Hey all, I have a 1988 Ford Ranger I've recently bought off craigslist.
I didn't realize all the electrical is messed completely up. The basics are it has a brand new computer i had to drop 150 bucks on, I have no idea where the grounds go and the miscellaneous wires go, when i got it it was all torn up and taken apart.
If anyone could please provide me with pictures of their first gen ranger wiring at the relays and ecm and around the ignition coil, i would greatly appreciate it.

I installed a new fuel pump relay, and I get fuel pressure, but it doesn't turn off after a couple seconds, This happened before and after i installed the new computer. Previously, there was no computer. I have taken out the fuel pump relay, and need a diagram with the wire colors and where they go, google is not helping me at all, i cant find anything. On top of all that, the last guy spliced different color wires on to the ends of the leads, so ill have to trace all the way back to the original wires to get the colors.
I get a code 87 when i run the diagnostics.

This truck has been a massive headache. I know it has spark, compression, and that the fuel rail gets fuel at high pressure as well. Al the injectors have constant power to them, i assume the ecm need to ground them to fire them. If someone could please help me, I would be forever in your debt, I need this running.

P.S.I attempted to wire the fuel pump before i had the computer, it would turn on when i turned the key to on, and off when i turned it to off, but it would continuously run when on. It did the same thing after i had the new computer installed. I didnt know where to install the ecm ground, so i just scraped some paint off and drilled it into the nearest side panel. Also, the purple wire is connecting the bypassed inertia switch the previous owner took out.

 

Have a look here: Ford EEC-IV

Computer needs more than one ground, they are NOT shared internally

You will have an OBD1(ViP) connector in the engine bay on the main wiring harness
Drawing here of what it looks like: Testing EEC-IV Equipped Engines : The Ranger Station

Fuel Pump slot on connector is labelled, if that slot is Grounded then fuel pump relay will close(fuel pump on) when key is turned on
Previous owner may have done this , added a jumper to that slot

Computer controls the fuel pump relay by Grounding it(pin 22 on computer), that ODB1 slot is connected to this computer wire, so by grounding that slot you are doing what computer does, but computer unGrounds it after 2 seconds
So if Fuel pump relay stays Closed after the 2 seconds then this wire is Grounded somewhere


Some older wiring diagrams here: Ford Ranger Wiring Diagrams : The Ranger Station


Grounds are important
Body parts are all painted BEFORE assembly so they are NOT good grounds just because they are bolted together
Engine and trans sit on rubber mounts so are also not good grounds
Frame is isolated from body and engine/trans by rubber mounts

This is why there are ground wires and ground straps where you NEED good grounds
Battery negative's largest cable should connect to the engine, thats where the highest AMPs are needed, Starter motor and Alternator
If there is a smaller cable then it should go to Rad support, head light ground
And also a jumper from there to inner fender for starter relay and other electrics mounted there

From the engine there should be two ground straps/wires, one from the engine's head to Firewall, this is the MAIN ground for ALL cab electrics, very important ground, needs to be clean and tight
Second strap is from engine to Frame, usually at or near Motor mount, this is the ground for tail lights and sometimes fuel pump motor and fuel gauge sender.

If you can't find one of the above Grounds then ADD IT, never read even one post about have too many ground wires, lol, it's true not one

 

Okay, thank you so much!
There is no wire in pin 22, instead there is one in pin 21 that is a ground. i followed a grouping of 4 or 5 ground wires and all had continuity. I rewired the fuel pump relay back in (guessed wires until it ran when the key was turned and didn't when it was in off position)
My ground for the ecm(screwed into the kicker) has continuity and a solid ground.
Im using a 12v test light for all of this btw.
I disconnected the ecm while the battery was still plugged in on accident, but now the obd1 system wont read off any codes, and im afraid i may have burnt up the brand new ecm. Is it possible i did? This is really stumping me, and im wondering if id just be better off buying new harnesses. Can i do that? is there a certain name for each of the harnesses?

 

No wire in pin22 ??, now that is odd, all Fords with fuel injection used fuel pump relay and pin 22 to activated it regardless of engine size, until 1995 and up when the newer OBD2(EEV-V) computer was used

Probably wouldn't find one, a wiring harness for 2.9l that is
Rangers used 2.9l from 1986 to 1992 and wiring harness would be the same for all those years, might have some extra wires for AC or EGR on different models years but all the ones you need would be there.
4.0l harness wouldn't work because it used MAF sensor, 2.9l was a MAP system
2.3l harness wouldn't work either, they went distributorless in 1989, and only had 4 injector hook ups, although you could add 2

There were people that swapped in 4.0l and 5.0l V8s into there 2.9l Rangers, and they may still have the 2.9l harness.
Check the "engine conversion/swap" sections in this and other Ranger forums, people often posted their "projects" if you see a 2.9l being swapped out send a PM to see if they still have the old parts, 1986 to 1992 would work

Check if the CEL(check engine light) come on when key is turned on
That means computer is booting up

Could be you blew the Fuse/fusible link that feeds power to EEC Relay, Brown base relay
That sends power to computer(EEC) and to fuel injectors when key is turned on.
Check if any one of the fuel injectors has 12v with key on, use test light
If it does then computer is also getting 12v

 

yes the Check Engine light comes on,
On the motor swap note-
I could ask for an old harness, but i had also planned on putting in a hand build 302 super or 347 into it, should i just go ahead and start on that? or would it be more beneficial to fork the money over for this harness and save up for the 302?

The way i see it, im gonna need to rip the whole harness out anyway, and i def need to weld in patches in the firewall form where the heater core leaked and destroyed the passenger side firewall and floorpan.

Does the engine harness and pcm have anything to do with the dash aside from ignition switch? Because the whole dash works well, aside from the cosmetic rusty parts.

 

No connection between computer harness and dash wiring in pre-1995 Rangers, although some may be taped in same loom

The ignition switch turned on the EEC relay in the engine bay and that powered up computer and 12v engine systems.
Then you have an engine temp wire, oil pressure wire, tach wire, starter wire and Battery light wire that ran to the engine from dash area, not computer

Computer just had the one Ground wire for CEL that ran to the dash

Up to you about new harness, I would spend a little time looking, 302 swap is not just around the corner it sounds like

 

UPDATE:
today i tried to start the engine manually with a fully charged battery(by putting a screwdriver on the starting solenoid)
The truck has a brand new starter the last owner installed. The engine started and when i pulled the throttle it continued to roar, however i still had the solenoid jumped(hoping i didn't burn out the starter)
It sounded as if the injectors were firing, and it was on time
This went on for about 10 seconds until the starter solenoid fried, and then it wouldnt crank anymore.

Still no crank from the actual key switch, and no codes from the obd1 testing. I saw some smoke, but it could just be from an old engine going for the first time in a while.

Could fuel pressure be the problem? maybe that why the pump never turns off? when i press the schraider valve it shoots out like crazy, so i dont know.

When i crank the key, the solenoid clicks (before i burned it out XD)

What do you guys think?

ps, i sprayed some brake clean in the intake before hand, put it was running for too long to have just been the brake clean firing.

 

Injectors are working and spark is close enough if engine started and continued to run

Replace starter relay(solenoid)

The small wire on the starter relay's small "S" post should be red/blue, that comes from the ignition switch via Neutral switch.

Ignition switch in START--------------clutch or NSS switch------(red/blue)------------"S" post on starter relay

Manual trans uses a Clutch switch on the clutch pedal push rod
Automatic trans has an NSS switch on the drivers side of transmission, just above linkage

 

the wire is red and blue

As far as finding a harness,
Does it have to be from the exact same engine arrangement? such as 2wd, 2.9l v6, auto trans?
Can it be from a 4x4 or a manual?

What years have the same harness?

THANK YOU SOOO MUCH, you are really saving my butt dude, i appreciate it a ton

 

Any harness from 1986 to 1992 Ranger 2.9l will work, 2WD or 4WD or manual or auto wouldn't matter.
Ford did move the EEC and FP relays into the engine fuse box at some point, but the wire is all there

Cab harness has a plug in to by pass clutch switch, just above where clutch pedal would be, if you have an automatic
And engine harness will have a plug in at rear of engine by firewall for automatic trans use, it is left unused on manuals


The red/blue wire runs down to the NSS(neutral safety switch) on drivers side of transmission.
It looks like this: http://www.merkurmidwest.com/catalog/i669.html

It screws down into trans from above shifter, a Cam inside the trans pushes NSS plunger up and down to make and break connections inside it.
It also activates Reverse Lights when trans is in Reverse
When trans is in Park or Neutral it will pass 12v from ignition switch to red/blue wire

There should be a Pink wire at the NSS, that's the 12v from ignition switch when key is turned to START, it needs to connect to Red/blue wire(there may be two Red/blue wires, one goes to distributor)
There will be a Pink/orange wire as well, that will have 12v when ever key is on, thats the power for the Reverse Lights, it goes to the Black/pink wire(Reverse Bulbs) when trans is in Reverse.

 

Update:
I replaced the starter solenoid with a new one, and took off the starter and got it tested at autozone(turns out it was broken)

I couldn't find the neutral safety switch. I may have, but all the wires were different colors (one red, one orange, one pink and red). Anyhow, my reverse lights function as normal and i'm told that a new one was put in when i bought the car.

I found 4 connectors on the driver side of the engine bay, are these supposed to be connected to something? When i ground the small green one, it sparks.

The white one and the black one do not fit together, trust me i tried. They are all right in the same area, and i cant find any info on them.

P.S.
Is it possible for a fuel pump to gain good pressure but not fast enough? Would that cause the ecu to not ground it? Would a bad fuel pump ground also stop the ecu from stopping the pumps from running after a few seconds when the key is on?

 

On my 1994 Manual trans Ranger I have an unused round connector at the center of the firewall, hangs from wiring harness, it is round and was used for automatic trans wiring harness.
So does the black connector go down to trans?


Check the Clutch switch by-pass, above brake pedal
Ranger manuals had a long clutch switch on the pedals push rod, 6 wires, Ford added a plug in for that switch connector for automatic tans use
Picture of the clutch switch connector seen here: How to: Clutch Switch Bypass | Ford Explorer and Ford Ranger Forums - Serious Explorations

Wire colors are probably not the same in 1988 but may be, if they are the same then maybe you can see if they change color at the connector for automatic

The Reverse light wires come in later, as manual or auto had that switch on the transmission, so no reason to have it in under dash wiring like the safety switch

 

Alright, so tonight i went in and installed the new starter, still no crank, my battery should be good, i had just charged it overnight and its within a year old.
Solenoid clicks in park position only, not in neutral(should it?), the fuel pump is still just running continuously while the key is in acc on position
The sensor itself looks good, but i didn't do any thing other than just look at it, it was pitch black outside.
Also, i found these two connectors under the dash, one unconnected from everything( i have no idea what it is), and one with a cap on it, near the break pedal ( i think this is the clutch safety switch and its plugged bc i have an auto)

My whole dash lights up and functions normal, all lights work, several warning lights turn on when in acc on but thats normal
I removed the ecm to try and back track to when it cranked before i installed it, but still no crank

Ill look into bypassing the switch, but i have little hope, and rations have run low. General morale is down, i don't think we'll last the winter.
Regards,
ShodMermaid336

 

yes, it should start in Park or Neutral

So Solenoid(Starter Relay) on the fender "clicks" when key is turned to START?

If so then that part is done, the ignition switch thru safety switch to Starter Relay is OK

Starter Relay on fender has two larger posts.
Battery positive is on one larger post, doesn't matter which one, BUT......all other wires will be on that post, the Battery Post, it is the power distribution point for the vehicle.

The other larger post will have just one large cable that runs to the starter motors large post.

Thats 1988 wiring

In around 1990 Ford started to change to Starter Relay on the starter motor, there was still one on the fender as well for power distribution, but wiring was changed for starter activation.

Look at the starter motor you have, if there is just one large post for large cable from fender mounted Relay then above wiring is correct.

If there is a smaller post on the starter's solenoid then you have a Relay in there as well, which is fine just wired differently, you have TWO starter Relays
Picture here of a starter motor with built-in Relay: Part 1 -How to Bench Test a Starter Motor (Step by Step)
#1 is the activation post/tab
#2 is where constant, high amp, 12volts is connected, larger post, larger cable connected directly to the battery positive
#3 is GROUND

If you connect 12volts to the larger empty post(#2) on starter motor nothing should happen because relay inside needs to be closed.

If the new starter looks like this, large post and small post then you need to rewire a bit, not a big deal.
You will connect Starter motors large cable, that is by itself on fender relay, to the large Battery positive post on fender relay, so starter motor now has full time high amp 12v power.

From the, now empty larger post on fender relay, you will run a smaller wire to the #1 post(smaller post) on the starter motor.

So starter motor has full time battery power
When you turn Key to START Fender relay will close and send 12v to Starter motor relay, it will close and starter motor will activate

On newer Rangers the positive battery cable was long and ran directly to starter motor, and the smaller "S" wire on the "fender relay" was run directly to the starter motors smaller post, fender relay was deleted after a few years and replaced with a Power Post for distribution, until full fuse box was added

 

 

Ok another update:
I turned the engine by hand, and removed the belts to single out the ideas of locked up pulleys
I thought it turned rough, but when i jumped the solenoid, it cranks fine
I cut out all the fusible links, and just twisted the wires together for now, to eliminate that
I took another look at the pcm, turns out i was reading it upside down, there is a wire in 22, however, it has no signal, not power or ground
I further looked at the fuel pump relay, and it seems there is a jump where two wires and the wire to the relay are all fused together.
So i cut the three wires apart, the one to the relay has power(yellow)
Then one of the same colored wires is a ground, the other is nothing again.

are all three supposed to be together? or should the nothing one be connected to power? or ground?
Why wont the engine crank from the ignition key(it only clicks), but it cranks when i jump the solenoid?

Also, weird incident, my radio no longer connects to anything, it stays on the same white noise channel. I checked all the fuses, they're fine. It turns on, the clock works, but it just doesnt connect to a station, This is not important though.

 

One vacuum line may be for the "air pre-heater", on most if not all vehicles there is an air diverter on the air cleaner boxes inlet
On cold start this diverter would close and cause air from a metal casing around the exhaust manifold to be sucked in to the engine, pre-heated air from exhaust heat.

This was vacuum operated and MISSING on most vehicles by the time they get to 15 years old, lol.

But plug both hoses until you find them a home.

And no it wouldn't cause a no start


So start motor still does not work?


The "i" post on starter relay was for the Coil's positive terminal in older spark systems
When an engine is running the alternator/dsystem voltage is about 14volts, and that will heat up a coil pretty hot and there is no reason for it, so to make coils last longer an Ballast Resistor was added to coils Positive terminal wire, this reduced voltage at the coil to about 8-9volts when engine was running, still good spark, and longer coil life.
BUT................when you try to start an engine, battery voltage drops below 10volts from starter motors draw............
So with ballast resistor in line coil voltage would be 4-5 volts, and very weak spark especially for cold starts.
So the "i" post was added to starter relay and a wire ran from there to coils "+" terminal.
"i" post has battery voltage only when starter motor is activated, so coil get 10volts, a hot spark for cold start.

In the mid-late 1980's Ford ran 2 wires to coils "+" terminal, one with resistor the other without resistor, without resistor wire was only active when key was turned to START
Resistor wire was connected when in RUN
All done in ignition switch

And by the 1990's better coils were available so no need for resistor any longer.


If you take a jumper cable from battery positive to starter motor does it crank?

maybe wire from starter relay to starter motor is bad?

 

If I jump the two large posts, it does crank, however i try to avoid that too much as thats how i broke the last starter and solenoid.

As for the vacuum hoses, i know i am missing my vaccum heater control valve, i assume one goes there

 

If you jump the two larger posts on starter relay and starter works but doesn't if you apply 12v to "S" post then you got a bad starter relay, simple as that, new or not

 

OKAY, IT FINALLY STARTED :D

I bought a new duralast solenoid, installed it, and started it and it ran!!!
However,
It dies if i don't give it gas and let it idle, and the check engine light is on, but gives no codes.
I have not tried driving it yet, it runs fairly rough, i am certain it needs engine mounts, the way it was bouncing around lol
Also, the fuel pumps still dont turn off after a couple seconds, it runs contiuously
But progress never the less! :D

 

Good work.

IAC Valve is what allows PCM to set idle
It should get 12volts on one wire from ECC relay when key is on
The other wire on IAC runs back to the PCM and is the GROUND, PCM pulses this ground to open and close IAC Valve to set idle, cold idle should be 1,100 or so
IAC Valve closes with no power, spring inside pushes it closed, the PCM should give it full Ground with key on so it opens all the way for starting.
This is why all fuel injected engines should REV briefly when started, hot or cold, because IAC valve is opened all the way, how much they REV up depends on how fast PCM reacts to startup and closes IAC Valve to set target idle

Fuel pump relay must be the issue
Its socket should have 12volt all the time from battery/fusible link or fuse
And a wire out to inertia switch
And thats how Fuel pump gets its 12volts

The relay part(coil) should only have 12v when key is on
but no Ground so relay stays open, fuel pump off
PCM grounds this relay

So if you pull out the Fuel Pump relay from its Green base, does fuel pump shut off?
If so then problem is in the relays 2 coil wires, or relay is stuck closed, broken.

If fuel pump doesn't shut off when relay is pulled out then someone has by passed this relay