So I have experienced about every common problem that I have read about with the 7.3 diesel. My latest problem has got me stumped and I can't seem to find the answer. My truck has been running great besides the fact that the first morning start-up is always hard, despite the warm summer weather. My problem now is, my truck cranks very slow, sounds like it is straining to do so. Have two nearly new (2 years old in January) Genuine MotorCraft MAX 100 month batteries that test perfect, fully charged and supplying more cranking amps than what they say, tested by NAPA and Auto Zone. Recently replaced the fender mount Solenoid, pulled the starter thinking that was it for sure, however it to tested good. I had found a post where a guy had the exact same problem and after replacing almost everything to do with start up it turned out to be a seized AC compressor. Well my AC recently stopped blowing cold so I thought (hoped) that was the problem. I released the Serpentine Belt to find that mine spins freely as well as all other pulleys, Water Pump, Power Steering, ect... I of course am not able to turn the main crank but can't imagine that is the problem? I know I need to replace my oil cooler as I have oil mixing with my coolant (NO COOLANT MIXING WITH OIL ) but that's been going on for a while and I plan to fix it as soon as I have a couple free days. My truck is my livelihood and needed to run my business, I have been working on this a couple days now and losing money as I am crazy busy right now! HOPING SOMEONE HAS HAD THIS SAME PROBLEM AND CAN STEER ME IN THE RIGHT DIRECTION!
Totally STUMPED! JennsHusbum.

 

If your confident the batteries are good,cables are good,clean & tight,then I wouldnt rule out the starter being the culprit.you really get what you pay for on these starters.

 

I only feel confident because I was guaranteed that they were good by both Napa and Auto Zone on the batteries and Auto Zone tested the starter (out of the vehicle). It sure seems to be a lack of power issue though, after it cranks slowly a couple times it starts to click. Like I said, the batteries still look brand new, were manufactured in 01/13 and are Genuine Motor Craft that I purchased less than a year ago. I have read about bad cells, not sure if the tests the Auto Parts Stores do test for that? I did just order a new OEM positive cable as the one on there is aftermarket and about 5/8" diameter (copper strand measurement) which I can't find a terminal to fit.

 

Had the exact same problem. Pulled the starter, had it "bench tested" tested fine. Replaced batteries, replaced old cables, replaced solenoid, on fender, replaced solenoid on starter. Still same slow cranking in the morning or if I let sit more than 4 hours. Bit the bullet bought a new ford motorcraft starter. Now it spins faster than it ever has... problem is the bench testers these auto parts stores have cant reproduce the load it takes to turn over these diesels.

 

I asked them about that and they assured me that there test was good, they based it on the cost of the machines! lol I still had my doubts though. Hate to keep dumping dollars into it to find out it wasn't the problem. I guess on the positive side, I will have new parts that should last a while. I believe the starter is still the original, 14 years old and nearly 300,000 miles. Guess I'll try throwing a starter in tonight.

 

How were the batteries "tested" hand held plastic box? need a carbon pile tester, since these diesels pull 500-800 amps on start, that why bench testing a starter isn't the way to go, same as the batteries. I dont know if these parts guys have that kind of equipment, I can load test a battery to a thousand amps and nothing glows red in the box. Water mixing with the oil, that is very scary, cooler or not. You dont think you have hydrolic lock do ya? a bad oring on an injector or a bad injector dropping fuel into the cylinder. Can you get the motor to go around acouple turns need four full turns then if it spins faster you know what it is.

 

They were tested with a handheld unit that supposedly measures the amps as well. They both were producing more than 900 cranking amps. As far as the water and oil mixing, there is no water in my oil, only oil in my coolant! I read a post that this is a common problem as the factory seals on the oil cooler aren't very good, it also stated that other than going through some extra oil, it wouldn't harm the engine? I plan on addressing it very soon.

 

Take the starter to a auto electric shop that actually works on starters and rebuilds them on-site. Most AutoZone parts-slingers are useless when it comes to knowledge involving anything beyond what their cute little testing machines tell them. As for the oil in coolant, yeah, that's usually oil cooler seals. Not a particularly difficult job, but it's messy, and overall rather irritating.

 

Most auto parts stores have quickie testers and load testers for batteries. Did they take them in the back and put them on the tester that requires 10 mins to go through a full cycle? Even then not sure they are really loading them down much.

That said I had the slow, seems like low battery, start problem. After checking everything else I replaced the starter and haven't had a problem since.

 

I agree and think taking them to an electric shop that works on them is a great idea. My question is do they have something that is going to give the same type resistance as a flywheel? And no they did not take them in the back, the batteries were tested with little handheld units that they assured me are accurate, the starter was bench tested, placed and strapped into a machine, closed the lid, made some noise and apparently tested a couple different things? If I recall correctly there were 3 different PASS alerts that came onto the display. Sounds like I should just fork out the couple hundred for a new one and hope that fixes the problem!
Anyone else have that HUGE diameter positive cable? Is that a good thing? The wire that returns to the main from secondary battery on drivers side is just a 4 gage that was connected to the terminal bolt on the nut side. Like I mentioned I did order an OEM cable (THERE NOT CHEAP lol) as it looks to be one piece and there will be no question rather I am getting a good connection or not.

 

Maybe there's something in here you may have overlooked or maybe a new place to look
https://www.ford-trucks.com/forums/1...pr-or-cps.html

 

Thanks John2001.
I read that entire thread and hope I don't have to go through all of that. I really thought it was going to be something simple and that it was electrical. I am finding that it can be so much more. I think I will try the starter thing and hope it is just that simple, good chance I might have to take this one to a mechanic, something I never do as I can usually figure things out and fix them myself. Gone are the days when autos were so easy to work on.

 

Do everything I did in that thread. Nothing was hard or invasive at all, just required another person. And don't jump like I did when checking voltage to the starter...