Regularly fry starter relays

[72hemi]

I need some help. I keep burning up starter relays in my 72 Challenger. It has the original harness and rallye gauges. If I'm lucky a relay will last maybe 10 starts. I've tried multiple brands and no luck.

[Slotts]

Hopefully, you still have a couple of the bad relays. Try removing the circuit board from at least two of them. If the center copper wire winding is fried, the issue is coming from the input trigger side of the relay. If the heavy contact arm is not able to close or blown off to run the starter, the issue is on the output load side. If multiples are showing the same defect will provide a start path to finding what the issue is.

Jim

[72hemi]

Thanks! I have 3 of them I can check. Will check when I get back home.

[72hemi]

Oh amd I have a high torque mini starter as well and an optima red top battery.

[GoodysGotaCuda]

Which part is failing? The control side or the output side? Do the "fried" ones still click?

[72hemi]

No clicky no nothing. I'll find out which side when I pull them apart.

[1 Wild R/T]

Not saying this is your problem but just something to be aware of....

Different vehicle entirely, 92 Ford F350.... Five starter relays in a month.... All with the same failure, the starter continues to crank when you let off the key... First one I did the diagnosis & slapped a new Standard Brand part on.... Second one I went through diagnostics again & came to the conclusion it was a bad part..  But just to be on the safe side I convinced the customer we should put a starter on it... Warrantied the part & let it go.... Third relay less than a day... Went over everything with a fine tooth comb.... Same result.... Decided there must be a issue with the supplier, tried another brand.... Wanted an OE but they didn't have any in stock.. Should be a clue but I wasn't getting it...   Used an Echlin & it didn't work out of the box.... WTH am I missing?  At my insistence the warehouse tracked down an OE part.. Out of the box it too failed..... Five bad relays? I must be crazy.... Well the man who's truck I'm working on has a second truck that's a sort of back up to the back up.... I grabbed the old original starter relay off that truck, bolted it on... And the truck has been trouble free for over four months now....

Chinese electrical component QC sucks.....

[72hemi]

Here's an update. I pulled two of them apart, and they looked fine on the inside. So I put them back together and tried to start the car with the 3rd one that was in the car and it worked just fine. Mind you this one too did not work a few hours ago. So then I started swapping the other two I took apart in and one of them worked and the other didn't. So we took that one apart again that didn't work to see if we missed anything and nope still looks fine. So I tossed that one. At this point I am believing it has to do with the under hood temperature as it is cooled off now. I have a 340 with Doug's headers and a mini starter.

I think my next move is to thermally isolate the components and go from there.

I have tried multiple brands of relays from multiple sources, ranging in prices and they all end up with the same result.

[71GranCoupe]

You have probably already checked, but loose connections can raise havoc on electrical contacts/contactors/relays.

[GoodysGotaCuda]

Chinese electrical component QC sucks.....

It does. I went through the same with Parts House "Lifetime Warranty" Voltage Regulators. Bad after bad, after bad part.

I pretty much avoid any part they want to give me a "Lifetime Warranty" on now.

[72hemi]

You have probably already checked, but loose connections can raise havoc on electrical contacts/contactors/relays.

Yes I have, even worked on making the ground stronger

[71GranCoupe]

You have probably already checked, but loose connections can raise havoc on electrical contacts/contactors/relays.99%

Yes I have, even worked on making the ground stronger

Just baazaar. You would think out of all the relays, one would last longer. They did originally, even when 40+ years old. Do you have a parts pick yard that might have a vintage car with a relay? Just trying to think of any possibility that will help. The original relays are all metal or at least 99% metal and should not be that sensitive to the heat, unless the header is extremely close, then relocating or trying to install a heat shield of sorts. 

[72hemi]

You have probably already checked, but loose connections can raise havoc on electrical contacts/contactors/relays.99%

Yes I have, even worked on making the ground stronger

Just baazaar. You would think out of all the relays, one would last longer. They did originally, even when 40+ years old. Do you have a parts pick yard that might have a vintage car with a relay? Just trying to think of any possibility that will help. The original relays are all metal or at least 99% metal and should not be that sensitive to the heat, unless the header is extremely close, then relocating or trying to install a heat shield of sorts. 

Yeah I am completely dumbfounded by this. I've had the car 20 years now and this problem has only recently surfaced. Good call on pulling a used old one from a wrecking yard. I will also give that a shot.

[Slotts]

How long has your mini starter been installed? What brand and model number? I would like to see what the specs are on that starter.

Jim

[RUNCHARGER]

Have you measured battery voltage? Are the cables big and in good shape? I had problems with solenoids on my forklift and the only thing that solved it was a large battery (it was just a 3.8 V6) and large battery cables. Low voltage or constricted current flow torches solenoids in a hurry.