It started getting cold in Pennsylvania. Yesterday was in the low 30's with a nasty windchill and this morning it was in the 20's. I have had my 2000 F-350 CC for about 3 months now and just recently replaced my GPR with the beefed up Stancor relay. I wanted to put it to the test and see if it would start the truck without it being plugged in. On a few of the other cold days it would take a little extra cranking to start and then the engine would surge (vroom...vroom) for a couple of seconds and then smooth out to its normal idle. Today it took a lot of extra cranking surged a little then stalled. Tried again, same result. I decided to plug it in and while it was warming I grabbed the multi meter and decided to test the glow plugs. I removed the 9 pin connector on each valve cover and tested each of the glow plugs. I wish I had the test board that I saw Danskool made with the 9 point harness because keeping the probe on each terminal while trying to balance my self dangling over the engine was a little interesting. At any rate all the glow plugs seemed to be in the acceptable range of resistance .5-2.0 ohms. After I figured the GP's were good I thought I would just put the meter on the battery to see how many volts they had. Both were right around 12.4v. (passenger battery new in 9/2011 according to the sticker. Driver side battery not sure of the date. Then I thought I would position the meter on the driver side battery so I could see it when cranking it. At this point the block heater was on for maybe 45min. I turned the key to the on position my GPR LED lit the volts dropped to around 11.3v I gave them time to heat up and then turned the key. The volts dropped steadily and the lowest reading I saw was in the 9's. I know that 10.5 is the magic number to stay above for the truck to start. It did start and surged for a couple of seconds and then began to idle normally. I checked the multi meter again and I could only get a 12.4 reading on the driver side battery. I went to the passenger side and had the same thing. Then after about 30 seconds I started to get a reading in the 14's like I would have expected when the alternator was charging. Then the same 14's on the driver side when I checked again. I would assume the second the alternator starts spinning it would provide that charge? I drove it around and got it up to temp ran an errand when I came out of the store it fired right up nice and strong. I was thinking my next step would be to stop at one of the local parts places and have them do the diagnostic on the alternator and the batteries to see if either are not performing correctly. Any other ideas or advice?

 

What weight oil is in your truck, and when was the last time it was changed?

 

I did an oil change on 10/2 probably 1100 miles ago. I used rotella 15w-40. I did consider using a synthetic like 5-40 for the winter but decided to stick with the standard oil instead.

 

That might be part of your issues on cold start. I recently switched to synthetic and it cured my cold start/stumbling/romping issues, but I also had Lucas oil treatment in my system which I needed to get out.

 

Are you using the rotella T6? I tried sifting through a lot of the oil weight threads but it's tough because everyone has their own opinions and depending on how cold of a region you live in, it might affect your needs/preferences too.

 

Yes, I went with T6.

 

You did a few things good and there's a few things you should know.
When replacing batterys always replace them both.
When checking batterys you should see the same thing on both batterys, so you should only need to check one. The only way to check each is by disconnecting one at a time.
Just because your wait to start light shuts off doesn't mean you have to crank the engine, give them another 10-20 seconds before you crank.
I use amsoil and my truck loves it, not saying yours would but I do suggest synthetic.
Don't forget to run an additive in your fuel for the winter.
Your voltage readings jumped up on your batterys because after a couple of minutes your glow plug relay shut off... That draws a lot of power and is normal.
Make sure your fuel filter is new/ clean.
You've covered the more complicated things already, I hope this helps you out a little

 

The glow plugs are still going to draw on the system as cold as it was this am, for about a minute. I seem to remember on mine, voltage readings doing the same thing last winter when I had my AE hooked up for my cold start issue thread.

Edit: sorry John. I started writing that response about 20 minutes ago, then went and was looking for some AE graphs to back up my assertions. You handled it more completely than I did anyway.

 

You guys are absolutely right and it was a huge AH HA moment as I was reading it. The funny thing is I have the GPR LED on my console so I should have realized that. But I bet that is why it was down around 12 and then jumped up to charging volts. What kind of fuel additive would you recommend?

 

Diesel kleen can be had just about anywhere. The white bottle. Also keeping a bottle of diesel 911 in the truck isn't a bad idea just incase it does ever gell up

 

It has been bitter cold here in Western MD the past few days. Mid 20s to low 30s during the day, teens at night and 25-40 mph wind. You're probably fairly close to me.
It seems like you may have some weak batteries and/or alternator on your hands. You say your voltage dropped to 9 while cranking? It obviously still started, but could've contributed to the slow nature of the start.
I had a similar situation with my Excursion last year. Had to plug it in every night for it to start, otherwise it acted as if the batteries were too weak, and sometimes it would be completely dead. I ended up with a new alternator & problem solved. This was with 2 brand new Interstates installed prior to the problem arising.
I think your GP's are working just fine. Are you getting a lot of white smoke?

 

I'm a new diesel owner and have a question on this subject. Is it ok to plug in the block heater in when I get home from work at approx. 5:00 p.m. and leave it until 5 a.m. when I leave for work should I do this when the low is under 30 degrees? The truck starts just fine I would say in less than 5 sec. the lowest I have left it unplugged is 20 degrees and it still started just fine. if not at 30 what temp should I plug her in?

 

There is really no need to plug it in for that long cause for one its expansive on the electric bill and two it could wear out the block heater sooner. I use a timer that I plug into the wall and set it three hrs before I need to leave.

 

I don't know any reason why it would hurt to plug it in that long. Is it necessary....no. You could always put it on a timer though.

Some don't plug it in until lows reach the teens, but if yours starts up fine at 30 degrees why plug it up at all?

 

I want the truck to be around for a long time. It has very low miles for an 01 and would like to see 10 years or so out of it. should be around 200,000 and some change at that point and still going strong with routine maintenance. but I do have a timer and will program it for a few hours every morning when in the teens then. I will be carpooling, it may not be drove for 5 days every other week. should I take it for a drive in the middle of that 5 day period?