I've been, looking at possibly buying a 1986 fiero 4cly auto that was experiencing torque converter lockup. I was wondering how safe it is to disable the tcc, specifically if it would be alright for a highway trip of about 4 hours (65mph)?

I've been trying to read about gm torque converters online but have gotten alot of conflicting information, ranging from "it burned up the converter in 6 minutes" to "drove one for over a year with no lockup without a problem"

Anyone have any fiero related experience/ insight into this type of issue?

[This message has been edited by Scribbles (edited 04-19-2013).]

Yes you can easily go that distance with the TCC connector disconnected. MPG will suck for sure. I've had to do it on a couple of vehicles when the solenoid hung up. If the TC is fried, you aren't going to make it any worse anyway.

Odds are you need new solenoid to fix it. Hopefully the TCC isn't stuck in lock-up already. It makes starting out and stopping a fun event.

I certainly wouldn't do it for a long time so fix it as soon as you can.

[This message has been edited by TK (edited 04-20-2013).]

I ran our 88 GT for many months (maybe 6 months and 6000 miles) with the TCC disconnected under the dash. You can disconnect at the trans as well, but under the dash is a lot easier. One of the connectors on the brake pedal will disconnect it if you pull the plug. Mileage dropped about 2 MPG with it disconnected.

Remember, before about 1985 or so, cars didn't have TCC functions. That is one reason why manuals always got better mileage than an auto. The TCC is disengaged a lot of the time anyway unless you are cruising under constant load. The ECM disengages the TCC when you need a little more power or any time you aren''t in 3rd gear.

I didn't fix the TCC solenoid right away because I didn't know where it was or how easy it was to change. Easy is relative. Not hard but not easy either. Do a search. I gave a pretty long description within the last month or so on what is involved. It took me about 4 hours to do the whole job including a trip to Autozone to get new plastic rivets for the wheel well pieces.

Trans runs hotter as well w/o TCC function.

Short version...
TCC allows "Sloppy" TC that gives more torque multiplier function.
This give you a better hole shot but worse MPG and more heat w/o lockup.
TC is major heat generator and lockup kills that.

Before TCC, car makers often used tighter TC to help MPG and manage trans heat.

note that Heat exchanger in radiator heats trans oil when TCC works... W/o that, oil is often too cold to work right. Especially in cold weather and/or highway driving.
Is why you put extra trans cooling (street cars) before/upstream radiator for All Lockup TC. Radiator make sure oil is warm enough to work.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

My sister had a Corsica for several years that ran unplugged, it was never a problem. Mileage difference was negligible on that car, thought it would be worse.

+1 - Fix the TCC problem. It's well worth it and it isn't that hard.

Phonedwgz is right. Implied in my last post but not explicit: You should fix the TCC when you get the car home. I wouldn't worry about it for the trip home if that is the only issue. Mine is also a V6 rather than a 4 but the trans should be pretty close and it is really easy to get to on the driver side once you take all of the wheel well stuff off. Took me about 2.5 hours to do mostly because I was learning what all is involved.