Starter issues !!!! Long start then nothing help!!!!!!

[MrOrange]

So i have been fighting this issue for about a week or so. Just purchased this 1970 cst10 truck , never did i have an issue with the cranking or running of it. As i started to drive the truck more frequently i noticed that the starter would have a longer and longer crank . I decided to replace the starter . This is when it all went to hell. now it doesn't crank at all unless there is a massive amperage sent to it ( my battery charger on start) and sometimes that doesn't work. The battery wire to the starter was getting real hot to i changed it over to a new 4 gauge. still same problem . Now there is a buzzing electrical noise coming from under the dash. I isolated it to a relay which i cant identify what it goes to. it was wrapped in a cardboard cover and has 2 separate pigtails one is brown and one is black. Any help would be much appreciated.

[NoNeck]

That is an electrical relay commonly used when aftermarket cruise controls are added to a vehicle. Of course some PO might have wired it to something else such as electric fans, etc. When wired correctly, this relay functions to open (set cruise) or close the circuit when the brakes are applied.

Here is a simple test to determine what it’s connected to:
Install the relay.
With a test light, probe the connection points on the left side of the relay. These (2) points are the relay contacts. (as shown on the photo)
One point will be hot (12 volts) and the other not-hot.
Operate stuff in the car until the not-hot goes hot.
If that doesn’t work, turn on the ignition and repeat the test.

It sounds like you have a current draw at that relay when the key is 'on'. The PO also could have wired whatever this operates into the 'brake/hazard light' fuse on the fuse block. I would try to disconnect it altogether and see if it helps your situation?

POP

[MrOrange]

Ok so figured it out . IT WAS THE STARTER THE WHOLE TIME!!!!!!! POS autozone part. REME MADE my ass!! I decided to back track and put the original starter back on after running out of options, and BAM! fires right up! I still have the issue with the slow crank after the engine is warmed up that i was trying to resolve before by changing the starter in the first place... even after the 4 gauge wire and replacing the coil and relay wires on the starter. I do wonder if i add another ground to the starter if it will lowers the resistance making it less hot?? I'm going first try a Napa starter and see how that goes.. Keep y'all updated

[MrOrange]

Thank you for the info , but sadly i tried all that and it tested good that y i tried the orig starter. My guess was the bad starter was pulling so much resistance from the battery it was shorting the relay. I'm pretty sure i don't have cruise but im gonna look now

[dmjlambert]

So what is the situation on your exhaust? Do you have headers that most people complain about heating up the starter, or regular exhaust pipes that are not close to the starter? How about your battery cables? Do they have emergency clamp-to-the-wire style ends or molded on terminals and in good shape?

[Steeveedee]

FWIW, I put on one of those little starters from the speed shop, added ground straps and even ran the battery ground cable all the way to the starter, and it still has trouble sometimes. I'm thinking of installing a water spray device to cool the starter when I stop for gas. It's generally when I'm towing the travel trailer when we go camping, so I just don't shut the engine off when refueling. This problem is endemic to these trucks. Maybe it's like gas tank size design. When I graduated high school (1970) and went to work for the local Chevy dealer, the Vega came out. I asked one of the salesmen why it had an 11 gallon tank. He told me that the tank was sized for making sure that people stopped every four hours (about 250 miles at an average speed of 65 MPH) for gas. That would be based on the worst mileage that could be expected for a given vehicle. With a 19 gallon stock tank, my truck with a 402 CI engine getting 13 MPG would fit that bill. Maybe BS, I dunno. On a test track with a woman 5 foot nothing tall driving at a constant speed, it might have gotten 13 MPG.

[MrOrange]

So update , I got a pair of header huggers , I installed the starter i bought from Napa at the same time. The angle of the exhaust flange at the end of the new headers is like straight down now. I have no idea how someone can install an exhaust on this , but im sure once i take it to the exhaust shop we can figure something out. starter fired right up . so thought i got the problem resolved ..NOPE was at subway and shut the truck off then tried to start it and bam same problem , well similar. sounded different this time.. but nonetheless wouldn't start again. i gave it a few minutes went out and it started again. Im guessing these starters overheat easily on the c10? Anyway im gunna keep trying stuff maybe header wrap and a starter blanket?

[dmjlambert]

Do I understand correctly from reading your posts above you have the header installed and blowing straight down on your engine mounts and starter as you drive around, and you don't have an exhaust pipe leading all that heat away?

[Ironangel]

Make sure you have the battery grounded to the motor block. https://shop.advanceautoparts.com/p/...E&gclsrc=aw.ds

[MrOrange]

i grounded the battery directly to the frame and it seemed to help tremendously , compared to the original ground which was bolted to the manifold bolt. I plan on adding an additional ground from the block to the battery also

[Ol Blue K20]

Heat soak is common on these old rigs. On my 89 V3500 with a 454 I installed a later model starter with the heat shield...problem solved. The starter I installed is from a 96 K2500 Suburban with a 454.