Harry Hilton

Getting near the tail end of a budget restoration of a 1987 F-150. The original owner did a handful of hackjob repairs/"mods" like poorly wired audio and aftermarket alarm system hacked into various harnesses, duralast/AutoZone everything (maintenance-wise)...you get the idea. I have just about all the kinks worked out on the truck save for a few electrical issues and disconnected harnesses that have bothered me since purchasing the truck.

Anyone who could provide some knowledge or advice on the following would be a great help.

1. Dash anti-lock light stays on. Replaced the ABS sensor and fixed a disconnected rear diff vent tube that I noticed while replacing the sensor. Light stayed on.

And 2. Identifying the following disconnected harnesses found in the engine bay. Located on the driver's side above the wheel well.

Steve83

1. Put the original back. Replacements are generally NOT compatible with these early 8.8" axles. Click this, read the caption, and keep reading the NEXT several:


(phone app link)

2. Identify connectors by their WIRE COLORS. It may be necessary to peel back some of the harness wrapping to expose the original colors. Look up the colors on this page & the NEXT several:


(phone app link)

There will be several possible functions for each color combo - make a list for each connector. When you see the same system mentioned for a few wires, you can guess that the connector belongs to that system. If you can't figure one out, post its colors, and the list of all possible functions for each wire in it.

Your first few pics are too close-up, which is why they're blurry. Back off so we can see the areas they're in, and so the camera can focus. Your last pic is the DLC:


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Everything will be easier if you clean it, and I don't mean the painted parts.


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And it will be easier for us to help you if we can see all the truck's details in your signature:


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Harry Hilton

1. Good to know. Pretty certain the original owner already replaced the ABS sensor as it looked too clean. I will get an OEM/Motorcraft unit to replace.

2. Awesome. And from the pictures I've seen of OBD-1 port scanners, the single wire connector is the one that goes next to the DLC into a scanner tool.

3. Understood. I have full intention to do a full engine degreasing and cleaning once I have fixed everything but in the meantime I will clean off the connectors/wires in question and re-post clearer pictures this afternoon with text caption confirmation of the wire colors for each connector.

4. Noted. I will add the door tag photo to my signature this afternoon as well. In the meantime, the details on my truck are as follows:

1987 F-150 Custom - 8ft bed - 2WD
4.9L Straight-Six - 84k miles
C6 Auto trans
Upgrades: PMGR starter, 3G (95a) alternator, all new wiring between battery/starter/solenoid/alternator. Hotter MSD coil, Taylor cap/rotor/plug wires, 205° thermostat.
​​​​​​
Random maintenance performed/parts replaced: water pump, power steering pump, serpentine/v-belt, IAC valve, TPS sensor, oil/filter, wix air filter, all new vac lines, coolant flush, and some other I'm probably forgetting right now.

Steve83

2. EEC-IV scantools are notoriously UNreliable. Click that thumbnail, and read the caption - all you need is a paperclip.
3. Not necessary to post - just look each one up yourself.
4. Don't put the photo in your sig - put the INFORMATION in it. You could have put what you typed into it already - just follow the link in my previous post.

BTW
Using the wrong thermostat temperature is a DOWNgrade. And an MSD coil does nothing that the stock coil didn't.

tpage

Top three image, the one with the pull out plug is the computer bypass plug. Just pull it out to bypass the computer.

Bottom is the test ports. using the stand alone plug, you will jump it to the plug with six ports/connectors. You can then use the check engine light, via blinks, to get error codes.

Can you take more photos of the test port plugs? Hiving to rewire my 87 and the person before removed them. Need to see about the wiring and where to attache to plug.

http://straighttalkautomotive.com/OBD1/ford-OBD-I.html
http://www.troublecodes.net/ford/
https://www.2carpros.com/articles/fo...-and-retrieval

Steve83

There is no such thing on these trucks.

tpage

OK, I might be wrong in the name and what the plug is. Here is a video, about one (1) minute in, where I got the name and what it does. I came across it while having to rewire an my 87' due to rodents and previous owner wire cuttings....

BLDTruth

That's the spout connector - it disables the computer's control of timing and runs the engine on whatever the base timing is set at.

tpage

What about the one next to the distributer, is that just used for setting the timing?

Thanks,

Steve83

The SPOUT is always an inch or so from the ignition module. On '87-91 trucks, that's on the distributor; on '92-96, it's on the driver's fender near the firewall. It's NOT in any of the OP's pictures.


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But it doesn't "bypass" anything - it just breaks the circuit that allows the EEC to tell the ICM how to adjust the timing. So the ICM uses base timing, just like disconnecting the vacuum line & keeping the RPMs low on an older mechanically-advanced distributor.