CPI Swap Question..from TBI

[peter paul fenske]

Hi Larry

I would leave the air valve alone, unless you really need it.
Racer types generally remove it.
The egr on the 97 is linear feedback. The 747 can't do it
The 730 I used uses digital egr so one of projects
is too make an adapter to use digital egr valve.
Got one from wrecker with harness for 25$ so spend money
there first before seeing Mr Good wrench
Most J cars will also supply a IAT although most 4.3 cals
for the 747 don't need it.
Better not to hook up anything you need.
I can send you a 4.3 cal if you need it.
Remember you are gonna run this like the original.

Anyways the 97 4.3 is quite nice. Got 650KMS on 20$ gas
on a long trip at US highway speed 75mph.
Also runs 15.0 which will embarasss a lot of
new muscle cars. Only mod is headers and KN filter

later:peter



>connector, injector connector, and suprisingly, I need to hook up an IAT
>sensor, and get a new EGR connector (since the CPI uses a different EGR
>valve with feedback than the Astro TBI). Finally, I found I have to run
>a relay to the air valve in the manifold...again no big deal, but now I
>have to find a connector for the valve itself...oh joy. Do you have a
>source on these connectors anywhere? I don't want to go through GM since
>they charge $20+ *just* for connectors...grrrr...
>
>Thanks!
>
>Larry
>
>PS> How does it run? Are you happy with the performance? 
>
>> -----Original Message-----
>> From:	peter paul fenske [SMTP:ffnsp955 at bcit.bc.ca]
>> Sent:	Sunday, June 28, 1998 2:27 AM
>> To:	diy_efi at efi332.eng.ohio-state.edu
>> Subject:	Re: CPI Swap Question..from TBI
>> 
>> 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
>> >
>> >
>
>