Mercruiser 3.0 to Chevy 2.8l TBI Conversion

[wdemaster]

Hello all,

I have a new project I have decided to undertake. Not so much because it needs to be done, more because I want to see if it can be done. I have a mercruiser 3.0 from the mid 70's with its original carburetor that I would like to swap out with a TBI setup from a 1992 S10 2.8L V6. The below link is part of where I got the inspiration from...

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?988-Help-with-marine-3-0-mercruiser-tbi-project&highlight=MERCRUISER

However, there isn't a huge amount of technical information contained in that post as far as what is needed to make this system work after it has been extracted from the vehicle. I don't have too many current questions, I just want to open a dialogue for any ideas or pointers that might be floating around out there.

Here is what I currently have:
-1228062 ECM
-A mostly complete wiring harness (minus the fuse box which was already cut from the vehicle)
-most of the sensors I need (I think)
-A pinout diagram of the ecm along with primitive wiring diagram for it

So, any ideas anyone has are welcome as long as I don't have to hear "it can't be done", because I have already heard enough of that.

My first real question has to do with the distributor. Will the ecm work properly if I don't have it control the advance of the distributor?

[RobertISaar]

so you want to do fueling only? certainly possible, but you'll need to feed the ECM the reference pulses that the distributor/ICM would have generated for it.

[Fast355]

Hello all,

I have a new project I have decided to undertake. Not so much because it needs to be done, more because I want to see if it can be done. I have a mercruiser 3.0 from the mid 70's with its original carburetor that I would like to swap out with a TBI setup from a 1992 S10 2.8L V6. The below link is part of where I got the inspiration from...

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?988-Help-with-marine-3-0-mercruiser-tbi-project&highlight=MERCRUISER

However, there isn't a huge amount of technical information contained in that post as far as what is needed to make this system work after it has been extracted from the vehicle. I don't have too many current questions, I just want to open a dialogue for any ideas or pointers that might be floating around out there.

Here is what I currently have:
-1228062 ECM
-A mostly complete wiring harness (minus the fuse box which was already cut from the vehicle)
-most of the sensors I need (I think)
-A pinout diagram of the ecm along with primitive wiring diagram for it

So, any ideas anyone has are welcome as long as I don't have to hear "it can't be done", because I have already heard enough of that.

My first real question has to do with the distributor. Will the ecm work properly if I don't have it control the advance of the distributor?

You will need to change the cylinder count in the .BIN and your LHM Netres pack will be wrong.

I am assuming you have a GM Rochestor 2bbl on the 3.0L. If so you will need a TBI to Rochestor 2bbl adapter.

Your ECM will need to be in a sealed container with water tight connectors through it.

The newer 3.0L Marine port fuel engines have a TBI EST style distributor on them.

1/2 of the benefit of EFI is controlling the distributor timing and the knock control

http://www.gmpowertrain.com/2013_pdf/F_VertREV_3.0L_Marine_061413.pdf

[wdemaster]

Yes, I had fuel only in mind. However now that I think about it, I believe I have a distributor that will accommodate the ECM controlling it. I have the link to the distributor I have installed below.

http://www.michiganmotorz.com/delco-voyager-marine-electronic-distributor-p-120.html

I don't have any information as far as being able to hook that up to an ECM or not being able too though. Any ideas?

As far as the adapter plate goes, I have access to a full machine shop, and I am a mechanical designer with access to a good CAD package. So I will have that part covered.

Thanks for the information!

-Wes

[Fast355]

Yes, I had fuel only in mind. However now that I think about it, I believe I have a distributor that will accommodate the ECM controlling it. I have the link to the distributor I have installed below.

http://www.michiganmotorz.com/delco-voyager-marine-electronic-distributor-p-120.html

I don't have any information as far as being able to hook that up to an ECM or not being able too though. Any ideas?

As far as the adapter plate goes, I have access to a full machine shop, and I am a mechanical designer with access to a good CAD package. So I will have that part covered.

Thanks for the information!

-Wes

If it is the one in the picture, looks like a small cap HEI EST module to me that has the timing control function bypassed by looping the EST output to the EST input.

[wdemaster]

If it is the one in the picture, looks like a small cap HEI EST module to me that has the timing control function bypassed by looping the EST output to the EST input.

So, in theory, I could break that loop and hook it up to the same spark control that was in the original truck providing I can edit the values for the base timing in the ECM? I had originally thrown out the idea of spark control for the simple fact that the boat really only runs at idle and wide open throttle. The stock advance curve in the module in this distributor is almost non existent, I believe it is at max advance by the time the motor reaches 2500 rpms...(that what I think I remember reading anyway)