Engine 1988 GT CA MAF plug different size?

Boogdidit · May 2, 2019

I have to get a voltmeter later on today

Mustang5L5 · May 2, 2019

Boogdidit said:
I Have power on red wire no power on the black with key on. I used a test light

Black would be ground. You won't have power there. This is fine.

Next up, you'll need to test output from the two other wires. You'll have to measure between them with engine running.

Boogdidit · May 2, 2019

Mustang5L5 said:
Black would be ground. You won't have power there. This is fine.

Next up, you'll need to test output from the two other wires. You'll have to measure between them with engine running.

Ok cool.

A simple voltmeter would work right?

Mustang5L5 · May 2, 2019

Yes. You'll need a way to carefully prob through the insulation to the wire to measure it while it's in use. Safety pins or a small pin work well.

Boogdidit · May 2, 2019

Ok. Ill get back to you as soon i do it.

Boogdidit · May 2, 2019

Mustang5L5 said:
Yes. You'll need a way to carefully prob through the insulation to the wire to measure it while it's in use. Safety pins or a small pin work well.

Worth a mention. Car wont idle with MAF plugged i until its warmed up some.

Blown88GT · May 2, 2019

Boogdidit said:
Ok so i pulled codes an i got

34 - egr
66 - MAF
95- fuel pump circut

http://www.fuelinjectedford.com/
34 - CM - PFE or EVP circuit has intermittently failed above the closed limit of 0.67 volts.
66 - CM - MAF sensor went below 0.4 volts during the last 80 warm-up cycles.
66 - KOEO & CM - TOT sensor output was less than Self-Test minimum value of 0.15 volts.
95 - KOEO & CM - Fuel pump secondary circuit failure. The EEC senses infinite resistance to ground from the fuel pump on the Fuel Pump Monitor circuit.

KOEO = Key On Engine Off, CM = Continues Memory, KOER = Key On Engine Running

Back in post #1, you said you are using a 70mm MAF housing?
That is not going to work. With the standard 19 lbs injectors & the 8LD ECU, you must use the 55mm housing.
This is why you are getting a Code 66 & why it will not run with the MAF plugged in.

Boogdidit · May 2, 2019

Blown88GT said:
http://www.fuelinjectedford.com/
34 - CM - PFE or EVP circuit has intermittently failed above the closed limit of 0.67 volts.
66 - CM - MAF sensor went below 0.4 volts during the last 80 warm-up cycles.
66 - KOEO & CM - TOT sensor output was less than Self-Test minimum value of 0.15 volts.
95 - KOEO & CM - Fuel pump secondary circuit failure. The EEC senses infinite resistance to ground from the fuel pump on the Fuel Pump Monitor circuit.

KOEO = Key On Engine Off, CM = Continues Memory, KOER = Key On Engine Running

Thank you. Will look into code fixes tonight.

Blown88GT · May 3, 2019

What about the 70mm housing?
Your pics look like a 55mm.
I'm confused.

Can you remove the ECU & open it up & take some pics?
Could be bad capacitors, burned or corroded traces.

Boogdidit · May 3, 2019

Blown88GT said:
What about the 70mm housing?
Your pics look like a 55mm.
I'm confused.

Can you remove the ECU & open it up & take some pics?
Could be bad capacitors, burned or corroded traces.

How do i “open” the ecu? Will i be able to close it back if thats not the problem? I recently watched a video of a guy having the same problem where it wouldnt idle cold with maf plugged in. It would fire, idle for maybe a second then die, but would idle cold without maf plugged in then Once warm maf could be plugged back in but idle was still rough. Said it was the 3 blue capacitors in ecu

Boogdidit · May 3, 2019

Here are pics of video and comments. Picture with tac up is when he starts it an second picture is when it dies.

Boogdidit · May 3, 2019

Blown88GT said:
What about the 70mm housing?
Your pics look like a 55mm.
I'm confused.

Can you remove the ECU & open it up & take some pics?
Could be bad capacitors, burned or corroded traces.

I think he thought i was the guy that started the posted an seen his pics. I dont have a 70mm

Mustang5L5 · May 3, 2019

I'd erase your codes, drive around a bit same run again. If code 66 returns, you really need to check MAF signal voltage at the meter, and then down at the ECU between pin 9 and 50.

Should be around 0.5 volts at idle and increase towards 5.0 v the higher you rev the engine.

Testing at the ECU will rule out a bad wiring fault somewhere between meter and ECU.

Could be a bad meter, but I'd troubleshoot and test first before firing the parts cannon at it

Boogdidit · May 3, 2019

Mustang5L5 said:
I'd erase your codes, drive around a bit same run again. If code 66 returns, you really need to check MAF signal voltage at the meter, and then down at the ECU between pin 9 and 50.

Should be around 0.5 volts at idle and increase towards 5.0 v the higher you rev the engine.

Testing at the ECU will rule out a bad wiring fault somewhere between meter and ECU.

Could be a bad meter, but I'd troubleshoot and test first before firing the parts cannon at it

Cannot drive car. Transmission is shot. An when the car is cold and MAF is Plugged it barley wants to idle if it even does and if it does i cannot step on gas pedal... it cokes engine completely. I have to feather gas pedal in order to get rpms up. When it warms up i can plug MAF in an the gas pedal doesn't choke the engine out. Still cant full throttle it without it sputtering.

Mustang5L5 · May 3, 2019

Then forgo erasing the code, and see if you can get a MAF reading at idle.

If not, duct tape a leaf blower to the MAF, get air moving through it, turn the key to on and see what you get for voltage.

Boogdidit · May 3, 2019

Mustang5L5 said:
Then forgo erasing the code, and see if you can get a MAF reading at idle.

If not, duct tape a leaf blower to the MAF, get air moving through it, turn the key to on and see what you get for voltage.

Ok will do.

Correct me if im wrong. To dump codes i start car with diagnostic terminals jumped an let run? Or is there something im missing.

Boogdidit · May 4, 2019

Heres pics of the inside of ecu

Mustang5L5 · May 4, 2019

Boogdidit said:
Ok will do.

Correct me if im wrong. To dump codes i start car with diagnostic terminals jumped an let run? Or is there something im missing.

You run them first with engine off and then start engine. There's a sticky at the top of this forum page showing the entire procedure.

ECU looks fine to me but can you take a close up of the capacitors? (Green cylinders).

Blown88GT · May 4, 2019

None of those caps are leaking.
Conformal coating is intact.
Conformal coating is the green tinged somewhat waxy coating over the entire circuit board assembly.
https://www.techspray.com/the-essential-guide-to-conformal-coating

Therefore, I will assume ECU is good.
I think these old ones are better than the later ones.
They were careful choosing parts & performing assembly, since it was all new to Ford & Hitachi (who designed & built much, if not all of it for Ford). You'll see Hitachi's name on the MAF sensor.
It looks like my original DA1, just about perfect. Even the port connector looks brand new.

Now I suspect a corroded connection between the MAF & ECU.
A corroded connection will cause a voltage drop, which is like adding a resistor where none is called for.
It's like a blockage in a water line to your house or what causes a heart attack in you.

BTW, I used to design & build circuit boards for the aerospace/defense industry, so in this area, I am an expert, especially old ones like this.
FYI. The 5th pic with the long "chip"with the yellow rectangle on top is the PROM (Programmable Read-Only Memory). Those were UV erasable & had a clear window on top, where you could see the real chip inside.. After they burn it with the program, they cover the clear window with paint or a sticker.

Boogdidit · May 4, 2019

Mustang5L5 said:
You run them first with engine off and then start engine. There's a sticky at the top of this forum page showing the entire procedure.

ECU looks fine to me but can you take a close up of the capacitors? (Green cylinders).

Ive done that and still nothing. Ive read somewhere that you unplug jumper wire when codes begin to flash in order to dump. The sticky say just let cycle through codes an they’ll dump themselves. Which is correct? Can i damage ecu with jumper cable installed an car stall out on start up?

Here are more pics of ecu internals.
Got as close to capacitors as i could while focused. Didnt want to bump the board

Engine 1988 GT CA MAF plug different size?

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