Moving from 1227747 What is the best TBI ECM to use?

[kilohertz]

I have been playing with the 1227747 on my Flathead Ford for a month or so now, and am becoming very familiar with it and the tables and scalars and such, but I have been told it is quite crude compared to some of the newer ones. I am leaving the 7747 on the Flathead as I am too far into it to change now, and I like the simplicity of it.

I am contemplating installing a TBI system on my '68 Firebird this year which has the Pontiac 350 in it, 4 speed T10 and 3.42 posi and would like to start searching the local wreckers for a good ECM system to use.

I would like to hear what the best, or next best ECM would be to use today, the next gen as it were. Would there be a huge learning curve for the new ECM or are the tables and such still familiar? I like the 747, and it certainly would do the job, I just thought if I am starting from scratch, maybe I should try something newer.

thanks!

[Fast355]

I have been playing with the 1227747 on my Flathead Ford for a month or so now, and am becoming very familiar with it and the tables and scalars and such, but I have been told it is quite crude compared to some of the newer ones. I am leaving the 7747 on the Flathead as I am too far into it to change now, and I like the simplicity of it.

I am contemplating installing a TBI system on my '68 Firebird this year which has the Pontiac 350 in it, 4 speed T10 and 3.42 posi and would like to start searching the local wreckers for a good ECM system to use.

I would like to hear what the best, or next best ECM would be to use today, the next gen as it were. Would there be a huge learning curve for the new ECM or are the tables and such still familiar? I like the 747, and it certainly would do the job, I just thought if I am starting from scratch, maybe I should try something newer.

thanks!

7427 is a definate improvement.

[dave w]

I agree with Fast355, the 16197427 is a definite improvement.:thumbsup:

The Dynamic EFI Systems (EBL_Flash) http://www.dynamicefi.com/EBL_Flash.php is a definite improvement for the 1227747.

The EBL_Flash computer is plug-n-play with the 1227747 harness.

dave w

[kilohertz]

Awesome! Thanks guys!

I just had a quick look at the page for this ECM, and without opening and studying all the different masks, is there a "preferred" one to start with, or use? At least I will be able to pick a 5.7L BIN which should be a lot closer for me to start tuning, compared to my 3.9L flattie. :rockon:

Cheers

[tayto]

I recently upgraded a stock 92 GMC to '7427 this past summer. it noticeably idled and ran better with a stock calibration (no tuning).

[dave w]

I think "Comparing" the 16197427 5.7 Auto .bin file with 16197427 BJFD 94 C-K Truck 4.3TBI 5 speed.BIN is a good idea.

Deceleration Fuel Cutoff (DFCO) might be different manual transmission vs. automatic transmission.

I recommend using a 2000 pulse per mile (2K) VSS with the 16197427, some members might or might not agree with my recommendation.

Likely . . . the smiles per mile is better with a VSS.:thumbsup:

dave w

[PlayingWithTBI]

I'm happy with my EBL Flash-II over the 7747 by far plus, it has "VE Auto Learn" and, with a WBO2 you can tune WOT too. all flash, no chips. It has boost and bottle capabilities as well. :thumbsup:

[ScottP]

As others had said, the 16197427 is a great choice for TBI applications, and can be found in
many 94-5 TBI trucks. I had planned to go this route on the 455 in my 70 Bonneville for a
long time, but ended up jumping right to a Gen 3 PCM instead - more on that later.

If you find a truck with a 16197427, my advice would be to pull everything - TBI, harness,
sensors, PCM, provided the price at your local u-pull-it is reasonable. Around here that
stuff is going for almost nothing.

The other piece of the puzzle that makes this a bolt-in affair on a traditional Pontiac including
the 350 in your 68 Firebird is a 7-wire HEI distributor from an '81 Pontiac, p/n 1103453. They
come off 265 and 301 powered Firebirds, Bonnevilles, Grand Prixs, etc.... With that distributor,
and the TBI to carb adapter of your choice, you can inject your Pontiac 350 with all stock GM
parts.

I've since evolved the EFI setup on my 455 through a bunch of stages. It ran a modified
1103452 distributor for quite a few years, and now has a 24x crank trigger and individual
LS coils, but it took me a few years of iterating and experimenting to get there.

[In-Tech]

^^^^^^^ very nice. the 7427 is an incredible increase in TBI technology, do not fear it :)

[kilohertz]

Thanks guys, appreciate all the info and advice.

Were the 7427 only available in '94-95 trucks/vans? Are there any tell tales signs for the vehicle to indicate it has this ECM as opposed to other ECMs from the same dates? Saves pulling a lot of glove boxes off the hinges. :innocent: i.e. VIN codes or glove box VIN stickers.

Also, while I have your ear, in the 7747, does the BLM data get deleted when the battery is disconnected? How is it stored in the ECM? I have been removing the battery cable every time I change the PROM tune, not sure if that is detrimental or not. I suppose I could be extra careful putting in the chip and leave the battery connected if need be.

Thanks!

[ScottP]

I believe that the 16197427 was only found in 94-5 trucks, SUVs and vans with a V8. The other PCM found
in those same years/vehicles was the 16196395. I haven't personally used one, by my understanding is that
it is equivalent and just as applicable.

Basically, if its a 94-95 GM truck, SUV or van with a V8, its a pretty sure bet it will have the PCM you want.

-Scott

[In-Tech]

The '6395 and '7427 both have red and blue connectors. I haven't seen any physical differences myself. Maybe some others can comment if I am wrong.

[tayto]

The '6395 and '7427 both have red and blue connectors. I haven't seen any physical differences myself. Maybe some others can comment if I am wrong.
this x2. i always just look for the red and blue connectors. i believe astro vans used 7427 but there may be internal differences on the ones with PFI. TBI ones should be ok to use but make sure to use a V8 calpak.

you can repin your 747 connectors to 7427, the pins are the same. there are many conversion threads here and elsewhere on the net.

[kilohertz]

As others had said, the 16197427 is a great choice for TBI applications, and can be found in
many 94-5 TBI trucks. I had planned to go this route on the 455 in my 70 Bonneville for a
long time, but ended up jumping right to a Gen 3 PCM instead - more on that later.

If you find a truck with a 16197427, my advice would be to pull everything - TBI, harness,
sensors, PCM, provided the price at your local u-pull-it is reasonable. Around here that
stuff is going for almost nothing.

The other piece of the puzzle that makes this a bolt-in affair on a traditional Pontiac including
the 350 in your 68 Firebird is a 7-wire HEI distributor from an '81 Pontiac, p/n 1103453. They
come off 265 and 301 powered Firebirds, Bonnevilles, Grand Prixs, etc.... With that distributor,
and the TBI to carb adapter of your choice, you can inject your Pontiac 350 with all stock GM
parts.

I've since evolved the EFI setup on my 455 through a bunch of stages. It ran a modified
1103452 distributor for quite a few years, and now has a 24x crank trigger and individual
LS coils, but it took me a few years of iterating and experimenting to get there.

Thanks for the info Scott. I just picked up a refurb'd dist you described, I have caps and coils from other HEI which should work. The ECM and harness etc will be easy to find, if not, I have a '94 farm truck here, but would rather keep it running.

cheers

[kilohertz]

Regarding the engine harness, are the Blue/Red connectors only available on the 94-95 trucks as well? If not, what years were the Red/Blue type connectors used and in what vehicles? Just trucks? Cars also?

Thanks!

[dave w]

1993 Pickups, Vans, and Suburban's with 4L60E Transmission also used PCM's (16168625) with the Red / Blue Connectors.

dave w

[stew86MCSS396]

Soooo happens I was given a Poncho 350 that supposedly has been gone through with new bearings/rings and a performance cam. Gonna attempt to run a TBI on top of Edelbrock spreadbore intake with an adapter. Have couple of Poncho HEIs here and still in the process/research of swapping out the guts from an Chevy EFI HEI into it. Another thing on the horizon is rebuilding a trans that has a BOP bellhousing which would be a CZF 200-4r. My feelings are torn on using the 427 although it's leap and bounds faster, so far I'm 0 for 2 using it to control TCC on a 700r4. I know you're using a manual trans so this is moot. I've read every possible thread about setting it up but can't seem to get it to work correctly. It's not that it's not working, it appears to lock up all the time as soon as it makes 1-2 shift. Right now using 4th gear pressure switch to energize TCC only in 4th but as soon as the 3-4 shift happens, it immediately locks up no matter what the speed is. I didn't do any of the wiring on either swaps but did double triple quadruple checked it to be correct. Whats weird is on the datalog, you can clearly see the TCC being commanded on/off at programmed speed but in reality that's not happening. It's like I have a internal short at all times. Sorry for the off topic rant... Speaking of red/blue connectors, you can still order them from Mouser...
http://gearhead-efi.com/Fuel-Injection/showthread.php?154-Need-427-ECM-Plug-source

[tayto]

i would check your internal lockup harness in the trans and map it out. might need to find a different harness or rewire

[stew86MCSS396]

Dont see how that can be the problem when the tcc worked as advertised with the original ECM.

[tayto]

you talk about a 2004r, then a 700r4. you also never mentioned it worked before and now it doesn't. the 7427 will control a "lock up only" transmission (700r4/2004r). if it's locking up immediately as soon as you shift into 4th, then it's probably wired that way internally. OR you have the TCC signal wire grounded (check that its on the correct pin) most ECM controlled TCC have 3 wires power, tcc signal, and "high gear" switch aka 4th gear switch. there is no physical connection between the 4th gear switch and the tcc solenoid aside both housing being grounded.

[kilohertz]

Look what I found yesterday! The wrecker had over a dozen of these, had to decide which 2 I thought would be the best, this is the first standard BIN I have seen. I just need to find a complete harness and I can start the conversion.

Let the games begin....finally, I am moving into the 90's :rockon:

cheers

[In-Tech]

If these files aren't already in the archives, please read both memcal's and post the .bin files :)

[kilohertz]

Will do. I looked in the archive and I didn't see either of these. I'll post them here and whoever knows how to get them to the archive can move them.

Cheers

[ScottP]

Great score - nice to see you're making progress.

You could post the BINs directly to the thread here:

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?303-16197427-PCM-Information-0D

I suspect that's where the most folks would be able to find them.

-Scott

[kilohertz]

I was looking here... http://www.gearhead-efi.com/gearhead-efi/bin/

I will post them in the 7427 section as you mentioned. I just need to lift the lid and see what type of adapter I need to make, I should have the parts here to do it. I'll post when I get it figured out.

Cheers

[dave w]

BPRJ is a 1995 7.4 Liter with Manual. possibly $31 or possibly $OE? . . . defiantly a very cool .bin to add to the library!:thumbsup:

BJYL is a 1995 5.7 Liter with a 4L60E, $OD

dave w

[kilohertz]

BPRJ is a 1995 7.4 Liter with Manual. possibly $31 or possibly $OE? . . . defiantly a very cool .bin to add to the library!:thumbsup:

BJYL is a 1995 5.7 Liter with a 4L60E, $OD

dave w

Thanks Dave!

I got the first EPROM out, the BJYL, started with that as there were lots of those, but only one of the BPRJ. I managed to extract it intact, guessing it's a 27C512??? All reference to MFR and part number are not printed on the EPROM, just date code of 9508.

Standby.

Cheers

[kilohertz]

I still am not sure what chip size it is but I was able to read it properly as a 27C512 and here it is. I'll let the more experienced folk check it out and confirm it's a good BIN file and I'll extract the 7.4 manual EPROM tomorrow. I loaded it into TunerPro RT with $OD and it looks like good data.

It's dinner and I need to light a fire...damn cold in here.

Cheers

[In-Tech]

The checksum(70BB) is correct so that file should be fine. Looks like a good read.

[kilohertz]

I decided to build a little adapter to allow me to read the EPROM while it is still mounted on the MEMCAL thus able to get a good BIN in case something goes south in the chip extraction. I can also use it for burning whatever chip I decide to use, undecided on that as my programmer won't do 27SF512. Looking for other options.

Here is the 7.4L Manual Transmission BIN file from the 7427 for the group to enjoy, I am not sure how to confirm checksum, maybe someone could tell me how to do it for future BINS. I also am posting a few pics of the little adapter I made, just a simple piece of cct brd with a little cut down the center to separate the 2 sides.

Cheers!

PS, extracted the second EPROM no problem, and both knock sensor hybrids. You can see one needs a pretty fine tip to get these out in one piece. :thumbsup:

[dave w]

My choice for programming EFI Chips is the BX32P https://www.newark.com/batronix/bx32p-barlino/programmer-bx32p-barlino-ii/dp/53M6869?ost=batronix+bx32p

My choice for Erasing EFI Chips is the LER-121A https://www.newark.com/leap-electronic/ler-121a/eprom-eraser-with-electronic-starter/dp/24M3344?ost=ler-121a

I admit, my chip programming and erasing choices are not budget friendly.:mad1: I've yet to find an EFI chip the BX32 won't program. The BX32 has a chip identify feature too. I use the LER-121A to erase memcal chips too.

dave w

[In-Tech]

Thanks for the files. hehe, you wouldn't believe the hodgepaws of adapters I have had to fudge together over the years. Good job :)

[ScottP]

The old timers probably all know this, but for those new to working with the 95 and earlier TBI and TPI
ECMs/PCMs/TCMs, Moates has a really nice selection of adapters and tools.

http://www.moates.net/hdr1-memcal-header-p-52.html?cPath=64

http://www.moates.net/gm-19851995-c-64.html

-Scott

[1project2many]

I was looking here... http://www.gearhead-efi.com/gearhead-efi/bin/

I will post them in the 7427 section as you mentioned. I just need to lift the lid and see what type of adapter I need to make, I should have the parts here to do it. I'll post when I get it figured out.

Cheers

That link opens a copy of the old .bin file library from the GMECM mailing list. I forgot we even had a copy of that.

[kilohertz]

Today I scored my 95 harness and another 7427 computer, plus most of the sensors, and I have a few questions.It was a long day of trying to carefully pull out the harness, and by the time I was getting it close to getting it out I was running out of light and I couldn't get to the back of the passenger side of the engine to get the O2 plug so I just cut the wires, and on the drivers side of the engine, just cut all the wires in the big bundle which go out from the engine harness back to the connector below the master cylinder. When I got home and washed up and recouped, I noticed that there was no fuel pump relay on the firewall and the big plug was missing from the harness, also no knock sensor plug. Is the fuel pump relay and plug somewhere else on these 95 C-1500? And where is the knock sensor? Maybe when I cut the O2 wires I also cut the knock sensor wire?? I can't seem to find any info on the second gen TBI harness removal process here so forgive me if this has been covered somewhere. I may have to go back tomorrow to get the things I missed??Thanks!

[kilohertz]

OK well my wrist has stopped bleeding and I had a chance to do some researching, and found the fuel pump relay is in the fuse box by the MC, and the knock sensor is by the starter, no wonder I couldn't find it or the plug, must have severed it in the little bundle going down the back of the engine on the pass side.

Going to start dismantling the harness tomorrow and clean all the dirt off everything. It was a very clean all original 95 and I also got the dist, coil and TBI. They are planing to crush it next week, I got there just in time.

Cheers

[tayto]

i don't know why you need the harness unless you are planning on running a 4l60e or 4l80e behind that flathead. you can repin the ecu plugs to the newer pcm style on your exisiting harness. there's also a few small wiring changes like bypassing the external knock module, as that is internal on the 7427.

EDIT: as for the fuel pump relay, 1995 was last year of tbi and first year of the newer style dash on the gmt400 platform. IIRC there was a big underhood fuse panel/relay box. it would not be my first choice in harnesses for modifying, 94 and earlier has the fuel pump relay mounted on the firewall.

EDIT 2: the knock sensor is on the passenger side by the starter. the wiring is usually with the starter wires, so unless you unplugged them you probably cut it. 7427 DOES NOT use an external knock filter. It is in the CALPACK. i would find a 7427 (with calpack) from a V6 with tbi to match your 6 cylinder flathead

[kilohertz]

i don't know why you need the harness unless you are planning on running a 4l60e or 4l80e behind that flathead. you can repin the ecu plugs to the newer pcm style on your exisiting harness. there's also a few small wiring changes like bypassing the external knock module, as that is internal on the 7427.

EDIT: as for the fuel pump relay, 1995 was last year of tbi and first year of the newer style dash on the gmt400 platform. IIRC there was a big underhood fuse panel/relay box. it would not be my first choice in harnesses for modifying, 94 and earlier has the fuel pump relay mounted on the firewall.

EDIT 2: the knock sensor is on the passenger side by the starter. the wiring is usually with the starter wires, so unless you unplugged them you probably cut it. 7427 DOES NOT use an external knock filter. It is in the CALPACK. i would find a 7427 (with calpack) from a V6 with tbi to match your 6 cylinder flathead

Hi Taylor,

You're confusing my 2 builds, this thread is about my upcoming '68 Firebird TBI swap so I am gathering parts for a completely new setup. I thought rather than mucking around with a 747 harness pin swapping etc. I would just start with the correct red/blue plug harness, which is what I have done.

Thanks for confirming the fuel pump relay location, it's not a problem to add the relay somewhere else on the Firebird. I will go back and find the knock sensor and plug as I want to use it for the Bird.

Thanks!

Cheers

[tayto]

Dont see how that can be the problem when the tcc worked as advertised with the original ECM.
ya my bad... you can use your extra 747 and get the fuel pump relay plug and whatnot.

[trlrider]

Thanks guys, appreciate all the info and advice.

Were the 7427 only available in '94-95 trucks/vans? Are there any tell tales signs for the vehicle to indicate it has this ECM as opposed to other ECMs from the same dates? Saves pulling a lot of glove boxes off the hinges. :innocent: i.e. VIN codes or glove box VIN stickers.

Also, while I have your ear, in the 7747, does the BLM data get deleted when the battery is disconnected? How is it stored in the ECM? I have been removing the battery cable every time I change the PROM tune, not sure if that is detrimental or not. I suppose I could be extra careful putting in the chip and leave the battery connected if need be.

Thanks!

My 1993 Suburban at some time in it's life had a dealer replaced ECM, and it was a '7427, so I lucked out when I bought it, swapped in earlier crate engine and started tuning.

[kilohertz]

My 1993 Suburban at some time in it's life had a dealer replaced ECM, and it was a '7427, so I lucked out when I bought it, swapped in earlier crate engine and started tuning.


I lucked out too. The truck I stripped was built 10/95, which technically is a '96. I was very happy to find the 7427 and red/blue harness. Stripping of all the old loom tomorrow and get it ready for install this summer...bloody snow.

Cheers

[tayto]

the vin is more accurate for figuring out year vs the manufatured date

[trlrider]

the vin is more accurate for figuring out year vs the manufatured date

eh? yes, the vin does tell what MODEL Year it was built for, it does not tell the manufacture date though normal decoding.
What does that have to do with what ECM it has?
I have a 1993 Model year that had a dealer replaced ECM, that just so happened to be a '7427. I even found a late model year '92 with a '7427 at the salvage yard.
GM does supersede ECM's for various reasons, so it is not all that unusual to find one in anything from '92 to early '96 depending on the vehicle model.

[kilohertz]

This is too funny not to share...

I stripped down the new harness today and removed the superfluous wires, it's amazing how many wires are not needed. The whole harness was covered in oil so I washed it and wiped it all off, it should work just great in the '68 Firebird. When I was finished I sat down next to the workbench and had a beer, and casually looked over at the distributor cap and distributor that I got from the same truck....and noticed it only had 6 posts. WTF, I thought this was a V8 truck. Too funny, turns out it was a 4.3 C-1500 so I now have a good distributor for a transplant into my '66 Corvair, which I am also planning on a TBI install with dual small TBI bodies...one day. I hate getting old.

I'll read the MEMCAL in the morning and if it's something new, post it in the appropriate thread.

Cheers

[tayto]

eh? yes, the vin does tell what MODEL Year it was built for, it does not tell the manufacture date though normal decoding.
What does that have to do with what ECM it has?
I have a 1993 Model year that had a dealer replaced ECM, that just so happened to be a '7427. I even found a late model year '92 with a '7427 at the salvage yard.
GM does supersede ECM's for various reasons, so it is not all that unusual to find one in anything from '92 to early '96 depending on the vehicle model.
'96 is when the c/k trucks went to vortec, completely different induction system, harness and PCM. 1993 I could see getting a 7427 considering it used the same connectors. i am having a hard time believing the '92 was "dealer swapped" to a 7427. surely there would be some gm literature for techs to back this up. kinda thinking it's more likely someone swapped a door from a 92. did you verify the vin in the door matched the VIN on the dash? While on this topic, i have read that mexico ran TBI up until 1998 or maybe even 2000. being in texas it could be very likely you have these truc,. But being in canada very unlikely.

Also, not sure how much you've done in the automotive industry, but VIN number is by far asked for more to identify a vehicle than the date in the door. Have you ever gone to the ANY dealer for parts before? they usually want your VIN number.

[kilohertz]

I successfully read the 4.3L BIN file, it's BJWX from the '96 7427 and if it's new I'll upload it to the BIN thread.

Cheers

Okay it seems the ECM/BIN file threads are locked and I can't post the BIN files I have to share, sooooo, I'll just put them here and someone else can move them to where they belong.

[1project2many]

Thank you! I'll see about getting these moved later today.