where is this located on the car? where does this get its vacuum source at? I have an EGR code and also no lock up so I figure trying to track down a vacuum leak for both seems totally rational. I also have a sort of random full throttle upshift issue, where anything other than low throttle it shifts at random points or not at all. my friend and I are thinking that the tv valve and sleeve are worn out and need replacing. what do you guys think. Oh we are working on a fresh rebuilt trans, 700R4 of course. Its in a 1992 Z, with 350 TPI. dont know if you needed that info, but there it is.

 

okay so I talked to a trans tech at one of the local shops around my house and he said that the 92 camaros dont use the vacuum switch to control converter lock up(under load) and that the ecm takes care of the entire situation from it's inputs(MAP, TPS, RPM) and and controls it from there. So my question then would be is this guy correct or is what everything else im reading correct. I still have yet to try out jumping the ALDL to see if that works. I will prob try that in a few days.

 

He is correct - there's no vacuum switch controlling the TCC lockup - it's all controlled by the ECM.

Shifting is totally controlled by the TV cable - it needs to be adjusted properly in order for the shifts to occur correctly.

 

so what would cause my car would have no lock up?

 

You sure it's not locking? It's not really something I was ever able to feel - especially when my car was stock - but stock I had a 305 TBI and not the 350 TPI like you. Stock, I could baely feel the shifts at all really ... 1-2 was easy to feel, 2-3 not so easy, 3-4 almost impossible to tell, and I never really felt the lockup. On occasion, when the TC was locked at say 45mph in 4th, and I come across a decently sloped hill, I could barely feel the TC unlock when the car was attempting to maintain the same speed - but usually it would so quickly change from 4th and locked to 3rd that noticing anything other than the change from 4 to 3 was impossible.

Now, I have carb and a manual lockup switch, and although I can't feel it lock, I can see the very slight RPM difference on the tach when I do lock it - at 65mph it's only about a 300rpm difference - you really have to watch for it on my car - and since I'm activating it, I know when to look.

I wonder if you can 'test' it - if the converter is locked, the car will bog down quite alot at low speeds (like below 35mph). So - I wonder if you could use the ALDL and test? My thought is to take a pair of test leads from an old volt/ohm meter, stick the leads into the appropriate slots in the ALDL, and connect the ends together with a switch.

1st test - see if there's any noticeable change at say 45mph when you flip the switch - if there's a change, then maybe the TCC is not locking as you suspect.

2nd test - If you really can't tell anything with test 1, then maybe drive the car on the highway with this switch OFF, the ECM should lock the converter (if it's working). Then flip the switch ON making contact and locking the converter - except it should be already locked, so no real change. BUT - when you leave at the next off ramp, and come to a stop, the ECM would disegage the TCC, BUT your switch making the contact would keep it locked, and thus you'd bog down right before the stop (you should notice this bogging down at about 30mph and the more you slow, the worse it gets).

To answer the question though - there's only 4 possibilities I can think of:

1) Fluid level - TCC lockup is just a solenoid in the tranny that forces more fluid into the torque converter - the more fluid it holds, the less it can slip - if there's not enough fluid then it would not 'lock'.

2) Wiring issue - there's a 4prong square connector drivers side of the tranny - these are the wires. Could follow them back to the ECM and wherever else they run - make sure they aren't broke, melted, etc. It's my understanding that the ECM provides grounds, not 12v+ ... so the red wire in the connector should in theory have 12v+ when key is in run position, and the rest I'm assuming are grounds from the ECM. And you should be able to test continuity on all the wires from that connector to wherever they run.

3) Wiring INSIDE tranny - I'm assuming that transmission fluid doesn't erode wiring and such since there's wiring floating in all that fluid forever - but you never know. Dropping the tranny pan you can see the wires on the inside (there isn't much), and check them. But that would be a PITA to drop the pan).

4) Something wrong with the ECM. Could maybe replace with one from a JY for the same motor/tranny combo and test this theory.

Don't know if any of that helps, and I am no expert (you see I make alot of assumptions) - but maybe that will give you some ideas and maybe more knowledge will chime in and point out where I might be wrong. Good Luck!

 

ok so I tried to jump out the aldl and the fuse for the gauges blew out. I replaced the fuse and tried again and as soon as I turned on the ignition it blew again. so I have no idea what could be going on. it looks like I will be installing some sort of "piggyback" system to run the lock up, like the B&M setup. since at the moment im looking for the best possible fuel mileage. that should work out alright I guess. my trans builder says that the tv valve is probably worn causing the inconsistent shifting. so I will probably end up ordering a new tv valve and sleeve and probably a new spring as well.