I'm blessed with the bastard 8063 ECU in my '88 Camaro. I have to burn my own chips (hell, the stuff to do it is in the mail), therefore, I have to swap computers. I'd appreciate a list on ECU #s that will work, Pablo has already suggested the 746 or the 7747. I have heard mention of wire swapping (scary), so if anyone knows where I could find wiring diagrams for my '88 I'd be most appreciative.

-Mark W.
<A HREF="http://www.angelfire.com/al3/thegreycar">'88 SC Camaro w/ 305 TBI</A>

 

YEp
those are the only two that will go in easily

like i said, the 746 will plug right in, but the 747 will require just one wire to be swapped with another and a couple of others cut.. its not a big deal at all

 

Which wires have to be cut? What wire has to be swapped? I might just go the 746 route to avoid cutting/splicing/ect. Could you point me in the direction of some diagrams? Thankz.

-Mark W.
<A HREF=http://www.angelfire.com/al3/thegreycar">'88 SC Camaro w/ 305 TBI</A>

 

Mark, I have the directions (but not with me) on how to do the swap of the 747 into your car... I'll post them here later. The 747 was never installed in an f-body from GM... It was used in many Astros, S-10's and full sized Trucks. This ECM is probably the most common one used by the folks on the efi-332 (diy-efi?) mailing list.

Like I said before though, there are better ECM's out there than the 1227747. I'd ask around for advice on this if I were you.

The process of swapping an ECM requires you to have the wiring diagrams for your vehicle and the donor vehicle in hand, just compare the pinnouts of each and re-pin the plug as needed. There is a tool out there that makes re-pinning the plug easy.(I didnt know about it when I did mine, I cut and spliced)

I used the wiring diagrams in the back of a Haynes (sp? Hayes?)manual.
http://www.diy-efi.org may have some diagrams kicking around.

 

dan, i never really got a good explanation, but i dont think using a different ecm is as easy as it seems. I think there is a problem regarding the injector drivers of using say a tpi ecm to run a TBI setup. I know there are kits to run TPI off a 7747 and they include an injector driver 'box' so that leads me to believe that to do the reverse some sort of circuit would be neccessary since the amperage and such would be different. Then again I never really found out what the deal with it was.

btw get on icq

 

I found a connector diagram for the 7747 ECU and I've compared it to the diagram in the back of the Haynes manual for the TBI ECU (I remember reading somewhere that the diagram was based on a '89 RS, but I can't find that now, but it's the same in '88 and '89 right?). Here's the differences I found, tell me if this sounds right...
<TABLE BORDER=1 ALIGN=CENTER>
<TR>
<TD>Conn</TD>
<TD>On TBI</TD>
<TD>On 7747</TD>
</TR>
<TR>
<TD>C12</TD>
<TD>MAT sensor signal</TD>
<TD>Not Used</TD>
</TR>
<TR>
<TD>C8</TD>
<TD>Power steering pressure switch</TD>
<TD>Not Used</TD>
</TR>
<TR>
<TD>A6</TD>
<TD>Ignition Feed</TD>
<TD>IGN-ECM Fuse</TD>
</TR>
<TR>
<TD>B6</TD>
<TD>Vehicle anti-theft system</TD>
<TD>Not Used</TD>
</TR>
<TR>
<TD>C2</TD>
<TD>Air port sol. control</TD>
<TD>EAC Sol.</TD>
</TR>
<TR>
<TD>C1</TD>
<TD>Air convertor sol. control</TD>
<TD>Not Used</TD>
</TR>
<TR>
<TD>A3</TD>
<TD>Canister purge sol. control</TD>
<TD>Not Used</TD>
</TR>
</TABLE>

It seems that the "Not Used" wires are the ones that get cut, which ones get swapped? Have I even used the right wiring diagrams?
Any help, suggestions, ect. appreciated...

-Mark W.
<A HREF=http://www.angelfire.com/al3/thegreycar">'88 SC Camaro w/ 305 TBI</A>

EDIT: Sorry about the big blank space, I can't figure out how to get rid of it...

[This message has been edited by Mark305TBI (edited September 14, 2000).]

 

To Swap the 7747,
remove c-15 and d-15
swap a-11 and d-2

As far as swapping to a different ECM, it is my understanding that it is possible and that there is not an injector driver issue. Contact Ed Write at Fast Chips for suggesions, he talked breifly about it with me(asked why I went to 7747 when there are better computers)

 

Oh Pablo, you can run TPI off the TBI computer w/o an additional box. One of the mags did a story on a shop that does it... they installed TPI on a late 80's truck with the 747 ECM. The resistance of the injector circuts ends up being similar because the TPI injectors are wired in parallel. I forgot what the resistance of the injectors are but if you print them for me, I'll show you how the equation calculating resistance in a parallel circut works.

[This message has been edited by Dan W (edited September 15, 2000).]

 

TPI off a 747 is possible.
Edelbrock has been selling a kit for doing that for years.
Trouble is the injectors fire 2x as often

TPI injectors once per engine revolution, TBI fires each injector driver alternately off of each ingition pulse.

Quickly run out of room for injector duration at idle. Lots of TPIs idle at Injector PWs of 1.2 and the injectors get erattic at .8msec so idles can get screwy

 

Interesting. I've been fighting an erratic idle in closed loop mode since my 7747/MPFI conversion. I'm begining to think about going to a 7730 (since I have about 5 of them now) just to fix the wild assed idle problem. In open loop, the car idles at 900rpm in neutral or in gear just fine. Once I'm in closed loop, the idle is ok in gear, but if I put it in park or neutral, it goes apesh:t and starts surging between 500 and 1300 rpm then dies. No vacuum leaks, I just suspect that the PW for 29lb injectors is too much for the 7747 to handle.

Any input?

Kelly 'GhoSSt' Rosato