Peaks and Holds & 730 P+H

[Ludis Langens]

peter paul fenske <ffnsp955 at bcit.bc.ca> wrote:
> Not so nice the ecm for a 2.0 LL8 is listed as a 1228321
> variant of 730????

Nope, it is a variant of the (P4) 1227748.  The '7748 is a minimum
function (but including cruise control) ECM that uses a MEMPAK with just
a 27128 EPROM.  No CALPAK or MEMCAL.  The limp home resistor calibration
is soldered onto the circuit board.  The '7748 supports two different L4
TBI engines: the 2.5 "R" (& "U"?) and the 2.0 "K".  The engine type is
selected by jumpering two ECM pins together in the vehicle wiring
harness.  I've also seen it used on the 2.2 "G" engine.

The '8321 uses the same circuit board as later production '7748's.  All
the components are the same except for the calibration resistors. 
Wonder if the '8321 is a dual engine type ECM and if so, what engine?

The '7748 replaced the 1226864 which replaced the 1226156 which replaced
the 1225610 which replaced a carberator.  All three of these C3 ECMs run
both the 1.8 and 2.5 L4 TBIs - using a jumper wire to select between
them.  I think the 2.0 "K" is just a bigger version of the 1.8.

BTW, all of the above ECMs use two edge card connectors.  A 24 pin & 22
pin on the end of the C3's, and two 24 pins on the side of the P4's.

"Bruce Plecan" <nacelp at bright.net> wrote:
> I have in my hands a 1227730, with a memcal ADDT.
> Can some one independently verify this Broadcast Code is for 
> a 87 "Cavalier" 2.0L, and TBI?.

Yup.  Lots of these in the junk yards.  This application eventually got
the dedicated '8321 ECM mentioned above.

Shannen Durphey <Shannen at mcn.net> wrote:
> I show that it fits an LL8 2.0l  HO engine and 125 trans.
> Superseded from part no 16057548

Hmmm, I've found a FML7554 MEMCAL used with one of these 2.0 engines. 
It must be the original part (16057548).  Time to dump the EPROM
contents and compare it to an ADDT...

-- 
Ludis Langens                               ludis (at) cruzers (dot) com
Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/