Effects of high amp alternators on the GP system

Tom S · Oct 21, 2011

Nick have you ohmed out all of your glowplugs to make sure you do not have a couple non-working ones?

Peroni · Oct 22, 2011

Tom S said:
Nick have you ohmed out all of your glowplugs to make sure you do not have a couple non-working ones?

Yes I have. This past April when I converted my vc gaskets to the SD style I pulled all the glow plugs to check, they had about 30K on them and went through one very cold winter with this cycling business going on. All looked and tested fine. For giggles I put in a spare set of brand new plugs after having tested them first with no change in operation.

I'm still left wondering why Ford felt a need to change the gp cycle with TDE1. If I plug in my NAW4 pcm all is good. I'm wondering how IH handles this with their programming?

At this point, if I can ever get hold of my tuner, I'm going to ask him to adjust the gp duty cycle.

Tom S · Oct 22, 2011

I was thinking this was in there to protect the glow plugs or perhaps even more likely the glowplug wiring as by now they had to know about the weakness there. I suspect the glowplug system is more likely to overheat when you have a few of them out to where they get higher voltage as the alternator is not sucked down as much. I am going to see if I can get some screen shots of the tuning for the glowplugs on the two different codes. TDE1 also runs the glow plugs a lot less from what I remember.

cowboy_dan · Oct 25, 2011

I've been following this for a while. Just thought I'd mention that I'm pretty sure my alternator died on the way in to work this morning. Battery voltage is low on the gauge, dash lights are quite as bright as they normally are. BATT light is not on. Key off batt is about 12.3V. Engine running batt is about 11.9V or so, and dropping. Current clamp on the pass side neg cable shows about 8 amps current draw with engine running.

5000+ miles in the last 4-5 weeks, and it crapped out the day I'm supposed to look at a place to live after work. When it rains...

Derek@Vision Diesel · Oct 25, 2011

Do you have the files saved on your computer? Ill adjust the DC for you if you'd like, its fairly simple

cowboy_dan · Oct 25, 2011

Alternator is replaced.
I let it run at high idle (approx 1200-1300RPM) while putting tools away.
Once I got done, the alternator was putting out 14.51V at 30A with the engine at normal idle. At high idle the voltage was the same, but current was in the 45-50A range.

Tom S · Oct 25, 2011

I am curious to see what the average stock sized alternator puts out when the glowplugs are on. I would bet 11v or so.

Derek@Vision Diesel · Oct 25, 2011

So a failing alternator is probably going to charge around 13 at an idle???

PsRumors · Oct 25, 2011

Tom S said:
I am curious to see what the average stock sized alternator puts out when the glowplugs are on. I would bet 11v or so.

Mine is 10.8

cowboy_dan · Oct 26, 2011

Strokeorcroak said:
So a failing alternator is probably going to charge around 13 at an idle???

Mine wasn't charging at all, at any engine speed. Voltage went down when running, not up.

cowboy_dan · Oct 26, 2011

Tom S said:
I am curious to see what the average stock sized alternator puts out when the glowplugs are on. I would bet 11v or so.

I'll try to find out this evening.

cowboy_dan · Oct 27, 2011

Ok, just after starting the engine, the voltage was 12.26V, and the alternator was putting out 84-85A.
Once the GP kicked off, the voltage went to 14.55V and current was about 40-45A and dropping.

No idea what the GP are consuming for current, my clamp meter won't fit around the + lead on the battery. I need to wiggle the harness up by the GPR enough to get the clamp on it one of these days.