2.3L ('83-'97) Should I toss this Ranger?

[Serfma]

Hi all! I recently purchased a 1990 Ford Ranger from my brother in law, and the history on the vehicle he said all he knew was that the seller said it had no spark, but he said he found it oddly had 2 crank position sensors but never had the time to look into it. After the last few days of struggling, it appears I have a later version 2.3L Lima instead of early like I thought. Obviously does not start, only cranks, and the wiring is an absolute nightmare. Apparently 3 freeze plugs on passenger side == early Lima, 2 freeze plugs == late. As far as I know so far I'm going to have to replace the wiring harness + ECU to match. Does anyone have any insight onto what I need to do, should do, or things to look out for?

My thoughts of what I have to do: Find a matching harness + ECU for a '95 - '97 Lima w/ Manual trans and replace it, and it should be good to go if the motor is good.

 

[RonD]

If its a 1989-1994 2.3l Ranger then you will be better off in selling this 1995-1997 2.3l engine and getting a 1989-1994 2.3l engine to replace it, plain and simple
There are people looking for 1995-1997 2.3l long blocks(block and head) I assume previous owner swapped over the 1990 intakes and brackets, and you want to keep those

Otherwise you are doing a non-standard engine swap, i.e. like swapping in a V8, only difference is you don't have to change transmission and motor mounts
They are both 2.3l but NOT the same engines

1989-1994 used a 60-wire computer
1995 and up used 104-wire computer
So quite a difference in wiring

The original owner just had bad info on what engine to swap in, there is no use compounding that with more bad choices

This is just my opinion, you CAN do anything you feel you need to, to "make it work"
And even if you "make it work" what happens if/when it has another problem......................you will have a Frankenstein setup, which can be fine if you are well versed in the electrics and mechanics of the system, but only you know what "you know", lol

IMO, if you want a reliable 1990 Ranger 2.3l then put the correct engine in it



As for the electrical question
There will be a Red/Light green stripe wire running to both coil packs and the ICM, thats the 12v power from the ignition switch(under steering column), also runs to Hall effect sensor(crank sensor)

The EEC relay isn't part of that power path, but EEC relay is activated by 12v on that same red/green wire
When EEC relay is activated it sends 12v to the EEC(the computer) and when that happens the CEL(check engine light) should come on
And you should hear the fuel pump relay close and fuel pump run for 2 seconds


You can see the red/light green(R/LG) wire in below diagram, it powers lots of stuff with key ON(RUN) and key in START position
If any one of those components wires are corroded it can suck down voltage

Anytime you are testing voltage in a vehicle, test battery voltage FIRST, so you have a reference point of what to expect

 

[Serfma]

If its a 1989-1994 2.3l Ranger then you will be better off in selling this 1995-1997 2.3l engine and getting a 1989-1994 2.3l engine to replace it, plain and simple
There are people looking for 1995-1997 2.3l long blocks(block and head) I assume previous owner swapped over the 1990 intakes and brackets, and you want to keep those

Otherwise you are doing a non-standard engine swap, i.e. like swapping in a V8, only difference is you don't have to change transmission and motor mounts
They are both 2.3l but NOT the same engines

1989-1994 used a 60-wire computer
1995 and up used 104-wire computer
So quite a difference in wiring

The original owner just had bad info on what engine to swap in, there is no use compounding that with more bad choices

This is just my opinion, you CAN do anything you feel you need to, to "make it work"
And even if you "make it work" what happens if/when it has another problem......................you will have a Frankenstein setup, which can be fine if you are well versed in the electrics and mechanics of the system, but only you know what "you know", lol

IMO, if you want a reliable 1990 Ranger 2.3l then put the correct engine in it

Hmm I see what you're saying. I did also think of swapping ECU + wiring harness to match the engine and it be essentially plug and play.

I also assumed with how it is now it'd run if I could narrow down the electrical issues with the ignition system lol

Just weighing out my options, I don't mind to put labor into it as it is, just would be an extra pain to pull the motor and find an old 2.3l around here lol

Edit: For the electrical part -- was running troubleshooting for the crank pos sensor and found that it was only showing 2v which is when I found that red/green line dropping when plugged in. Is this a grounding issue perhaps?

 

[RonD]

If its a short to ground then fuses blow or wires melt

Test your volt meters ground from engine metal to battery positive, if its a ground issue you will see a drop from direct battery test voltage

Switch to OHMs and test ground wires on connectors to engine block, should be 0 ohms

 

[Serfma]

If its a short to ground then fuses blow or wires melt

Test your volt meters ground from engine metal to battery positive, if its a ground issue you will see a drop from direct battery test voltage

Switch to OHMs and test ground wires on connectors to engine block, should be 0 ohms

We're all good there. What in the world could be it I wonder? Verified EEC is the original that belongs to this year ('90) truck.

Could ignition switch potentially cause an issue? I feel like it wouldn't seeing that with ICM unplugged we're fine. Unless the ICM I purchased was bad out of box and causing the exact same issue.

 

[Serfma]

Basically crank sensor + icm / whole circuit (unplugged as well) is receiving only 2v instead of the expected 12v with icm top connector connected

 

[RonD]

So with coil packs and hall effect sensor plugged in and ICM unplugged that red/green wire shows 12volts at the ICM connector?

Volts are tricky in that corrode connections show 12v until ANY load is applied, that's when you see the voltage drop

 

[Serfma]

So with coil packs and hall effect sensor plugged in and ICM unplugged that red/green wire shows 12volts at the ICM connector?

Volts are tricky in that corrode connections show 12v until ANY load is applied, that's when you see the voltage drop

Coil packs unplugged, crank unplugged, couldn't find noise capacitors in case they're leaking to ground somehow. Once ICM is plugged and grounded does the voltage drop. Haven't spotted any corrosion within these connectors. I'm checking for any and all red / green wires in case they used the power for something else.

Maybe they tapped into the 12v inside the dash for something?

Edit: nothing under the dash /:

 

[RonD]

Plug IN coil packs and hall effect sensor, then test with ICM UNPLUGGED

 

[Serfma]

ICM top unplugged, ICM bottom plugged, cps + coil packs plugged: 2.87v

Removing bottom icm plug: 9.30v

Battery voltage: 12.67v

 

[RonD]

You have a bad 12volt connection feeding the red/green wire
Any amps are drawing it down, that shouldn't happen
I could see 12.6 going down to 12.5v maybe with key on

Could be in ignition switch, or the thru firewall connector

Could even be battery connection to fuse box in engine bay
Do head lights work, not dim?
Does blower/fan work in HIGH?
These draw way more amps than spark system

 

[Serfma]

You have a bad 12volt connection feeding the red/green wire
Any amps are drawing it down, that shouldn't happen
I could see 12.6 going down to 12.5v maybe with key on

Could be in ignition switch, or the thru firewall connector

Could even be battery connection to fuse box in engine bay
Do head lights work, not dim?
Does blower/fan work in HIGH?
These draw way more amps than spark system

I'll have to check tomorrow on it and I'll report back!

 

[Serfma]

You have a bad 12volt connection feeding the red/green wire
Any amps are drawing it down, that shouldn't happen
I could see 12.6 going down to 12.5v maybe with key on

Could be in ignition switch, or the thru firewall connector

Could even be battery connection to fuse box in engine bay
Do head lights work, not dim?
Does blower/fan work in HIGH?
These draw way more amps than spark system

Reckon I should replace these before I keep testing lol

 

[RonD]

Yes, you have a chemistry experiment going on there

 

[Serfma]

Yes, you have a chemistry experiment going on there

Unfortunately not the issue! Out of sheer stubbornness I've ended up making some major progress. I can say that with a very high chance that a full harness replacement would fix the issue, however it is itching at me to find out why this is happening.

Do you by chance have a diagram of the wiring harness and it's connectors? Or the layout in general? It will allow me to explain better but I'll attempt anyhow.

These steps were tested with the key in the ignition set to RUN:

I have piercing probes from work so they worked out great!

Tested battery voltage at ignition switch: Good.
Tested right below switch before it enters the thickest part of the harness behind the instrument cluster: Good. (It had been spliced, tested both sides and was good)

Could not test firewall plug because it was difficult to find and probe, but I don't think the firewall plug is an issue because:
Tested again at ICM connector and had 2v-ish (I say -ish because my battery keeps dying from leaving the key on and I have to recharge it lol)
Tested yet again at ignition switch just to verify the voltage was higher still, and it was.

I decided to follow the engine harness around and came to the driver side far wall behind the coolant/windshield washer reservoir and saw two grey connectors and spotted two red / lt grn wires. I probed both on both sides and had battery voltage! Tested yet again at ICM, voltage drop. Wire loom looks clean, wires look clean. I'm going to get a video here in a few.