Need Help Diagnose Starting Issues

[masayahin]

Recently have starting issues after an hour ride/driving, suspected old Battery and did a jump start without looking at voltage, struggle to start at first crank but went thru with first crank (jumpstarted), so I thought it was the Battery. Always jumpstarted (3 times) to start/move the truck while it still had the old battery before buying a new one.

Replaced it now with "New" Interstate Battery Megatron and still won't start right off the bat... Jumpstarted it again and "struggle to start at first crank but went thru with first crank (jumpstarted)". Checked voltage

12.5v - New Battery voltage (Engine Off)
14.3v - Engine Idle

I had let the engine Idle/Rev for good 15 minutes but still won't re-start afterwards?

Was searching the forum and saw lot of possible culprit and solutions... starter, alternator, relay, contacts, etc... but just wanted to see if anyone can point me to the proper directions on where and what to replace....

If starter or contacts, why would it start when jumpstarted? just need to convince myself.

I wanted to check them all but having a current 24deg weather outside doesn't help and would want to put my money first on items that really need replacement rather than randomly changing parts (which eventually will happen). btw, its a 97 with 202,xxx miles only. Thanks for any reply.

 

[Brian757]

To me it sounds like your alternator may be on its way out.

The alternator simply takes over for the battery after the vehicle is started and supplies the voltage to keep the car running. Starting the truck is the single most strenuous job for the battery, and that is why your truck can't start on its own but when jumped, it will start right up and the battery is/could be keeping the truck running.

Theres a few things you could do prior to swapping out your alternator, as they are somewhat expensive.

You could take the wires off of the battery and sand down the inside of the wiring clasp that meets the terminals. Corrosion can mess with the voltage. I know I've had that happen once where the positive battery wire had so much corrosion, it only let ~4 volts through, and my truck wouldn't start obviously. In your case, you have a new battery, so maybe the wires instead of the actual battery terminals.

Also, a test to see if your alternator is bad(If you dont want to take it somewhere to test), you could start your truck, and pull the negative terminal off. If the truck dies, then your alternator is bad. If it stays running, then your alternator is fine. (Although this isn't the safest, but its a backyard mechanics thing.)

The battery could also have a bad cell, maybe a dud. Its a possibility.

Take a multi-meter and poke around.

 

[krenaud33]

12.5v - New Battery voltage (Engine Off)

Shouldn't this be closer the 12.8v ? I assume that is what it is fully charged. I agree with Brian that it sounds like a bad altenator. Take it to Autozone or similar discount parts store and have them test the altenator for you.

 

[masayahin]

Thanks Brian, will check shortly the Alternator by doing the negative terminal step. just need to warm myself up, was outside for a while my fingers are still freezin

Thanks kre, will re-check Battery and see if it is at 12.8v (with/without load) and it is "New" just bought it yesterday and was still sealed.

Appreciate any other feedback.

 

[Brian757]

Thanks Brian, will check shortly the Alternator by doing the negative terminal step. just need to warm myself up, was outside for a while my fingers are still freezin

Thanks kre, will re-check Battery and see if it is at 12.8v (with/without load) and it is "New" just bought it yesterday and was still sealed.

Appreciate any other feedback.

Stay warm! Update us. Most people figure it out and don't share. We want results!!

 

[KSWAY]

Make sure you have a good connection from battery to your starter.

 

[masayahin]

Make sure you have a good connection from battery to your starter.

Thanks. I suspect it should have but will check this one too... it was properly starting before and jumpstarted it from battery terminals but will let you know.

Truck is also new to me so I have no history whether PO did clean/replace those cables.

 

[Buckaroo]

Battery should be 12.6v (12.5v seems close enough)- check w/o engine running and after turning on high beams for 15 seconds or so to remove surface charge. The 14.3v across the terminals with the engine running indicates alternator ok (under those conditions). Repeat test with high draw items on (blower on full, high beams, back window defroster) and, if ~14v, I wouldn't think the problem is alternator. Look for high resistance (i.e. voltage drop) in starter feed cable (loose connections, corrosion, physical damage), high draw on starter (mechanical) or perhaps bad starter.

Buckaroo

 

[masayahin]

Thanks Buck, yes without engine running (Battery with load) it's at 12.51v (~12.6v as indicated give or take).

12.51v - Voltage Engine off
14.52v - Voltage Engine Idle
14.58v - Voltage Engine Rev
12.71v - Voltage Battery without Load (Terminal/Clamps removed)

Tried the Neg Terminal removed while idle and engine did not shut off and remained continuous idle with no fluctuations, good indication Alternator working as it should.

But it would start right up only when jumpstart'd, looked at the terminals/cables and couldn't find any fault... why would starter only work when jumpstarted?

jumpstarted it using the clamps/terminals and if +/- cable is faulty then it shouldn't have enough current to crank the starter.

Starter works everytime as long as it is jumpstarted.

Alternator is good; +/- Cables is good; Starter is good.

What could it be? really need assistance before pulling/doing something unnecessary.

 

[Brian757]

Thanks Buck, yes without engine running (Battery with load) it's at 12.51v (~12.6v as indicated give or take).

12.51v - Voltage Engine off
14.52v - Voltage Engine Idle
14.58v - Voltage Engine Rev
12.71v - Voltage Battery without Load (Terminal/Clamps removed)

Tried the Neg Terminal removed while idle and engine did not shut off and remained continuous idle with no fluctuations, good indication Alternator working as it should.

But it would start right up only when jumpstart'd, looked at the terminals/cables and couldn't find any fault... why would starter only work when jumpstarted?

jumpstarted it using the clamps/terminals and if +/- cable is faulty then it shouldn't have enough current to crank the starter.

Starter works everytime as long as it is jumpstarted.

Alternator is good; +/- Cables is good; Starter is good.

What could it be? really need assistance before pulling/doing something unnecessary.

I'm glad you eliminated that. Alts are pricey. How does the ground wire look? Never rule it out. The fact that it starts with a jumpstart indicates your getting a parasitic draw from your power supply.
I would inspect the starter contacts, just to eliminate them as well.

 

[masayahin]

Thanks Brian, will have to scrutinize the cables and starter contact by the weekend and keep all posted if that would resolve it.

Appreciate any other feedback and anyone who'd experienced same fate.

 

[Brian757]

Thanks Brian, will have to scrutinize the cables and starter contact by the weekend and keep all posted if that would resolve it.

Appreciate any other feedback and anyone who'd experienced same fate.

Sorry I wasn't specific(Just in case you weren't sure), but the ground wire that connects in unison with the negative terminal. How does it look at the connection between the frame and the bolt?

 

[Buckaroo]

When you jump it from another battery, you are adding amps. This could overcome marginally higher resistance. Check voltage drop on cable from battery to starter (one lead on B+, other lead on starter terminal while engine is cranked, voltmeter set to DC volts). The reading should be 0.1v or so - let us know the results. If you are seeing 1-3v, there is too much resistance. Please forgive me if I am telling you something you already know........You can also check the voltage drop on the wire from frame to negative terminal in the same way (adding to what Brian said). One lead on ground screw in frame, other on negative terminal, crank the engine, reading should be 0.1v or less).

Buckaroo

 

[masayahin]

Just to follow-up on this matter.

Was about to start removing all cables, check on starter, etc... but decided to start by changing the old cable clamps since they are cheap (and I have this "while you are there" attitude) then everything worked properly like before, so ended up fixing it by luck.

17 year old clamps went bad fast even though it was previously working properly.

Thanks for the feedback and support.