot on the throttle letting more air in. With the iacv you get the best of both worlds, you get more air on cold start, and when its closed the throttle body position is used as a base for the warm idle.

It is also possible you don't have a leak and your throttle body is cracked open too much, cause the iacv can add air but it can't remove air coming from somewhere else.
there is sort of a sweet spot adjustment where you wan't the iacv doing less when warmed up.

Before you get your next tune make sure you can have access to your tune, there are a crazy amount of tuned supras out there and not that many secrets on aem v1 and v2 to hord.
So unless your tuner is the beez knees like Alpha etc.. request for it to be unlocked. In my experience, most tunes need touching up and sometimes tuners are hard to reach quickly.
Or just take your time and learn how to do it, but it is a little overwhelming at first. The good news is you got the cold start down, cause it sounds like it starts fine and that can be tricky sometimes.
 

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Discussion Starter #7
Ahhh, ok I see, so yes a vacuum leak would cause the car to raise in idle speed alongside temperature up until the temperature levels out. So I need to check the throttle plate screw and for vacuum leaks around the injectors and to test the wiring of my IACV. Gonna be a nice saturday trying not to get frustrated. I assume that if I adjust the throttle screw then I need to readjust the TPS in the AEM as well?

The car does start well and I would like to try tuning it myself. I have the time and something else to drive while the supra is down so I might as well learn. Here is a screenshot of the idle chart from the last time I was messing with the car.

248203
 

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Public service announcement time:

If you're chasing vacuum leaks with any sort of flammable liquid, please have a fire extinguisher that is in good condition and ready to be used nearby at all times. Nobody likes a car-b-que.

Good luck sorting out your idle issues. It's one of the things that really makes a car nice, a reliable idle. :)
 

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your idle target 1875 rpm on cold start (idle target base table looks like 1300ish + 500 rpm offset vs start table) on start should not be above your idle correction below which is 1700. lower that rpm offset vs start table to like 200 rpms instead of 500 and taper it to 0.
That will give the aem a chance to have more time to correct, then you can start messing with the idle % vs target % and hear/see the change in idle.

Also 1300 is high for all temperatures, to get it more normal make it like 1100-1200 cold start and 800-900 when warm.
This will also help keep the total idle target number below the 1700 number which is fine to start with.
you can go back and tweak it later but you are on the high side and the aem doesn't like that.

I would also zero out the rpm offset vs tps table to start with.

Its looking more like a software tune issue to me, I wouldn't mess with the throttle plate screw or tps yet until you play with the settings some more.
Tuners pretty much know the settings that get them close, and for some reason they never seem to be whats in the basemap, but it will usually get it started.

I can also tell you I had that run away idle issue in winter lots of time when I was on an aem ems v1.
when that happens shut it off and then restart and try again, usually the idle wont shoot so high on the second start.
generally you need to tweak all those start and idle parameters each season until it works all year round, or set it for a large amount of + and - correction.

Last tip before I forget, when you get to the final part of tuning that idle target vs % table (the main one), you want to set those so that you have a negative correction under idle learned value. somewhere between -2 and -5 will do the trick. that makes it so that when you let off the throttle you will have the air you need to not stall from a rich mixture (at 0 correction), and then the idle will pull back to -2 or -5 while you are actually idling. If you tune for 0 correction or a positive correction, the idle will dive when you let off and takes a second to catch itself.. which isn't the right way to do it.

good luck! It's not so bad once you start messing with it and then you won't have to rely on someone in the future for the small stuff.
I would still consider a full tune fuel and timing wise on a dyno some day but make sure they don't lock you out.
 

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Discussion Starter #10
Haha, thanks @te72, sometimes we all need a safety reminder. I appreciate you looking out. I do keep an extinguisher nearby. Cheers.

@Ali_SC3 I will try your settings tomorrow when I make it out the the garage and see if that helps me out any in trying to get my idle to respond. Ill try everything I can think of in the AEM before I start messing with any mechanical workings. I don't need to "fix" any problems that aren't actually problems.

That idle target of 1875 didn't start out that high when the car was cold. It crept up along with the actual idle speed. I think when I first fired the car it was running about 1400. I have the idle target map flatlined at 1200 for the moment until I figure out what the problem is that isn't letting me manipulate the system.

I would love to get this thing tuned for idle this weekend. I'll let you know how it goes. You've been a big help so far.
 

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Discussion Starter #11
yep, still stumped. I had no luck in playing with any settings in the AEM. I still have no control over idle at all. Could there be some reason that my AEM 3.5 bar MAP sensor isn't triggering my IACV. My engine load just chills around -9.9 while the car is running unless I step on the throttle. I've read that the infinity EMS need the 12v terminals removed in order to work. Is there some sort of wiring I need to change for the IACV to respond to a MAP sensor in the AEM V2. I still can't find a vacuum leak anywhere on the car and the throttle plate and TPS are calibrated. I'm still lost
 

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Discussion Starter #12
Ok, Found some new tables and charts that relate to the idle and to the IACV. But Im not sure what all is set correctly and what all isn't. Have a look and see if anything jumps out at you.

248303
248304
 

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Ok, Found some new tables and charts that relate to the idle and to the IACV. But Im not sure what all is set correctly and what all isn't. Have a look and see if anything jumps out at you.
View attachment 248304
I'm a bit more familiar with Megasquirt, but something did seem off to me. Top left panel. Idle target: 3000???

That seems odd to me.
 

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Discussion Starter #14
The idle target was so high because the whole map was selected when i took that screenshot.

Im about fed up. the iacv works but nothing i do in any chart or setting has any effect on idle at all. The only things that make idle respond are timing and fuel.

If I adjust my idle FB min and max then the learned value just maxes to whatever number i set it at. Im about to take a hammer to this EMS. Ive been battling this thing for 2 years now and have given up on it several times and its about to go in the trash.
 
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