fattie92

ok iv looked this topic up and all i found was " youll have to change the carb and distributor and the lock up converter might not work"....


i know there is a lock up converter kit for the swap.. and the carb and distributor arnt a big deal.. but what else is involved?? what can you get rid of, and cant get rid of? i have a 350 in my 84 trans am, with the stock lg4 wire harness in it with no knock sensor. someone needs to make a tech article about this.. so can someone give me a good detailed description of what this swap all involves? thanks
ryan

fattie92

ttt

99Hawk120

It's very, very easy.

You don't have to get rid of anything, though I suppose you can unplug and remove the sensors for the ECM

Remove CC carb and distributor.
Install non-cc carb and non-cc distributor.
Remove check engine light from instrument cluster.

All done.

I plan on leaving all of my crap in place because I have to pass visual inspection. It will make it easy to swap back to the CC setup when necessary. I plan on finding the CE wire down by the ECM, cutting it, and putting a connector on it so I can reconnect at any time. Easier than removing the bulb

fattie92

can i do that even if i take the ecm totaly out? and what about the lock up for the tranny?

five7kid

iTrader: (14)

The lockup will require a new circuit/control. Either a switch you operate manually, or a retrofit kit you can get from Summit or Jegs.

fattie92

what happens if you dont put the switch in to lock it up?? is it gonna ruin the tranny?

99Hawk120

Sorry, I have a stick, never considered the lockup issue.

Yes, the computer controls the lockup, you'll have to find another way to do it.

Damon

The problem with not having a functional lockup converter is that in OD at moderate speeds- 35-50 MPH or thereabouts you will be running near or below the stall speed of the converter, which builds a lot of heat in the tranny. Heat is your transmissions enemy- it will kill it quick.

SO...... you can either leave it in regular Drive around town and save OD strictly for the highway or you can buy the above mentioned kit to make it work without the ECM.

SilverTA

Hmmm. Is there any way to do this without having to uninstall the check engine light? I imagine that's a good feature to have. If it's uninstalled, what is the risk of suffering serious engine due to a lack of feedback?
Thanks

fattie92

i might not have to swap over now.... i think i fixed my problem...well find out for sure tomorrow.

Momar

If you get rid of the computer controlled part of the engine, your engine light will be on all of the time. The computer would not know when to turn it on anyway unless it was still running the engine.

Ben

flyway190

Won't unplugging the ECM have the same effect?

99Hawk120

Yes, but it gives you unsightly dangling wires

SHAGME

my buddy has a 86 with a lg4 and has his stock dist and ignition system but an edelbrock cark on it andit runs great. so what gives?? I am confused.

Momar

If he has an aftermarket carb, and the stock distributer and ignition components he is not getting near what he should out of that motor. It cant advance without the computer so it will not make as much power as it should/run as well as it should. He should get a aftermarket distributer w/ vacume advance.

Ben

SilverTA

So in other words, I'll have to get a quadrajet or other aftermarket carb, a new distributor with vacuum advance, and unplug the ECM. Bear with me here, why do you have to unplug the ECM? To keep the engine computer from trying to run the carberator?

flyway190

Let's see if I can make this simple and be sure we're all on the same page. There are 4 major outputs from our computer that we really care about:

The first is the primary air/fuel ratio on the carburetor. On non-cc carburetors, this is adjusted mechanically using metering rods and jets. On the cc carb it's adjusted via a special set of metering rods and jets that can be electronically adjusted in a way. If you unplug the computer from the cc-carb, it will always run rich, and you will not be able to adjust it.

The second is the distributor advance. Non-cc distributors have vacuum advance, controlled by vacuum from the carb and adjusted using weights and springs. Cc-distributors advance electronically based on a signal from the ECM. If you unplug the ECM from the cc-distributor it will not advance much if at all. I'm not quite sure what the computer does if it is hooked up to the distributor but not the carb.

The third is the torque converter lockup control. If the computer is unhooked from it, you have to get a kit or wire up a switch to control the solenoid.

Fourth is the check engine light, and if you've unhooked the other three outputs, you might as well unplug the computer. The check engine light won't come on unless it's told to.

Anyone have anything to add? Hope this helps.

SHAGME

ok thnks making better sense now. I know more about old mustangs than computer controlled new stuff but Im learing everyday.