Alternator late to kick in, harder starts

[Exalted85]

So I'm dealing with a new issue. The truck is having some hesitation starting..and for some reason the alternator isn't kicking in for about a minute. Sometimes the voltage will drop off even after the alt has kicked in. 

 

I did the w-t mod..but I haven't put a new line from the pdc to the passenger side battery..I know this isn't supposed to be necessary, but could it affect anything like what I'm describing? This issue didn't pop up after the mod..It's been about a month. 

 

The only other thing that I can think of..is my gf used my truck to jump her car a couple times in the morning..I've never jumped anything before, and I wasn't present when she did it. Could the added load of jumping her car, whilst cycling the grid heaters on a cold truck, have caused any type of issue? 

 

Any ideas what could be going on here? Here's a video 

 

[Mopar1973Man]

W-T ground wire mod done?

 

Battery Condition?

 

Alternator performance / AC noise?

[KATOOM]

Unless there is something completely different going which you're aware of in this video that I'm not...it just looks like the grid heater system is cycling after start.  If you ramp the idle up to about 1100-1200 rpm the grid heater will remain on for a continuous period of time as long you hold the throttle there.  I cant remember how long it remains on either but it doesnt cycle as often when the throttle is ramped up.

 

And...I wont jump start anyone or anything with my truck.  They're too sensitive to any electrical quirks, and things can easily go wrong jump starting something.  I just tell people that I cant or I dont have cables.

Edited December 11, 2018 by KATOOM

[Tractorman]

15 hours ago, Exalted85 said:

The truck is having some hesitation starting..and for some reason the alternator isn't kicking in for about a minute. Sometimes the voltage will drop off even after the alt has kicked in. 

 

Some things that your video doesn't show...

 

*  You say "some hesitation starting" - does that mean the starter is cranking slowly?,  or is it cranking at normal speed and just takes longer for the engine to start?  (Starting the video before you turned the key would help us diagnose.)

 

*  Are you operating the throttle or is the engine going to high idle on its own?

 

*  What is the ambient air temperature?  Is this a cold start? - as in the first start of the day?

 

I am going to assume some things here.  It was the first start of the day.  You waited to start the engine until the "Wait to Start" light went out.  The starter cranked for a longer than normal period of time.  When the engine started either you brought the engine rpm up and held it there or the high idle feature was enabled.

 

2 hours ago, KATOOM said:

If you ramp the idle up to about 1100-1200 rpm the grid heater will remain on for a continuous period of time as long you hold the throttle there.

 

(Thanks KATOOM for this information)

 

So, if this was your procedure, I would say that the alternator was charging normally throughout the duration of the video.  The grid heaters would have drawn 200 amps while waiting for the "Wait to Start" light to go out.  The starter would have drawn about 400 amps while cranking.  After the engine started the post cycling of the grid heaters would have begun - again drawing 200 amps continuously because of the high idle. 

 

The alternator puts out 136 amps maximum - much less than the 200 amp draw from the grid heaters.  The battery voltage falls to around 12 volts and remains there ( as it should) because the alternator that really is charging just can't keep up.  The grid heaters draw whatever current is available from the alternator (which is not enough) and draw the remaining current from the batteries which drops the voltmeter down to around 12 volts and holds there..

 

I noticed in your video that when you said the alternator just kicked in, it appeared that the engine had dropped to an idle and the grid heaters had cycled off  just a moment before.   That would explain the rise to 14 volts in the voltmeter. 

 

If the starter is cranking slowly, then I would be looking at batteries that are in poor condition, corroded or loose wiring connections, worn starter contacts, etc.

 

- John

Edited December 11, 2018 by Tractorman
Thanking KATOOM

[Dieselfuture]

When jumping a vehicle, if cables got cross-connected or touched each other, then the diode bridge in alternator gets fried. That alone will cause all kinds of issues. I also don't jump anything with my truck, unless absolutely necessary, even then it is only I that touch the cables. I would also use a high idle feature when jumping or winching. 

Hate to say it but our trucks electrical system is weak. After doing all these mods it is better but still not perfect.

[kzimmer]

Technically, it's safest for your truck to jump start someone with your engine NOT running, key off. 

[Tractorman]

7 minutes ago, kzimmer said:

Technically, it's safest for your truck to jump start someone with your engine NOT running, key off

 

I agree, and that is my method.  I have jump started many vehicles in this manner.  I still have the original Bosch alternator (brushes and bearings at 215,000 miles) with 303,000 miles on the alternator now.

 

- John

[Dieselfuture]

Good idea 

[dripley]

3 hours ago, Tractorman said:

 

I agree, and that is my method.  I have jump started many vehicles in this manner.  I still have the original Bosch alternator (brushes and bearings at 215,000 miles) with 303,000 miles on the alternator now.

 

- John

I might still be using mine had it not failed in this way.

I guess the bolt was not tight. Just wore its way thru. Still have it matter of fact. Figured I would find a way to fix it one day. One day has never arrived though.

Edited December 12, 2018 by dripley

[KATOOM]

4 hours ago, kzimmer said:

Technically, it's safest for your truck to jump start someone with your engine NOT running, key off. 

 

Agreed...  Except my concern is not my running engine but the potential problems of the vehicle which needs to be jumped.  Unless your battery cables are completely disconnected then there's still risk of damage.

Edited December 12, 2018 by KATOOM

[015point9]

Wonder if there are some kind of diode a person could install to prevent elec problem...to keep elec only going outbound from battery be used to jump disabled vehicle

[Tractorman]

1 hour ago, dripley said:

I might still be using mine had it not failed in this way.



 

I don't see a problem with the alternator - it looks to me like it has a quick-connect feature.

 

- John

[Dieselfuture]

14 minutes ago, 015point9 said:

Wonder if there are some kind of diode a person could install to prevent elec problem...to keep elec only going outbound from battery be used to jump disabled vehicle

That or when using a winch, I have one but only used it few times. Might use it more often if I knew it wouldn't cause damage to electrical stuff. It's a cheap 12k Harbor freight so it probably draws more amps then a worn winch. I often thought about selling mine and getting a quality winch but just don't need it to justify getting one. Hf was on sale for 300 new so I got it idk, on my old Chevy I had, I wouldn't be scared using it, but on this dodge boy it makes me think ha ha. 

[KATOOM]

2 hours ago, 015point9 said:

Wonder if there are some kind of diode a person could install to prevent elec problem...to keep elec only going outbound from battery be used to jump disabled vehicle

 

Just carry one of these around if you plan on helping people jump start their vehicles,  (just a picture I got off the internet)

 

[Mopar1973Man]

LOL. 

 

Just helped a friend jump start a Detroit Diesel. The funny part was 225 Amp battery charger wasn't enough I stacked on my 1996 Dodge Ram 1500 and we got it spun over on a cold day. Little battery packs are good for little cars. For sure will not start a diesel engine.