Found a mistake in a wiring diagram

[JeepsAndGuns]

While working on my test harness I was following the wiring diagrams I got from here. I was wiring up a 7727 and when I went to test it, check engine light would do its thing and fuel pump relay would cycle, and I would get spark from the coil when I spun the distributor, but injectors would not fire and fuel pump relay was not coming on. Its like I was not getting a signal to the ecm that it was running. (I did not have my laptop hooked up at that time though)
So I start checking my wiring and found that the pinout in this attachment is incorrect. (I was using this pinout to wire it up)
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=437&d=1322074489

(http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=437&d=1322074489)Its in the 7727 info thread
http://www.gearhead-efi.com/Fuel-Injection/showthread.php?332-1227727-ECM-information

It lists pin C3 as reference signal, and pin D13 as bypass. This is backwards. Pin C3 is bypass and pin D13 is reference.

Wasnt sure where to post this so I put it here.
I swapped the wires and retested. All works, and there appears to be no damage to anything.

[dyeager535]

Better?

[JeepsAndGuns]

Looks good! Now we just need to update the attachment in the thread. Mark or another mod will need to do that.

[EagleMark]

I wasn't sure how a factory service manual was wrong and no one noticed for 22 years? So I started looking and thinking... Hmmm 90 Corvette.... large cap HEI distributor..... differant EST module and... which also brings up, if your using a starter bin from Large Cap then Spark Latency Vaules are also differant to small cap.

http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=443&d=1322074515

[RobertISaar]

and that's why i tend to use the diagrams views rather than the pin views, there seem to be less little mistakes like that.

i'll see if i can change it.

EDIT: there, should have the fixed version uploaded. not sure if wire color or circuit number needed changed, so i didn't mess with it.

[EagleMark]

Point I was making is I don't think it needs to be fixed, it's a differant distributor and EST module then he is using. Maybe add the corrected version with notes for those doing conversions.

[RobertISaar]

it may be a different dizzy/EST module with a different pinout, but the connection on the ECM is the same for the EST module, even for DIS.

[EagleMark]

Now that I look at pin out and wiring to distributor it is wrong?

[RobertISaar]

if you go to the thread and open the attachment now, it is the corrected version.

[EagleMark]

Thank you! :thumbsup:

[JeepsAndGuns]

there, should have the fixed version uploaded. not sure if wire color or circuit number needed changed, so i didn't mess with it.

Yea the diagram that mark posted above is what I looked at that made me notice the pinout was wrong. The pin number and wire color on the pinout was correct, just the discription was wrong.

I had been noticing that almost all the same pins from the different ecm's shared the same wire color codes for the same functions. Makes things easy, I give that much to gm. When I went to hook up those wires, I thought it was odd the colors were different, since most others were matching up. But I figured the different color wires was because this 7727 came from a V6 $A1 car that had dis, and I was using a pinout from a V8 $8D car, so I put my faith in the pinout I had.
So it turns out that the 8 pin, 7 pin, and dis modules all share the same color codes on the wires to the ecm. I'm glad we got it fixed!

[EagleMark]

Thank you! :thumbsup:I need to correct that and say "Thanks everyone!"

Since you guys are working with it hands on I'll leave it up to you to get correct.