MS3 New Install - TPS issue - (EEC-IV conversion)

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DonMaximo
Experienced MS/Extra'er
Posts: 193
Joined: Fri Aug 29, 2014 2:11 pm
Location: Lewisville, Texas

MS3 New Install - TPS issue - (EEC-IV conversion)

Post by DonMaximo »

Team,

I'm installing MS3-PRO on a 1992 Ford Mustang using a EEC-IV ECU (A9L). I'm using the FK60 BOB for the installation.

I'm attaching my pinout chart where MS3 White Pin #9 (TPS) connects to EEC-IV pin #47 which is Gray w/Wht Stripe.

I'm also attaching the 91-93 Ford EEC-IV pinout. For the MSPNP & MS3, EEC-IV pin #47 is used for TPS.

I'll be attempting to document this installation for other Mustang enthusiasts interested in the MS3-PRO route.

The Ford TPS sensor has a 3 prong plug whose wires are colored: Gray, Green, and Orange.
The connector which attaches to this sensor has wires colored: Black, Green, and Orange.
Black and Gray come together when plugged in.

Problem Description
When Key-On, the TPS is measuring full/WOT voltage. Pressing throttle does not change this.
I learned this when I had everything connected for the first time and wanted to calibrate my sensors.
I've attached a datalog as well. The only other observation is related to PW. Even when I attempt to start, it appears that No fuel is being supplied. When I Key-ON, I can hear fuel pump, but the fuel pressure gauge has Zero pressure. I seem to recall the stock ECU would have fuel-pressure with Key-on.
Fuel pressure is observed however when turning over the motor.

Again, the focus is on TPS at this time.


Problem Diagnostics
Tests A, B, and C were conducted under the hood and focused on the TPS sensor and 3-prong connector which returns to EEC

Test #A:
When key-on , TPS disconnected, voltage at harness plug:
Gray = 5.03v
Green = 153.5 mv
Orange = 4.73v

Test B:
When key-on , TPS disconnected, ohms at sensor plug:
Green & Black = 1.086 closed 4.32 WOT
Green & Orange = 3.5 closed 0.54 WOT
Black & Orang = 4.4 closed 4.4 WOT

Test C:
When Key-on, TPS connected, volts at wires:
Black/Gray = 4.97
Orange = 4.77
Green = 4.96

Tests D, E, and F are ohm measurements and were acquired by connecting each of the 3-prong TPS connectors to a long pigtail and probing all 60 EEC pins. Results were noted Only If I measured ANY ohms registered. The attached Ford EEC Pinout is intended to help make sense of the finding below:

Test D:
Gray/Black
#6 = 22.91
#25 23.63
#30=1.1
#46=0.2

Test E:
Orange
#7=10.29
#25=10.29
#26=0.2
#30=10.29
#45=19.91
#46=10.24

Test F:
Green
#47=0.2


Thoughts, Ideas, suggestions ?

Thanks,

-D
1992 Mustang Conv,
363" Man-o-War (8.2"Deck), Dart Pro-1,
NA, EFI Victor,
TKO600, 373 gears,
MS3-Pro
Innovate DLG-1 (dual WB O2)
Ignition LS2 coil on plug (Crank trigger+ Explorer cam sensor)
kaeman
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Joined: Sun Nov 06, 2005 12:31 am
Location: NORTHERN CALIFORNIA

Re: MS3 New Install - TPS issue - (EEC-IV conversion)

Post by kaeman »

the pulse width isn't a problem, as long as your tps sensor reading is bad(full open) you are in flood clear during engine cranking, which turns off the fuel to let the flooded engine clear out the excess fuel.

TPS issue: did you power up the tps sensor from the megasquirt or are you trying to leave it connected to the eec module. if you don't supply power and ground to the sensor from the megasquirt and run the signal wire back to the megasquirt you are probably getting feedback from the eec, if you are powering the tps from the megasquirt then check that the ground wire is making a good connection, if its not then the signal will be the same as the tps power supply. ie stuck around 5 volts. (wide open throttle).

Fuel Pressure issue: megasquirt only turns on the fuel pump for a quick prime when key switch is first turned on, after that the fuel pump relay will only be powered up if you have an ignition signal showing the engine cranking or running. that's a safety feature to kill the fuel pump if you have mechanical failure and the engine dies you wont pump high pressure fuel onto a fire or something like that.
good luck
64 el camino, 383 SBC, 11.7 to1 CR, accufab tb/rhs intake, 44lb injectors, trick flow heads, xr292r solid roller cam, belt drive camshaft, dry sump oil system, 2400 stall, turbo 350, spooled 9 inch, strange axles, 3.89 gears, dual wideband, full sequential fuel/cop, MS3x using 1.4.1 code.
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