Can't get codes to pull.

Rick's Fords

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Dec 25, 2004
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Using testlight method found at http://www.troublecodes.net/Ford/ and get nothing. I was reading another post, and someone said they couldn't get codes the EEC had a bad ground (near the battery). I just regrounded everything near the battery, sanded stuff down and all, still get nothing.

I'm getting really frustrated, this thing is running like I just put a big ole cam in it, and putting off some black smoke now. What the hell would have made it run so rich from Wal-Mart to home?
 
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Computer will not go into diagnostic mode

With the power off, measure the resistance between the computer test ground
(black/white wire) on the self test connector and battery ground. You should see less than
1.5 ohms.

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If that check fails, remove the passenger side kick panel and disconnect the computer
connector. There is a 10 MM bolt that holds it in place. Measure the resistance between
the black/white wire and pin 46: it should be less than 1.5 ohms. More that 1.5 ohms is a
wiring problem. If it reads 1.5 ohms or less, then the computer is suspect. On the
computer, measure the resistance between pin 46 and pins 40 & 60: it should be less than
1.5 ohms. More that that and the computer’s internal ground has failed, and the computer
needs to be replaced.

If the first ground check was good, there are other wires to check. Measure the
resistance between the STI computer self test connector (red/white wire) and pin 48 on
the computer main connector: it should be less than 1.5 ohms. More that 1.5 ohms is a
wiring problem

The following is a view from the computer side of the computer connector.
eec04.gif


Diagram courtesy of Tmoss & Stang&2birds

88-91_5.0_EEC_Wiring_Diagram.gif


See the following website for some help from Tmoss (diagram designer) & Stang&2Birds
(website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine
 
Did the tests using a Fluke 77/AN multimeter.

Power was off during all tests.

Between EEC test ground and Neg bat terminal, with the EEC connected, I got 1.98, EEC disconnected, nothing registered on meter.

EEC disconnected, between EEC test ground, and pin 46 on the EEC connecting harness, 0.00 or 0.01, which would mean that wire was good?

With the EEC complete removed from car, between pins 46 and 60, nothing registers, between 46 and 40, nothing registers, between 40 and 60, 0.00.

The last test you mentioned to do if the first turned out good, I didn't understand, how would you test from the STI to a EEC pin with it disconnected?

My conclusion, when I accidently mistook a connecter to be the STI (which was hot) and jumped it to the EEC test ground, I shorted the EEC.

Please correct me if I'm wrong, looking up prices now.
 
My EEC is part # E7SF-12A650-A1B, I can get one that is part # E7SF-12A650-C1A, are they compatible? It came out of an 87 5.0 HO with 5 speed, mine is an 88 5.0 HO with 5 speed.
 
Here’s the theory, and theory is all I can help with. I have no experience with the Fluke meter, and I do not know if it auto-ranges or not. I also have no knowledge of how well you can use it and interpret the results. So all you are going to get is theory.

The black/white wire (pin 46) is signal ground for the computer. It provides a dedicated ground for the EGR, Baro & TPS sensors as well as the ground to put the computer into self test mode. Since it is a dedicated ground, it passes through the computer on its way to the computer main power ground that terminates at the battery pigtail ground. It should read less than 1.5 ohms when measured from anyplace on the engine harness with the battery pigtail ground as the other reference point for the ohmmeter probe. What sometimes happens is that it gets jumpered to power which either burns up the wiring or burns the trace off the pc board inside the computer. That trace connects pins 46 to pins 40 & 60. Only an experienced electronics technician can open the computer up & repair the trace if it burns up and creates an open circuit.

The STI (Self Test Input ) is jumpered to ground to put the computer into test mode. Jumpering it to power can produce unknown results, including damage to the computer. The ohm test simply verifies that there are no breaks in the wiring between the test connector and the computer input.