legacycentral bbs

I have an automatic ecu out of a '91 that I want to put into my '91 manual. I have read the posts about auto to manual conversions and because I am electrical dumb, I am still not smart. Why would a manual car have the black and white wire to pin 20 connecter there in the first place? If you have an automatic car and convert it to manual you are supposed to cut that black and white wire 20 to make the ecu think there is a manual installed. I have not yet removed my ecu yet so don't know what I will find. But think I might find that there is no wire connected up to pin 20 on the connecter. The ecu, yes, connecter, no. I will look toninght when I get home from work.

That's a great question. I'm sure vrg3 can probably answer your question better than I.

Your manual car isn't likely to have the connection at all on the factory harness, as it would make the ECU run in Auto mode, so you should be able to plug it in and have it work properly.

I'm having trouble understanding what you're asking -- are you asking whether a manual Legacy Turbo has a wire at the ECU's "transmission ID" pin?

It's also unclear what you're trying to do. Are you trying to convert a Sport Sedan from manual to automatic? Or are you just replacing the ECU?

As I've said many times here, automatic and manual Legacy Turbo ECUs are the same, and all Legacy Turbo ECUs are interchangeable, so you can put an ECU from any turbo model in your turbo car with no modification, as Dave confirms.

But if you're swapping transmissions, I think you'll find that there is no "transmission ID" wire on your manual car. You'll need to cut a nonessential wire from another ECU connection, move it to the right position, and ground it. Maybe you could use the "Trouble code output" pin; I don't think it's necessary for anything.

I put an ecu from an automatic car into my manual car. You are right, it plugs right in. There is no pin 20 on the B48 connector harness for a manual car. I thought this might fix a problem, however it did not. The car runs about the same, which is pretty good, I think. The problem is as follows: the check engine light is always on. With the original ecu in, it showed two codes, and I replaced those components. They were the knock sensor and the purge control solenoid. When you connect the black to black and green to green diagnostic leads together , the car won't start, the cooling fan cycles on and off and a solenoid(?) on the passenger strut tower clicks. I would like to get to a point where I could clear any codes and use the diagnostic leads like they are supposed to be used.

May I make a suggestion? I would find it helpful if you organized your posts into paragraphs; your thoughts and questions would be easier to follow that way.

When both pairs of connectors are connected, all the solenoids and relays and whatever are supposed to cycle on and off like that.

What happens when you try to start the car with both pairs connected?

What trouble codes does the new ECU show?

The car will not start with both pairs of connectors connected.

The car will not start with just the green pair conected.

The new ECU has trouble code 22.

There is a little nick in the insulation, bare wire visible, about an inch away from the connector that plugs into the connector for the knock sensor. Just reporting this "as found" condition, don't know if it matters. Did wrap it with electrical tape.

But what happens? Do you have spark but not fuel? Or fuel but not spark? Or neither? Does the fuel pump run?

When you turn the key the engine does not turn over. Starter does not crank. Just the various solenoids clicking and the cooling fan going on and off. I'd say fuel but no spark.

Pretty sure the fuel pump is on. What is an indication that the fuel pump is on?

Huh?! That shouldn't be... the starter circuit doesn't have anything to do with the ECU. The engine will turn over even without an ECU in the car. You've tested this a few times? The solenoids and relays keep clicking even while you're trying to crank the engine? Did the radio shut off like it's supposed to?

So in this case it doesn't really make sense to say there's fuel or spark because the engine's not actually rotating so there's no need for either.

But anyway:

If you listen carefully, you might be able to hear the fuel pump running (when everything's cycling it too cycles on and off every second or so). It can help to remove the cover over the fuel pump assembly.

You can check for spark by removing one of the plug wires, putting a spare plug in it, and resting the plug on the intake manifold or another ground. You can see the spark jump the plug's gap. You'll want a friend to help with this.