Starter just keeps going?

[bennylava]

I'm having an electrical issue with my 87 TBI 350 truck. 2wd, automatic. For some reason, after you turn the key, the starter just keeps going and going. The truck doesn't get driven all the time. So a week ago, I went to grab a bite to eat and when I came out, the truck wouldn't start. I guess it also has some kind of dying battery, or perhaps an alternator charging issue. But I cranked on it for a little bit, because it sounded like maybe, just maybe it would start.

All was good for the first few tries at cranking the engine over. However, on the last try, I noticed that the starter did not stop trying to turn the engine over once I had stopped turning the switchkey in the cab. I took the key out, and the starter was still going. So I hurried and popped the hood and took the battery cable off. Luckily I managed to do this in time, before the starter killed itself. But now, a week later when I attempted to start the truck, the engine did not turn over and the starter just made a high pitched whine and span itself into oblivion. A good deal of smoke came out from underneath the hood. So my guess is that now this starter is probably dead.

I haven't had a chance to inspect everything yet, but I figured someone here would probably know what will make a starter just keep spinning after you stop turning the key. Any ideas what could cause this?

[mongocanfly]

sounds like you need a starter and solenoid. ..you could also have some shorted wires on the starter that could cause the starter to keep spinning...much like jumping the solenoid with a screwdriver..

[bennylava]

Only thing is, its a new AC Delco starter. It might have 50 starts on it. The solenoid may be dead now, but is there anything common that might be the cause?

[raggedjim]

Charge the battery completely (or buy a new one) and your problem will stop. The low voltage of the battery is causing higher current draw and welding your solenoid contacts.

Good luck, Rg

[wilkin250r]

Jim nailed it.

Oddly enough, a motor draws LESS power as it spins faster. Which means if it's spinning slowly, it's going to try to draw huge current (the end result being, if you stop the motor completely, it acts like a dead short and attempts to pull an unlimited amount of current)

Since heat is all current-based, that higher current that is caused by the low voltage welds the contacts of your solenoid. I've never had it happen with a car, but I've done it to a few motorcycles.

[Dead Parrot]

You mentioned the new starter. Assuming it came with a new solenoid, you might have just lost the solenoid lottery. It happens. If you can test the unit and if the starter passes, replace the solenoid unless the whole thing is covered under warranty.

[75C10]

I had a near new starter fail with similar symptoms. Once it started to roll over only disconnecting the battery would stop it. Turns out a c clip on the end of the solenoid came apart and this was enough to keep the solenoid engaged continuously. Put in another new starter and no further issues.

[franken]

Originally Posted by raggedjim

Charge the battery completely (or buy a new one) and your problem will stop. The low voltage of the battery is causing higher current draw and welding your solenoid contacts.

Sorry, but that violates Ohm's Law which we can't do. Lower voltage means lower current.

Chances are the excessive cranking welded the solenoid contacts if anything. I'd reconnect the battery and see if it starts cranking again.
Measure the battery voltage with the engine off and running. That will give an idea of whether its charging.

[raggedjim]

I don't want to argue the specifics.

OP put on a new battery and get back to us.

Rg

[franken]

Yes, definitely don't think, use logic, or take measurements. Swap parts and spend money. Its the only way to be unsure.
Better yet, buy a new truck. Why waste time?

[raggedjim]

Originally Posted by franken

Yes, definitely don't think, use logic, or take measurements. Swap parts and spend money. Its the only way to be unsure.
Better yet, buy a new truck. Why waste time?

Well, he can also fully charge the battery he has. No cost at all, and I would bet it will solve his problem (as long as the solenoid contacts haven't permanently welded).

My opinion is based on years of experience, no one has to take my advice, in fact, I always tell people to never take advice from strangers on the internet.

I might add, you are using ohms law for a resistive load, but a motor is an inductive load, so you should use P=IE or to transpose for current, I=P/E

Good luck, sorry I rubbed you the wrong way, Rg

[franken]

Its not personal, its simply facts and you seem to want to deny them. Less charge means less energy which means less current. You can live in a fantasy world, just don't try to BS the internet and expect not to get called out. Your number of years of misunderstanding have little to do with the topic at hand.
You've also introduced an equation for resistive power in the same sentence that discusses induction so clearly, you have no clue.
Ohm's Law applies to inductive loads. Current is proportional to voltage. That is, as voltage goes up or down, so does current.

[raggedjim]

Well, If I'm wrong, I apologize to the OP for mis-leading him.

Rg

[bennylava]

Originally Posted by raggedjim

Charge the battery completely (or buy a new one) and your problem will stop. The low voltage of the battery is causing higher current draw and welding your solenoid contacts.

Good luck, Rg

I have been having battery issues and slow starts prior to this. I just got the battery though, and I don't drive the truck all the time. So I was thinking that maybe my battery might not actually be dying. And that it had just gotten low. I guess from now on I will leave a battery tender on there. Just to be safe. I'll also get the alternator checked, I can't remember if I've ever had it checked or rebuilt. Had the truck for 8 years, been fixing it up ever since I got it. This maybe this is all because of a dying alternator. No telling the condition of that alternator.

Originally Posted by franken

Chances are the excessive cranking welded the solenoid contacts if anything. I'd reconnect the battery and see if it starts cranking again. Measure the battery voltage with the engine off and running. That will give an idea of whether its charging.

That is the weird thing. Sometimes after you disconnect the battery, you can come back a while later, and the starter will behave normally. The truck will just start up. Then if you drive somewhere and kill the engine, the problem will come back. Just cranking and cranking with the key out, and having to disconnect the battery to get it to stop. Well... this was before all that smoke poured out and the engine stopped trying to turn over, and the starter just made a high pitched whine. My guess is that all that will happen now, is just more of that high pitched whine. Which probably points the the dead solenoid, right? With a starter motor that is still perfectly good.

[wilkin250r]

Originally Posted by franken

Sorry, but that violates Ohm's Law which we can't do. Lower voltage means lower current.

Actually, Jim was spot-on.

Your interpretation of Ohm's Law is assuming a constant resistance. With an electric motor, resistance is a function of motor speed. As speed decreases, resistance decreases.

If the relationship were perfectly linear, 20% under-voltage would result in 20% lower speed, then everything would balance perfectly. However, that's not the case. 20% lower voltage (for example, driving a 12V motor with only 10V) results in SIGNIFICANTLY lower motor speed. Like 66% less, perhaps more, especially when we add the load of turning the engine against it's compression. It's huge.

If we assume a typical starter motor to have a 0.12 ohms of resistance at full speed (resulting in 100 amps @12V), then cutting that speed by 66% results in cutting the overall resistance by 66%, leaving us with about 0.04 ohms of resistance. By ohms law, I=V/R, 10V / 0.04 = 400 amps.

So that starter motor that's drawing 100amp @12V, becomes 400amps @10V. (assuming the battery can supply said amperage and voltage).

[Sabaka454]

You have both electrical resistance and mechanical resistance at play with the starter motor. Nevertheless his problem is on the control side of the circuit which also has a mechanical actuator. The bottom line is his starter solenoid is sticking and needs to be replaced. Don't overthink it guys

[wilkin250r]

I think it is important to also understand underlying causes. IF (the key word) the solenoid problem stems from the excessive cranking and low battery, replacing the defective solenoid won't truly fix the problem.

Then, the debate on how a low voltage could create higher current needed a resolution.

I don't believe it's over-thinking. I think it's ALL relevant.

[bennylava]

Just to be clear, the starter motor itself should be just fine, right? I wouldn't think that cranking for an extra 10 seconds, a few times, would be enough to harm it. But I just want to cover all my bases cause I really don't want to have a starter issue again later on down the road after I've put this whole problem behind me.

[raggedjim]

Benny, it's hard to say without having a test done on the starter. If it overheated enough to break down the insulation on the wiring you could have problems with it, but starters are designed for severe duty so it is probably fine.

The thing to remember is solenoid contacts don't just weld together for no reason. There is something causing it to happen, whether it is a mechanical bind, or welded contacts, or excessive heat from extended cranking. If the contacts are pitted it will happen again. At the very least you should inspect the contacts for weld marks and pitting.

I'm sorry for any drama on the thread, I just want to help you figure out the problem.

Rg

[bennylava]

Yes I'm going to have the battery and alternator tested. But as I am tiring of battery related issues, I'm probably going to get a deep cycle battery as well. I just like having all my bases covered and if a deep cycle battery would help with a few other potential issues, then I'd like to have one. And I have run into a few situations where that would have really helped me out.

I have a hunch that the alternator wasn't charging the battery well enough, and that may be the root of the problem. In which case my battery may now be dying as well.

[homemade87]

Originally Posted by bennylava

Yes I'm going to have the battery and alternator tested. But as I am tiring of battery related issues, I'm probably going to get a deep cycle battery as well. I just like having all my bases covered and if a deep cycle battery would help with a few other potential issues, then I'd like to have one. And I have run into a few situations where that would have really helped me out.

I have a hunch that the alternator wasn't charging the battery well enough, and that may be the root of the problem. In which case my battery may now be dying as well.

Just a note on the new battery . Do not get just a deep cycle battery . Either get a dual purpose or a starting marine battery . The difference is the deep cycle battery is made for long low amp draws . The starting battery is made for high quick amp draws like starting . The dual purpose is kinda the best for both worlds and would be fine . They design the plates in the battery different for the two .

[cadillac_al]

The bottom line is you need another starter and they are dirt cheap. I just bought hi torque mini starter for $36 on ebay. When they die you just chuck 'em.

[bennylava]

Originally Posted by homemade87

Just a note on the new battery . Do not get just a deep cycle battery . Either get a dual purpose or a starting marine battery . The difference is the deep cycle battery is made for long low amp draws . The starting battery is made for high quick amp draws like starting . The dual purpose is kinda the best for both worlds and would be fine . They design the plates in the battery different for the two .

Do you have a recommendation on a dual purpose deep cycle? I was thinking of maybe going with the Optima Yellow Top.

Originally Posted by cadillac_al

The bottom line is you need another starter and they are dirt cheap. I just bought hi torque mini starter for $36 on ebay. When they die you just chuck 'em.

Could you post a link to that mini starter? All the mini starters I looked at were higher priced than a replacement AC Delco starter.

[homemade87]

Originally Posted by bennylava

Do you have a recommendation on a dual purpose deep cycle? I was thinking of maybe going with the Optima Yellow Top.



Could you post a link to that mini starter? All the mini starters I looked at were higher priced than a replacement AC Delco starter.

The yellow top battery would be just fine . It is a dual purpose battery for starting and is commonly use in the stereo world because it will stand to be cycled when run down . Best of both worlds .

No battery likes to be stored any length in time in a discharge state . An AGM battery seems to not like it more . So if a battery is down charge it . Wet cells are a little more forgiven .

In the end its still hard to beat a wet cell for starting power .

[cadillac_al]

I bought this one but haven't got it on the truck yet. It was recommended to me from the Camaro guys. It does require newer style starter bolts 4.3" long.

http://www.ebay.com/itm/LUCAS-Starte...72.m2749.l2649