I need a detailed ECM pinout diagram

[Matt69olds]

I have been searching for a intermittent misfire on my 92 Yukon. Occasionally, the #1 injector (the on on the passenger side) won’t pulse. No injector pulse, swapping injector plugs and the problem follows the connector.

Make a long story short, the dark blue wire (#1 ground) terminal was push out the back of the ECM connector. No connection, no ground, no injector pulse. Now, my problem:where did that wire go?!

I found a diagram online, it said dark blue injector ground goes in connector C, pin 16. Only problem, that cavity is already occupied. So obviously the diagram I have is incorrect.

 

[Matt69olds]

So, does anyone have any clue where the dark blue wire is suppose to go??

 

[yevgenievich]

Does it ohm out to the injector connector? Confused how the problem was intermittent if that pin was fully out

 

[yevgenievich]

88-98 Service Manuals

Over the years I have collected a bunch of GM service literature. Links to PDF Scans of service and STG manuals and a links to the Parts manuals. You'll need the FREE Adobe Acrobat reader to open these files. Get it directly from Adobe here {http://get.adobe.com/reader/} If you're not...

www.gmt400.com

 

[Matt69olds]

Does it ohm out to the injector connector? Confused how the problem was intermittent if that pin was fully out

The pin was just barely in the ecm connector. It came out when I unplugged it, unfortunately I didn’t get a good look where it came from to reinstall.

That’s definitely the same dark blue wire to the #1 injector, as verified by a continuity test.

 

[yevgenievich]

You must be registered for see images attach

 

[Matt69olds]

That’s it!! The illustration I found online said C-16, your illustration says D16. D15 is blank (as is in my connector) and cavity D14 is green, ground trigger for injector 2 (and I have a dark green wire in cavity 14)

Only problem, the terminal refuses to go in all the way.

 

[Camar068]

not knowing the connector at all, but you may need to clock the pin in the hole. Look at the other wires going in and put it in the same way.

just a thought.

 

[yevgenievich]

There is specific orientation to terminals. Otherwise cavity might be damaged

 

[Matt69olds]

I’m guessing the cavity is damaged, the terminal flat out refuses to go in. It will go in other cavities ok.

I’m guessing that particular terminal has been screwed up since day one. This truck ran flawlessly up until a few months ago when it occasionally would shake and barely run. The miss has slowly degraded and become more frequent. A few months ago, my son and I replaced a blower motor that howled pretty badly. I’m thinking that fooling around with the blower motor compromised a less than ideal connection that has degraded over the last few months.

 

[yevgenievich]

Either try to straighten the slot with a pick. Or open ecm and put a jumper to near by pin that is empty and use that cavity

 

[Matt69olds]

I have friend with a bunch of these trucks, I’m going to see if he has another ecm connector. If so, I’ll either splice the connector or repin the replacement. Thanks!!

 

[Camar068]

Either try to straighten the slot with a pick. Or open ecm and put a jumper to near by pin that is empty and use that cavity

d@nm good thinkin' there

 

[Matt69olds]

It’s fixed. I got a replacement terminal from my local GM dealership (cost a $1.04) and cleaned the cavity with a pipe cleaner. Terminal snap in place, spliced the wire together, runs like a champ again.

Wish all repairs were that cheap.