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Speed Density to Mass Air Conversion
(cont.)
Fig 1. Ford EEC-IV 60 pin harness orientation.
The final steps are to make the wiring changes at the
engine harness to computer connector. Using a 10mm socket,
back out the bolt until the connector disengages from
the computer. Do not pry or force it apart! |
With the connector freed from the computer we can prepare
to "re-pin" the connector. |
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|
Remove the red pin lock insert by gently prying it out
with a thin flat blade screw driver - the smaller the
better (2mm blade suggested.)
|
On many harnesses you will find this blue wiring "template".
It's used to ease assembly at the factory, but prevents
us from moving or inserting new wiring. Carefully break
it out using pliers. |
| |
|
Looking into the mating side of the connector reveals
the individual pins and the tab retainer securing the
pin in the connector. |
The pin can be released by carefully pushing back the
lock with a pin or small screwdriver. Simultaneously pull
back on the wire and it will release from the connector. |
| |
|
The conversion to mass air calls for moving certain existing
wires to new locations. Pull the wire and pin out and
then install into the pin slot as directed. Always double
check the pin number per the diagram above. |
Install the injector, MAF, O2 sensor, and power wires
from the new conversion harness into their pin positions
in the connector. Note the new wiring is also marked with
the pin position it belongs in. |
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|
You'll end up with the factory "speed density"
injector wires just hanging out loose. Tape them together
if you wish, we do not recommending cutting them out in
case you need to convert back. |
A potentially confusing connection is at the injector
power lead (pin 57). Remove the existing lead. You can
strip the pin off as this will get spliced with the
new harness lead marked "PWR-EEC 57". Take
the new harness red lead marked "INJ 1-EEC 57"
and place into position 57 in the connector.
|
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|
With all the wiring under the hood completed, the final
step is to swap out the computer. Pull the driver side
kick panel off to gain access to the computer. Pull it
out and replace it with the new mass-air computer. |
We're using an A3M processor from a 1992 Mustang. Any
88-93 5.0L processor will work, regardless of whether
it is an automatic or five-speed car. There are likely
slight differences in timing and fuel curves between the
two, however unlikely to make a noticeable driveability
difference. |
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|
With every connection made and double checked, reconnect
the battery and fire up the vehicle. Let it idle for until
fully warm and then shut off and run a self diagnostic
test by grounding the self-test lead shown (located in
the relay panel behind the air filter box.) |
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Conclusion
After a weeks worth of driving our mass air converted F150,
we are simply amazed at the difference in how different the
engine performs. The truck jumps off idle reminiscent of our
old '88 Mustang 5.0L. It very noticeably gets through the rpms
much quicker, indicating some increase in power. With initial
timing set at 10 degrees advanced we did notice significant
detonation in overdrive under light to moderate load. We backed
the timing down to 8 degrees and now have only very slight pinging
with 87 octane. We're sure that this is due to the amount of
timing the Mustang computer adds to initial being much more
aggressive then what the heavy F-150 can handle. However simply
changing driving habits and shifting down to "D" rather
then letting the engine load up on 'OD' takes care of the problem.
On a side note, even with the first weeks worth of heavy-footed
driving, fuel economy is up 2 mpg.
In the next few week's we'll be using an EEC tuning software
to make some modifications to the mass air computer to see if
we can make additional gains. Look for this and our initial
engine modifications in the next issue. 
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Posted by 1979F1004x4, 08/31/10 09:10am:
What a cool article, i would like to do this, I want yall to do more with this truck
Posted by leon2, 07/20/11 03:47pm:
love the pics very informative
Posted by pollito09, 09/23/11 03:48pm:
seems to be the most straight forward write up I have found
Posted by F158, 01/04/12 03:51pm:
i just did this to my 95 f150 with a 5.8l it is impressive
Posted by Cobra-F150, 04/16/12 02:59pm:
Just did this conversion to an 89 f-150 with a thumpr cam. Instructions were quick and simple and the truck runs and sounds like an old 5.8 mustang.
Posted by cwilson0823, 06/20/12 09:14am:
I am currently converting two Ford trucks (1986 bronco 302 & 1987 f150 302) from speed density to mass air flow. I have one major problem. I am trying to do this without costing myself a lot of extra money. My engines are in great running shape so I don’t want to have to change my entire cam/lifter assembly just to do this conversion. Is there a way around this and still make this system work efficiently ?
Posted by Samsbolt390, 07/20/12 12:21am:
@Cwilson0823 let me know on your progress I also have an 86 Bronco that I want to update to MAF, I figured that the cam would be a given but didn't know if 86 was or wasn't a "Roller" motor.
Posted by cwilson0823, 08/24/12 12:36pm:
An 86 model would be speed density. Tweecer reps say the cam has to be changed or a chip to modify the firing order has to be run.
Posted by Cobra-F150, 09/08/12 08:51pm:
Nothing has to be changed as far as the cam and lifters for this conversion to work. If its a 351 then you have to Chang the firing order to a 302's. I've done 14 of these conversions using nothing but junkyard donor parts.
Posted by cwilson0823, 09/30/12 02:09am:
Ok. This engine does not have the roller cam. That wasn't introduced until the later years. Are you sure. If you're correct that will definitely save me a LOT of money and time. If you're willing to contact me directly please let me know. Remember, this is an 86 model. Thanks..u
Posted by Samsbolt390, 02/04/13 12:27am:
So did you make progress with your Bronco upgrade?
Posted by dino30, 03/18/13 03:08pm:
I amI am working on a 90 bronco 302 on 38in tires , converted to a full roller valve train, 1.6 roller rockers and a mild cam , next step is to get the rest of the parts to convert this truck to mass air .. Slowly we are building one bad bronco .. thanks for the write up , this is very helpful ..
Posted by , N/A:
Posted by vencent2, 10/27/15 12:10pm:
What is in the next issue? And how can I find it
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Table 1:
EEC-IV 60-Pin Connectors
Speed Density vs. Mass Air
|
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|
Mass Air
|
|
|
|
1
|
K A PWR |
K A PWR |
|
|
|
2
|
BOO |
|
|
|
|
3
|
VSS + |
VSS + |
x
|
|
|
4
|
IDM |
IDM |
|
|
|
5
|
Mileage (85-86 only) |
|
|
|
|
6
|
VSS -- |
VSS - |
x
|
|
|
7
|
ECT |
ECT |
|
|
|
8
|
FPM |
|
x
|
19
|
|
9
|
DataBus -- |
MAF RTN |
•
|
|
|
10
|
A/C on |
A/C on |
|
|
|
11
|
TAD |
|
|
32
|
|
12
|
|
INJ 3 |
•
|
|
|
13
|
|
INJ 4 |
•
|
|
|
14
|
|
INJ 5 |
•
|
|
|
15
|
|
INJ 6 |
•
|
|
|
16
|
IGN GND |
IGN GND |
|
|
|
17
|
STO |
STO |
|
|
|
18
|
Mileage (88-89 only) |
|
|
|
|
19
|
|
FPM |
|
|
|
20
|
GND |
GND |
|
|
|
21
|
IAB |
IAB |
|
|
|
22
|
FPR |
FPR |
|
|
|
23
|
KS (5.0L) |
|
|
|
|
24
|
PSPS (5.0L) |
|
|
|
|
25
|
ACT |
ACT |
|
|
|
26
|
VOLT-REF |
VOLT-REF |
|
|
|
27
|
EGR sensor |
EGR sensor |
|
|
|
28
|
Data Bus (+) |
|
|
|
|
29
|
HEGO |
R HEGO |
|
|
|
30
|
MLPS |
NDS |
|
|
|
31
|
CANP |
CANP |
|
|
|
32
|
|
TAD |
|
|
|
33
|
EGR |
EGR |
?
|
|
|
36
|
SPOUT |
SPOUT |
|
|
|
37
|
V PWR |
V PWR |
|
|
|
38
|
EPC |
TAB |
|
|
|
40
|
GND |
GND |
|
|
|
42
|
|
INJ 7 |
•
|
|
|
43
|
|
L HEGO |
•
|
|
|
46
|
MAP |
BARO |
|
|
|
47
|
TPS |
TPS |
|
|
|
48
|
STI |
STI |
|
|
|
49
|
HEGO GND |
HEGO GND |
|
|
|
50
|
|
MAF |
•
|
|
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51
|
TAB |
|
|
38
|
|
52
|
|
INJ 8 |
•
|
|
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53
|
|
|
|
|
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54
|
|
A/C WOT Cutoff |
|
|
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55
|
|
|
|
|
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56
|
PIP |
PIP |
|
|
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57
|
V PWR |
V PWR |
•
|
*
|
|
58
|
INJ 1 4 5 8 |
INJ 1 |
•
|
|
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59
|
INJ 2 3 6 7 |
INJ 2 |
•
|
|
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60
|
GND |
|
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| |
Notes:
3,6,8 -
VSS and FPM wiring included with new harness.
Wire in if not present in speed density vehicle.
57 - *Splice old V PWR with new PWR. Refer to step 26
(left). |
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Contacts:
Professional Mass Air Systems
720 Terminal Road.
Lansing, MI 48906
517-327-3900
FordFuelInjection.com
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