CPI Swap Question..from TBI

peter paul fenske ffnsp955 at bcit.bc.ca
Sun Jun 28 11:41:47 GMT 1998


Hi Larry

Well I hooked up a 97 4.3 vortech to a 730 ecm in my S10.
I essentially followed the wiring diagram fer a 91 camaro
and used the 3.1 auto cal for the camaro. 
The 97 differs from earlier cpi in that 6 injectors feeding
poppets are used instead of one central injector.
These were saturated types which the 730 can drive

I have afeeling the old cpi is peak and hold.
Measure the dc resistance if it is 2 or 3 ohms it is peak and
hold. 

So prob go to the 747 4.3 application. use the wiring as is
make up a plug fer injectors.
The tps on mine was the same as 2.8 3.1 style plug
so you might need a different plug. wrecking yard or
parts store should do it. 

All the other sensors are identical.

You might have to adjust the base pulse but you might luck
out and all will be fine.

As for the air divider well a lot of people leave it out.
It does give a bit of better low end torgue but at
a cost of a wee bit of top end breathing.

take care:peter

Ps use your stock HEI. Don't have wiring, most public
libraries do have mitchells.

>Short of finding a factory Astro harness for use with this manifold,
>what do I need to do to make the TBI harness work with the CPI. I assume
>I'll have to repin the ECM connectors, and possibly get new connectors
>for the sensors/controls on the CPI. Does anyone know how adaptable this
>is? Also, can I use the same ECM, with perhaps a different Mem-Cal?
>
>FWIW, I am buying this manifold as a take-off from Howell EFI, and they
>*do* offer a factory harness modification service...for around $550.
>Being the frugal type, I'd rather do this myself.
>
>PS...does anyone have a copy of a 1992 wiring diagram/pinouts for the
>CPI motor? I know it came in S10 trucks, Blazers, and Astro vans....
>
>TIA!
>
>Larry Kurek
>
>




More information about the Diy_efi mailing list