Help with lockup

[GrndNatnl]

I figured I should ask this question here instead of General Tech.

I have a switch wired up to the top right & left pins of my ALDL for TCC lockup switch. It was working great... and today I noticed it would not lock up the converter. The other day I used a GM trouble code scanner to check for codes (which there was none but the good 'ole code 12). I hooked the wires back up into the correct ports, and last I drove it today, the switch doesnt lock it up. Could this have anything to do with the ECM? Or could this be a TCC solenoid problem all of the sudden? Shouldnt be any problems considering the tranny was rebuilt with a crapload of new parts 20k miles ago. Is there a sure way of testing the automatic lockup on the highway? Traffic is so bad around here, its hard to test much of anything. I've noticed it running in 3rd a lot. I let off the gas, RPM goes down,.. soon as I touch it again, it stays low for a second, back up.

 

[MeanBuicks]

First thing I'd check would be TCC solenoid resistance. Place a multimeter across the solenoid + & - terminals (should be A & D on your connector) and read the coil resistance. A good solenoid should measure 24-26 ohms.

If that's fine, verify you have 12V at the connector. If so, it's time to pull the pan for a closer look.

 

[GrndNatnl]

Ok, heres the scoop...

I thought the terminals were A and F? I have the switch wired to A and F.. top right and top left. Or you using different pins to test only?

I took it for a spin this morning, down the long back road behind the neighborhood. It goes into OD by itself, and seems to lock up. I was playing with the switch at different points, and heard it lock up. I'd flip the switch.. it would hesitate about 1 second then lock up and the RPM would go down. I'd flip it back, and it would come right back up. But only at certain speeds. Doesnt seem to lockup like I last remember fooling with it.

I even tried leaving it in D (3rd) and bringing it to about 2500 rpm and flipping the switch.. nothing. Thought I should hear it do something then, but not too sure. Anything I'm doing wrong or missing out on here?

 

[Scott231]

Sound sto me like the ECM is locking up the converter when the parameters in the chip are met (Note, RPMs have nothing to do with TCC lockup)...and subsequently, the wiring to your switch is not working/ Assuming you need assistance:

1. Verify that the wires to the switch are well connected,
2. Verify that the wires to the ALDL connector are well connected, and finally
3. Verify that when the switch is thrown it completes a circuit (those cheap little switches you get for under $10 at any parts store would not qualify as high-quality parts).
   [/list=1]
   
   The brake switch is out of the question if the ECM is still locking up the converter...

 

[GrndNatnl]

Just checked all the connections and the switch functions. (Via the on/off light). It just feels that sometimes it locks it up, and sometimes it doesnt. I know when it does, because I'll flip the switch, it'll lock & unlock; I can hear it. But then theres other times where it ignroes the switch.

It's been a frustrating morning, as I'm also struggling to wire my boost gauge to the lights still. I tried using the empty "LPS" terminal in the fuse box, but the light only has one wire going to it and doesnt ground on anything. I tried touching it to all kids of stuff to ground it but no light. So I used a test light to test the LPS port, when I did the first coupld times, the little bell dinging slowed down and the check engine light came on. Then I checked it once more and everything went POOF. So I started the car, played with the lights, turned car back off, dinging bell worked again. Talk about confusing the hell out of me. I dont even know what to wire gauge lights to now. I need a good ground, aside from a good lamp power source.

 

[MeanBuicks]

Re: Ok, heres the scoop...

Originally posted by GrndNatnl
I thought the terminals were A and F? I have the switch wired to A and F.. top right and top left. Or you using different pins to test only?

I was referring to the transmission case connector, not the ALDL.

 

[John Larkin]

Sounds exactly like what I went through. I ended up needing a new solenoid. The advance auto brand one is working fine for me. Get the one for a 700-R4. It comes with shims and is purportedly a better unit. Check your wiring and resistance as you go. Don't do like me and button it up half done.

 

[Russ Merritt]

Anyone doing a search on this, don't forget the ecm fuse (10a) under the dash. Upper right on the box.

 

[Bonden]

The transmission in my 87T is not locking up either. With a scan tool (unknown brand) connected, it shows the lockup is off at any speed. Apparently, the ECM is not sending a signal to the selenoid to lockup. Anyone know how can I resolve this issue ?

Also, when driving about 30 - 35 or less with tranny in D, if I take my foot off the gas, the engine will drop to an idle, like not connected to the tranny at all until I give a little gas, then it will sorta "catch up" with the tranny again. Not a very clear discription I guess.

Any ideas will be appreciated -

Thanks

 

[Low Budget]

Been there.

Also, when driving about 30 - 35 or less with tranny in D, if I take my foot off the gas, the engine will drop to an idle, like not connected to the tranny at all until I give a little gas, then it will sorta "catch up" with the tranny again. Not a very clear discription I guess.

Sounds clear to me. Done that!

I hope you're all fixed up by now. I had the exact same thing on my 87 GN right after some inept trans guy (Read: Cottman + Wife's cousin.) rebuilt mine and told me, "We'll see how you like my transmission." I didn't. Did just what yours did, followed quickly by not wanting to shift at all!

I unfortunately can't say what the problem was. Except all the Turbo Buick specific
200-4r (brf) parts were missing and replaced with standard 200-4r parts. Nice!! I took it to Level 10 where it cost me a fortune to get all the goodies replaced. (Including them finding me a brf valve body to replace the one I feel was stolen by the last guy.)

Anyway, hope you're all set.