Ford Power Stroke Nation banner

1 - 15 of 15 Posts

·
Construction Babysitter
Joined
·
761 Posts
Discussion Starter #1
I will see if I can describe this and have it make sense. On cold startup, to voltage gauge will drop down to about 1/4 up on the voltage gauge when the glow plugs are on. After wait to start light goes off, I start the truck and it starts with no problem. After the truck is running, the voltage gauge will begin to rise up to its normal running location (about 2/3 on the gauge). After a couple of seconds of running, the voltage gauge begins to jump around from 1/2 to 2/3 on the gauge and will do this for a few seconds, then will return back to normal position. There is a slightly noticible difference in engine tone when it is jumping around. The truck has 2 brand new batteries, a new valve cover gasket and one new UVCH because one of the glow plug circuits was fried. I have ohm tested all of the glow plugs at the top side of the harness and all came up at 0.7 ohms. It also has a new alternator, and appears to have a newer GPR. My questions are:

Should it take a few seconds to get up to normal voltage after the truck has fired up? I am used to seeing the voltage gauge jump right to its normal reading immediately after the truck has been started (this has been my experience on my other powerstrokes).

Is this jumping around of the voltage gauge the glow plugs cycling on and off? I thought when they cycled on and off they would stay on for a few seconds then turn off and back and forth. This voltage fluctuation is about every second.

If this is how the glow plugs cycle, should there be such a draw that I can see it on the voltage gauge when the truck is running?

If I need to make a short video, I can do it if I didn't make sense with my description above.

Thanks fellas
 

·
Construction Babysitter
Joined
·
761 Posts
Discussion Starter #2

·
Registered
Joined
·
173 Posts
Check out your GPR, it could be the cause.
 

·
Construction Babysitter
Joined
·
761 Posts
Discussion Starter #4
The GPR is fairly new and the system is functioning. What should I check out on the GPR? Is there a spec for voltage drop across the big leads?
 

·
Registered
Joined
·
33 Posts
Mine will hang around 1/3 for 30-60 sec after startup then jump to normal. however if I put it in gear and start accelerating during that time it will jump as you are describing so I just let her sit til it is up to normal then it will stay there.
 

·
Registered
Joined
·
4,042 Posts
That doesn't seem normal. I'd have the alternator checked.
 

·
Registered
Joined
·
89 Posts
i have this issue also, what is the GPR
 

·
Registered
Joined
·
5,494 Posts
Did anyone solve this? I have the same issue. I installed a new alternator and GPR.

Thanks
What issue? The voltage bouncing around or a lower voltage for about 1-2 minutes?
 

·
Registered
Joined
·
312 Posts
Mine do this too if I just let them idle. As soon as I take off they quit cycling. I just figured the GP system continued to cycle to assist in warm up. All the Dodges do this and is what I am used to. THey will sit there and cycle the grid heater on and off for up to 5 minutes at idle, to assist in a quicker warm up.
 

·
Registered
Joined
·
622 Posts
That gauge is dumb....mine doesn't work until I am halfway to work about 10 miles or so....my aeroforce gauges reads the real voltage. And it is good.
 

·
Registered
Joined
·
3 Posts
Does anyone have an update on on the bouncing voltage while the gp are cycling. Mine has recently started doing this. Some say it’s normal but a bouncing voltage at 1 sec intervals isn’t normal. It’s normal to have a low steady voltage during gp operating and then the voltage will jump up to normal operation after the go shut off. I can hear the motor surge along with the voltage surging during idle at start up. This only happens to me during a cold start. It never does it when the oil is warmed up. Any input would help I know this is an old thread. Thanks
 

·
Registered
Joined
·
3,358 Posts
Install a White-Rodgers (Stancor) 586 902 I always install on my trucks, much more robust then stocker. Mine has always shown a discharge on my trucks then pops up to normal. Recently on the Tan truck was pulsing as noted above, swapped in a Leece Nevel 200 amp alternator, no pulse and discharge barely happens, which makes total sense due to larger charge capacity. I’d check alternator output might be faulty, on its way out even though its new.
j
 
1 - 15 of 15 Posts
Top