What exactly is involved in adjusting my idle afr for my tii? My car is idling rough and very rich, and I am trying to pass the smog test. I ran the smog test with a cat (no airpump) and some methyl hydrate in the gas tank, but my car managed to pull a 1500ppm (max allowable is 328ppm) for hydrocarbons, and the carbon monoxide was slightly over the max allowable value. Any help is appreciated, thanks.

 

You pull fuel from the IDLE bins. Do you have any way of measuring AFRs?

 

I PMed you Aaron Cake.

 

Show us your idle map.
Ill lean it out for ya.

 

I'll keep you posted. The only windows computer I have is my mom's laptop and it's in a shop getting fixed. I will pm you rx72c if that's okay.

 

I'm going to reply to you PM here so the answer will benefit everyone. Hope that's alright...

It may be difficult to get an emissions friendly idle without some way of measuring AFR. But, you can try.

Get the car fully warmed up and then make sure that the idle is steady enough. Begin pulling fuel. You will notice that RPM will increase, as will vacuum. Continue slowly pulling fuel from the current load bin and slightly from the surrounding bins. The best idle is where the engine is smoothest and vacuum is greatest. Most emissions tests will want a factory idle RPM, which for the RX-7 is 750RPM +- 50. You may need to physically adjust the hard idle screw while you are making fuel changes. It often helps to give it some timing as well. I tend to idle these cars around 15 degrees.

It helps to have a slightly richer bin on overrun (below idle speed) to "catch" the engine if it attempts to stall.

No idea. Most tuners will idle engines ridiculously rich for some reason. It think it makes their job easier and masks a poor tune. The engine should idle well around 13.5:1. Maybe a little richer if it is unsteady or you find RPM dropping with electrical loads.

It takes a considerable amount of time to tune a car properly, but a whole day just to make it pass an idle test seems a little excessive.

If you have the laptop adapter, you can save your map onto the adapter. But unlike other ECUs, the Microtech won't let you save maps to disk or edit them offline.

 

Thanks aaron, if I hit any more speed bumps I'll let you know. Rx72c is helping me with the idle map, so hopefully just leaning out the idle mixture will do the trick. One more question, since that microtech adaptor also stores your maps from what I can understand, will it be fine if I remove it?

 

It's fine to remove the adapter. It is only used as "disk space" for saving maps. But you do need it to communicate with the ECU.

 

I noticed you said you should be able to get it to idle at 13.5:1.


Their is a not a chance in hell with microtech to get a good idle at that afr mixture.

As soon as you switch if off and restart it it will just stall. the afterstart feature on the microtech only goes for 5 seconds.
Thats why most microtechs are setup for 11.7-12:1 to cover up for all the wholes in the microtech system. it is not laziness thing, not on my part anyway.

 

very true. Thats the only way my car will run.

 

My car idles fine at 13.5.

The limited configuration of the ASE is one of the reasons the Microtech is not the best ECU choice. I agree, it is harder to get a decent startup with such a lean idle. I find the only real time it is an issue is on certain hot starts. It may want to stall but a quick blip of the throttle will take care of that. That to me is an acceptable compromise compared to a stinky, plug fouling and fuel wasting idle. Adding a bit of timing dramatically improves a leaner idle, as well as a bit more split. But once again, the limiting factor is the Microtechs poor timing maps.

All the Megasquirt cars I do will start up and idle happily at 13.5. Using the BAC valve to regulate idle speed in closed loop makes the car start and idle better then stock.

 

I will love to have my bridgeport idle at 13.5:1 so i can save some fuel.Can you share your idle map?

 

My idle map is nothing special. I'm using the matrix table with different sized injectors so I doubt it would be much help to you. But I can post a screen shot if you wish.

Dial in more timing then people recommend. Idle around 15-18 degrees with 15 degrees of split and you will find a dramatic improvement.

 

Thanks for the tips Aaron

 

So the adaptor is just for saving extra maps that you want to keep, not the ones currently being used by the ecu when driving around? I can drive around with the adaptor unhooked and a map is programmed into the ecu itself, not only the adaptor, correct? By the way, I will have my idle map posted soon for those willing to help.

 

Correct. The adapter gives you 4 "memcals" which are space for storing 4 maps. It is only necessary when the laptop is connected.

 

UPDATE!I have my bridgeport idle at 12.5:1 with 15 degrees of split,timing is at 20 degrees,rpms at 1150 pulling 15" of vacuum,my plugs look way cleaner now and tan in color,she sounds great really steady loud brap brap brap.

 

I'm with rx72. It will die if I go any leaner than about 12.8

 

+1 with rx72 my idle afr is 12.5-11.9

 

My car just passed aircare with flying colors! One problem though, my engine seems to dip down to maybe as low as 500rpm and almost dies when I first start my car. I have to give the car a bit of gas to get it to idle normally. Also, my car does the same thing driving when I disengage the clutch to coast, letting the rpm drop. I have to ease off the throttle to avoid this. Is this caused by a rich afr?

 

Richen up the bin to the left of you idle a bin a little bit.

Also bump the idle timing slightly in that same bin.

Try increasing the after start percent a little to solve the startup issue and make sure that with the now leaner idle, you don't need to increase the cold start enrichment.

 

Hm, I'm having trouble connecting to my ecu. Is your computer supposed to show that you are connected as soon as you plug in the computer and switch the ignition to on? btw, does the free software from microtechefi.com work well?

 

The free software is the same software youll get when you pay for it.

Also the dip is from having a lean idle.

If you richen it up alittle. It will stop doing it.

 

I'll find a way to connect to the ecu and I'll show you guys the idle map. I don't feel like paying for a rebuild if you know what I mean :p. I'm very paranoid about the car running rich, maybe I should invest in a wideband o2 sensor for peace of mind... Would I be able to just run the wideband sensor to a gauge without having to connect it to the ecu as well? My stock o2 sensor is connected to the ecu and my afr gauge (not getting any signal from the sensor). But anyway, I don't think my ecu is meant to run a wideband.
I'll keep you guys updated, I'll be needing a lot of advice and help.

 

If you are trying tune without some kind of feedback (wideband is easiest) then yeah, that's not going to work very well.