|
Written by Administrator
|
|
Saturday, 01 January 2005 |
Quick Comparison
- CIS-E3 (OE in the 5-cyl type 89's)
- Pros:
- Has knock sensing
- Was already in place and working ;)
- Relatively Simple
- Cons:
- Not optimized for a turbo'ed motor
- Accuracy could be better (camshaft reference only for timing)
- Load compensation output (to mimick the air plate potentiometer) is hardly availible on any aftermarket EFI ECUs
- No aftermarket options to change the timing maps
- MAC11 (ECU found in MC-1 10v turbo cars)
- Pros:
- Timing accuracy is improved by getting engine position from crank reference
- Has knock sensing
- The extra needed sensors bolted up to the engine
- MAP input for accurate load compensation
- Tuned for the exact motor I was running
- Aftermarket chips can be installed for higher boost levels, and more aggressive timing maps
- Cons:
- Means I had to do more wiring
- Had to find a space for it
- Need to get a new chip to change the timing maps
Whys and Hows
I chose to switch to the MAC11 ECU because, well... I could. ;) Well that and the fact that the timing resolution is
improved upon by using a crank mounted sensor as opposed to the CIS-E3 which only gets it's signal from the distributer
windows. The MAC11 is also known to be solid, reliable and feasible up to some pretty silly levels of boost with a chip,
where the CIS-E3 igntion gives you a fixed map that you can only adjust by advancing or retarding the entire map(twisting the dizzy). The MAC11 also has a MAP
input so it knows the exact intake manifold pressure, where the compensation for this by the 90's ignition system was faked by the 034efi
controller, to give it a rough estimate of load.
The matter of installing the MAC11 was time consuming, but quite straight forward. I only had to add two sensors (the timing reference, and rpm sensors down on the tranny housing),
and the wiring associated with each. The rest of the wiring was just a matter of cutting and splicing into the stock wiring harness after removing the
CIS-E3 computers. I had to use a 5kt distributer (it has the needed single reference window), and I also used a 5ktq knock and temp sender. Everyhting else
stayed, even the 90's coil.
One of the things I had to work out was how to get a timing reference of 5 pulses per cam rev to the 034efi controller.
Previously I was getting them from the CIS-E3 5 window hall sender plate, but now with the single window plate for the MAC11 I had to find an alternate
source. I chose to use the coil trigger output of the MAC11 (pin 22), The 034 picks it right up, and hasn't had any problems with that signal all the way up to redline, yay! ;)
The timing variances from that signal (as the MAC11 is adjusting the timing values) do not seem to be effecting the fueling much at all, at least not to the point where any variances
can't be tunde out.
The following is a quick chart of how I wired the ECU up:
| MAC11 Pin |
Desination* |
| 1 - Colt Start Valve |
|
| 2 - Ignition Module Ground |
Grounded to chassis ground behind pass. kick panel |
| 3 - Charcol Canister Selenoid |
|
| 4 - Decel Valve |
|
| 5 - N/C |
|
| 6 - Code wire (For auto trans) |
|
| 7 - Tachometer |
Ignition Control Unit, pin 17 G/BL |
| 8 - CIS Freq Valve |
|
| 9 - Ground |
Ignition Control Unit, pin 22 BR/R |
| 10 - Coolant Sensor |
Ignition Control Unit, pin 1 BR/R |
| 11 - RPM - |
made small independant harness for this |
| 12 - TDC - |
made small independant harness for this |
| 13 - TDC + |
made small independant harness for this |
| 14 - Overheat Switch |
|
| 15 - Knock Signal |
Ignition Control Unit, pin 13 BR |
| 16 - Knock Sensor Ground/Shield |
Ignition Control Unit, pin 12 BR+W |
| 17 - Boost Gauge |
|
| 18 - Ground |
Ignition Control Unit, pin 22 BR/R |
| 19 - WGFV |
|
| 20 - Idle Switch |
Made new harness for this, and WOT |
| 21 - FPR Ground Control |
Ignition Control Unit, pin 14 G/V |
| 22 - Ignition Module Control Signal |
Ignition Control Unit, pin 16 G
Sensor Side pin 12 of the 034EFI controller |
| 23 - Intake air temp, and Hall sender ground |
Ignition Control Unit, pin 10 BR/W |
| 24 - Intake Air Temp Sensor |
Ran a wire, and soldered a spare sensor resistor for a spoofed reading |
| 25 - Hall Effect +12v supply |
Ignition Control Unit, pin 4 R/BK |
| 26 - WOT Switch |
Made new harness for this, and idle |
| 27 - Hall Sender Signal |
Ignition Control Unit, pin 24 G/W |
| 28 - RPM/TDC Sheild |
Made a new harnedd for these sendors |
| 29 - RPM Return ground |
Made a new harnedd for these sendors |
| 30 - O2 Sheild Ground |
|
| 31 - Fault Code Light |
Ignition Control Unit, pin 3 BR/G |
| 32 - Brake Light Switch |
|
| 33 - O2 Sensor Signal |
|
| 34 - Cali code wire |
|
| 35 - +12v Voltage from Ign. switch |
Fuel Control Unit, pin 19 BK/R |
|
*Ignition and Fuel control modules are the connectors for the CIS-E3 computers, the color code of the wire is listed to the right of each pin #
|
Stage Ia ignition 
