battery or starter?

[V]

So I've been ignoring a warm/hot start issue with my car now but finally need to fix it. Alternator charges fine. Car can sit days and start fine. But if i start it and drive a very short distance, even just a minute, the car cranks slowly and then acts like it has a dead battery. Battery will be around 12.2 volts when it acts up and during cranking, it'll drop to 3.5-4 volts. When i let off the key. Voltage returns to 12. Fires up great when jumpstarted. I've narrowed it down ta bad starter that may be dragging and causing excessive current draw or a battery where the cells are separating under load. Car has had slow cranking since at least October, but never needed a jump like it did twice in the past 2 days. I have a used starter i can put in but im not so sure that's the main issue. Could a failing starter have damaged the battery over the past 6 months? I guess Ill have to battery load tested at an auto parts store and replace if bad(can't find a date on battery- id assume 3 years at most). If original, the starter could have 147k miles on it. The used one i got had 70k on it and look clean.($58). I did clean battery terminals and that did seem to make cold starts even nicer but did not affect warm/ hot starting. So who thinks battery and who thinks starter?

[The_Bishop]

If you have a clamp-on amp meter, you can see what the draw is on the positive lead when cranking, give you an idea on if it's the starter.

[sweetbmxrider]

Yeah I'd want to see the amperage its pulling down. You can definitely wipe out a battery with a **** starter. Being that its hot start only, I'm going to say your starter killed your battery I don't even know how its cranking at 3.5-4 volts. Hell anything under 9.5 volts and most anything in the car doesn't want to work or does funky ****.

[3.4 grape of wrath]

Don't leave out the starter solenoid from the equation. The contacts can get pretty nasty and not make good contact. The solenoid will usually click when low voltage is present which protects the starter motor. Cranking at 4 volts or lower should not even happen.

[V]

Let me rephrase... "Turning the key trying to crank results in a drop to 4v." It stops cranking and basically all electrical goes dead. Let off key, goes back to 12v.

[ThoR294]

Originally Posted by sweetbmxrider

Yeah I'd want to see the amperage its pulling down. You can definitely wipe out a battery with a **** starter. Being that its hot start only, I'm going to say your starter killed your battery I don't even know how its cranking at 3.5-4 volts. Hell anything under 9.5 volts and most anything in the car doesn't want to work or does funky ****.

this

[V]

On monday when Im done with work ill have to remember to grab my clamp-on ammeter and test my car when i start it cold. Then when i get home, I'll try restarting it and see what that hot start reading is.

[V]

Amp testing was pointless today, I only had a AC clamp on meter. I'll try to see if we have a DC one at work tomorrow.

Let me also add, In the past few months, occasionally, when I would try to start the car, I would turn the key and there would be nothing. Mostly no sound or anything. I'd have to turn a few times and then finally the starter would come to life. A few of those time, I would get a click or a very short turn of the starter before it went silent. But even those times, after turning the key a few more times, the starter would then work.

Because of that, that is why I feel it is more starter than battery related.

[LTb1ow]

Sounds exactly how my old (bad) starter was before I replaced it.

[ThoR294]

i had a bad battery made me think it was the starter. it randomly wouldnt start then it would.

put LT4 starter in, same issue a week later. replaced battery... all good

[V]

Well this morning, the starter finally died. I get the solenoid click and nothing else. battery voltage stays fine as I hold the key to the crank position. Tried it when I got home from work, still just the one click every time I turn the key. I guess it's time to swap out the starter, and the clutch stuff as well. fun.


edit:
Got the car towed to my garage last night. Made stands for it and got it up in the air today.