Electrical Car dosen't run without jumping the EEC IV test port

Mcmahst · Feb 27, 2024

You two are a pair I always hope I receive in Texas Holdum

General karthief · Feb 27, 2024

Mcmahst said:
You two are a pair I always hope I receive in Texas Holdum

If it has anything to do with gambling I have to wear a hat to cover up the capital L on my forehead

Fox2newedge · Feb 27, 2024

Thank you. I'll take a look... and most likely send out this ECU for testing and repair. I will check continuity on my other ECU when I get a chance and report back.

Thanks again Mustang5L5!

Noobz347 · Feb 27, 2024

General karthief said:
You'd have to depend on me and Noobz, in either case you're screw'd

Now, what kind'a BS...

Oh look! A penny.

mine

General karthief · Feb 27, 2024

Noobz347 said:
Now, what kind'a BS...

Oh look! A penny.

mine

you'd run out into traffic to grab a quarter

Fox2newedge · Feb 27, 2024

I am going to send out the ECU to ECU Exchange. But in the meantime, I decided to open the ECU to see if I could see a burned trace. The inside of this ECU is very dark and difficult to see. However, I could see one that appears burned, but I'm not sure what it is too.

On the bright side, I tested the continuity on the other ECU and it checked out ok. I may go ahead and put it back in the car again to start the testing over.

Mustang5L5 · Feb 27, 2024

Yes sir. That is definitely burned

Question is how? This is a 5-spd car right? Try one more thing before you send the ECU in. Plug it back in. Backprobe pin 46 to ground and turn the key to on. Do you measure any voltage?

The o2 harness jumper being configured wrong would cause this.

Really you want to check this to prevent burning up the ECU when it comes back repaired.

Mustang5L5 · Feb 27, 2024

Also, you have another trace that is burned as well. This one is pin 46. I’d need to poke around a bit to see what the other trace is for.

This ECU has issues

Fox2newedge · Feb 27, 2024

Yes sir, 5 speed car. I had read somewhere about burning a trace in the ECU due to an improperly pinned O2 harness.

I will try that... but just so I'm clear, I will put the ECU back in and then ground pin 46? Or test pin 46 for voltage at the ECU? I apologize. I'm not sure what you mean by backprobe pin 46.

Thank you!

Mustang5L5 · Feb 28, 2024

Put ECU in, with it plugged in, you stick the probe from the meter into the connector on the backside to make contact with the pin 46 wire. Thats backprobing

Set the meter to voltage. Turn the key to on and see what you get. Should be 0 or very close to 0.

Another way is to just locate the o2 sensor harness under the MaF and take a pic of the jumper location.

A 90 5-spd should match top left

Fox2newedge · Feb 28, 2024

Got it! I will take a look at the O2 sensor harness and test the voltage at pin 46 at the ECU. I'm guessing it will have voltage being that it has voltage where the EEC DLC was cut off.

Fox2newedge · Feb 28, 2024

Good evening all!

So I took a look at the O2 sensor harness and it looked like it was pinned properly for a 88-90, 5 spd. Just for safety sake, with the ECU plugged in, I checked the voltage on pin 46. To my surprise, when I turned on the key I got .04 volts. It jumped to .05v when I cranked the engine.

Knowing there wasn't much current on pin 46, I decided to pull out the A9L and put my A3M back in and test with it. It also had .04v at pin 46 with the key on. However, this time I heard the fuel pump charge without the signal wire and CEL wire twisted together at the EEC DLC.

So... I tried starting it and it fired right up. Though it seems to be running very rich (the idle is slightly lopey because of it). But at least there is headway... though I'm not sure why because I just tried this ECU last week and it wouldn't charge the fuel pump.

Question... the A3M is out of a '93. Would that be an issue running it in this 1990 car?

Thank you again everyone!

Mustang5L5 · Feb 29, 2024

A3M and A9L are both manual ECU's and pretty close to identical. Shouldn't be any issue.

Do you have the two wires disconnected at the test port (other than the teo fuel pump wires that need to be) torun with that ECU connected? They def need to be separated as that is not a normal connection

Fox2newedge · Feb 29, 2024

Yes, they are disconnected (except the fuel pump wires). But now I need to get an EEC IV test connector so I dont have all the bare wires hanging out under the hood.

Thank you again for all the help.

Mcmahst · Mar 3, 2024

Here’s what you need:

Amazon product ASIN B0040CYSNE

AeroCoupe · Mar 3, 2024

Search for “Standard S-609”. Couple of the auto parts houses local to me carry it.

Mcmahst · Mar 4, 2024

But Amazon makes it easy

General karthief · Mar 5, 2024

Mcmahst said:
But Amazon makes it easy

Too easy.
All you have to do is 'point an shoot' then 'hurry up an wait'. It does beat digging through buckets of greasy, 30 yr old wiring harnesses.

90sickfox · Mar 5, 2024

The A3m is a convertible ECU. Back in the " old days " people thought they made more power because of the added weight in the car. Something about the tuning from FORD. It's probably not true but still an old myth of mustang fanatics. Just like the ssp cop cars made more power because of special computer tuning by ford. To my knowledge they used the same computers and strategy as every other LX 5.0.

Mustang5L5 · Mar 5, 2024

There were some subtle differences. The A9T (for the SSP cars) was rich-tuned when in closed loop, but would run a little leaner at WOT. They also got a little bit more spark advance and a little extra EGR flow.

Electrical Car dosen't run without jumping the EEC IV test port

wonder how much it would cost to ship you a pair

Member

Stangnet Facilities Maint Tech... Er... Janitor

wonder how much it would cost to ship you a pair

Member

Attachments

That is…until I whipped out my Bissell

That is…until I whipped out my Bissell

Member

That is…until I whipped out my Bissell

Member

Member

Attachments

That is…until I whipped out my Bissell

Member

lube between the nut and the face. I know my lubes

wonder how much it would cost to ship you a pair

Wasn't a pretty sight...and I've got big hands

That is…until I whipped out my Bissell

Similar threads

Privacy & Transparency

Privacy & Transparency