| Zen and the Art of MAF by Jim |
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| In your quest for improved
performance, suddenly your Lincoln has hit a brick wall,.no
matter what you screw on it in terms of trick parts and
pieces it won't speed up,..in some cases it even slows
down,.driveability goes to hell,.worst case scenario,..you've
blown a head gasket. Welcome to the outer reaches of
Speed Density fuel injection controls. Speed density is
great,.realistically a lot simpler than Mass-Air, but
terribly inflexible. After you radically change/improve
VE of the engine, the speed density system goes "tilt"
because the load/fuel mixture tables are chiseled in
stone,..buried in the processor,..so when you exceed
these parameters, the system can no longer effectively
compute injector pulsewidth (fuel/air ratio) and timing.
The net result is loss of driveability, or in extreme
cases, engine failure due to detonation caused by lean
mixtures and/or over-advanced timing. Yeah, I know you
naysayers are saying "but a custom chip will fix
this",,correct,.IF you have access to a chip burner
and a wheel dyno with A/F monitoring equipment,.but do
you want to have the chip (re)burned every time you make
another mod? You can change the air/fuel/timing
parameters in the speed density system, but you can't get
rid of the inherent inflexibility that is designed in to
the system. |
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| The cure to this dilemma is a Mass-Air
conversion. The first hurdle is the cruise (see LSCMAN's
and my earlier posts) and the second is the message
center in the dash. Contrary to popular opinion, the dash
computer WILL work with the Mustang MAF processor. The
only input to the message center from the processor is a
fuel flow signal from Pin 34 DOL (data out line) . This
pin is unused in the MAF 91Stang application, however the
pin and signal do exist (contrary to the vague answers I
received from FMS, FoMoCo, and virtually everyone else I
asked). |
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| Another thing,..all of these changes made
to my LSC were done over a month or so,.NOT a weekend.
Once a racer, always a racer. Never change more than one
thing at a time. Even though you've got my rambling
drivel for instructions DO NOT try to do all this in one
fell swoop. One step at a time,.that way if something
goes schitzo, you KNOW what it was and at what point
things went awry. I did cruise conversion,.190lph fuel
pump,.MAF conversion,.30# injectors/chip,.and then the KB
blower,.and subjected it to cold starts, heat soaks, and
everyday driving between each change. |
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Scrounge Parts! |
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| You need an '89-'93 Mustang MAF EEC-IV processor (stick or auto, either will work, but the stick processor is better for performance applications), a MAS (mass airflow sensor) and the wiring plug for the it, and two air intake hoses for a MAF 'Stang (about 35-40 bucks at the Ford dealer). | |
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Disconnect and plug the
vacuum line to the MAP sensor. Don't unhook the wires,
however, it's still used as a BARO (barometric pressure)
sensor for the MAF system. Install the MAS and the hoses,.make
sure everything's sealed up good,..if you use silicone
make sure it's the "sensor safe" flavor or the
EEC will have an identity crisis right off the bat. |
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You need to get the wires from the MAS to the EEC-IV processor buried in the passenger side kick panel. Don't even think of trying to route them with the OEM processor harness unless you want to remove the inner fender liner (and if you've done your cruise conversion first like you're supposed to you'll vividly remember what a pain in the ass that was). Inside the passenger side footwell waaaay up under the dash just above where the carpet ends is the A/C evaporator drain boot(a black rubber gornick). It's held in place by a single push in fastener. Measure out (away from vehicle centerline) 2" and up 2" from this fastener and drill a BE hole. This hole will end up directly below the A/C accumulator and inside the frame rail. Feed your four MAS wires through this hole and secure,.leave 91em long,.you can stuff the excess behind the carpet when you're done. Like this....
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| Remove the EEC-IV processor by pulling
out the passenger side kick panel. Disconnect the ground
leads in front of the processor, and remove the screw
holding processor in. Pull processor down and out on
floor and disconnect the huge gob of wires by backing out
the 10mm bolt in the center of the harness plug. |
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| Now comes the part of the job that
requires complete concentration and NO mistakes (and no
Budweiser, MLH, etc?..you gotta think). On the back of
the gob of wires that is the processor harness is a black
plastic cover. Remove and shit-can this, cause it won't
even begin to fit when you're done. This wiring (at the
processor plug) is the one part of this conversion that
ain't pretty when you're done,.closer to 'crude but
effective,. Fortunately, it's gonna be out of sight. You
need a sharp pick. Steal one from your local dentist/jeweler/locksmith
or improvise. In the face of the EEC-IV connector that
was closest to the processor is a red plastic insert that
holds the pins locked in place (no, they aren't gonna all
fall out without it). Carefully, working end to end with
your pick, lever this red gizmo out of the plug. Use the
pick to reach in and release the lock 'ears' inside the
connector and remove the following wires,..pull 'em out
of the harness,..tie 'em together,.. #2 BOO brake on/off #35 S/C (Speed Control) vent #38 S/C vac #39 S/C switch ? #41 S/C switch + #50 S/C switch These wires will no longer used. They're for the
original cruise that already went south?? |
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| Now, ONE AT A TIME?..(trust me, do this
one at a time,.I didn't and ended up checking the whole
plug,.60 pins,.with a VOM to find out what I #@%&ed
up) Remove wire #11 and install it in position #32 Remove wire #51 and install it in position #38 These wires control the two air mgmt. solenoids
directly in front of the pass. side strut tower |
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| Now, the wires from the MAS. There should
be four?.I'll number them 1 thru 4, starting at the
intake (front) end of the MAS?. #1 VPWR Splice into wire in Pin #37 on the EEC-IV connector. No &^%$!% scotchlocks,..solder it!., #2 GND Splice into wire in Pin #40 . Ditto on the solder?. #3 MAF RTN Install a new EEC-IV pin ( or cut one off the discarded wires) and SOLDER it on. This is Pin #9. #4 MAF SIGNAL Install an EEC-IV pin. This is Pin #50. |
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| Now, take a 12'-14' long #14 or #16 wire.
Glom on to another EEC-IV pin for this wire, and put this
in Pin #19, FPM (fuel pump monitor). This wire has to go
to the large pink/dk blue stripe wire on the fuel pump
relay. Incidentally, the fuel pump relay is on the bottom
of the rear package shelf on the driver's side. I tucked
this wire under the trim panels, removed the bottom of
the back seat, and pulled it up into the trunk. This wire
can be attached with a sleazy/easy scotchlock or T-tap
connector. |
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| Check and double-check all your wiring
and pin locations in the processor connector. Re-install
the red lock insert, re-install the harness to the
processor, and re-connect the ground lead you
disconnected to remove the processor. Don?t reinstall the
processor in it's home in the cowl panel yet,..leave it
on the floor. Re-connect the battery ( you DID disconnect
it, didn't you?) and turn on the ignition,..fuel pump
should run for the requisite 3-5 seconds, and the 'Check
Engine' light should come on. If it doesn't, go back to
the 'check & re-check' step |
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| Fire it up! Idle is gonna be kinda stupid
at first and probably won?t be 100% until the vehicle
goes through a few cold to hot cycles. Take it out and
test drive/flog for a few beers/miles. No 'Check Engine'
light after drivin' it? Cool! Re-install the processor up
in the cowl (don't forget the ground lead) and replace
the trim panel |
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| Read and re-read these instructions. Get a manual that has the 'pinout' diagrams for both the MkVII and the Mustang and study the diagrams until your eyes cross. The Probst manual from FMS is a good one,.. If you never do any other mod to your Lincoln this is the one that you should!! The improvement in performance and drivability (especially at low speeds/off idle) is beyond your wildest dreams!..throttle response is dramatically 'crisper'. If you can read (and evidently you can, cause you're readin' this) and you can wire a stereo, alarm, concert lighting system, etc. (cheap shot, eh Frank?) you CAN do this. With a little creative scrounging you should be able to do it for two or three hundred bucks. If you can't find a used processor, go order one from your local parts store?..you oughtta be able to buy one for $100-$125 exchange if you don't get stupid and tell 'em what the core is out of,..just ask for one for a ?89-?93 Mustang with a 5.0 and a stick (Carquest/Cardo reman #EM681). | |
