Can not get PCM bins to display correctly

[1project2many]

16196395 and 16197427

Apologies. The C3 manual trans ecm is 16196396. The 6395 is interchangeable with 16197427.

Using the bcc lookup from moates, it lists quite a few manual trans bins for the 7427 pcm, but I have no idea what those were for (car, truck, van, etc..)

There are none specifically listed in GM's database for a 7427 and either of the 5 speed transmissions GM offered in the smaller trucks / vans. There were three part numbers associated with that pcm over the years so maybe someone's done the work to cross them to the 7427 in that list. In the GM database there was an entry for transmission type which was sometimes left empty. If the person making the excel spreadsheet assumed that meant manual trans there are going to be a bunch of errors.

Tunercat has a calibration ID utility which was made using the GM database. It can be used to cross check cals from the spreadsheet.

would you simply copy and pase over the changes you made to one table into the 2nd one to make them both match?

In the beginning, yes. The closed throttle table is primarily for idle and low speed driving.

[JeepsAndGuns]

are you studying here? Fine that's way cool cause I'm all ears, I do not have much time in on any C4s. But if your trying to get your truck running? just an idea. data is always better!

I probably havent been very clear. I am not running the 7427 pcm at this time. I am currently running a 7747 system. I am planning on swapping in the 7427 pcm, but not at this moment. I am simply trying to learn what I can about the ins and outs of this pcm and tuning it before I sawp it in. I am simply researching and learning right now. Just the ammount of stuff in the defination kinda scares/intimidates me. There is just SOO much more in there than the 7747. So it might be a while before I am brave enough to swap it in.
You may ask why I want to swap it in? I do plan on building a mpfi intake and converting my engine over to batch fire and ditching the tbi. And since the 7427 can also be used with tbi, I figured I would swap it in now and start getting used to tuning it before I swapped in the mpfi.

As for my engine, its not stock, but its not built. I guess you could just say very mild. Specs:
AMC 401
40 over, stock type pistons
comp cams XE256H cam
heads shaved 20 thou, mild port and polish work and gasket matching, 3 angle valve job.
edlbrock preformer non egr intake.

When I started tuning the 7747 system, it hated, I mean hated every stock chevy v8 timing table I tried in it. No power, poor running, backfired out the tb, all kinds of trouble they gave me. They were just not adding enough timing. Seems my engine likes a lot of timing. I have since built my own timing table based on what my engine likes. Thats where I came to LOVE the emulation feature of the moates autoprom and tunerpro rt. Making changes while running made all the diffrence. I could make a change and instanly the engine would tell me if it liked it or not. My current table is actually a highly modified 4.3 v6 table.
Looking at the table in the 7427 bin I have, it just might barely be driveable, but would run so poorly, you wouldnt want to drive it. I base that gues off of comparing it to other stock chevy tables I have tried in the past.

[EagleMark]

Ah! Now I understand what your doing and a smart man for planning ahead.

So in theory you have a 7747 tune and need to get it into the 427? good start anyway!

[gregs78cam]

Yes to begin with I would take the timing table you have working now on the '7747, and import it into both Idle and Open Throttle tables. Start there, then later you can make changes and experiment with two different tables if you want to.

[1project2many]

Older engines often need more advance due to poor combustion chamber characteristics. In the Chevy EFI world I've found the big block cals from 88 and 89 to be good starting points for other, older engines. By 88 GM had figured out how to get better emissions by improving the combustion chambers so many of the 4, 6, and smaller v8 engines were getting redesigned cylinder heads. But the big block didn't get new heads until 96. In fact the L19 big block actually used a carby intake manifold until about 93. These cals are great because they account for the large volumes and poor flow characteristics typically found in old carby intakes, and they are set up with more advance when cold due to poor chambers, large bores, and low compression. Realizing that you already have a working cal, here is the long list of BCC's of big block calibrations used with the 94-95 454 which had old heads but the newer intake.

BCC= BHDF4632 Scan id= 4705 Part number= 16194631
BCC= BHDH4637 Scan id= 4715 Part number= 16194634
BCC= BHDJ4640 Scan id= 4725 Part number= 16194639
BCC= BHDK4643 Scan id= 4735 Part number= 16194642
BCC= BHDL4647 Scan id= 4745 Part number= 16194646
BCC= BJKU8036 Scan id= 8035 Part number= 16198034
BCC= BJKW8040 Scan id= 8045 Part number= 16198038
BCC= BJKX8043 Scan id= 8055 Part number= 16198042
BCC= BJKZ8050 Scan id= 8075 Part number= 16198049
BCC= BMHM9483 Scan id= 9495 Part number= 16209482
BCC= BMHN9487 Scan id= 9505 Part number= 16209486
BCC= BSUT1740 Scan id= 1745 Part number= 16231740
BCC= BTPU4932 Scan id= 4975 Part number= 16234932
BCC= BYYC8378 Scan id= 8645 Part number= 16248378
BCC= BYYD8381 Scan id= 8655 Part number= 16248381
BCC= CAJP2707 Scan id= 2745 Part number= 16252707
BCC= CAJR2710 Scan id= 2755 Part number= 16252710
BCC= CAJS2712 Scan id= 2765 Part number= 16252712
BCC= CAJT2716 Scan id= 2775 Part number= 16252716
BCC= CFFY6679 Scan id= 6685 Part number= 16266679
BCC= CFFZ6681 Scan id= 6695 Part number= 16266681
BCC= CFHA6688 Scan id= 6705 Part number= 16266688
BCC= CFHB6690 Scan id= 6715 Part number= 16266690

You know, I have to retract a previous statement. The following cals are listed for a 454 with the 5 speed NVG4500 and the 6395/7427 pcm:

BCC= BHDB4621 Scan id= 4675 Part number= 16194620
BCC= BHDC4624 Scan id= 4685 Part number= 16194623
BCC= BHDD4629 Scan id= 4695 Part number= 16194628
BCC= BMHJ9470 Scan id= 9465 Part number= 16209468
BCC= BMHK9476 Scan id= 9475 Part number= 16209474
BCC= BMHL9479 Scan id= 9485 Part number= 16209478

I have attached any cals which I have from the above lists including 2 manual trans cals.

[JeepsAndGuns]

Intresting info on the older bins. The timing table I am currently using is based off a 88 4.3 v6 table (just highly modified now) The bcc I stole the table from is AKSB. I noticed it was more advanced than the newer ones, but didnt think much of it.

Big thanks on the bins! Funny thing is, I am actually going to be running a nv4500 trans in the future. I will take a look at the ones you gave me and see how they look.

[EagleMark]

So I wonder if the manual bins used in the 427 type PCM was for CA only like I was told?

Good work! Thanks for sharing!

Also the reason the BB came with carb intake and adapter to TBI for so many years was they still used a carb engine in big trucks. Info came from a detroit engeneer so I beleive it to be true.

[JeepsAndGuns]

I looked at a couple of those 454 bins last night. If they are manual bins, how come they still have data in the trans paramiters?
Also, if they actually came from the 6395 ecm (mistakes can happen), would they still work in the 7427 pcm?

Heres my current 7747 spark table. If anyone cares to see it.






Now, if I was to transfer this table into 7427 bin, there are cells that the 7747 bins dont have. So would I simply enter in the numbers in the cells they both have, then use the 3D map and grab and move to smooth over/match up the other cells? I'm thinking yes?

Heres something I have noticed about manual bins, it was on 7747 manual bins and is also on the 7427 manual bins. The timing drops off at the lowest map line (30 on 7747, 20 on 7427) Its not retarding, but its much lower than the rest of the higher map areas. Would this have something to do with compression braking? Mabey removing a little bit of timing to help the engine slow down? I have a manual trans, but I have not tried this. I'm almost tempted to this weekend just to see what it does.

[EagleMark]

Wow that's a smooth table! Have you ever looked at a stock one? Not smooth... whenever I have tuned with knock sensor I found not smooth! I have had the priviledge of looking at timing tables of dyno tuned engines, not smooth, HP rating was smooth... but everyone smooths? Now I have to go look at my stock Lt1 timing table... Smoother than any 7747 I have looked at?

My understanding is the 395 and 427 are the same PCM. Just found another odd ecm number today ends up being the same as another common one. 1227747 has an identical one that starts with 161****. No real clear explanation as to why GM did this.

Haven't worked on a manual bin in a while but the main differnces I remember was with IAC logic as to not let throttle snap shut to idle during shifts. This not also makes shifting easier it was implemented on cars before EFI to reduce an emmision. Side effect was easier shifting.

Just because there is trans data in the bin does not mean it's turned on? I have never done a 427 manual conversion yet but have seen several places in the mask to turn it off. Then the other data is moot. Just like having EGR turned off, or vats off, or? Stuff is still there... My sons 345 IH is manual and I have a 427 PCM and harness 75% complete and have been looking for a manual bin because of the IAC or? logic for shifting, I would think to be an easier start? I'm sure the experianced 427 guys will have real information...

[JeepsAndGuns]

I tried a manual bin on my 7747 system once, I actually did not like it. It kept it reved up and made shifting funky. Sometimes it would hold it open at a higher rpm than what it needed. It also kept it open when trying to decel. I would let off the gas and it would keep going, I got no compression braking. I switched back to a auto bin and havent looked back.
Thats the only thing that worries me about another manual bin.
You mention seeing places to turn off the auto trans settings, what settings are they exactly (what are they labeled as?) I might make me up a couple starter bins, one auto, one manual, and see how they compare.

[Six_Shooter]

The manual logic is to hold the RPMs above idle, and in some cases slowly return to that point as well, to make shifting smoother. In my manual cars they have always held somewhere between 1000 and 1250 RPM until I was completely stopped, then return to idle. I have had no problems with engine braking, so there might have been something else going on there, like a setting that would hold the RPM higher than it should be.

To set up a manual $0D/$0E find the large and well put together XDFs that have "0Dv.250" in the title. I don't recall the exact names, but these files have large amounts of info in them in the parameter description boxes on how to change things for different applications, including setting up for a manual and for non-electronic automatic transmissions. I beleive they have been uploaded to moates.net, if they are not in the library here.

[1project2many]

For many years truck engines were "tall deck" and did not use same intake as "standard deck" pickup engines. This may have changed with the advent of the Gen 5 engine but I'd have to do research to confirm.

In GM during the '80s and '90s trucks were often the last vehicles to get new or upgraded powertrains and often the changes were simple and straightforward. GM used carby intake because they could. One ton emissions standard are far less stringent than smaller trucks' requirements and the engineers were able to pass emissions without developing a new manifold. And even though there was a new manifold used for a couple of years, no significant effort was expended on design as the PFI equipped Gen 5 was released in 95.

The manual trans cals I've listed are not CA only cals.
BHDD is a 1993 federal cal for the 3500HD truck (15,000# GVW)
BHDC is a 1993 federal cal for 3/4 and 1 ton trucks to 11,300 gvw
BHDD is a 1993 leaded fuel cal (O2 sensors disabled)
BMHJ is a 1994 federal cal for the 3500HD truck (15,000# GVW)
BMHK is a 1994 federal cal for 3/4 and 1 ton trucks to 11,300 gvw
BMHL is a 1994 leaded fuel cal.

GM part numbers changed as ECMs/PCMs were upgraded. Since the only way to get a replacement was to buy a remanufactured GM / Delco unit, it stands to reason that GM would change the part numbers as a way to keep track of revisions in parts and in the remanufacturing process. As an example, many of the 1227XXX ecm's had faulty solder joints. It was so common that many techs wouldn't bother diagnosing driveability until after they did a "tap test" to the ecm. I have had very few problems with 1619XXXX controllers having faulty solder connections.

I looked at a couple of those 454 bins last night. If they are manual bins, how come they still have data in the trans paramiters?

More than likely they started with a manual trans bin and made appropriate changes from there. Generally you will see "manual trans" and "shift light enable" flags set as well as all trans codes disabled in the manual trans cals.

I tried a manual bin on my 7747 system once, I actually did not like it. It kept it reved up and made shifting funky. Sometimes it would hold it open at a higher rpm than what it needed. It also kept it open when trying to decel. I would let off the gas and it would keep going, I got no compression braking. I switched back to a auto bin and havent looked back.

The 4.3 + light duty 5 speed calibrations were by far the worst ones for this. GM would hold the throttle follower open for a long time after letting off the throttle. I rarely start with a 4.3 cal for anything.

[EagleMark]

All the $OD and $OE def files are in our library/photgallery.

EDIT: I just added the Zip file with all 427 defs
http://eagle-mark.com/pictures/displayi ... play_media

[1project2many]

Heres something I have noticed about manual bins, it was on 7747 manual bins and is also on the 7427 manual bins. The timing drops off at the lowest map line (30 on 7747, 20 on 7427) Its not retarding, but its much lower than the rest of the higher map areas. Would this have something to do with compression braking? Mabey removing a little bit of timing to help the engine slow down? I have a manual trans, but I have not tried this. I'm almost tempted to this weekend just to see what it does.

Engine braking is best done with DFCO. This kills all fuel to the engine and believe me, it slows the truck down. Set DFCO so it's active when rpm is above 1800 or so, MAP is below 30 kPa, and set the enable timer for a couple of seconds. Don't bother doing anything with the timing since no fuel = no combustion.

In order to get engine braking through timing you would want to advance the timing to the point where it was fighting rpm. Dangerous place to play, on the edge of knocking, but that's what you'd need to do. Retarding the timing means combustion pressure builds as the crank throw is closer to 90 degrees from TDC. That means less pressure can produce the same torque so you could actually cause the truck to feel like it's accelerating. Retarding timing warms the exhaust and ultimately, with low enough advance, the exhaust valves will be opening while the fuel/air mix is still reacting and you'll get popping out the tailpipe.

When working out why a cal is set up a certain way you have to remember GM's priority levels. 1) Emissions. Violating emissions means massive fines, wasted efforts designing new cals, bad publicity. 2) Economy. You must produce vehicles capable of meeting CAFE standards or you will face fines for all vehicles in the fleet which do not. 3) Warranty. Vehicles needing work under warranty cost the company money and earns a bad reputation in the public's eye. 4) Performance and driveability. This is bottom of the list. GM's approach was the customer will buy whatever we give them. Cals from the '80s and early '90s had so much room for improvement that it wasn't funny. Very little was done to make excellent calibrations. As the 90's progressed we started to see this change and by the time OBDII rolled around GM had really gotten their act together.

Which cals are you looking at? I've sampled BHFM, BHDC, and ARHT and I don't see it the same way. BHDC uses 8 degrees more advance at the 400 rpm row which may be for spark advance based idle speed control, or it may be part of a stall saver or a starting aid since desired idle won't be 400 rpm.

Your 7747 cal is probably pretty snappy off the line at part throttle, no? That's a fair amount of timing change.

[JeepsAndGuns]

I checked the dfco settings in my bin, mph and time are right, but theres two settings for map. It has allow above 13.31, and disable under 33.97. Do those seem ok? I have noticed, my engine will have a very slight surge when slowing down/decel. Nothing big, just enough to feel, engine/exhaust sound changes slightly during the surge.

The bins that had slightly lower timing at high map was bins such as ASDX, ASDW, ASDN, etc... The tables are exactly the same as the auto bin except the high map. Compare to something like ASDU.
I fired up the autoprom and did a run while emulating so I could try it and see if it made any type of a diffrence. I didnt notice any, so who know why they did it. I changed it back to where I had it.


I also spent a couple hours today putting together a couple starter bins for the 7427. I made one from from the auto bin that came with my pcm BJYK, and one from the BMHK manual bin posted up here.
I followed the directions in the paramiter comments to set them up for manual trans (even the manual bin I had to change a couple of those settings) The turned off the trouble codes for transmissions, and turned off egr. I then made the timing tables. I inputted the data from my 7747 bin into the new ones in the areas I could. Then did manual smoothing to fill in the areas where there was nothing for me to input from my old table. So I have tried my best to mimic my timing table into the new bins, I guess I will see how it goes.
Heres what the new one looks like if anyone cares to see.