I wanted to post an update/recap to cover some previously discussed related topics since this thread has gotten quite long and I'm getting a lot of questions that have already been answered in this thread (but may not be easy to find).

V6 N/A CODE MASKS:
The $A1 code mask is the newest available for the 7730 ECM and I have only tested it to work with DIS. Will it work with a distributor? Perhaps. But I haven't tested it so it is something I hesitate to sell as a mail order tune.

There are two versions of the $88 code mask GM used. One was for distributor F-body applications and the other was for FWD DIS applications. The $88 DIS version was not used for very long by GM as they quickly switched to using the $A1 mask instead for DIS applications. I don't have much experience with the $88 DIS mask so much tuning work might be required getting it dialed in (on a custom build especially). Why use the $88 DIS version you ask? It does NOT use a 3-wire A/C pressure sensor like the $A1 code mask requires.

V6 BOOST CODE MASKS:
The $8F code mask was used with the 3.1L Turbo Grand Prix DIS V6 and is set up for a 2-bar MAP sensor. It used a funky EGR valve that had a position sensor which was different than the digital (3-solenoid) EGR valve used by $A1 code mask engines. This EGR valve saw limited production use so I usually recommend anyone wanting to use this code mask just NOT use an EGR valve and have it disabled in the programming. This code mask does NOT use the 3-wire A/C pressure sensor.

The $58 code mask was used with the 4.3L Turbo Syclone and Typhoon distributor V6 engines and is set up for a 2-bar MAP sensor. It also does not use the 3-wire A/C pressure sensor but should be compatible with the stock Fiero EGR valve control system if using one is desired.

OTHER CODE MASKS:
The $8D code mask was used with the TPI V8's and I've heard it can be modified to run a V6. I have not had the chance to experiment with this so it is something I hesitate to sell for a mail-order application. If it can be modified to successfully run a V6 engine, then it would have the benefit of being able to work with the stock Fiero EGR control system.

Code59 is an open-source 3rd party mask that was based off the factory $58 code mask with changes so it could work with a 3-bar MAP and some fairly radical builds. There is an entire website devoted to the Code59 mask if anyone is interested in reading up on it. From what I've read, it sounds like this is an on-going project and people using it frequently experience bugs or other issues so it is not something I'm interested in working with at this time.

7730 NOTES:
It is very important to note that no matter what code mask you are using, the 7730 ECM seems to be much more sensitive to pre-existing electrical and mechanical issues than the stock Fiero ECM is. So if you have any such issues, the 7730 ECM upgrade will probably exacerbate them.

A/C PRESSURE SENSORS:
The $A1 code mask requires a 3-wire A/C pressure sensor be installed on the hi-side of the A/C system to report actual hi-side A/C pressure so the ECM can determine whether or not to activate the A/C clutch relay, when to turn on the radiator cooling fan, and when to raise the desired idle speed (depending on A/C clutch relay state). If you have a working A/C system and you wish for it to remain under ECM control, you MUST install an A/C pressure sensor. Not letting the ECM control the A/C system but having an A/C system installed and working on the car can result in engine stalling and erratic idle problems among other things.

GM used these 3-wire A/C pressure sensors on R12 and R134a systems. 1991-92 W-body GM cars with the 3.1L V6 had R12 and a sensor for or from one of these cars will have the R12 threads. The R12 sensor will screw onto the stock Fiero hi-side test port up in the spare tire compartment, but it needs an O-ring to seal it. The stock Fiero hi-side test port is not machined to accept an o-ring seal so it can be tricky to get one to install with a sensor and seal properly. In the past, I've put 2 o-rings on the fitting then screwed the sensor on and the bottom o-ring helps force the top o-ring into the sensor as it seats. I will tell you it is much easier to get the o-ring to seat and seal if the system does NOT have a charge in it. A fully charged system may make it impossible for you to install the sensor without blowing out the o-ring seal.

All 1994-newer GM cars and trucks used R-134a so a 3-wire A/C pressure sensor from any of these vehicles will have R-134a specific threads. You can have an R-134a pressure sensor fitting welded into a set of existing A/C lines if your welder knows what he or she is doing. I've been able to do it for people without melting/ruining the rubber hose on a set of existing lines that connected the A/C compressor to the Fiero. I can offer this service for a good price to anyone who can send me their A/C lines off their car (PM or email me for more info).

Code masks not requiring the 3-wire A/C pressure sensors are easy to work with on Fiero applications.

DIGITAL EGR ADAPTER PLATES:
See this thread: http://www.fiero.nl/forum/Forum4/HTML/057540.html

KNOCK SENSOR:
A knock sensor is NOT required when upgrading to the 7730 ECM (but is a very good idea to use if you are putting boost or nitrous on your engine). But if you decide you want to use one, it must be matched up with the mem-cal you are using in the 7730 ECM. The mem-cal is what contains the EPROM chip, cal-pak IC chips, and knock sensor interface circuitry. The mem-cal is what is removable from the 7730 ECM. The EPROM chip and these other devices are soldered onto the mem-cal. There is a 4-LETTER code printed either directly onto the mem-cal's blue cover or onto a silver sticker attached to the EPROM chip inside (or onto the cover) that I can decipher that tells me what year/make/model and engine/trans the mem-cal was used with.

LEAN CRUISE:
On code masks that support it, lean cruise has proven it CAN be buggy in operation at times. I've had some applications where it only worked "right" about 50% of the time. When lean cruise works like it is supposed to, the ECM locks the fuel lean and runs the engine lean (like it is supposed to) while the car is cruising down the highway at a steady speed. When it isn't working right, I've seen it lock into a rich fuel mixture and force the engine to run rich for the time limit the system stays in "lean cruise mode". It is up to the owner to monitor scan data to make sure lean cruise is operating properly if they elect to have it enabled in the programming.

OTHER NOTES:
Like the stock Fiero ECM, the 7730 is aging quickly. If you are working with a stock 2.8L engine, then the 7730 may be your only choice if you want to upgrade from the factory ECM. However, if you are using a newer DIS engine, an OBD2 PCM might be an option for you. OBD2 PCMs do require the 2nd crank sensor (the 24x unit that mounts on the outside of the timing cover and reads a 24x reluctor wheel on the harmonic balancer) and a camshaft position sensor. All production Camaro/Firebird 3.4L SFI engines came with these sensors. The DIS system uses its own 7x crank sensor that reads a reluctor wheel mounted on the crank inside of the block. The DIS ignition module sends a low resolution 7x signal to the ECM which it uses primarily for fuel and base ignition timing control. The 24x sensor is used primarily for misfire detection and finer ignition timing control. The OBD2 PCMs cannot be made to work without the 24x crank sensor at this time. They can be made to work with any manual transmission, a 4T60-E auto, a 4T65-E auto, and perhaps control the TCC solenoid in a stock Fiero 125-C auto (although I have not had the opportunity to test the latter yet).

It is much easier to tune an OBD2 PCM to work with custom builds than it is the 7730 ECM. The OBD2 PCMs primarily use the Mass Air Flow (MAF) sensor to perform all fuel and spark timing calculations which streamlines the tuning process (yes, they will work with boost too). 7730 and stock Fiero ECMs employ speed density which means they calculate fuel based on RPM and manifold vacuum - which can make tuning tricky, especially when aftermarket cams are used. I will say the stock Fiero 2.8 ECM has a lot more tolerance and is generally easier to work with on custom builds using aftermarket cams than 7730 ECMs are.

-ryan

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OVERKILL IS UNDERRATED

Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com

[This message has been edited by Darth Fiero (edited 05-06-2013).]

[This message has been edited by sleevePAPA (edited 05-12-2013).]

I think the thing that really scares me (and I sent a PM to Darth about this) is the wiring. I don't feel comfortable having to re-pin or rewire or even add new sensors. But I guess Ive already stated that too many times........Sorry. I'm hoping I could get some help hands on re-wiring my formula for this. My car has a 3.2 and i think this ECU would be a huge jump in performance of this motor.

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[This message has been edited by Fierokid87 (edited 05-18-2013).]

[This message has been edited by Darth Fiero (edited 07-25-2013).]