Alternator voltage on ISC engine

PatrickA51 wrote:


I knew that the ISC was a Cummins Diesel, but not about the ambient temps, thank you for taking the time to post that. I have not noticed it in my Ram 2500 IL6 6.7L Cummins Turbo Diesel. Learn some thing new every day.

Cummins uses 'grid heaters' on their motors

My 5.9L has them and so does your 6.7L

This is the grid heater on a 6.7L---finger is pointing to #1 fuel---grid heater is just below hand in intake manifold where air horn connects

I often hold the AUX start button on for a couple of minutes until the thing is warmed up. This supplies extra power to the grid. I do not idle much so get moving asap so it can warm up.

Old-Biscuit wrote:

sch911 wrote:
Charge air heater grid cycling on/off with a cold engine?

THIS ^^^^^^

ISC is a Cummins Diesel
Cummins uses 'grid heaters' vs 'glow plugs'

Voltage WILL fluctuate from 14V to 12V when ambient air temps drop below 59*F
They will continue to cycle on/off (up to 30 seconds) until intake manifold temp goes above 59*F---even with engine running

Each grid heater pulls close to 95A...thats 2300W
Just one of the reasons for dual batteries and high amp alternators

I knew that the ISC was a Cummins Diesel, but not about the ambient temps, thank you for taking the time to post that. I have not noticed it in my Ram 2500 IL6 6.7L Cummins Turbo Diesel. Learn some thing new every day.

Old-Biscuit wrote:

sch911 wrote:
Charge air heater grid cycling on/off with a cold engine?

THIS ^^^^^^

ISC is a Cummins Diesel
Cummins uses 'grid heaters' vs 'glow plugs'

Voltage WILL fluctuate from 14V to 12V when ambient air temps drop below 59*F
They will continue to cycle on/off (up to 30 seconds) until intake manifold temp goes above 59*F---even with engine running

Each grid heater pulls close to 95A...thats 2300W
Just one of the reasons for dual batteries and high amp alternators

Most excellent responses! Thanks guys!

Good info to know. Thanks.

sch911 wrote:
Charge air heater grid cycling on/off with a cold engine?

THIS ^^^^^^

ISC is a Cummins Diesel
Cummins uses 'grid heaters' vs 'glow plugs'

Voltage WILL fluctuate from 14V to 12V when ambient air temps drop below 59*F
They will continue to cycle on/off (up to 30 seconds) until intake manifold temp goes above 59*F---even with engine running

Each grid heater pulls close to 95A...thats 2300W
Just one of the reasons for dual batteries and high amp alternators

You didn't mention what type of coach you have. I just finished changing the alternator on my ISC. My problem was that the "Duvac" wire had broken off totally due to corrosion. However, in order to fix the problem, I had to remove the alternator and it was in very bad shape overall so replace it. Point is, the Duvac wire is critical to overall operation. This is a smaller, third wire on the back, in addition to the two bigger wires.

Charge air heater grid cycling on/off with a cold engine?