Had the truck in to get the radiator replaced, the mechanic mentioned that the coil was sparking and probably on it's last leg and that might be why it was often hard to start.
As I was trying to get it started this morning , I saw a little smoke coming off the starter solenoid so I went t and got a new replacement. I followed the directions and hooked up the wires as it was before. It cranked fine, but still wasn't starting (there was moisture in the carb so I thought it was just that). I kept cranking trying to get it to catch and then poof big hiss of smoke and that brand new solenoid was toast, the terminal for the + lead had melted right off.I hooked it up just like before and I figure it woulnd't have cranked if I had it wrong right? So why did it fry the solenoid? Did they give me the wrong replacement part or is there some other issue going on?

I'm attaching photos of the before and after as I was disconnecting and reconnecting the wires

 

Here you go:

https://www.ford-trucks.com/forums/1...i-mean-it.html


Lots to digest in there, but a few highlights:

1) Some aftermarket brand relays are total crap. Avoid store brand relays from discount chains. Get a genuine Motorcraft relay, or a top quality aftermarket such as Wells, Cole-Hersee, or NAPA Premium.

2) A failed or aborted start attempt is very tough on the starter relay. Get your ignition problem fixed so the truck starts easily.


Also, carefully remove the positive battery cable, the short one between the battery's (+) post and the starter relay. Using a post hole digger, make a hole in your backyard as deep as you can. Drop this cable to the bottom. Full the hole with a mix of large rocks and readi-mix cement. Follow all directions on the bag to ensure the cement cures properly. Proceed to your local parts store and procure a replacement with a factory-crimped battery terminal. I mention all this because that "emergency" bolt-on terminal (as seen at the bottom left of your picture) will cause nothing but grief.

Once you get a quality relay installed, and have replaced the cable and buried the old one, please report back here and also at the thread linked above. It will be helpful for others to know what did and didn't work.

 

Hey there. Bummer!


Even though they gave you the "wrong" type, it's only a newer version for newer trucks and should have worked fine. What year is your truck by the way?

The new parts available these days are crap more often than ever before, but the Ford starter relay/solenoid is particularly prone to cheapness. So you may be dealing with a problem still, or you may have just run afoul of a crappy new part. Normally they take these under warranty, but since they know you already had a heat issue they may take exception. But it does not hurt to find out.

Aside from the crappy parts potential, they may have given you a mis-boxed Ford PowerStroke glowplug preheat relay. Probably not as robust for starter duties. Not sure how to check the part number on the part itself though.

All that aside your old tired wiring and the starter may be putting too much strain on the relays now. I notice your positive cable is a clamp type. Supposed to be only "temporary use" but I've used them for years that way and they're fine if kept tight and clean. Yours does look "ok" at the battery, but obviously it's now toast at the relay side.

I would replace the cables (all three of them) at this point. Use 2ga upgrade sizes and keep the first one as short as possible. Then put the new 2ga starter side on there too and make sure the starter contact is clean and tight.
Then the new 2ga ground cable directly to the engine block (not up at the alternator bolt if you can avoid that) and as close to the starter motor as you can get a good clean bolting spot on.

That's all I can think of for now. You need new wires for sure. Whether you need a new starter or not only time and/or testing will tell.

Good luck

Paul

 

oops, started typing a long time ago and did not see kr's post before hitting send. Looks like you're covered, and seems like there's a consensus for tossing the old cables!

Paul

 

I should add that up-sizing starter cables is not a requirement. My 2ga recommendation is simply because I think factory battery cables and sizes on older trucks were just adequate and I feel a little bit of overkill is a good thing.
Used to recommend 4ga as the upgrade, but since 2ga has become so common in the stores, is really still very inexpensive and larger cables can carry more current while you're sitting their cranking and not complain as much, I still recommend going big when it comes to battery cables.

Paul

 

Hey guys, thanks a lot for the replies. Since I forgot to put this in the post, it's an old 1986 F250 with a 351 in it. The engine runs like a dream (when it starts) but the bottom is more rust than metal at this point so I'm just trying to keep it going til fall when I can afford an upgrade. I love these old 70s/80s era trucks its just unfortunate this one is costing more than it's worth to keep it on the road. I don't mind picking up some heavy 2GA cable though, all I need is a ft or so.

I checked out that link you posted and it looks like exactly what I need, but quite the read so I'm going to save it for my morning coffee tomorrow and see if I can figure this out.

If I had to guess though you guys are right, this cheap Chinese plastic BS is not a suitable replacement for what I need, I'll track down a real part and that should solve at least some of the problem!

 

Don't pick up cable and put ends on it as you may be right back where you are.
Measure the 3 cables and take note of the ends and buy the right size & ends on the cables.
Dave ----

 

My 86 F250 351 W has the same relay as you replacement. No problems.
I agree with others about the aftermarket crap. I had a relay ( like your replacement) unused sitting in the box in the garage for about a year. When I installed it, it wouldn't work. Dissected it. The contact washer was steel (instead of the original copper) and rusted so it wouldn't make contact. !@#$%^&* Corrosion / rust can cause resistance and heat and is a possible cause of your problem.

 

Can you please add details of your experience to the database thread linked above? I'm trying to consolidate such hard-earned experience in one place. Specifically, stuff such as "Brand ABC part number 123 failed almost immediately. Brand XYZ part number 789 worked fine"


Re: Heat damage - Please look at the thread linked above, and scroll down to step #14. This simple test makes sure the electromagnet inside the relay receives full battery power. Reduced power to the electromagnet means reduced clamping force at the contacts, leading to arcing, welding, and heat damage. Even a top quality relay will fail under such conditions. Run that quick test to help rule out an external problem that will damage the new relay, too.

 

If any connection gets hot there is resistance. Notice the crusty looking cable got hot?

Clean tight connections will not melt anything. I always wire brush or use a grinding disc to clean all washers and nuts before assembling these parts with some dielectric grease to help the connection and prevent rust.

I wonder if you can test a solenoid itself before using it by mounting it, putting 12v to the signal terminal and checking the battery and starter sides with an ohmmeter before wiring them up. Motorcraft solenoids are the ones to look for, of not maybe a more expensive American aftermarket brand.

Once you have it all right you can disconnect the coil and crank of for a bit. Make sure all the connections are still cold.

 

Unfortunately, the values recorded by an ohmmeter are not conclusive. If you were to observe several ohms, yep that's bad. However, to conclusively say a starter relay is good by measuring resistance across the contacts? You'd have to discern a maximum teensy fraction of an ohm, well beyond the sensitivity of most meters. Or if the contact made "perfect" continuity but only at one tiny spot, this would trick an ohmmeter into saying all was good, yet in practice the relay still couldn't handle the massive amp flow of the starter.

That's why I swear by this hybrid voltage drop test. Three simple hookups, and it tells you everything you need to know about the complete starter circuit:

https://www.ford-trucks.com/forums/1...w-starter.html

 

That Bat cable from the battery to start relay needs to be replaced. That was the cause of you issue in the first place. And off the self universal fit will do the job. Ideally you be looking for a 2 gauge cable.
The later style starter relays in my opinion are not as good as the earlier ones. The earlier ones tend to last longer than the later style ones just due to having thicker contacts.

 

I made the mistake in the past & replaced mine with store brand solenoid & burnt up 2 Starters because the Solenoid would get stuck on (Keeping the starter in advanced state) when turning over the engine, could small then starter cooking.
Lesson learned on these solenoids.

 

More details, please. Specifically, what brand failed and which one worked?

 

When I went through a similar solenoid fiasco I found an old thread and followed the recommendations. Bought a echlin solenoid from Napa. I've had perfect use for about 2 years now out of mine. Only sold at Napa, make sure it says "echlin" on it as that is the high quality brand. Mine looks like the one in the pic don't know about the exact part #.