I have a 1996 F Super Duty with 7.3L and 205K miles. I've been experiencing longer start times with white smoke on startup and if I don't start it for a few days the batteries don't have enough juice to get it started. Here's some info on what I've done

• Batteries are new and I've taken them back for testing and they are good according to the test.
• I've checked for a parasitic draw and it's within limits, no current draw down while sitting.
• Alternator checks good with 14+ volts on batteries after startup, however, the battery light flashes on and off on the instrument panel, intermittent.
• I've felt the alternator and GP relay in the cold morning and they are not warm.
• Fuel injectors and glow plugs replaced at 189K (motorcraft GPs)
• Fuel filter has been replaced but I haven't checked the fuel pressure, she runs great when started.
• I've checked the glow plugs at the connectors (1.4 ohms) and the glow plug relay seems to be working fine. I do get only 9 volts on the glow plug terminal of the relay with the key on.
• Recently I had a new fuel pump put on and new hard fuel lines from the pump/fuel bowl to the quick connectors on the right side of the engine. this wasn't a problem with starting until 90 day's later.

Anway, I'm just tired of keeping this thing on charge all the time so I can ensure startup, it's a farm truck so it doesn't get driven daily. It gets started more to get it moved out of the way for something else, haha. What am I missing here? It's becoming a PITA!

 

What is your parasitic draw? You want around 50mA. If you have a radio with memory there will be some draw, I think the PCM also has a keep alive memory in these.

Are you batteries 850CCA? Ever checked voltage between them when the truck is running for drop?

Random alt light is probably the stator plug being loose.

 

Thanks for the info and I'll check those things tomorrow and get back to you.

 

I'm with Hit Man X that this sounds like a wiring problem resulting in intermittent poor charging, and I would add the alternator to the list of suspects. These trucks don't require much electrical power to run once started, and can go quite a while just on the batteries. But the batteries might not be getting charged up sufficiently to spin the starter briskly, and the glow plugs draw considerable power before cranking. If the batteries aren't getting topped back up, you won't know it until the next start.

My alternator failed with the initial symptoms being intermittent voltage dropouts down to battery voltage that increased and became permanent. I also had a sterndrive boat where the ring terminal on the red alternator cable cracked. Stayed in place so not identified with visual inspection, but same pattern of intermittent dropouts becoming permanent. Shop found it when they tugged on the cable.

I'm not sure if it's the stator plug, but the wiring just off the plug on top of the alternator often gets bent by tools and people laying on the alternator. Eventually that can break wires. And a good check of all main cables and connections for corrosion may be warranted. Batteries and alternator may be good, but not able to push enough amps through all the crud.

 

Reminds me of my dead V90 Volvo. Alt put out 14V. Battery saw 12.9 area. Huge drop. Turned out just crap on the alternator lug and stud. Cleaned. Dropped to 0.1V drop from alt to batt. Worked for me.

 

@Hit Man X @paddler excellent thoughts and I apologize for the delay as work has taken priority and the truck isn't a daily driver. I hope to do some troubleshooting by the end of the week. Once I get some answers I'll let you know, stay tuned...,
Thanks much!

 

Ground points...

Had the same issue ongoing for quite a while went through all the same steps. Finally, I traced all battery ground cables and straps (engine to frame, engine to firewall etc.) and disconnected each cable wire brushed them, and the connection points, same with the bolts/nuts. Reconnected with dielectric grease. Problems solved.

 

Another thing to check is starter condition.
the starter should spin FAST.
a weak or bad starter will cause the issues you are having trying to cold start

 

Yeah, that's a point I missed. If the only symptom of "dead or low batteries" is slow cranking and not something like low voltage on a multimeter, time on charger to full charge, dim headlights, etc., then the list of possible causes for slow cranking includes:

• Batteries actually are low, from any of the causes already discussed
• High resistance connections in the high-current starter circuit- corroded cables, connectors, grounds (starter not getting full amperage and voltage)
• Starter is weak, and even with full voltage and current available, can't turn over fast enough for reliable start.

I jumped to the conclusion that OP already had a differential diagnosis that pretty clearly indicated low batteries. But generalized "slow cranking" isn't enough to differentiate between the possible problems. Diagnosis comes down to what do I REALLY know (symptom or instrument reading), what does that tell me, and what DOESN'T that tell me.

Note that slow cranking gives more time for heat of compression to dissipate, possibly resulting in not enough heat to reliably ignite fuel. If glow plugs also aren't hot (failed glow plugs, harness issues, high-resistance connections/wires, low batter voltage/current), you're going to have starting problems, and lots of white smoke which is unignited fuel vapor.

 

a bad/weak starter AND glow plugs will draw so much power out of brand new batteries the truck will not start.
i had the same issue with my 02. i was getting ready to do a top end on the engine when the starter finally quit. never thought of it because it was only an issue starting.
put a new starter and positive cable in 60,000 miles ago. and forgot all about redoing the top end because the problem all along was nothing more than a tired starter.

 

Very expensive but cured my problelms.

https://www.custombatterycables.com/...troke-diesels/

 

I keep forgetting to order my positive cables from there. Already did my negatives.

 

Not only is it a nice set of cables it force's you to clean all the connections up as your installing the kit.

 

Thanks everyone, I'm finally back in the saddle here, was wiped out with the covid crap for 3 weeks! Here's where I'm at now..,

Fully charged the batteries - truck started right up and runs great.
Batteries are both about a year old and are 850 CCA
Did a parasitic draw test this morning and I'm at 25 ma, been checking it every few hours to ensure that's not my issue, I'm probably going to rule that out.
I will check all grounding points from the batteries - Great idea!
I'll install a new pigtail on the alternator, battery light on cluster did flash when I moved it around a bit a few weeks ago. No battery light at all today when I'm fully charged.

I'm leaning toward both the alternator or ground wires being suspect here, more to come.

 

Hey Hit Man X! Update on where I'm at...,

• Checked the parasitic draw with the drivers side battery disconnected (positive and negative) disconnected.
• Checked the draw by inserting the multi-meter between the negative post and and connector to ground - 25ma - good!
• Reconnected the drivers side battery and the current jumped to 99ma and fluctuated between 70-99ma, never really settled down for about 10 minutes then stood at 90ma. Mm?

What do you think? Maybe a ground issue on the driver's side battery? I did pull every fuse while it was at 90ma and no change.
Also, the batteries will hold good enough to start for several days but after 5 day's she's a no start.

Thanks!