It appears the 7730 stock ECM on my car just went bad, rather than replace it with another 7730 I wanted to follow this article here:

https://www.thirdgen.org/newdesign/t...nversion.shtml

and install a 7749 in it's place because when I put my ProCharger on I planned on doing this anyway to get rid of the FMU.

Here is my question, this car is my daily driver and I need it up and running quick. Just to get going can I simply use my current SLP MEM-CAL or do I HAVE to make a custom PROM one no matter what? I know it won't see boost or know what to do or anything but I'm not boosting right now anyway and I need to have this car going ASAP.

Can I do that just for the interim?

Thanks!

 

The 749, and 730 are close cousins, the 749 can use the same memcal as the 730 was using. Just swap a few pins around and away ya go.

 

If you keep your current mask, you can just swap ECMs. Simple plug and play. Once you add boost, and change to $58 mask code, you will need a 2 bar MAP and swap a few pins at the ECM. Bob

 

Awesome! So I'll just wire up with 7749 in place of the 7730 as per the diagram and simply plug in my current MEM-CAL.

Then like you said when I add boost, I'll do the correct PROM burn for that application and add the 2 bar MAP sensor.

Wait a second, please clarify one thing first: The way SATURN5 posted it it sounds like if I'm not running boost I don't even need to change the wires as per the diagram, just wait until I do add the boost to do that. BUT the way Grumpy posted it sounds like I DO need to swap the wires now

 

Using a '749 ECM with the current MEMCAL (from your '730) just swap the ECMs, no re-wiring. The TCC will be lost though. This is a fact of life as the '749 doesn't have the output driver the original '730 code (mask $8D) uses.

Can also swap to a '749 and also swap to the $58 mask (turbo stuff). Now you need to do some re-pinning as the $58 code uses some different outputs then the $8D mask. Of course you gain the TCC back as it is on a pin that has a driver.

If this doesn't confuse you nothing will. There is a '730 to '749 swap page around. Bort92 comes to mind. Anyone have the actual URL, please post.

RBob.

 

Got it, now thanks! So if I want TTC I will have to rewire and use the SY/TY bin checked for 8cyl and of course remapped for running my 305. Hmmm....

 

Try this:

http://www.speedtoys.com/~bort62/7749/Main.htm

 

Sweet, thanks for that link!!!

 

I have a couple more questions that come to mind now:

I've got a copy of the most recent $58 bin, the BBZB 1580, but I need a copy of the best available 7749 ecu file for use with TunerPro that I can use to edit it.

Is there a modded $58 bin that has been made which will control the EGR, charcoal canister purge, and AIR pump diverter relays? I am in CA and this is critical.

Thanks!

 

Don't know if this will help, but I'm using a 749 with a 730 Memcal and the S_AUJP code. The harness is for a 165, and I made a conversion harness to go from 165 to 730. That being said, it seems to work OK, other than running lean up top (still haven't spent time to figure that out).

So if you take a 749 and stick the 730 memcal in it then it should work right off the bat.

Oh yeah, that thing with the TCC is correct, I lost my lockup going to the 749 /w/ 730 code/harness from the 165.

 

I found a post that was only a couple months old where Grumpy was working on a hybrid file that was a full 32KB bin, open source, patchable, etc. Same post I found the link to the new ecu file that was on Craigs site.

Anyway, what has happened on this project? I could not find any more recent posts and since I am going to need the EGR, charcoal canister purge, and AIR pump diverter relays working here in CA I am in much need of this. Any info on it?

Oh an in light of this info it seems like you would be able to do nothing more than simply re-pin a 7730 ECM and burn the hybrid bin to your PROM, plug in the MEM-CAL be an good to go right? I guess the only thing you loose is some kind of injector driver (which I don't fully understand) but it appears that from reading posts here that can't be used on our V8's anyway...

 

The EGR just needs a couple values changed. Rbob posted a fix a couple weeks ago. Not sure about the CCP and AIR. You can use the $58 code with a 730 ECM, its the pinout thats important. To use a 730, wire it as a SyTy, burn your bin and go. The 730 only has one injector driver circuit populated from GM. However the 749 uses the same board and the bits could be used to "upgrade" a 730 into a quasi 749. This would also give you four addtional outputs the 730 has over the 749. With the availability of high flow saturated injectors, using/needing the secondary driver circuit isn't required. The secondary driver circuit was used in the Sunbird turbo application as it used 4 P/H tpi injectors. The drivers can be upgraded to use 8 P/H tpi injectors, again info is available here. Bob

 

So then if a person already has a 730 then there is no point at all in using a 749 ECM since the additional injectors drivers are not needed right?

I quoted you as mentioning upgrading the 730. Why would a person do this? What is there in the 730 that you would want to upgrade? You mention it has 4 more outputs too so this to me would make using a 730 over a 749 a no brainer...

 

Actually it would be easier to add the quad output driver from the 730 into a 749 .... But.....

The only real need to run a 749 is if you want to use 8 P/H TPI injectors. You still need to modify the 749 to be able to do this, it's just another option. With the availability of large +55LB saturated TPI injectors, a 730 would work just fine. It's all just how you want to go about getting there. Bob

 

I am new to the 749 vs. 730 ECM for boost topic and found this thread while searching for info.

I have to decide on what injectors to buy for my setup. Originally, I was thinking of getting Ford 42#/hrs. Now I am leaning to getting the Seimens/Deka 60#/hr. The cost vs. future upgrades shows that the 60s are the better was to go for me.
The decision I need to make is going with a 730 ECM w/$58 code and saturated 60s, or go with the 749 ECM w/$58 code and peak-and-hold 60s. This means I have to modify a 749 ECM but that isn't that big of a deal because 730 donor part ECMs can be had for less than $50.

I think that I would be better off going with the 749 and peak-and-holds due to the ability of smaller minimum pulsewidths. The engine is a 355ci with ported 882 heads and LT1 intake. Currently, the engine is N/A and the PWs with 730 ECM and 24#/hr injectors is 1.7ms. So I am guessing that the PWs will go done to about 1.7ms * (24/60) = .7ms with the 60 peak-and-holds.
Overall, anyone have any opinions of the peak-and-hold vs. saturated for the 60#/hr Seimens/Deka or Mototron 60s?

Thanks

 

I love the 60# shorty Mototron on my combo. Works great.

 

Thanks for the reply. I think I made up my mind and will get the 60#/hr peak-and-holds or 72#/hr peak-and-holds. Buying new injectors for engine upgrades is getting to be a pain.

Using the great work of Ludis shows the wiring for the 730 and 749 ECM and it looks like I can use my 730 ECM and install the second injector driver and a few .050 ohms resistors. Or I could just use a 749 with a few resistor changes.

The peak-and-hold seem better because I plan to go to a tighter lobe separation cam later on that is better suited for boost applications. I am guessing it will require even less inject pulsewidths. At the same time, 72#/hr injectors are the same price as 60#/hr and that would be nice to have in case I find better heads and headers. I have to run through the numbers, but the 72#/hr injectors sound good.

If the $58 code does in fact do some sort of 'quasi' mode for small pulsewidths then it seems like they would work fine. I am not sure how that works though because I read a post from Grumpy questioning how the 'quasi' mode is supposed to operate and that he ran some tests on the bench that didn't support the 'quasi' mode theory.

I am still in the middle of fabricating steel for the setup so I haven't had much time to look through the $58 disassembly to see how it operates. At worst, some parameters or code will need to be changed to make 'quasi' mode happen because the 72#/hr peak-and-hold injectors sound good to me.

 

That's probably best. With that small displacement, you'll need all the precision on that pulsewidth down low you can get.

A friend of mine runs an LT1 with one of the Acceleronics boxes and 80#/hr on his turbo 383. It works very nicely down low. I'm sure you could get similar performance from the 749 driver upgrade. I might have some spare parts in that direction if you need them.

 

The plan is to go with even smaller cubic inches in the future so that is why I am headed down this route right now. I really don't care if I explode the 355ci engine. It is more of a learning tool right now. The horsepower numbers amaze me when you thow in some boost and it seemed like a good thing to learn in terms of ECM stuff.

The pulsewidths I need at idle seem like something the peak-and-holds can do. It forces me dig in to the $58 code and the wastegate stuff. I think being able to control the wastegate electronically is a good thing. At a flip of a switch you can go from 6psi to 14psi of boost and turn the water injection on. The farbrication part has been fun so far. I think the code stuff will be just as good. I hope the engine lasts long enough to figure out how the code works.

I bought five 730 ECMs for a good price from a yard a while back so I should be all set. Thanks for the offer though. It looks as though the injector drivers can handle the 4 extra injectors. They just need the resistor change to get the hold current right. Without the change the current would be too small to keep them on.

 

Yep, that's exactly it.

If it serves as motivation, my friend did all his own header/turbo work by hand, did some learning on diameter requirements of the intake tracts, and ended up putting 680 hp down to the wheels through an A/T with that 383 at 19# of boost. It took a couple of tries to get rid of all the bottlenecks, but he's very happy now.

I'd think a smaller engine like a 327 spinning up to the high end (9000+) would just be insane!

Keep us posted on how it goes. Pics would be real interesting as well, you don't see too many nicely done V8 DIY turbo setups.

 

Hmmm. Wonder if they could replace the injectors supplied with the Edel MPFI kits?

 

I run a mod. 749ECM with 8 p/h injectors and $58 code and it works great, It took some tuning but now its really fun to drive, cant wait til I get the boost # up..........

 

What are the idle pulsewidths, cam, and intake? As for tuning.....did you mess with the so called quasi constants/tables?

Thanks

 

My combo can you see on my webpage, se sign...

I had to change some constants, I posted it a few weeks ago search for "$58 big injectors" by me.......

PW at idle is around 1.0 mSec @900 rpm

 

That is a nice setup you have. Thanks for the PW info. I quessed that I will be around .6ms at idle and judging by your setup it seems like a good guess.

Why did you swap the drivers in the 749 ECM? I understand the resistor change. I was just going to put some more resistors in parallel with the existing resistors.

Thanks,

 

The ohmite resistors you installed........I am guessing that they are each .050 ohms and are 2 WATTS each judging by the size of them. Shouldn't they be 4 watts each due to the 2x increase in the peak current? Or are they the 4 watt versions?

 

I used
Fairchild Semiconductor HUFA76429P3 hexfets.
And .05 ohm 1% 2 watt resistors

/N.