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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: frotosride on March 18, 2012, 09:02:40 pm

Title: how does the ECM control lockup?
Post by: frotosride on March 18, 2012, 09:02:40 pm: I have done extensive research on making my own lockup controler if need be however, The 700r4 and ecm cam in the truck and are all oe. What I would like it to make a way to tcc lockup when I want it. The main reason I want this is because I have noticed that at any speed over 55mph I cannot achieve lockup. From what I read the ECM maily switches the ground on/off inorder to achieve lockup. My question is, if all the ECM does is switch the ground how does it monitor the parameters and is there a constant +12v supply to the tranny? If anyone has an OE wiring diagram I would greatly apprecitive. I want to also know what each of these wires control and what pin they are associated with...Light blue, pink, tan...A,B,D pin?

If there is no safe way to maintain the ecm control and make a manual override then I will just use a vaccum switch and 5=pin relay to acchieve what i want with a manual override switch.
Thanks in advance for any help.
Title: Re: how does the ECM control lockup?
Post by: VileZambonie on March 18, 2012, 10:14:54 pm: Did you search this on here? There's been several posts on this.

http://forum.73-87chevytrucks.com/smforum/index.php/topic,7310.msg42965.html#msg42965
Title: Re: how does the ECM control lockup?
Post by: DrDaryl on March 19, 2012, 12:04:00 am: Hey Vile, the "4th gear switch" on the diagram you referenced--where does it screw in?
thanks
Title: Re: how does the ECM control lockup?
Post by: Captkaos on March 19, 2012, 09:37:49 am: It goes in the transmission.
Title: Re: how does the ECM control lockup?
Post by: frotosride on March 19, 2012, 01:59:20 pm: I have searched through countless post on this sight and I haven't found the answers yet. This is why I decided to post a new thread.
Title: Re: how does the ECM control lockup?
Post by: VileZambonie on March 19, 2012, 08:30:10 pm: Sorry, been extremely busy and getting ready to leave for a trip. Unless someone else has time right now, search "lock up" "tcc" "converter clutch" etc
Title: Re: how does the ECM control lockup?
Post by: Captkaos on March 20, 2012, 02:10:36 pm: There are links in the post Vile put up that show you how to hook one up manually.
Title: Re: how does the ECM control lockup?
Post by: frotosride on March 22, 2012, 11:46:13 pm: Thanks, Vile and Capt, I prety much got the manual hook up part down and it looks like thats the way I'm going to got after I try just adding a switch to the ground and pray it doesn't mess up my ecm...If so then I will have to do the manual hook up. Good luck on the trip. I 'm being relocated to Norfolk, Va and thats why i want to figure this out. However, I now have a new issue I have to deal with....seems that I gave a little too much loud pedal and completly smashed the drivers door and all but decentigrated the window. Thanks to a good friend who has more than ample parts of our favorite year model chevy trucks I picked up a door for $50 and now its prep and paint time.