I just bought an 81 that has a regular vac. advance dist on it. The carb does have a lots of hoses going to it. What do I do to get rid of this carb or what can I abandon and plug. If this is done can the computer deal in the battery box be chunked?? I have no idea if anything is working properly. The car runs and drives. I did find a leaking vac hose, large on the driver side down low, the other with it was plugged. Well, I plugged the open one and now when I start the car, after 30 seconds or a minute, it just dies. It will crank right up again. There is a a lots to learn here......much more than the 62!!!Thanks

 

Anything you plan to "chuck", please send to me. God bless, Sensei

 

The computer controls the carb, the ign advance &, if it's an auto, the TCC lockup. Easy to junk the whole lot, but you'll need to get a replacement carb & dist. The TCC can be locked with a simple wiring modification. Oh yes, the computer also has input to the emission control systems in a small way.

 

You should have only one hose going to a vacuum advance distributor. You will also have couple of hoses for the EGR valve and solenoid. And of course there are the lines for the headlights...which is a large hose on the driver's side going up to the front.

Like was said, to get rid of the CCC (computer) completly requires a different carb...one that does not have the TPS, and air/fuel mixture solenoid. Easy to get....just about any Q-Jet will work.

Good luck with it

 

It has single line to dist, headlights off manifold. If I change the carb what all can I do away with? All the EGR stuff? The pump is already gone.

 

The EGR can go. The computer can go after you revise the TCC lock-up. The PCV should stay. The EFE can go or stay. The two TVSS can go, unless you keep the EFE.

 

One of the TVS's (on the d. side of the stat housing) controls the purge func of the vac cannister.
When I got my '81 the computer was in place, along with the CCC type carb & dist, but all emission systems had been removed apart from the charcoal cannister (which worked until I broke the TVS ) ie. you can remove all AIR, EGR, EFE & still keep the CCC system, or you can remove the whole lot.
If you search through the archives you should find some decent pics of L81's, with & without the CCC system, showing vac hose routings, etc, with & without emission control systems.

 

If someone knows the archived threads please let me know. I don't know what an EFE is! Don't care about EGR Don't know if I need the vac sensor or the purge TVS And don't know if I need the canister. The AOR pump and management is gone don't know about the EFE TVS. Kind of like that ad on TV (with Daisy Duke, the new one) "I don't know what it is, but I DON'T want one"

 

OK, here's a pretty scabby pic of mine shortly after I got it (it's a bit prettier now!):

Hopefully it will give you an idea of what it looks like with most of the emissions stuff gone.
At the rear of the carb is a vac pipe going to the red solenoid. This solenoid, and the other one with it on the bracket, is for the EGR system & can be completely removed & the port on the carb blanked off.
The vac pipe on the front of the carb that goes nowhere connects to the air filter housing to control the flaps in it (completely forgotten what they're called!).
The vac pipe at the rear, from the manifold, which joins to the metal pipe goes to the Th350 trans & is required. The other one goes to the h/lights, brake booster, etc via the small white filter. The cruise control had also been removed on mine so I haven't a clue about the vac hose pipes for it.
On the stat housing are a pair of TVS's. the one of the p side controls the EFE (I think?) & the other one is used for controlling the purge of the charcoal cannister.
Just out of view, on the firewall behind the brake booster, is a metal bracket with some bits on it. There's a relay for the AIR system, one for the TCC/EGR systems & a MAP sensor hiden up inside it (with a thin vac pipe going to it). If you completely scrap the computer none of these will be needed, but it would be worth keeping the EGR/TCC relay in place for hooking up the TCC lockup again (I can help with this as I spent weeks trying to get mine working. It's the one thing that I don't forget with this car!).
Towards the front are a couple of red crimp connectors. The wire from these goes to a sensor in the manifold close to the stat housing. This is the coolant temp sensor for the computer & won't be needed if you scrap the computer (if Sensei doesn't want it then there's a home for it in England ).
Here's a pic from the other side:

I can't remember where the small vac pipe from the lower rear of the carb goes (can look if nobody posts an answer).
The pipes from the TVS, along with the fat one from the carb, go down to the charcoal cannister. Don't pay much attention to these as somebody had altered everything to do with them (& then I broke the TVS into 2 parts, so it didn't matter anyway ).
You can see the EGR bleed solenoid & the other thing clearly on the bracket bolted to the p.side vavle cover. If the EGR system has gone then this whole ugly lump can be removed. If you keep it for whatever reason, have a close look on the underside as there's a square hole for a vac fitting that may be left open to the atmosphere. I had a vac leak at this point & it tooks ages finding it.
The only other thing I can think of when looking at these pics is "What a mess"!!!

 

Hey Paul, very good writeup as always on your car. I would add to this thread that I would endeavor to keep the charcoal canister for a couple of reasons. 1 because it actually does some good when its plumbing is in working order by keeping the raw gas fumes from evaporating into the atmosphere and if there are no leaks on the vacuume control parts it doesn't rob any horsepower, so it works for free. 2 is a safety thing, the gas in the carb bowl WILL evaporate or try to when you shut the motor down and the heat from the engine soaks thru the carb while its parked, gas evaporates into gas fumes and in the right ratio can be explosive (thats gas engine 101) and lastly it will keep the garage from smelling like gas all the time, this is especially important if the garage is under part of your house.
I agree there are a LOT of hoses on these syatems, 6 on an 81 just for the evap canister. They car be rerouted to look better, some can be eliminated and cleaned up a bit when you remove the EGR system and air pump and diverter valves, will make a big difference in how it looks.

 

Thank you for the information, and for taking the time for such a complete answer. Yesterday, I knew almost nothing about these systems. What does TCC stand for? If I remove items, I will let you guys know. Darrel

 

SIXFOOTER,
agree 100% about the charcoal cannister doing a good job & being worth keeping. What I found with mine (& this could be worth checking if you ever smell fuel, or suspect a small vac leak) is that the gaskets under the valves had perished and were leaking.

TCC = locking torque converter (Torque Converter Clutch?).

 

Hey Darrel

the TH350 tranny in your car was furnished with a TCC or Torq Converter Clutch. It has a mode called Lockup and it is controlled by the ECM and only goes into Lock in 3rd gear in cruise or light acceleration. What it does is to lock the converter and eliminate the normal Slip in all torq converters, this improves gas milage and limits the heat generated in the transmission. If you do decide to dump all the computer stuff you will need to hook up something to make it work, usually a brake light switch and a toggle so you can turn it on and off.

 

One in the same. The MAP sensor is the vacuum line from the lower rear port.

 

UKPAUL,
Would you happen to know what the modification is to make the TCC lockup work without the computer? I have the motor out of my 81 now and am replacing it with a non computer motor. Thanks.

 

Richard,
the computer just grounds a wire from the TCC/EGR relay to get lockup. If the stock wiring is still all in place then it's the wire coming from pin B on the relay. There will also be a relay for the AIR system that looks the same, but the wiring for the two is different - the EGR/TCC relay doesn't have a wire on pin D.
If you ground the wire manually then you'll just be doing what the computer did. To make it easy, if you take off the d.side console side cover you should be able to see a tan/black wire with a shiny, har black plastic block in it, somewhere around the front of the shifter plate/console area. The plastic block will have a partially exposed spade terminal in it (it's the TCC diag test point). If you cut this wire and join one end of it to a switch (the end of the part that goes to the engine bay!) & connect the other side of the switch to a good ground, then you should be able to use the switch to select lockup & still have the brake releasing it. The reason I say cut the wire is that I've not looked at the connector at the computer. If the wire is joined to one that goes off somewhere else then it may cause unexpected results. If it doesn't then you needn't cut it & can just tee off the diag connector.

If the wiring has been pulled apart then you'll need to do a bit more work. Obviously you'll still need to fit a new switch, but I'll explain how the stock system works (apolgies if it sounds condescending - I like to keep it in simple steps so I don't confuse myself ).
The relay is an electrical switch that opens/closes one circuit depending if power flows through another. On the TCC/EGR relay the switch opens/closes the circuit connected to pins A & E. Pushing power between pins B & C is what does this. Normally, the power to do this comes into the relay on pin C via the TCC switch on the brake pedal (if the brake is pressed then there's no power to the relay, so it cuts the connection between pins A & E, switching off lockup). This power then goes out via pin B, where it goes to the computer (via the TCC diag connector). If the computer wants lockup then it grounds this wire, thus switching the relay so that power can flow between A & E, causing lockup. Hope that makes sense?!
That's the switching bit, but what gets switched? Pin A on the relay is a direct connection to a ground point somewhere. The wire on pin E comes from the connector on the trans case. This is where it can get confusing! The harness from the trans goes to a connector located just behind the rear of the d.side valve cover. Wires are connected on pins A, B & C & these go down to the trans connector, to pins A, D & C respectively ie. pin B at connector goes to D on trans. Pin A on the connector (and case) is a 12v supply. This goes through the guts of the trans & comes back out on pin D. This then goes to pin B on the connector behind the valve cover & then on to pin E of the TCC/EGR relay.
So, when the relay gets switched by the computer, the power going into the trans can flow because the relay closes the switch in it's return path to ground. This current flowing then activates the TCC solenoid & somehow the converter locks up.

So that's how the stock system works & how you change it really depends on what's left of it. If it's intact then you can do it by using a switch to ground the black/tan wire, with the diag connector, as described above. If the wiring has been Bubba'd then a few easy mods will fix it. Due to the small current flowing through the solenoid I don't think you really need a relay (I'm not an electrical engineer, so don't take that as gospel! What I do know is that the current flowing is a lot less than I've got running through a headlight bulb that hasn't got a relay protecting it. I've wired my 200-4r to run lockup without the relay & it works just fine). To get lockup you just need to let current flow between pins A & D on the trans connector (pin C, though wired, wasn't connected in my trans). What I did with my 200-4r was probably the easiest way to do it. By cutting & joining wires near the relay & connector you can get it all working quite easily. You need a 12v supply that gets cut when the brake is pressed. With an L81 this is easy as it's already done for you by the TCC switch on the brake pedal. You'll find this wire connected to pin C of the relay (purple). This wire needs to go to pin A on the trans, so snip it off of the connector to the relay & then cut all the wires off the connector at the top of the trans harness. Join the purple wire to the A pin on the connector (if you leave a couple of inches of wire on the connector when you cut it, you can solder/splice/use crimp connectors). Next is to take the return from the trans (pin D on the trans case, pin B on the connector) to a switch that you've fitted somewhere. This will be easy as you've already got the black/tan wire (with the diag test point) running from this area right through the cabin near where you'll probably fit the switch. So snip the wire off of pin B of the relay connector & join it to pin B of the trans harness connector. Then get in the cabin, find the black/tan wire under the center console (with the black plastic block in it), use an AVO to verify that it is the correct one, & then cut it & join it to one of your switch terminals. Connect the other switch terminal to a good ground & you should then be able to select lockup with the switch, as long as the brake isn't pressed.
This probably sounds complicated, but it's easy once you actually have it all in front of you. All references to colour coding are probably futile as mine were all dirty grey! If you do the mod by cutting and joining wires, be aware that the wire that was originally connected to pin A on the trans harness connector (pink/black, or dirty grey!) is live & should be insulated so it doesn't short anything afterwards.

Hope this helps I've done a word doc copy of the relevant circuit if you need it (it's a lot easier to follow than the verbage above!) & can send it if you want it.