Hard Start Issue

[nspctr1]

I posted previously about my 92 998 with the stock 6.2 having a non start issue after the freeze in February. I checked fuel pump, power to IP, glow plugs etc and everything checked fine. I checked the batteries and they tested out at 12.1 volts and 12.5 volts. I assumed that if the batteries had voltage that they were not the problem and that's where I was wrong. Because even though they had voltage and were powering the accessories they were still inefficient in providing the CCA's needed to fire it off. After checking everything multiple times for power etc I made a last ditch effort to just have the batteries checked. As I discovered they were showing 12 volts but the CCA's had dropped to below 300 on each one of them. I had the batteries charged, reinstalled them and boom, the truck fired off just like it used to. Just thought I'd share this with you guys who may be having the same issue as I.

 

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[nspctr1]

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[Coug]

So a fully charged 12V battery is above 12.6V.
at 12.5V it would be 80-90% charged.
A battery at 12.1V would be about 35-50% charged.

When batteries are cold, they also lose starting capacity.

At freezing temps, a battery has at best is 80% of it's original capacity available.

So in other words, your batteries were discharged to begin with, and being out in freezing weather made it worse.

Back in the military, if the weather was freezing, we'd have to go start them once a day and run them for at least 30-45 minutes in order to keep the battery fully charged up.
You can also put a battery charger on them to help out; if the battery starts dropping voltage due to the cold, the action of the battery getting charged will help warm it up and keep it usable.

 

[Milcommoguy]

I posted previously about my 92 998 with the stock 6.2 having a non start issue after the freeze in February. I checked fuel pump, power to IP, glow plugs etc and everything checked fine. I checked the batteries and they tested out at 12.1 volts and 12.5 volts. I assumed that if the batteries had voltage that they were not the problem and that's where I was wrong. Because even though they had voltage and were powering the accessories they were still inefficient in providing the CCA's needed to fire it off. After checking everything multiple times for power etc I made a last ditch effort to just have the batteries checked. As I discovered they were showing 12 volts but the CCA's had dropped to below 300 on each one of them. I had the batteries charged, reinstalled them and boom, the truck fired off just like it used to. Just thought I'd share this with you guys who may be having the same issue as I.

So are you saying your low CCA, available amperage / capacity (flat batteries) could not spin the engine 150 RPM +/- to start. If cranking engine is a struggle to turn it over , that's a problem. The range of voltage, charged to marginal is just a few tenth of volts. In 24 vols system both batteries need to play nice.



Good batteries for sure and all cables and connections clean. Some of the pictures of rigs showing battery boxes are iffy, IMO. High current starting connections / terminals in and out of battery box down to starter and those both sides of feed thru's need a good checking / cleaning. Crappy connections with excessive voltage drop... BAD NEWS. If a cold start... Glow plugs are going pull down marginal capacity right out of the gate too.

IMO, Between monitoring the in dash voltmeter and listening to the spin up / cranking of engine, operators should be able to detect something going flaky on start-up.

Listen to the HumV. Might be a telling story, CAMO

 

[TOBASH]

Corroded battery leads and wires can lead to a poor charge state which over time will damage batteries. Sometimes batteries are good BUT poor charge state leads to good batteries testing as under charged.

 

[Mullaney]

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I have to agree with all three of the guys...

A crummy connection to between the battery and the cable end will make you go "off the deep end". Charging is haphazard and cranking will be too. Dielectric Grease lightly applied on freshly cleaned battery posts and terminals will keep those connections in good condition.

You might try a cleaning tool like the one below. There are other kinds but this type doesn't eat as much lead off your connections.

 

[nspctr1]

Sorry for late response. the connections are clean and dielectric grease has been on them since I bought the rig and went through it 3 years ago. Turns out that even tho the batteries were showing 12.2 volts that the CCA was below 300 therefore causing a no start issue. Charged batteries and the truck started right up. Thanks for all of the info

 

[Coug]

Sorry for late response. the connections are clean and dielectric grease has been on them since I bought the rig and went through it 3 years ago. Turns out that even tho the batteries were showing 12.2 volts that the CCA was below 300 therefore causing a no start issue. Charged batteries and the truck started right up. Thanks for all of the info

Just for reference, when a battery is at 12.2V it's basically dead for starting purposes. 12.6 is considered a full charge, and anything less than that will be hard on the starting system as the starter motor will try to draw more amps with lower voltage.