420A 2gNT AFX ECU questions

[nothingfiction]

i have been looking at the Howell Automotive AFX ECU for a long time now and i keep getting somewhat mixed reviews. By that, let me clarify... Everything i have heard is all good news... Unless you want to go turbo. But what if someone did want to go turbo?

i would have to say that the majority of what everyone on here has said about it is it can not be run with a turbo setup because the AFX ECU advances timing and unless you can find a way to retard the timing it wouldn't be a good investment ect ect ect and they just keep repeating this over and over and over.

Originally Posted by TalonSpeed

The afx ecu can be ran with a turbo no problem. It does advance timing, but it also takes away the factory fuel cut rev limit and replaces it with a higher ignition cut revlimiter. Boost + fuel cut = lean which then = detonation. this is why most turbo neons use an afx ecu.

Originally Posted by DSMcrazy3

The biggest gain from them is from the timing advance caused.. I've read several stories and some people describe fairly noticible gains, while others see no difference. I also read that you should run no less than 93 octane.(due to the timing advance) So fill up with that, if you haven't already.

For some reason something about the^above^ post gets me. i have read that it can take some time to "learn" your cars character maps so you probably will not notice any gains right out of the box. As for the octane used... any opinions on that? i'm cheap and gas prices suck and keep rising. Catch my drift? And for thirds... another person who mentions it advances timing... Since the 2G N/A runs rich from factory... you would think this could "learn" to lean it out a bit, right? and if you get cams and cam gears you could retard the timing so it's not so advanced right? Or am i mistaken? Please explain.

Originally Posted by AEMEclipse140

I was wondering if Anyone using the afxr ecu realy disconnects their downstream 02 sensor? which is the best way to go about it just clip the wires and leave the sensor in there or plug it with something?

i have been wondering about this too. On Howell's site it says they take out many other annoying factory drawbacks or whatever. i have always wondered if the rear O2 was one of them. What about the EGR? the Question was asked... but no one answered him. So no one searching still has any idea. (by the way... that was posted in 2004)

Originally Posted by Locke

rev limit. 7500 for the street AFX, 8100 for the race AFX

i emailed Howell and they said that they only sell the Race Only model for all versions of the 2G Eclipse... the only reason "Street" is even listed is because it is a generic description they use on all of their AFX ECUs.

Originally Posted by bullettDSN

...an immediate noticeable difference in power and redline. Should rev up to 8100 (but mine somehow lost it's redline and it went down to 7800. Don't know why). At any rate, you should notice a definite power change in fuel pulled and timing advance alone

Could this be a problem with how the ECU "learns" your car? and... Another comment about the timing advance. My concern is mainly with how our (or at least mine) cars run too rich. Would i be better off looking into upgrading my fuel pump and/or fuel rail and/or injectors? Or would that make my concern worse? My O2 logger says it is generally in the rich zone a few notches above stioch. i'm not seeing any oil or anything from my exhaust pipe as i have read some people do. But when i look at my header... and i know headers get hot and change colour and such... But mine... i'l have to take a pic and you tell me if it looks "normal" for being like 4-6 years of use.

But anywho... On all of the other questions and notes listed above... Can anyone help explain to me any of this?

 

[NeMiZiS]

I've been wanting to buy an one of these for a long time.
I'm sure one of our members that has been using one will chime in.
This is going to be an awesome thread, if we can keep people from arguing.

I haven't heard of having to upgrade your fuel pump from using the AFX.
So your main question is, should you get it if you are going to turbo the car?
I'm in the same boat.
The way I look at it is, I know I'll be able to afford the AFX ECU way before I'll be able to rebuild my motor and turbo the car.
Then later if you want to turbo, Mega squirt is the best option.
You could sell the AFX ECU and probably get most of your money back.

 

[nothingfiction]

To me, megasquirt just seems way too complicated for me. Too much wiring. the AFX is just plug and play. And like you, it's going to be a while before going turbo too.

i'm not saying everyone/anyone has to upgrade their fuel system at all. Maybe it is just my car, and i was wondering if that might help me at all. i have heard and read some about the AEM EMS systems that are plug and play as well, but thats still over a grand too, while the AFX is only 500 (ish). i know you get what you pay for so we dont need someone to repeat that in this thread.

 

[LD25Delta9]

I was about to write a big 2 page response but I'll say only this. AFX=NA and only NA for good reason. MS=NA, Boost, NoS. AFX=500+SH, 1 tune, no support. MS=560+SH, endless tunes, massive support.
AFX= $500 wasted when you want to go turbo. MS=$560 well spent on NA or turbo setup.

If it's wiring that is holding you back, there is a very easy to follow diagram that comes with MS. If you can't solder 2 wires together, how is it you have the coordination to drive?

That's my $0.02.

Oh almost no one runs in stoich all the time. You're fine. That's your ECU compensating for CAI and exhaust.

 

[Locke]

Please excuse my brevity, and do keep in mind the age of much of the information you quoted.


Aggressively advanced ignition timing in boosted cars is dangerous. Running higher boost levels increases the risk. It is safer to run less ignition advance, and more boost.

The AFX allows broader adjustments to LTFT and STFT; this is how it learns.

Since the AFX both leans the fuel curve and advances the ignition curve, you should run only premium fuel. Both of these characteristics can lead to dangerous knock.

Ignition time and cam time are different things. You cannot compensate for ignition timing by adjusting cam timing.

I, personally, am unsure of how the AFX deals with useless (from a performance standpoint) sensors.

Years ago, Howell offered 2 tunes for 97 2gnt's. Apparently now, according to yourself, they only offer the one tune, but they offer it for multiple years now.

The Rev limiter is not self-adjusting in the AFX. Mark's issue with his ECU bringing the rev limit down was likely either CKP related or his ECU became faulty.

Adding larger fuel injectors will make your car run richer than it already does, and there is little reason to upgrade any part of the fuel system while still NA.

You could always pay somebody to install and tune the MegaSquirt for you, if you were to go this route.

AEM EMS does make plug and play systems (as far as connecting them to a wiring harness) but they do not make them for the 420a DSM. To use an AEM, you will still have to wire it in. I am doubtful that the AEM EMS can decode our special trigger wheel, either. To my knowledge, the MegaSquirt is the only stand-alone EMS that can properly decode the 420a trigger wheel. If I am correct, then a conventional trigger wheel would have to be mounted.

 

[bullettdsm]

Thanks Locke

I came on here to address the issues with some long winded post. You summed it up nicely. The only thing I would reiterate is there is NO reason (other than "bling") to upgrade any part of a good working stock fuel system if you are running NA.

MB

Incidently, fwiw, I would recomend the AFX/ECU for a good plug and play piece (if you are afraid of tackling electrical installs).

 

[nothingfiction]

Thank you for that information. With all of that i think using the megasquirt may be better since it does have more tunability.

As for what i said about the race only unit... This is what Howell emailed back to me about the product...

From: Howell Automotive
Sent: February 19, 2010 8:07:19 AM

That unit is in race only. The description is the generic one for all
the AFX computers. Sentry key was no available in the 1997 model year.

 

[nothingfiction]

Trying to revive my thread...

i have decided that i think megasquirt is the route to go... but i was wondering...
is it possible and/or what would happen if you ran megasuirt over the afx ecu?
any benefits?

Also... with the megasquirt, your able to turn sensors off right?
That damn rear o2 sensor pisses me off and none of the bypasses i have tried work. it always comes back on eventually.

 

[rstare]

If you're using MS as a standalone, it will replace the stock ECU. This removes the entire OBD2 system. So, you won't have any CEL's. Otherwise, if you're using MS as a piggyback, you'll probably get more CEL's than just the rear O2.
MS doesn't use any input from the rear O2, as it's only use is for monitoring the effectiveness of the catalytic converter.
There would be absolutely no use for using both the AFX ECU and MS, that I'm aware of. I don't even know if it's possible... :/

 

[nothingfiction]

i've been looking at the MS kit from Symtech Complete 420A Megasquirt EMS Kit - SymTech Laboratories But my question is is this REALLY everything i need? And also... what is LC-1 ? i know it says it's the wideband. i got that much . And from reading all the other threads wideband is always preferred. But what exactly is it? i mean simply. is it the controller to manipulate what you want? More info on this would be helpful to me. Thank you.

and before someone blows a headgasket over me having a link, i don't know if outside links are too accepted here, so i apologize in advance. if you don't like it just kill it, or tell me to and i will.

 

[rstare]

Posting outside links are fine.
LC-1 is a wideband. A wideband is essentially a better version of your current O2 sensor. Your stock O2 sensor is a narrowband. It has an output range of 0-1v. When it outputs .5v you are at stoichiometric. Anything other than that is relatively inaccurate. A wideband puts out 0-5v and is accurate anywhere from ~9:1 - 20:1 AFR. So, it is almost a must when tuning.
A wideband isn't a controller, the MS is the controller. The wideband is simply a sensor that gives information about the AFR to the ECU.

If you talk to Paul at Symtech he can make sure your unit is built with everything you need. Your other option is to build it yourself. Here's some links:
MegaSquirt-I Programmable EFI System PCB3.0 - Kit w/ BLACK CASE DIYAutoTune.com
12&#39 MegaSquirt Wiring Harness (MS1 / MS2 Ready) DIYAutoTune.com
GM Closed Element CLT / IAT Sensor with Connector DIYAutoTune.com
GM Open Element IAT Sensor with Connector DIYAutoTune.com
Bosch BIP373 Coil Driver Mod Kit DIYAutoTune.com

Above is all you would need to build your own unit.

 

[VelocitàPaola]

LC-1 is a wideband. A wideband is essentially a better version of your current O2 sensor. Your stock O2 sensor is a narrowband. It has an output range of 0-1v. When it outputs .5v you are at stoichiometric. Anything other than that is relatively inaccurate. A wideband puts out 0-5v and is accurate anywhere from ~9:1 - 20:1 AFR. So, it is almost a must when tuning.
A wideband isn't a controller, the MS is the controller. The wideband is simply a sensor that gives information about the AFR to the ECU.

Sort of...

A wideband oxygen sensor system consists of both a controller and a sensor. Technically, the LC-1 is the controller and the Bosch LSU4.2, which is also used by many other controllers, is the sensor.

A narrowband oxygen sensor simply needs power and ground (and optionally a high current power source for its heater), and it will generate a signal. This signal is not linear, it is a sinusoidal waveform with a mean value approximately indicating the AFR. Its amplitude is no less than 0V, or whatever the ground potential is at, and no greater than about +1V.

A wideband oxygen sensor will not provide any meaningful signal without a controller. The controller carefully controls the sensor's pump while interpreting various outputted data to creating a linear 0V to +5V signal. There would be no usable signal without the controller.

Megasquirt doesn't control anything related to the oxygen sensor, it just uses the signal to control the rest of the engine.

 

[96TurboGS]

A narrowband oxygen sensor...Its amplitude is no less than 0V, or whatever the ground potential is at, and no greater than about +0.1V.

Scoping my O2 a while back and I got a maximum amplitude of .9v with an operating voltage of .1-.9v. I made a narrowband light show with 10 LEDs 7 years ago that worked well (with a small delay and average). The only time I seen under .1v is when the engine was off. .5v from the sensor is considered stoich.

 

[VelocitàPaola]

Scoping my O2 a while back and I got a maximum amplitude of .9v with an operating voltage of .1-.9v. I made a narrowband light show with 10 LEDs 7 years ago that worked well (with a small delay and average). The only time I seen under .1v is when the engine was off. .5v from the sensor is considered stoich.

Yeah, that was a typo. It's fixed now.

I always found .45V indicates a stoichiometric condition.