- Joined
- Dec 25, 2002
- Location
- mont, AL
So having aquired a stash of ecus that represents an average of whats found here (lh 2.2/2.4/rex) i've got some stuff to share (this is a continuance of a post i made about two years ago on the subject at hand):
lh 2.2 NA:
fuel:
8.3mhz (crystal on the board)
no socket
Board layout is the same as the turbo ecu, most capacitors are the same values, however theres a large number of resistors that differ. at a glance both the turbo and na ecus appear the same, a closer look reveals several differences (of which I dont and dont care to track down)
lh 2.2 Turbo:
fuel
8.3 mhz
no socket
Ignition:
8.8 mhz, two connected boards. rather dull really.
lh 2.4 Turbo (no na ecu) last three digits are 563:
12 mhz (crystal)
approximately 2x the number of FET's as found on the lh 2.2 board
more diodes, and about 1/3rd the resistors.
socketed eeprom (thats chillin in my stack of chips). Larger harness connector than lh 2.2
Ignition:
8.0 mhz
one board (as compared with the earlier ezk versions that have two connected pcb's)
far fewer components, perhaps 1/4th the number of resistors, a few extra chips, one largely heatsinked fet. Part number on the siemens chip is: 2-227-355-302 (9019) (unresearched beyond what lh 2.4 info i've managed to glean. 16bit capable of running up to 16mhz iirc)
REX... Since info is largely sparse and from what i've been able to gather also largely incorrect, heres some thats correct with some things I noticed whilst playing with my rex car before ditching that and going with t3h ms:
FUEL:
there are multiple ecus, the 1990 ecus have one pcb, they run at 8mhz, and the processor is a motorola zc407531vfn (motorola's website doesnt pull up any info, still searching around)
more fets than the lh 2.4 board
later model ecu (p/n: 3531658)
has two pcb's
8mhz
several more ic's including what appears to be an external rom (soldered not socketed)
Ignition:
both appear to be the same (but then I could be looking at two 90 rex ICU's)
socket used is the same as the lh 2.2 ecu/icu and the 2.4 icu
Chip is a motorola ZC98909VP, running at 4mhz, aside from this its not any more or less exciting than the ezk 2.4 box.
as i research the various chips i'll post findings here. I'm more interested in the Rex stuff as its largely unknown, and well goddamnit i'm curious, even if its largely worthless from a performance point of view.
Rex notes:
It relies *heavily* on its o2 sensor (which is different from most other narrow bands that i've seen, but this could merely be a coincidence)
the slightest bend in the trigger wheel on the flex plate will yield wild results with the ecu, including but not limited to : it firing only on two cylinders (whoops) and/or it throwing a check engine code and reverting to fail safe ignition timing (bastard).
When coupled with a wideband hooked up to the ecu running narrow band sim, the ecu will hold the car almost perfectly at 14.7:1...... at all times. punching it will not yield a drastic change in air/fuels (it would occasionally go down to 13.9 for a second). without the narrowband connected the ecu pitches a huge fit.
with inaccurate narrow band readings it won't nesc. throw a CEL, however I noticed on mine when i'd connected the 5v wideband signal, the higher the voltage (hehehe whoops) even over 1v, the more fuel the ecu would pull, literally until the car died at 23:1. in an intersection (****er). and would not crank back up until the signal was disconnected, then it promptly threw a check engine light and I watched my fuel gauge plumet towards E.
How does Rex react to positive pressure? I dunno. One of yall try that **** out sometime and fill me in.
lh 2.2 NA:
fuel:
8.3mhz (crystal on the board)
no socket
Board layout is the same as the turbo ecu, most capacitors are the same values, however theres a large number of resistors that differ. at a glance both the turbo and na ecus appear the same, a closer look reveals several differences (of which I dont and dont care to track down)
lh 2.2 Turbo:
fuel
8.3 mhz
no socket
Ignition:
8.8 mhz, two connected boards. rather dull really.
lh 2.4 Turbo (no na ecu) last three digits are 563:
12 mhz (crystal)
approximately 2x the number of FET's as found on the lh 2.2 board
more diodes, and about 1/3rd the resistors.
socketed eeprom (thats chillin in my stack of chips). Larger harness connector than lh 2.2
Ignition:
8.0 mhz
one board (as compared with the earlier ezk versions that have two connected pcb's)
far fewer components, perhaps 1/4th the number of resistors, a few extra chips, one largely heatsinked fet. Part number on the siemens chip is: 2-227-355-302 (9019) (unresearched beyond what lh 2.4 info i've managed to glean. 16bit capable of running up to 16mhz iirc)
REX... Since info is largely sparse and from what i've been able to gather also largely incorrect, heres some thats correct with some things I noticed whilst playing with my rex car before ditching that and going with t3h ms:
FUEL:
there are multiple ecus, the 1990 ecus have one pcb, they run at 8mhz, and the processor is a motorola zc407531vfn (motorola's website doesnt pull up any info, still searching around)
more fets than the lh 2.4 board
later model ecu (p/n: 3531658)
has two pcb's
8mhz
several more ic's including what appears to be an external rom (soldered not socketed)
Ignition:
both appear to be the same (but then I could be looking at two 90 rex ICU's)
socket used is the same as the lh 2.2 ecu/icu and the 2.4 icu
Chip is a motorola ZC98909VP, running at 4mhz, aside from this its not any more or less exciting than the ezk 2.4 box.
as i research the various chips i'll post findings here. I'm more interested in the Rex stuff as its largely unknown, and well goddamnit i'm curious, even if its largely worthless from a performance point of view.
Rex notes:
It relies *heavily* on its o2 sensor (which is different from most other narrow bands that i've seen, but this could merely be a coincidence)
the slightest bend in the trigger wheel on the flex plate will yield wild results with the ecu, including but not limited to : it firing only on two cylinders (whoops) and/or it throwing a check engine code and reverting to fail safe ignition timing (bastard).
When coupled with a wideband hooked up to the ecu running narrow band sim, the ecu will hold the car almost perfectly at 14.7:1...... at all times. punching it will not yield a drastic change in air/fuels (it would occasionally go down to 13.9 for a second). without the narrowband connected the ecu pitches a huge fit.
with inaccurate narrow band readings it won't nesc. throw a CEL, however I noticed on mine when i'd connected the 5v wideband signal, the higher the voltage (hehehe whoops) even over 1v, the more fuel the ecu would pull, literally until the car died at 23:1. in an intersection (****er). and would not crank back up until the signal was disconnected, then it promptly threw a check engine light and I watched my fuel gauge plumet towards E.
How does Rex react to positive pressure? I dunno. One of yall try that **** out sometime and fill me in.