This seems to be a very popular subject lately…

Some of you may know the story… free F350 in California… drove it home 220 miles with no issues.

Last week, while cranking the engine after the battery had gone dead, there was smoke coming from the positive battery cable (I think). My helpers sprayed a little water on it and it stopped… now the truck will crank but not start.

I spotted some green corrosion on the + terminal of the starter but have not pulled the starter to clean it.

Now what I have done to troubleshoot this problem…

The inertia switch is 'on'.

The fusible link @ the solenoid has power in and out.

The fusible link going to one fuel pump relay DOES NOT have power.

No power at all to any connector on any relay on the left inner fender.

The fuel pumps do not power up or make any noise when the key is switched on.

I tried to ground the terminal @ the EEC test connector but it's not there… empty slot.

Now what?

I cleaned up some corrosion on the relay plugs.
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Missing wire to the EEC plug… and no power to it.

Same connector as above.

This fusible link goes to the fuel pump relay on the left side inner fender and has zero power.

This fusible link goes to the starter solenoid and has power in and out.

 

Any change? I see you never got a reply.

Key "on" power to eec relay via the wht lt blu wire, it powers the fuel pump relay via the red wire. Should read "bat" voltage at the eec relay via the yellow wire.

You state no power at the eec relay, I'd check the brown fuse link at the fender mounted starter relay.

There is more than one fuse link at the fender mounted relay, '87? there is like 5 or 6 of them.

You have three wires to the eec test port, 4 including self test and it wouldn't have power to it?

 

This diagram from an '89 might help shed some light:


Page 2

 

There's only 3 wires to the EEC connector… no 'self test' wire is present as far as I can tell… no white/lt. blue wire.

I'll get a chance to take another look tonite...

 

Ok….after getting a better ground (not sure if that made a difference) I now have power to the 1st terminal from the right (as seen from the back side of the connector) on the EEC test connector as shown in my earlier photo… it's the heavy white wire… 90% sure it might have that light blue stripe (hard to tell). Not switched as it always stays on.

I also have power to the EEC power relay @ the heavy gauge white wire. No other power to the FP relays right now.

The 20 gauge blue fusible link does not have any power...

And I just got rained out...

 

If no power to EEC relay you wouldn't have any power at STO, not sure but sounds like you're saying you corrected that much before getting rained out.

Can't see colors in your images, just not clear enough to make them out.

"Self test" is the individual wire with the white connector on it shown in your second picture of the EEC test port. To shinny in the image so can't tell you what color the wire is for reference and does not appear to follow my diagram perfectly far as conductor color goes. I use a Haynes manual and while the diagrams are correct its not uncommon to find color to be wrong at times across the model years, for the most part errors limited to the earlier models.

 

We had two bad relays when I was picking up the truck last month… got used relays from the junque yard. I'll clean up the remaining corrosion with some baking soda, clean the terminals as good as I can (I used a dental pick yesterday) and I might pick-up a new fuel pump and EEC power relay tomorrow. I really like to use new parts whenever practical and electrical parts are usually somewhat dodgy when you buy 'em used…IMHO of course.

 

Cleaning connector contacts such as relay socket I grab one of my DW nail files from the pack in her drawer (she thinks she hid them), they work great stiff but not to stiff and the proper thickness, I cut a section just a hair wider than the corresponding pin.

Uses the connectors own tension to provide the pressure needed against the file cleaning both sides at the same time. Finger nail files are coarse one side and fine the other, so I flip it both ways for couple passes, cleans em up quick and easy little dialectic grease and ready to go again.

 

Good trick...

 

IT RUNS!!!!!!!

Installed a new EEC relay and a fuel pump relay… fired right up. I went thru the electrical system and decided to buy NEW parts to replace the JUNKYARD parts the PO bought before I drove the truck home from CA.

Now on to a couple new sensors for the oil pressure and water temp, a new 195F t-stat, fix the power steering leak, get the front power windows to work... yada-yada-yada.

 

Question… Does anyone use dielectric grease on the electrical connections for the EEC, relays, etc? Sure would cut down on corrosion even with the modern weatherproof connectors.

 

I use it on any connector that has an O ring or packing as an added seal against moisture, you bet. Also good for ignition boots. For single pin connectors, spade lugs, relays etc., and grounds, or anything exposed I really like NO-OX, it holds up.

It pays to go over all connections and grounds. Disconnected the battery on the Ranger and hit every connector and ground I could get to. The "weatherproof" connectors aren't.

 

Ford didn't use 'weatherpack' connectors on these trucks but what they have isn't bad. But I DO like to use the grease. I always had better luck with a repair staying repaired on my big trucks/trailers if I used the grease.

Thanks.

 

Hey, you called 'em "weatherproof", not me!

Yeah, they work but what these trucks go through is pretty brutal. The older trucks have well known problems with corrosion, but their electrical systems and electronics are primitive compared with today. And it doesn't cost anything really other than time. Preventive maintenance goes a long way.

 

Yes, always!