Just came across something I think might come in handy for tuning. I finally got the Accel 300+ ignition working in the Jeep and I started looking at other neat gizmos for the whole thing. Accel has this thing called the Accel 375+ rev limiter with a bunch of cool stuff like a 3 stage timing retard and a MAP sensor display that is switchable between 2 and 3 bar sensors.
Do you guys think this would come in handy for tuning an ECM? I know data logging is absolutely necessary, but wouldn't knowing a particular MAP reading for a specific engine event (like backfire or stumble) be helpful in the tuning process? I am very seriously considering spending $200 on this tomorrow and I think a little input from the DIY PROM community might weigh pretty heavily in a decision to do this.
TIA...:hail:

 

When working on the 1227148 stuff there's a little display called a Scanmaster that is scrollable for LV8, CTS, MAT, BAT, RPM, TPS, MALF. Single display, .5" Numeric display.
Very handy to glance at for drivibility stuff.

 

I wonder if that would be adaptable to a 1228746 set up. I'd love to get more for less or the same.
So the MAP sensor reader would be a good idea?

 

What am I missing here?
Time/ PROMID/ IAC/ Temp/ SPEED/ MAP/ RPM/ TPS/ INT/ O2/ Batt/ Knock/ BLM/ rich/lean

With winaldl it gives the map reading continuously. And the rest of the items above. So why the need for a separate $200 gadget to tell you something you already know?
You are running the 8746 with a naturally aspirated motor so I'm a little confused about what this toy will tell you that will help tune?

 

Good point...guess I can put that $200 to another toy that will be useful. It would also mean that I'd have one less electronic gizmo to wire up...again...That ignition was probably the last of my beginner's luck. This might push it over the limit.
Sounds like a good time to quit while I am ahead.

 

The only issue here is that you are only running 160 baud with Winaldl- about one slice of datalogging every 1 and a bit seconds (about 1.2 s on my mask).

If it was me spending the $200, I'd be looking at a '749 or a '730 with $58 code and an injector driver board. Then you could datalog at 8192 AFAIK. This should buy you the drivers, ECM and cable.

Grumpy has mentioned running the $58 code in TBI mode elsewhere.

John

 

The $200 would also get you close to 1/2 way towards the price of the Innovate Wideband O2 sensor, which can also do datalogging of the 02 and other items like map, tps, rpm, etc - at 12 samples per second (off the website, I don't have one yet).

There is also a thread where RBob explains how to convert the speed limiter function in the '8746 to a rev limiter...

Patch Method Demo

 

I actually have a '730 in my shop for a future project. How exactly does one go about converting it so that it can be used with TBI? This is VERY interesting.

 

A 730 can only be used in a single TBI setup. The 749 has two injector drivers, and just needs to be wired in the Peak and Hold mode to drive 2 P+H TBI injectors.

 

What about wiring differences between the two ECMs? Like the differences in where individual sensors and components wire to the ECM? I am sure there are some wiring differences between an '8746 and a '749. How would I account for this? Rewire the thing with a 749 harness?

 

Grumpy,
Would you care to elaborate on wiring in P+H mode? You have piqued my interest. If I can use this ECM with my current set up and get the 8192 baud ALDL logging, that would be most cool. I believe that the '730 ECM I have is operational. Being able to get all this running with the 8192 baud capability along with the AutoPROM would be great! (I know that AutoPROM has the 8192 baud log rate.)

 

Not Grumpy. . . But, go here:

http://www.diy-efi.org/gmecm/ecm_info/

Click on the 1228746 ECM and get the diagram for that one.

Then back and click on the 1227749 ECM and at the bottom get the diagrams for the turbo Sunbird. The Sunbird uses PnH's and you will see the pair of jumpers between two ECM pins.

RBob.

 

Like RBob mentioned just wire the 749 as it was used in the SUNBIRD application. That sets the injectors in P+H mode.

Attached is the adapter that I use for my 749 in a non stock application. Using an adapter like this, keeps it all plug and play.
BTW, all the sensors GM uses other then the VSS, and knock detection stuff, are generally universal.

 

Grumpy...I wish I could see the image you attached. Something screwy is going on with my computer here at home...Win XP. Thanks to both of you for the info.
Aren't there differences in the pinouts between what I have (8746) and the Sunbird ECM? I can't just plug the wiring harness from the 8746 into the 749, can I? That would be really cool if I could, but I can't see ANYTHING like this being that easy.