EMB and 360cc injectors
 

Received the following in the form of a profile comment, and felt it warranted a proper dicussion:

I gather you've been experimenting with larger injectors on the stock ECU.

Yes, the EMB is probably capable of wrestling these injectors under control, as well as providing for variable ignition retard. I won't be able to properly idle injectors that are significantly larger than this, certainly not the 550s you alluded to in an earlier message.

I'd suggest however that unless you are being offered a spectacular deal on one, that you consider other options as well. The EMB is getting a bit long in the tooth, and it's fairly limited as compared to some other devices. Its sole means of reducing fuel is by trimming the AFM signal, which is why there's a practical upper limit on the size of injector you can run. The eManage Ultimate, for instance, trims the injector pulses directly, and can thus handle 440/550 injectors with ease. Likewise, there's an AEM piggyback that's gained some popularity which has similar features.

I've been running an EMB on my 1999 for over a year with no trouble. I'am also using 360cc 323GTX injectors A/F at idle 14:7
I think people forget that the ecu's in the Miatas are 1980's tech. so even the old EMB is still a upgrade. 360's on the NB = over 400cc due to higher fuel pressure anyway. easy to add fuel and or timing as well as take it away I'am running 10psi at wot A/F 11-11.5 @ 70 % duty cycle. 210whp 180tq @ 6,500 rpms T-25 .48/.49

Yeah, I ran 370cc Scion injectors on my NB with a EMB.

ive been running 360cc injectors on my 1990 for three years now without ANY issues at all. the car idles perfectly and i have data logged the afr's at idle and they are just like stock.
The 330cc limit was imposed because thats the value of injector change that the stock ecu Stops reducing the injector pulse width at idle due to afm voltage. if you set your injector change to more than 330cc, it will still run the "same" afr altered voltage as 330cc.

if you need to lean out your idle even more for whatever reason then you can also change your clocking crystal in the stock ecu from 4Mhz to 4.4Mhz for an instant 10% leaning of your base fuel map.
If anayone is at all concerned about overfuelling with 360's then the crystal mod is the first thing to think about. (it will also remove your 7200rpm rev limit. :)

Having said that the megasquirt is a better choice if your electronically mindede.

I've been having problems programming my EMB for the past year. I have a nbfl 2002 1.6cc with O2 clamp (olderguy) and Fuel Injector Clinic 365's, 8psi on a garrett 2554. When i'm in the highway setting up the values on the map everything seems ok, afr: 11.2-11.7. The next day i'll run the car and it'll be rich again 10.3-10.6, no matter on what gear i'm on or revs. Why does it do that? Are my injectors too large? Should i look into something that has slipped my mind?
I was hoping that with the o2 clamp the problem would be solved but not much light has been shed on the matter. But i have to admit that the hesitation of adding more fuel while going into boost (0.1,0.2 bar) is gone and i know that the o2 clamp worked.
Any suggestions guys?

Wow, thats some thread necromancy.

Basics first. You are using the injector correction? AFR's out of boost?
Your injector size should be fine, i run 425cc without problems.
Take a log when in good afr´s, make sure to log added and total injector duty.
Added duty certainly should not change without tuning changes, but normal might if some parameter is off.

Also, when tuning, You are making sure that the newly tuned map stays in the EMB, i guess you have a couple of saved maps from tuning, compare to the map that is in your EMB on startup when too rich, might be that it doesn't stick.

AFR's out of boost are around 14.7 (+- 0.3). I don't remember the correction factor, and i can't check it at the moment (for sure the "after correction factor is 360", i don't remember the initial).
Whenever i change values on my map i export to the main unit, so i don't see the reason why it shouldn't keep the values changed.
Yes, i have compared the map that i saw in front of me with the one that i saved, and they are the same.
I will also check the duty cycle but i don't quite understand what you mean by "Added duty certainly should not change without tuning changes, but normal might if some parameter is off."
Any more ideas??
thanks btw

To clarify, if added duty goes up when it gets rich, then it is the EMB adding, and if so, check your maps. This probably is not the case.

If normal duty goes up, then it is the ecu that for some reason is adding more fuel. Why it would do that I'm not sure, but it would probably be helpful for you knowing is its the oem ecu or the e-manage that is messing up your fueling.

Also, make sure that your o2-clamp is correctly set, if you are feeding the ecu with a really lean signal it will throw all the fuel it can at the engine. If your fueling was fine before installing the clamp, I would say this is a likely culprit.

From where can i see whether it's the ECU or the EMB adding fuel? Give me specific info please, because i'm not that experienced.
Before i install the o2 clamp the tip-in fueling was 14.7 even in 0.1,0.2 bar condition. Now it fluctuates around 12.8-11.5 at the same boost levels, so the signs are optimistic but on WOT and at 0.55 bar it goes to 10.3-10.6.
The problem of "losing" the values each time dates back a long time and i've been having problems since then, it's not the o2 clamp that changed something.
I had also observed in the past, that when the check engine went on (the fault referred to the O2 sensor which was not true and i have changed 2 already) that's when i used to "lose" the inserted values. When i erased the fault from the ECU it seemed to recover for some time and then it reappeared. But when it reappeared (the check engine light) it didn't lose the values (going to rich fueling at WOT) right away, but after a few days!
I know it's a f...ing mystery on what the hell is going on. I have other people with 1999 models having no trouble at all. On the other hand i know some owners of nbfls who half of them have trouble and the rest don't, go figure!!

Well, I'm posting from a computer without the software installed. But you do have a menu that says real time display or something similar, where you can see curves of what is happening at the moment. You can also record this.
Here you have boxes you can tick, where you can choose to see injector duty;
normal - what the ecu puts out according to oem map.
added - what the emb adds.
total - combined and ultimate duty that the injector sees.

if you check the voltage from your o2-clamp, what does it show?
I'm not sure this is your problem, as it seems inconsistent. why your ecu / e-manage would change map until next startup is still a mystery, but data will obviously help you get a grip on the problem.

The check engine light is interresting, the car might be going in to safe mode, i.e. rich and retarded timing. And in that case you will most certainly see the "normal" injector duty go up if you log it. What code? p420? might have to do with your rear O2 sensor reading to similar to the upstream one, in that case it can be that the catalytic converter is dead, or it could be an upstream air leak. If this would make your car enter safe mode however, I don't know.

I really don't think I can help you more than this, but please put it out here if you solve it, always nice to help the next one in line.

Well i changed my zeitronix o2 sensor and things got better i must say, but the check engine light still hasn't gone off.
I checked duty cycle: Normal d.c 63%, Total d.c: 72%, rpm:6800. The injectors are set from 190 to 365.
If the car would enter safe mode it should be rich in all cases, right?

Yep, would be rich and retarded at all times.
The light will stay on untill you reset it.
But your zeitronix? Is the WB connected in place of one of the OEM narrowbands?
Good thing that your getting closer to solving it.

Can i use These on an 03¿