http://mystyk3.tripod.com/relay.html

If clicking the link doesn't work, try copy and paste.

1991 F150 5.8

Anyway, here's the problem-

Yesterday I went to start the beast and all I heard was what sounded like grinding coming from the right side of the engine bay. Without even thinking about it, I jump to the assumption that it's the starter. I pulled the old one, called the wife to pick me up and bought a new one. Installed the new one, and got the same grinding sound. So I took a little more time to diagnose the issue- had the wife turn the key while I was under the hood and came to the certain conclusion that it was the starter solenoid clicking repeatedly but unable to make contact.

Well, just to get the truck home and out of the hardware store parking lot, I took my jumper cables, attached one to the positive battery terminal, the other to a big f-ing screwdriver, and jumped directly to the starter. It fired up and I drove it home. By this point I had to go to work and just let it sit for the night.

Today I picked up a new solenoid [BWD Select], installed it, and now I just get a click. The weird thing is, when I first turned the key ON, I got the usual relays clicking and fuel pump priming sounds, but after I tried to START it, I didn't get those sounds after cycling the key off. But, after waiting about 5-10 minutes, I got the relays and fuel pump to engage when turning the key ON again.

So I'm positive that something is shorting when I turn the key to start, then after 5-10 minutes it resets and I'm able to try starting it again. This is just me but that sounds like a relay problem. So I started chasing wires, which is where the above relay comes into play- I wanted to pull the relay off the connector to trace a circuit, and in the midst of wrestling it off there, 2 yellow wires that hooked into the same place on the connector just "fell" out of it. It's pretty nasty corrosion.

So what's the above relay, is it tied into the ignition circuit, and where's a source for a replacement connector OR terminals so I can just replace the terminals inside the connector?

Thank you!

BTW- I did try locating this relay in my chiltons manual and thru FFI.com and couldn't figure out what it was- otherwise I wouldn't have posted this. Also, it's located in the right rear area of the engine bay with the EEC test plug, RABS test connector, and all the main engine harness connectors.

 

quote
So what's the above relay


The relay with the loose wires may be the EEC power relay, you should be able to get another one. It may come with wires installed that you would splice, solder, and seal...I'm seeing 2 yellow, 1 red/light green, 1 black wires in diagram

 

Yeah it looks like the EEC power relay, but I don't think that's your problem. I think you have a bad battery cable from your battery to the solenoid, or you just have a dirty battery terminal(s). What's happening is when you try to start it, the load you are putting on it is breaking whatever meager connection there is and shuts everything down due to heat from the resistance. When things cool down, the poor connection is restored and the process starts all over.

If you are able to use jumper cables to get it to start, then it's gotta be the cables from the battery to the starter, or the terminal(s) is/are dirty.

 

My money is on a cable too!!!

 

The relay with the loose wires may be the EEC power relay

Yea thats it, that connection loose/corroded explains all the symptoms you describe (other then the no crank condition), intermittent fuel pump/relay actions when cycling the key off and on again.

Also note that same circuit, yellow wire, also feeds the keep alive memory function of the computer, so it has been lost.

So yea start with that, you'll need a relay/connector to repair it. Any auto parts will have what you need to do so. It will have a wiring diagram right on the side of it with the pins numbered to go by, just solder/shrink tube it in place of the old one.

 

Thanks for the response guys. I'll let you know how it comes out.

 

Well I cleaned up connections at the battery, starter solenoid, starter, and ground. So I have to be getting good connection now.

But the corroded wires are really f-ing me. I tried just cobbling things together to at least get it started, and it just won't go, so I'm gonna have to get that connector replaced before I can go any further.

Thanks again for the help- I've got a friend on the way to pick me up and take me to OReilly's.

 

How is the EEC power relay going to cause clicking at the starter solenoid?

 

I don't think the EEC power relay was the original problem, but when I got to screwing around and tried pulling apart the connector, the wires fell loose and it became a problem.

danr1, what parts store do you use? Because on the way to oreilly I called autozone, advance auto parts, and napa and none of them could get it- they all said it's a dealer only item. Is there another name I should be calling it? Cause I've just been calling it the EEC power relay connector.

Anyway, since I couldn't find the connector, I bought an assortment of female spade connectors and spliced the wires directly to the relay. Same crap is happening- turn the key, click, and then nothing.

So comes my next question- does the starter solenoid ground thru the fender? Because I got to thinking about it and I didn't think to clean the mounting surface when I changed the solenoid, and that could at least be a contributing problem.

Thanks again.

 

Well I answered my own question- even if it does, cleaning the mounting surface didn't help either.




I'm going to try jumping the battery to the starter again, see what happens. If it fires then I know my cable is bad and I've got to replace it, which will have to wait till morning.

Why does it seem like when someone else is having a problem I can suggest tons of things to check, but when I'm having the problem I feel completely clueless?

 

The ground to check would be battery to block, although I don't think you will find a problem there. It still would be good to check and clean it up. The fact that your jumper cable (just a new positive cable) from the vehicles battery to starter got her going. Would still indicate that your positive cable/connection, or solenoid is at fault. A bad cable is easy to spot by a dark coloration of the individual fibers of that cable, or the connectors having a blacken look, coating to them.

 

And the winner by a terminal is... battery cable!!! Congratulations, you've won a complete replacement for yourself while you join your distant relatives in--- the recycle biiiiiin!!!!

I cut open my old one to give it a look and sure enough, the fibers were dark and there was plenty of corrosion forming. My guess is the starter/solenoid were never a problem, and replacing them only made it worse. So I picked up a new cable this morning and it fired right up. Funny how sometimes it's the simplest things.

Now I just need to find that darn EEC relay connector....

 

Which I have also done. I think the parts guys I were talking to may have thought I was talking about the main computer harness connector. But this one looks exactly like what I need. Only thing is I'll have to splice the 2 yellow wires to the one yellow wire but that's no big deal.

BWD PT5685 - Connector 1991 Ford F-150 | O'Reilly Auto Parts

 

Just don't forget who said "battery cable" first. :-)

 

[quote=DBGrif91;8986860] Only thing is I'll have to splice the 2 yellow wires to the one yellow wire but that's no big deal.


Disconnect the battery ground first, because one of those yellow wire's has a fuse link in it