Tbi conversion help

[yevgenievich]

Stock tbi pump is weak, but will support stock hp motor all day long. A stronger pump would work as tbi has a built in regulator.

 

[Tonyorlo]

Need a little help,

I've searched with not much luck, but I need a wrong diagram for the 747 ecm. I mainly need it for the 12v + , grounds and the fuel pump wires. Any help?

 

[yevgenievich]

There should br a relay on the harness, is fot the fuel pump. Also, i found a tbi distributor if you need it, free+shipping.

 

[Tonyorlo]

I honestly have not even pulled the harness out of the box. I'm going to get the engine out of storage and into the garage this week and want to be prepared. I did find a diagram for the 747. That's great that it still has the fuel pump relay, it saves me a little bit of work. Everything else seems pretty straight forward.

I may take you up in the distributor offer, I think mine is the same, if not I will contact you. Thanks!

 

[Tonyorlo]

Kinda bad news, I got the engine that I have had in storage out to go over it. Pulled a head and 2 cylinder were full of water, they could of been like that for years. They are way past the point of honing and need bored. I'm going to use it as a core at the junkyard. So I will be getting a earlier carbed small block now. If anyone is interested I will sell the 747 setup to them.

 

[Tonyorlo]

I'm buying another 350, an earlier one with a square bore intake. How do the square bore to tbi adapters work? Will I have any problems with it?

 

[yevgenievich]

I'm buying another 350, an earlier one with a square bore intake. How do the square bore to tbi adapters work? Will I have any problems with it?

It should work ok. I believe you can olso bolt in the new style tbi intake on the old style head by redrilling the angles on the midlle holes.

 

[4WDKC]

Kinda bad news, I got the engine that I have had in storage out to go over it. Pulled a head and 2 cylinder were full of water, they could of been like that for years. They are way past the point of honing and need bored. I'm going to use it as a core at the junkyard. So I will be getting a earlier carbed small block now. If anyone is interested I will sell the 747 setup to them.

You could get an efi engine and still use the 7747, or you can get a vortec which is roller cam, get the ecm and harness from a 00-02 express van and still have efi.

 

[Tonyorlo]

I think I will keep the 747 harness and modify the vortec intake to work on the early heads. It's hard to tell how long I keep this truck, but if it's long term I will most likely go with megasquirt or maybe even drop an LS engine in it.

 

[kevinde1]

It should have the ESC module since it was a manual. It's the little module with the plugin that has the cut wires.

I thought this was the EGR solenoid?

 

[1987 GMC Jimmy]

What's shown in the picture is the ESC module that controls timing advance/retard when you're driving. The EGR solenoid is under that on the other side of the carrier. It's like a little box with nipples and a connector. The MAP sensor is on the rear top of the carrier behind the ESC module.