6.2 with 700r4 converter lockup

[Itali83]

hey guys, I’ve got an 87 suburban with the 6.2 and 700r4. This is my first 6.2. I’ve had several ‘87 tbi Jimmy’s and some early 80’s carb’d pickups all with 700r4’s and am very familiar with the operation, theory and switches involved with converter lockup.

That said, my 87 burban won’t lock the converter. Do the 6.2’s have lockup converters? I’m assuming yes. If so, what’s involved to get the converter locked? I mean, what switches and what conditions need to be met for lockup? There’s no ecm on this truck right? Thanks in advance.

Ben

 

[Matt69olds]

I’m not real familiar with the 6.2 engine, or with the electronics that control it. I’m guessing there is a speed sensor (to determine the proper speed for lockup), probably a coolant sensor (keep the converter from locking until the engine is warm), some kind to throttle position (unlocks the converter during heavy throttle), and a brake switch to unlock the converter when you step on the brake pedal. Inside the transmission there is a 4th year pressure switch, and maybe another thermal switch that will lock the converter if the fluid gets too hot.

if I remember correctly, pin F of the ALDL plug under the dash is the test terminal for the lockup converter. Put a test light on it, with the key on the test light should be on. Step on the brake, the light should go out. That tells you the power side of the lockup circuit is good. The computer will control the ground side.

 

[82Diesel]

Yes all of the 700r4s the 6.2s came with are Electronic Lockup, The plugins are on the RH side of the injection pump that go down to the Trans. No ECM as of Yet... That didn't come out until 89-93 something like that but was only used in the 88-98 vehicles with the 6.2 until 91...

But there are some... out there with factory 4l60e trans as early as 1990-91 in the Suburbans & Blazers with the 6.2s.
Holy grail though.