Background first, questions below. Thanks

This hasn't been a great summer for my Excursion. Early July we had the A/C pulley cook itself, and that may be related to my current troubles. Hubby replaced condensor, pulley, etc. All seemed well.

About 10 days later, I had some trouble getting it to start. This was after towing a horse to town (15 minute drive) and leaving it sit about an hour. Took several tries but eventually it did start. That was a Sunday, and I drove it all that week until Friday. That evening we drove to a friend's place for a party, and when we tried to leave several hours later, the truck would only crank. Seemed to be cranking well, but wouldn't turn over. Came back with my DashBoss a few days later and couldn't find anything particularly interesting, but I wasn't too sure which parameters I should be looking for. No DTCs

In the meantime, we were moving to a new house and it was just easier to make do with one vehicle than try to figure out the Excursion. Plus my mechanic was really ill, so we left it sitting there. Did try a couple of times to start it over the next several days, and then hooked up a battery charger.

After a total of 2 weeks, I had a tow truck meet me at my friends house to tow it to the new house (a new house with a shop!) and the driver asked me to try starting it. Not expecting much I turned the key and it fired right up. But, not being able to drive 2 vehicles home, and really not trusting the Excursion I had him haul it home anyway. Once home it fired up a couple of times, and then wouldn't start again. Left it sitting until our mechanic was well enough to come over and scan it with his SnapOn unit, but when he turned the key, it started up perfectly. Nothing out of the ordinary showed up with his scan so we decided I'd drive it until it failed again, which it did about a week later.
Hoping to get a scanner on it while it isn't starting, we left it parked to wait for mechanic, making sure batteries were charged. A few days later he stopped by and, lo and behold, it started like a champ.

So I started driving it again, with no issues for about a week, until yesterday. No start again. Today I dug out my DashBoss again, did some reading here on FTE about what to check for and started scanning. What immediately stands out is rpm while cranking - very low (35-61). Could be the starter is weak? Faulty A/C pulley slowing it down?
FICM main volts is good at 48.5, FICM logic volts do drop to 10.5. Battery voltage is just under 12 KOEO, dropped to 10.66-11.2 while cranking.

So - I think my next step is load testing batteries and I was hoping to find a file on that in the tech folder, or a dedicated thread to make sure I do this properly, but no luck so far.
I have a pair of Optima yellow tops, and a SOLAR battery tester BA5.

Do I need to disconnect batteries to test properly? Am I looking for cold cranking amps?
Off to try it now, hopefully I'll get some answers!

Also note: Excursion is equipped with PATS, and there is a remote start installed. Will also check A/C pulley.

 

Okay, assuming that I did that correctly, batteries are good according to the tester. I got two numbers, 550 and 1224. Plus a green light that they're good.

 

You will have to disconnect the batteries to test them. The passenger side usually goes first and they will balance themselves out. I've been looking at load testers on Amazon, will probably get one. Otherwise you will have to take them to an auto store to get them load tested. Here's a thread Mark worked hard on that may help. Checking the batteries is the first step. Youre ficm logic volts are low, but that may be because of the batteries.

Troubleshooting a No-Start condition - Ford Truck Enthusiasts Forums

 

PS: There is a recent post where a remote starter may be causing starting problems.

 

Disconnect one batteries terminals, test that battery. Reconnect terminals, repeat on other battery.

550 and 1224 would mean one hurt battery.

35 to 61 would be a very, very low cranking rpm, you need 150 for the PCM to engage the injectors. I'm guessing the rpm is the wrong parameter. If you can, video trying to start it.

 

Just for good measure, check the IPR data. IMHO, batteries don't quit one day and then charge themselves back up a few days later. I'm thinking you just ran them down trying to start it. But yeah, once they run down, it may sound like it's cranking OK, but if you're not getting at least 150 RPM, the computer won't let it start. Not like a gasser that can sometimes kick just barely turning over.

On the other hand, you can lose high oil pressure from any number of locations, and that would make it not start warm but start later when cold (cold oil is thicker and sometimes doesn't leak through a bad o-ring until it warms up). Owners with a bad o-ring are almost a daily post here.

You could also have a ground on your wiring harness that will cause intermittent no-starts. I had a truck that would do that. I'd get under the hood and slightly tug on the harness in a few places, get back in and it would start. Never tried to figure out which tug did it. There are posts somewhere here that talk about likely locations.

And, yes, the A/C clutch can be freezing up and dragging down your starter, making it hard to turn over, then running down your battery when you try.

 

Checking batteries is free (for most people anyway). IMO that is a very good starting point. I agree Doug .... batteries aren't going to fix themselves, but one battery can start the engine - unless it gets weak. Jack hit on a good possibility IMO, w/ a great suggestion (post a video).

I recently did a load test on my batteries, just because I do it as a preventative measure on a somewhat "loose" schedule.. My drivers side battery was at 12.6 volts when disconnected. It went to zero on the load test. I charged it and it read 13 volts, but again dropped to zero under a load. The passenger battery passed the load test. With the one bad battery, MAYBE an occasional start had been a little slow, but not very noticeable. The difference (improvement) was VERY noticeable w/ the new batteries,

 

Mark,

Carbon pile or ???


Edit - our layout sucks.

 

Carbon pile. I have the one you use on my Amazon watch list - just don't have the funds at the moment.

 

I actually think the carbon pile method is really good. It's on my spare money list.

The funny thing is, with a 6.0 you could fudge a carbon pile test just using one of our batteries at a time with the jumper.

400a/battery ca.

I just don't want to do that to a starter.

 

Mark, which one are you using now and whats on your wish list? Thanks.

 

Harbor freight sells their 500A carbon pile tester for $55. I will have to look up the one Jack uses unless he can post a link quickly.

 

Wow, nice price!

 

I believe this is the one Jack uses

 

So I went back and reread the posts. If I have this right, you have Jack's on your wish list and Jack has yours on his. LOL. So which is better, seems one load tests and the other is a conductivety tester. Note, I didnt do very well in my electrical engineering classes.