TBI ECM Upgrade 6026-7747-8625 Pinouts
01-01-2005, 02:03 PM
#1
Supreme Member
Thread Starter
TBI ECM Upgrade 6026-7747-8625 Pinouts
I have been meaning to do this for a few weeks and with the holiday downtime, I was able to do it for myself. Thought I'd share it for anyone else who's contemplating this ECM swap.
There were a couple of fuzzy areas but ben 73 and Bill USN have helped clear them up. Those changes are now reflected in this version updated on 7.11.2005.
There were a couple of fuzzy areas but ben 73 and Bill USN have helped clear them up. Those changes are now reflected in this version updated on 7.11.2005.
Last edited by Dominic Sorresso; 07-11-2005 at 10:45 AM.
01-01-2005, 02:52 PM
#3
Supreme Member
Thread Starter
Ben,
I'm thinking the MAP Ground found at W14 of the 6026 probably goes to B4 on the 8625. But the question I have now is that
the wiring is currently from a 6026 going to a 7747 connector. Some of those wires were not used for the 7747(ie canister purge, MAP Ground) which appear to be usable on the 8625 and vice versa for the Crank Signal. So it seems that the idea of swapping out a 7747 to 8625 and back again may not work unless you use 2 adapters, both built around the 6026 wiring not an adapter converting the 7747 connector to an 8625.
Ben, you did your 6026-> 8625 conversion native to the 6026 since you had an adapter built for the 6026->7747 upgrade. My 7747 connector has the 6026 wiring re-routed directly to it. Maybe this isn't a big issue, but I'd like to clarify it first.
I'm thinking the MAP Ground found at W14 of the 6026 probably goes to B4 on the 8625. But the question I have now is that
the wiring is currently from a 6026 going to a 7747 connector. Some of those wires were not used for the 7747(ie canister purge, MAP Ground) which appear to be usable on the 8625 and vice versa for the Crank Signal. So it seems that the idea of swapping out a 7747 to 8625 and back again may not work unless you use 2 adapters, both built around the 6026 wiring not an adapter converting the 7747 connector to an 8625.
Ben, you did your 6026-> 8625 conversion native to the 6026 since you had an adapter built for the 6026->7747 upgrade. My 7747 connector has the 6026 wiring re-routed directly to it. Maybe this isn't a big issue, but I'd like to clarify it first.
Last edited by Dominic Sorresso; 01-01-2005 at 02:56 PM.
01-01-2005, 08:13 PM
#4
Junior Member
Join Date: Jul 2003
Posts: 11
Likes: 0
Received 0 Likes
on
0 Posts
I got my 7427 TBI swap running today and I might be able to fill in some of the blanks. All this is to the best of my knowledge as I have not fully worked all the bugs out my system yet
Still a newbie
The manual I have shows two switched ignition feeds to the ECM, E15 and F15. I used E15 as the crank signal and F15 as the switched 12V source to the ECM. It also has a 12V constant feed and that is E16 as your chart shows.
My manual also has the MAP ground at B4 and it also grounds the EGR, IAT, and something for the transmission. It shows B3 providing a ground the CTS and TPS.
Hope this helps.
Still a newbieThe manual I have shows two switched ignition feeds to the ECM, E15 and F15. I used E15 as the crank signal and F15 as the switched 12V source to the ECM. It also has a 12V constant feed and that is E16 as your chart shows.
My manual also has the MAP ground at B4 and it also grounds the EGR, IAT, and something for the transmission. It shows B3 providing a ground the CTS and TPS.
Hope this helps.
01-02-2005, 03:34 AM
#5
TGO Supporter
Join Date: Jan 2003
Location: Australia
Posts: 519
Likes: 0
Received 0 Likes
on
0 Posts
ok, here is what I did in the 'grey' areas..
Pk/N switch: I connected this to one of the 3 'range A/B/C' wires. Datamaster now sees Pk/N as Pk/N, and when out of Pk/N, it thinks its in D3 all the time. I'm at work and don't have my final notes handy, so i can't say just now if it was a,b, or c..
The ESC goes to B15 as per your notes, but you must bypass the ESC module as this is no longer needed. Also you must put a 3.9k resistor between the ESC wire and ground. My knock sensor is working well like this, tested and proven ok.
E16 must have an 'always hot' battery supply, get this from the 6026's White 10 and/or 15 terminals
Crank signal is not needed. It appears that the 8625 turns on the fuel pump during cranking when it sees DRP's
Air divert valve, dunno about this, it seems the 8625 has no provision, I didn't spend any time on this as I don't have one anyway ;-)
It seems that the 3, 0-5v analog sensors are wired a bit differently in some cars. Some are paired with common supplies, some aren't. For example, the 84 vette has a single 5v ref supply for the CTS and a shared one for the TPS and MAP, whereas the MAP has its own ground return and another is shared by the CTS and TPS.
The schematic i have for the later trucks (93-) shows that they are wired with 3 separate 5v refs, but the CTS and TPS share a ground return. The MAP has its own ground.
This leaves us with a spare 5v ref from the later PCM that we don't use. This is fine.
This is how mine is wired:
Sensor Desc 6026 8625
CTS +5v Bk4 B8
Gnd Bk11 B3
TPS +5v Wh11 F14
Gnd Bk11 B3
Sig Bk5 A15
MAP +5v Wh11 E14
Gnd Wh14 B4
Sig Bk20 B13
I think that covers it.. ;-)
Ben.
Pk/N switch: I connected this to one of the 3 'range A/B/C' wires. Datamaster now sees Pk/N as Pk/N, and when out of Pk/N, it thinks its in D3 all the time. I'm at work and don't have my final notes handy, so i can't say just now if it was a,b, or c..
The ESC goes to B15 as per your notes, but you must bypass the ESC module as this is no longer needed. Also you must put a 3.9k resistor between the ESC wire and ground. My knock sensor is working well like this, tested and proven ok.
E16 must have an 'always hot' battery supply, get this from the 6026's White 10 and/or 15 terminals
Crank signal is not needed. It appears that the 8625 turns on the fuel pump during cranking when it sees DRP's
Air divert valve, dunno about this, it seems the 8625 has no provision, I didn't spend any time on this as I don't have one anyway ;-)
It seems that the 3, 0-5v analog sensors are wired a bit differently in some cars. Some are paired with common supplies, some aren't. For example, the 84 vette has a single 5v ref supply for the CTS and a shared one for the TPS and MAP, whereas the MAP has its own ground return and another is shared by the CTS and TPS.
The schematic i have for the later trucks (93-) shows that they are wired with 3 separate 5v refs, but the CTS and TPS share a ground return. The MAP has its own ground.
This leaves us with a spare 5v ref from the later PCM that we don't use. This is fine.
This is how mine is wired:
Sensor Desc 6026 8625
CTS +5v Bk4 B8
Gnd Bk11 B3
TPS +5v Wh11 F14
Gnd Bk11 B3
Sig Bk5 A15
MAP +5v Wh11 E14
Gnd Wh14 B4
Sig Bk20 B13
I think that covers it.. ;-)
Ben.
01-02-2005, 05:11 PM
#6
Supreme Member
Thread Starter
Big/Ben,
No pun intended . I am incorporating your changes into the chart.
Ben, do you see any issue with routing the Crank Signal to E15 while the Switched Ignition goes to F15? If you could provide the
P/N switch info at your earliest convenience, that will help me finalize the chart which I will then re-post here.
As there was a MAP Ground coming from my 6026 wiring but not used in my 7747 connector, I am wondering if I pinned that MAP Ground wire to some "spare" slot in the 7747 connector so it would be there when I hook up the 8625 adapter and still allow swapping back to 7747. I would do the same with the Canister Purge. The only other obstacle would be to engineer a way of using the same Knock Sensor for both ECMs. One bypassing the ESC control and one not.
Is the 3.9k resistor located directly in the line you are running from the KS to the 8625 ECM connector? I could see splicing a second KS connector and running that line to a "spare" pin in the 7747 connector so that when the 8625 was hooked in, it would have the ESC signal thats expected. It would be a matter of switching wires down at the KS to switch ECMs.
No pun intended
. I am incorporating your changes into the chart. Ben, do you see any issue with routing the Crank Signal to E15 while the Switched Ignition goes to F15? If you could provide the
P/N switch info at your earliest convenience, that will help me finalize the chart which I will then re-post here.
As there was a MAP Ground coming from my 6026 wiring but not used in my 7747 connector, I am wondering if I pinned that MAP Ground wire to some "spare" slot in the 7747 connector so it would be there when I hook up the 8625 adapter and still allow swapping back to 7747. I would do the same with the Canister Purge. The only other obstacle would be to engineer a way of using the same Knock Sensor for both ECMs. One bypassing the ESC control and one not.
Is the 3.9k resistor located directly in the line you are running from the KS to the 8625 ECM connector? I could see splicing a second KS connector and running that line to a "spare" pin in the 7747 connector so that when the 8625 was hooked in, it would have the ESC signal thats expected. It would be a matter of switching wires down at the KS to switch ECMs.
Last edited by Dominic Sorresso; 01-02-2005 at 05:14 PM.
01-04-2005, 03:28 PM
#7
Junior Member
Join Date: Jul 2003
Posts: 11
Likes: 0
Received 0 Likes
on
0 Posts
Ahhh, this must be why I am still battling with code 43. I am using a 95 350 truck knock sensor and it is not working properly. From what I have read in the factory manual the internal resistance of the knock sensor lowers the voltage to 2.5 volts and the knock sensor generates an AC signal that rides over the 2.5 volts the PCM uses to detect knock. With the 95 truck 350 knock sensor I am reading 4.9 volts at the PCM on B15. I assumed this meant my sensor was grounded to block but had too little resistance to knock the voltage down to 2.5 volts. The manual says code 43 will set when voltage is less than .63 and greater than 3.1.
I am still confused by all this because I am running the 95 ks and it appears to be the same part number for TBI knock sensors from 87-95. Howell even sells one ks for all 1985 and later speed density systems TBI and TPI. Adding the resistor makes perfect sense to get the voltage down but I still don't understand why my 95 ks doesn't have the correct resistance. I think I am missing something...or I still have some issuses with my system...could be a combination of both. The latter is very likely
Any info to shed some light on the 7427 knock system would be appreciated.
I am still confused by all this because I am running the 95 ks and it appears to be the same part number for TBI knock sensors from 87-95. Howell even sells one ks for all 1985 and later speed density systems TBI and TPI. Adding the resistor makes perfect sense to get the voltage down but I still don't understand why my 95 ks doesn't have the correct resistance. I think I am missing something...or I still have some issuses with my system...could be a combination of both. The latter is very likely
Any info to shed some light on the 7427 knock system would be appreciated.
Trending Topics
01-04-2005, 03:46 PM
#8
Supreme Member
Thread Starter
Big,
I assume then this has been the only issue you have encountered with the way your ECM is wired? So sending the crank signal into F15 has presented no problem for you? I am waiting for Ben to identify the pin he used for the P/N switch and then I can modify the chart for final posting.
I assume then this has been the only issue you have encountered with the way your ECM is wired? So sending the crank signal into F15 has presented no problem for you? I am waiting for Ben to identify the pin he used for the P/N switch and then I can modify the chart for final posting.
01-04-2005, 04:20 PM
#9
TGO Supporter
Join Date: Jan 2003
Location: Australia
Posts: 519
Likes: 0
Received 0 Likes
on
0 Posts
Dom,
I'm going to have to pull out my underdash panel to get that last little bit of info for you. I didn't make any notes on that one.... I'll do it in the next few days...
I'm going to have to pull out my underdash panel to get that last little bit of info for you. I didn't make any notes on that one.... I'll do it in the next few days...
01-04-2005, 06:01 PM
#10
Junior Member
Join Date: Jul 2003
Posts: 11
Likes: 0
Received 0 Likes
on
0 Posts
Dom,
The knock system has been my only apparant issue.
After I reviewed the schematic I drew for how I wired the ignition and battery feeds I did use F15 for a crank signal. However, looking again at my factory manual schematics E15 and F15 are just switched ignition sources that are tied together and have a 10a fuse. Looking at the notes in the pin out chart it has that without E15 you will get a no start. It has no DTCs or symptoms for a problem with F15. This might explain why I haven't had any problems with the way I wired it.
I am not sure what F15 does but I am going to rewire mine to a switched ignition source. Not sure why I was wanting to incorporate that crank signal in the first place
. Thanks ben73 for the good info.
The knock system has been my only apparant issue.
After I reviewed the schematic I drew for how I wired the ignition and battery feeds I did use F15 for a crank signal. However, looking again at my factory manual schematics E15 and F15 are just switched ignition sources that are tied together and have a 10a fuse. Looking at the notes in the pin out chart it has that without E15 you will get a no start. It has no DTCs or symptoms for a problem with F15. This might explain why I haven't had any problems with the way I wired it.
I am not sure what F15 does but I am going to rewire mine to a switched ignition source. Not sure why I was wanting to incorporate that crank signal in the first place
. Thanks ben73 for the good info.
01-05-2005, 08:48 AM
#11
Supreme Member
Thread Starter
Originally posted by ben73
Dom,
I'm going to have to pull out my underdash panel to get that last little bit of info for you. I didn't make any notes on that one.... I'll do it in the next few days...
Dom,
I'm going to have to pull out my underdash panel to get that last little bit of info for you. I didn't make any notes on that one.... I'll do it in the next few days...
ben73,
Thanks for all your help and enthusiasm on this. Same for your efforts Big.
01-07-2005, 07:29 AM
#12
TGO Supporter
Join Date: Jan 2003
Location: Australia
Posts: 519
Likes: 0
Received 0 Likes
on
0 Posts
It's also important to note that the '8625 is looking for a brake pedal switch input at E13. 12v=brake off, 0v=brake on, therefore if you chose to neglect this one, the pcm will never lock the TCC as it thinks the brakes are on all the time....
You can either wire 12v to it permanently, and allow your existing TCC brake switch to open the TCC circuit when you brake, or you can do it properly and run a wire from your brake switch....
I just figured out why my TCC wasn't locking ;-)
Ben.
You can either wire 12v to it permanently, and allow your existing TCC brake switch to open the TCC circuit when you brake, or you can do it properly and run a wire from your brake switch....
I just figured out why my TCC wasn't locking ;-)
Ben.
01-07-2005, 07:51 AM
#13
TGO Supporter
Join Date: Jan 2003
Location: Australia
Posts: 519
Likes: 0
Received 0 Likes
on
0 Posts
One last thing about the TCC..
The stock .bins won't allow the TCC to lock if the trans is cold either..
If you are using an older 700r4 without a temp sensor (as the pcm is intended to be used with a 4l60e), you can either put a resistor across B4 & B5 to simulate a 'normal' temp, or there is an option in the bin to ignore trans temp.....
On the topic of using this pcm to control only the engine in a 700r4 or manual trans car, the .bin also has provision to adjust the speed input from a 4l60e's 40pulses/output shaft rev, to 2 pulses/rev.. I did this and the speed displayed by datamaster matches my speedometer exactly. Without this change, the pcm will see 20x the true road speed. 0-255mph in 0.5 secs, cool!! ;-)
The stock .bins won't allow the TCC to lock if the trans is cold either..
If you are using an older 700r4 without a temp sensor (as the pcm is intended to be used with a 4l60e), you can either put a resistor across B4 & B5 to simulate a 'normal' temp, or there is an option in the bin to ignore trans temp.....
On the topic of using this pcm to control only the engine in a 700r4 or manual trans car, the .bin also has provision to adjust the speed input from a 4l60e's 40pulses/output shaft rev, to 2 pulses/rev.. I did this and the speed displayed by datamaster matches my speedometer exactly. Without this change, the pcm will see 20x the true road speed. 0-255mph in 0.5 secs, cool!! ;-)
01-07-2005, 09:15 AM
#14
Supreme Member
Thread Starter
Ben,
IF the vehicle is a manual, like my ZF-6, does the Pk/N switch input matter. Does the brake switch input matter if I have no need for the TCC lock? To your knowledge, do these inputs affect any other ECM controls other than the TCC lock parameters?
IF the vehicle is a manual, like my ZF-6, does the Pk/N switch input matter. Does the brake switch input matter if I have no need for the TCC lock? To your knowledge, do these inputs affect any other ECM controls other than the TCC lock parameters?
01-07-2005, 02:27 PM
#15
TGO Supporter
Join Date: Jan 2003
Location: Australia
Posts: 519
Likes: 0
Received 0 Likes
on
0 Posts
Hi Dom,
From what I have seen in the hac, the pk/n and brake switch probably wouldn't matter for manual trans car. There are different idle speed tables for pk/n and drive and as far as i can remember, thats about it. I would install it with 12v on the brake input so it appeared off all the time and also connect the pk/n terminal so it looked like it was in gear all the time. I think this would just be a little tidier
From what I have seen in the hac, the pk/n and brake switch probably wouldn't matter for manual trans car. There are different idle speed tables for pk/n and drive and as far as i can remember, thats about it. I would install it with 12v on the brake input so it appeared off all the time and also connect the pk/n terminal so it looked like it was in gear all the time. I think this would just be a little tidier
01-13-2005, 09:51 PM
#16
Supreme Member
Thread Starter
Originally posted by ben73
Hi Dom,
From what I have seen in the hac, the pk/n and brake switch probably wouldn't matter for manual trans car. There are different idle speed tables for pk/n and drive and as far as i can remember, thats about it. I would install it with 12v on the brake input so it appeared off all the time and also connect the pk/n terminal so it looked like it was in gear all the time. I think this would just be a little tidier
Hi Dom,
From what I have seen in the hac, the pk/n and brake switch probably wouldn't matter for manual trans car. There are different idle speed tables for pk/n and drive and as far as i can remember, thats about it. I would install it with 12v on the brake input so it appeared off all the time and also connect the pk/n terminal so it looked like it was in gear all the time. I think this would just be a little tidier
Are you suggesting that I pin one of the 12v BATT inputs to the brake switch on the 8625? So use pin B1 for 7747 to E13 on the 8625? Any further clarification on which "range" input you put the P/N switch in?
Last edited by Dominic Sorresso; 01-13-2005 at 10:02 PM.
02-05-2005, 10:29 PM
#17
Supreme Member
Thread Starter
I justposted the final version of the 6026-7747-8625 Conversion chart. Thanks to Dirk for getting the board back up.
07-09-2005, 12:40 AM
#18
Junior Member
Join Date: Mar 2005
Location: Delano, MN
Posts: 44
Likes: 0
Received 0 Likes
on
0 Posts
Car: Take your pick. Probably a '72 Cheyenne/20 or '91 Maxima
Engine: Truck has a 350 W/454 TBI, 350 Injectors, 7747/G2/Atmel
Transmission: TH350...Aint dat a bitch
Originally posted by Dominic Sorresso
Ben,
I'm thinking the MAP Ground found at W14 of the 6026 probably goes to B4 on the 8625. But the question I have now is that
the wiring is currently from a 6026 going to a 7747 connector. Some of those wires were not used for the 7747(ie canister purge, MAP Ground) which appear to be usable on the 8625 and vice versa for the Crank Signal. So it seems that the idea of swapping out a 7747 to 8625 and back again may not work unless you use 2 adapters, both built around the 6026 wiring not an adapter converting the 7747 connector to an 8625.
Ben, you did your 6026-> 8625 conversion native to the 6026 since you had an adapter built for the 6026->7747 upgrade. My 7747 connector has the 6026 wiring re-routed directly to it. Maybe this isn't a big issue, but I'd like to clarify it first.
Ben,
I'm thinking the MAP Ground found at W14 of the 6026 probably goes to B4 on the 8625. But the question I have now is that
the wiring is currently from a 6026 going to a 7747 connector. Some of those wires were not used for the 7747(ie canister purge, MAP Ground) which appear to be usable on the 8625 and vice versa for the Crank Signal. So it seems that the idea of swapping out a 7747 to 8625 and back again may not work unless you use 2 adapters, both built around the 6026 wiring not an adapter converting the 7747 connector to an 8625.
Ben, you did your 6026-> 8625 conversion native to the 6026 since you had an adapter built for the 6026->7747 upgrade. My 7747 connector has the 6026 wiring re-routed directly to it. Maybe this isn't a big issue, but I'd like to clarify it first.
Also, how does one go about bypassing the EST module? Aside from the resistor mod to the knock sensor, would I just want to connect the knock sensor directly to the yellow/red wire that goes to the 7747's "spark control in" (comes direct from the est module)?
Diagram for reference:
http://www.chevythunder.com/1227747_ecm_198892.htm
07-09-2005, 04:43 AM
#19
TGO Supporter
Join Date: Jan 2003
Location: Australia
Posts: 519
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by greenbuggy
and nobody seems able/willing to post a complete pinout of the 8625 for whatever reason so I can see what exactly these "extra" wires are supposed to do.
Diagram for reference:
[url]
and nobody seems able/willing to post a complete pinout of the 8625 for whatever reason so I can see what exactly these "extra" wires are supposed to do.
Diagram for reference:
[url]
Its no secret, you just had to ask ;-) Here is all I had to work with..
http://i4.photobucket.com/albums/y13...tte/95pcm1.jpg
http://i4.photobucket.com/albums/y13...tte/95pcm2.jpg
http://i4.photobucket.com/albums/y13...tte/95pcm3.jpg
http://i4.photobucket.com/albums/y13...tte/95pcm4.jpg
http://i4.photobucket.com/albums/y13...rvette/PCM.jpg
http://i4.photobucket.com/albums/y13...vette/PCM2.jpg
http://i4.photobucket.com/albums/y13...vette/PCM3.jpg
Last edited by ben73; 07-09-2005 at 04:50 AM.
07-09-2005, 08:39 AM
#20
Supreme Member
Thread Starter
Greenbuggy,
Actually since I wrote that, I have constructed a harness connector allowing me to go from a 7747 to 8625 fairly easily.
I built a separate harness to bypass the ESC module. Just unplug the module and jumper the harness connector the way ben73 has provided in the diagram above. Plus, I will use Pin C1 on the 7747 harness connector for the Cannister Purge and have hooked that up to the corresponding 8625 pin F16. The pinout I have posted here is the final vesion. I should have indicated that. Re-reading the post it leaves the impression I hadn't finished it when in fact I had finalized it with Ben73 and simply replaced the original graphic with this final one.
My adapter harness is wired just as you see it laid out here. Hope that helps.
Actually since I wrote that, I have constructed a harness connector allowing me to go from a 7747 to 8625 fairly easily.
I built a separate harness to bypass the ESC module. Just unplug the module and jumper the harness connector the way ben73 has provided in the diagram above. Plus, I will use Pin C1 on the 7747 harness connector for the Cannister Purge and have hooked that up to the corresponding 8625 pin F16. The pinout I have posted here is the final vesion. I should have indicated that. Re-reading the post it leaves the impression I hadn't finished it when in fact I had finalized it with Ben73 and simply replaced the original graphic with this final one.
My adapter harness is wired just as you see it laid out here. Hope that helps.
Last edited by Dominic Sorresso; 07-09-2005 at 09:59 AM.
07-09-2005, 09:29 AM
#21
Member
Join Date: Nov 2003
Location: Al Udeid, Qatar-Worldwide service
Posts: 167
Likes: 0
Received 0 Likes
on
0 Posts
Car: IH Scout
Engine: 345 V8 TBI
Transmission: 727
I built a separate harness to bypass the EST module.
I understand the ESC if the knock sensor goes straight to the PCM.
But why the need to bypass the EST?
My adapter is almost done but now I'm confused/concerned?
07-09-2005, 10:00 AM
#22
Supreme Member
Thread Starter
Bill,
My typing error. ESC module. I have edited it in the original response above. Sorry for the confusion.
My typing error. ESC module. I have edited it in the original response above. Sorry for the confusion.
07-10-2005, 03:05 PM
#24
Member
Join Date: Nov 2003
Location: Al Udeid, Qatar-Worldwide service
Posts: 167
Likes: 0
Received 0 Likes
on
0 Posts
Car: IH Scout
Engine: 345 V8 TBI
Transmission: 727
It runs!
OK, a little update.
i just got my motor to fire up and run on the 8625 ECM with the adapter I made to plug into the original 7747 harness.
I'm still running on the BBNT bin but it's all I have besides the BBMT.
I had to make a change to the wiring crossover to get it to work!!!
The E15 to C9 will not work. It has to have 12v on that wire.
I moved it to A6 with F15 and it fired right up.
So can I just erase and program the 27C512 like I do the 2732's.
I tried to look at some data using datamaster $OD but no joy!!
Has anyone uploaded a good ECU or XDF file and baseline TBI bin for these yet?
I've seen bits and pieces on Moates site.
i just got my motor to fire up and run on the 8625 ECM with the adapter I made to plug into the original 7747 harness.
I'm still running on the BBNT bin but it's all I have besides the BBMT.
I had to make a change to the wiring crossover to get it to work!!!
The E15 to C9 will not work. It has to have 12v on that wire.
I moved it to A6 with F15 and it fired right up.
So can I just erase and program the 27C512 like I do the 2732's.
I tried to look at some data using datamaster $OD but no joy!!
Has anyone uploaded a good ECU or XDF file and baseline TBI bin for these yet?
I've seen bits and pieces on Moates site.
07-10-2005, 04:04 PM
#26
Member
Join Date: Nov 2003
Location: Al Udeid, Qatar-Worldwide service
Posts: 167
Likes: 0
Received 0 Likes
on
0 Posts
Car: IH Scout
Engine: 345 V8 TBI
Transmission: 727
Got it. Thanks.
One more note.
I know A11 and A12 are tied together inside the 7747 for the grounds.
But since A11 wasn't connected to anything on the cross-over, I tied it to A12 on my adapter. I just bridged between them with the 1 ground wire.
One more note.
I know A11 and A12 are tied together inside the 7747 for the grounds.
But since A11 wasn't connected to anything on the cross-over, I tied it to A12 on my adapter. I just bridged between them with the 1 ground wire.
Last edited by Bill usn-1; 07-10-2005 at 04:07 PM.
07-10-2005, 05:35 PM
#27
Supreme Member
Thread Starter
Re: It runs!
Originally posted by Bill usn-1
I had to make a change to the wiring crossover to get it to work!!!
The E15 to C9 will not work. It has to have 12v on that wire.
I moved it to A6 with F15 and it fired right up.
So can I just erase and program the 27C512 like I do the 2732's.
I tried to look at some data using datamaster $OD but no joy!!
I had to make a change to the wiring crossover to get it to work!!!
The E15 to C9 will not work. It has to have 12v on that wire.
I moved it to A6 with F15 and it fired right up.
So can I just erase and program the 27C512 like I do the 2732's.
I tried to look at some data using datamaster $OD but no joy!!
the Switched Ignition?
Ben,
Did you need to do that?
07-10-2005, 06:07 PM
#28
Member
Join Date: Nov 2003
Location: Al Udeid, Qatar-Worldwide service
Posts: 167
Likes: 0
Received 0 Likes
on
0 Posts
Car: IH Scout
Engine: 345 V8 TBI
Transmission: 727
Re: Re: It runs!
Originally posted by Dominic Sorresso
Are you saying you took the Crank Signal and moved it over with
the Switched Ignition?
Ben,
Did you need to do that?
Are you saying you took the Crank Signal and moved it over with
the Switched Ignition?
Ben,
Did you need to do that?
The ECM would not even power up before I moved the wire.
I had no 2 seconds of fuel pump...nothing..
The diagrams I got off of here don't even mention a crank signal. They both say 12V.
Makes sense given their color.
07-10-2005, 06:12 PM
#29
TGO Supporter
Join Date: Jan 2003
Location: Australia
Posts: 519
Likes: 0
Received 0 Likes
on
0 Posts
Re: Re: It runs!
Originally posted by Dominic Sorresso
Are you saying you took the Crank Signal and moved it over with
the Switched Ignition?
Ben,
Did you need to do that?
Are you saying you took the Crank Signal and moved it over with
the Switched Ignition?
Ben,
Did you need to do that?
E15 needs to be connected to a wire that has 12v when the key is in the 'on' position, i think this is A6 on the 7747.
07-10-2005, 09:22 PM
#30
Supreme Member
Thread Starter
Re: Re: Re: It runs!
Originally posted by Bill usn-1
Yep I no longer have anything connected to C9 of the 7747 harness.
The ECM would not even power up before I moved the wire.
I had no 2 seconds of fuel pump...nothing..
The diagrams I got off of here don't even mention a crank signal. They both say 12V.
Makes sense given their color.
Yep I no longer have anything connected to C9 of the 7747 harness.
The ECM would not even power up before I moved the wire.
I had no 2 seconds of fuel pump...nothing..
The diagrams I got off of here don't even mention a crank signal. They both say 12V.
Makes sense given their color.
The diagram I posted clearly has a Crank Signal outlined at 8625 pin E 15. Given your input and Ben73 I will change the chart to display the update.
07-11-2005, 01:04 AM
#31
Member
Join Date: Nov 2003
Location: Al Udeid, Qatar-Worldwide service
Posts: 167
Likes: 0
Received 0 Likes
on
0 Posts
Car: IH Scout
Engine: 345 V8 TBI
Transmission: 727
The diagram I posted clearly has a Crank Signal outlined at 8625 pin E 15.
The other pin was A11 of the 7747.
You have it listed as Air Sw Sol IIRC but it is sensor ground.
I tied it to A12 system ground just in case a ground was floating on the sensors.
Inside the 7747 A11 is physically tied to A12 so only 1 of them is grounded on the motor.
This would leave a floating ground if A11 isn't grounded to the motor.
Last edited by Bill usn-1; 07-11-2005 at 02:24 AM.
07-11-2005, 10:48 AM
#32
Supreme Member
Thread Starter
Bill/Ben,
I have updated the original .jpg to include all the latest updates you have recommended. 7747 pin A11 now shows being tied with 7747 pin A12 at 8625 pin A1. 7747 pin C9 is not used and 8625 pin E15 is tied with 8625 pin F15.
I have updated the original .jpg to include all the latest updates you have recommended. 7747 pin A11 now shows being tied with 7747 pin A12 at 8625 pin A1. 7747 pin C9 is not used and 8625 pin E15 is tied with 8625 pin F15.
07-11-2005, 01:20 PM
#34
Member
Join Date: Nov 2003
Location: Al Udeid, Qatar-Worldwide service
Posts: 167
Likes: 0
Received 0 Likes
on
0 Posts
Car: IH Scout
Engine: 345 V8 TBI
Transmission: 727
Got it logging.But it does have a DTC error!!
Guess it doesn't like the TBI ignition!!
I would also recommend checking the grounds on the 7747 pins D1 and D2. They are also internally connected. You can see both bridges(A11-A12, D1-D2) on the PCB where I desoldered the connector.
Here's a couple pics of the adapter right now.
Still need to pot the connections when I know it is final.
Here's the parts.
Guess it doesn't like the TBI ignition!!
I would also recommend checking the grounds on the 7747 pins D1 and D2. They are also internally connected. You can see both bridges(A11-A12, D1-D2) on the PCB where I desoldered the connector.
Here's a couple pics of the adapter right now.
Still need to pot the connections when I know it is final.
Here's the parts.
Last edited by Bill usn-1; 07-22-2005 at 05:07 AM.
07-05-2019, 01:28 PM
#35
Junior Member
Join Date: Jul 2019
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
Re: TBI ECM Upgrade 6026-7747-8625 Pinouts
Hi, i am not sure if there is something i dont see but i would really be interested in this 6026 7747 chart which is mentioned a couple of times... but cant see it anywhere here...could somebody help me find that chart?
Thanks a lot in advance,
Manfred
Thanks a lot in advance,
Manfred
09-29-2021, 07:37 PM
#36
Junior Member
Join Date: Nov 2011
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
Re: TBI ECM Upgrade 6026-7747-8625 Pinouts
Ben73, I hope you are still active and helping others with their tuning projects. I have a '92 Chevy 4x4 S-10 with a semi-modified 4.3L and 700r4. Due to the modifications I've made to the motor, I've swapped the ECM to a faster 8625 PCM. So, I am in need of your help in tuning my 4.3L and getting the 8625 to control the 700r4. Thank you in advance.
Thread
Thread Starter
Forum
Replies
Last Post
tonys91rs
Engine/Drivetrain/Suspension Parts for Sale
3
10-10-2015 03:31 PM
rudolphschenker
Transmissions and Drivetrain
1
09-04-2015 02:41 AM
