EEC-IV just fried

[YungICY]

Today I was takin a look at all my valves, followers, ect because I have a loud valve tick. After inspecting and everything seemed to be fine I put it all back together.



I jumped in the truck to move it out of the driveway and when I turned the ignition on I noticed something out of the norm. I always listen for the fuel pump to come on for 2 seconds then shut off then I start the truck. This time it came on, and after three seconds I realized the pump was still on so I turned of the key. Just before I turned the key off though I heard a pop.



I looked over to see some smoke coming from the ashtray/radio area and from the glove box followed by a terrible smell. After much searching I pulled out the computer. Problem found.



So now my question is, what other cars computers will also plug right in? And also, is there anything that may have caused this to happen or was it just a bad computer going out in its final blaze of glory?



Btw this is an 85 ranger with the 2.3 efi.





Sent from my Windows Phone 8 using Tapatalk

 

[RonD]

Unless you have a leaking windshield or heater core not sure why you would get a short in the EEC.
I would pop the top of the EEC and look to find the short inside.

Jumping can be dicey with electronics, best bet is to leave key off and jump battery for a few minutes to charge it, then remove jumper and try to start.
A bad battery can cause jumping alternator to output 15+ volts, so if you must turn on key to start with jumper cables attached leave the other engine off, so you just get battery level voltage not alternator level.

Common rule for EECs is: "EEC are different for each vehicle/ year / engine / transmission model"
So you should look for a, '85 Ranger Lima computer

Ford's common EEC part number is 12A650
An EEC will have a number on it like E5TF-12A650-J1B
So common part number is in the middle
If you go to this page it can help you ID the program code:
http://oldfuelinjection.com/?p=17

You should try to match that code

 

[YungICY]

Funny you should mention the windshield. I literally just got it replaced today. I don't think moisture was an issue though.



I did pop open the case on it. That is definitely where the burning electronics smell is coming from and I can see the black venting residue on the outside of the case but I didn't see what actually burned up.



I didn't notice anything out of the norm while replacing everything with the valve cover I was previously working on but I did short out two connections on the back of the alternator while tightening a bolt.


Sent from my Windows Phone 8 using Tapatalk

 

[YungICY]

Thanks for the link. I think I was literally just looking at that.


Sent from my Windows Phone 8 using Tapatalk

 

[YungICY]

So I just put a new computer in and its still a no go. I have no idea what to even start looking for.


Sent from my Windows Phone 8 using Tapatalk

 

[kimcrwbr1]

Do you hear the EEC relay click when you turn on the key? Check for battery pos to the relay I believe it should be next to the computer at least it is on the V-6 computers and make sure the computer has a good ground there also.

 

[RonD]

Symptoms would be helpful......

I know the computer fried, that could have been from alternator issue outputting over 20volts.

Could you have clamped or shorted a wire in or to the valve covers when you had them off.
Computer powers many of the sensors so a shorted sensor wire could cause power supply in computer to burn out, i.e. the magic smoke comes out and it don't work no mo'

 

[YungICY]

I will check for a wire around the valve cover.



Symptoms are:

Fuel pump relay doesn't click on (replaced as well as ecu)

No spark

Can't seem to find any burnt wiring

No blown fuses

The relay located right next to the ecu DOES click on when key is turned on

Everything else does seem to operate as normal as far as I can tell (starter, dash lights, etc)

If I manually click the fuel pump relay the pump does turn on


Sent from my Windows Phone 8 using Tapatalk

 

[adsm08]

Check for power into the coil, and for a switching ground out of the coil. The ground is best tested with a dumb light. The light should glow and pulse weakly if the circuit is working properly.

You have one engine that doesn't run, and a host of symptoms that seem unrelated on the surface, but I bet if you start diagnosing them individually you will find the common root cause.

 

[YungICY]

I'm about to ask a really stupid question but what is and how would I hook up a dumb light.




Sent from my Windows Phone 8 using Tapatalk

 

[kimcrwbr1]

I think he means a test light
http://www.ebay.com/itm/6-12V-DC-Au..._Automotive_Tools&hash=item258779ab89&vxp=mtr
You can get at any part store just clamp it to ground and search for volts the light is in the handle.

 

[adsm08]

I think he means a test light
http://www.ebay.com/itm/6-12V-DC-Au..._Automotive_Tools&hash=item258779ab89&vxp=mtr
You can get at any part store just clamp it to ground and search for volts the light is in the handle.

Well yes, but in the case of the test I want him to do he wants to hook it to power, and then look for ground.

You want a "dumb" light, someone dependent only on what it is given by the car, rather than a self-powered or smart light such as a power probe because the way the ground gets switched will confuse the more advanced ones.

If you have the parts laying around you can actually make one from some wire, alligator clips, and a headlight.

I use that setup for load testing because the starter is the only thing on the car that pulls a higher load than the headlights, so if it lights a headlight it will run anything.

 

[YungICY]

That makes sense. I'm gonna start deducing problems tomorrow when I have sunlight and the warmth of daylight. Feel free to keep throwin suggestions and advice out there though.


Sent from my Windows Phone 8 using Tapatalk

 

[RonD]

The relay next to the fuel pump relay(the one you said clicks) is the EEC relay, an important one.

The EEC relay supplies power to:
Fuel pump relay
Coil
Fuel injectors
computer

The EEC relay is activated by the key but the power it passes to the above systems comes from a fuse, and the power out of the relay is just 1 wire that is spliced to all the systems.
If you look at this diagram you will see some of what the EEC replay powers:
http://www.therangerstation.com/tec...les/Diagram_ElectronicEngControls2_3_1of3.JPG

That big s134 spider top right

Now the relay is clicking but is it passing power to "all that stuff"
Could be inside the relay the contact is bad or wire out to splice 134 is bad, this is assuming power fuse is good, relay clicking has nothing to do with that fuse.

 

[kimcrwbr1]

The yellow wire going to the EEC relay should have full time hot from the battery if not the fusable link is likely fried? 20 guage blue in line fusable link