Ya damn autocorrect. Sometimes tech is not as smart as a blue-haired English teacher. Does not help much either when the poster was not wearing his reading glasses either. lol

 

Ok actual diagram posted this time DOH.

 

Well, it looks like somebody spent too long typing, as the previous post explained that when the key is held to start, the dwell is adjusted for a better spark, versus increasing the coil input voltage.

 

PFFT , no worries we have all been guilty of that lol.

 

Changing the dwell is going to change the timing, that is just a play on words. Increasing the dwell time is going to delay or retard the timing. What does this? The white wire going into the module.

And the voltage is increased during cranking, if you look at the diagram I posted, that is done by the wiring in the ignition switch, nothing to do with the module.

 

Hey guys, I think we're getting seriously sidetracked here. While all these details are interesting, we don't really need to know such specifics to troubleshoot a slow starter.

Remember, the starter system worked fine the day it rolled off the assembly line, and then for many years after that, under all conditions, be it hot, cold, etc. All we need to do is return the truck to this configuration, or a reasonable facsimile thereof, and we should regain proper starter operation.

Think of the starter system as two kids on a see-saw:

One side is the supply. This includes the battery condition, state of charge, good cables, clean connections, strong starter motor, etc. These factors (and others) influence how much oomph the starter can deliver to spin the crankshaft.

The other side of the see-saw is the demand. Lower compression, such as when the engine is cold, reduces the load which the starter system must overcome. As an engine warms, compression improves, so a little more oomph is needed to get it spinning again after a brief stop. Let a warm engine sit for half an hour or so? With no cooling, piston rings may expand too much and cause excess drag, which increases the demand imposed on the starter system. Conversely, if you flood the engine (warm or cold), oil is washed from the cylinder walls, compression decreases, and less load is imposed on the starter system. And before Dave chimes in, too much ignition advance also increases the load imposed on the starter system, but fortunately I know a five second trick to remove that factor during troubleshooting. More on that later.

So keep thinking of Supply and Demand, our conveniently named kids on the see-saw. We want to feed a steady diet of little chocolate donuts and whipped cream to Supply. Demand? Let him eat nothing but celery sticks. When Supply exceeds Demand, all is well. The other way around? The starter speed bogs down, or doesn't turn at all.

Sounds really basic, but is easy to overlook. We have virtually no control over Demand, but we can make sure Supply is pleasingly plump. It's very important for Supply to have a healthy reserve over Demand under all conditions.

Back to that one Demand factor we can control: Ignition timing. For troubleshooting, just take it out of the equation completely. Pull and ground the center lead at the distributor cap. Voila, no excess demand from having to overcome too much timing advance. If no substantial increase in starter cranking speed, the ignition system wasn't at fault. You don't have to go down that road. Stop. Turn around. You don't need to track down a Duraspark module with the elusive chartreuse grommet, original equipment only on Lithuanian spec trucks built on Tuesdays during freak sunspot activity. They go for a hefty premium on eBay, but you don't need one. Your existing module is perfectly adequate.

That's the extent of what we can do with Demand. But we do have plenty we can do with Supply.

Heat, for example, can be a serious detriment to to the output of the starter motor. Electric motors just aren't happy when too hot. In many cases, the output returns to normal when cooler. Remember, underhood heat peaks about a half hour after shutdown. This is also when compression reaches max, due to thermal expansion of the piston rings. Starter output (Supply) decreases, while Demand increases. The see-saw is tipping the wrong way. Feed some brownies and Cool Whip to Supply, stat!

So here's where we do have control, on the supply side:

https://www.ford-trucks.com/forums/1...w-starter.html

This simple test checks the entire supply side of the equation. No disconnecting any wiring, other than the center lead at the distributor cap. No wire brushing any cable connections. No nothing, just finding the source of any Supply side problems, while simultaneously ruling out the one Demand factor over which we have control.

I can't believe how many guys are intimidated by this test because it seems like so much electrical mumbo-jumbo. If you can measure battery voltage with a meter, you can do this test. Five minutes is all it takes. See the end of post #1 for a quick recap of how to do the test. You don't have to really understand how, but dang it works. For example, I don't fully understand how my lungs transfer oxygen to my bloodstream, but am willing to accept that it does work and make full use of this on a regular basis.

Okay, off my soapbox for now. But for every new thread about a slow starter, here's how it should play out, three posts max:

#1) Hey guys, my starter sometimes runs slow, yada yada yada...

#2) Run this test...

#3) Thanks, that test was amazing. It took me straight to the fault in mere minutes, with no wasted time or money. I've renamed my first-born son in your honor!

 

You don't give it enough credit, it's good for more than starters. I've never used it on one anyhow, maybe someday, mine's in the parts pile atm. But have used it on tractor wiring a time or two. I think we have down right beautiful tangents when we help folks look for the magic pill. Sure, the op's no better off, but the rest of us have learned another thing or two lol.

 

The entire electrical system is based on low voltage high current DC, so it takes very little corrosion, or a loose connection, to cause trouble. If the charging system has high resistance alternator current output is reduced and the battery will tend to be undercharged, adding to the starter/starting misery. Doesn't help the lights, ignition or accessories any either.

 

He replaced most of the starting system already. While it still could be something there, I don't think a timing problem is getting seriously off track, it can cause the exact symptoms he is having. His problem is heat related, timing is one of the common causes of heat related starting problems. Not saying that is it and nothing else, but it is a top contender.

 

Dave, you'll have to forgive me for poking the bear, so to speak. OP hasn't been back for four days, while the rest of us fill up several pages debating how many angels can dance on the head of a pin. Can't blame the poor guy if he's gone elsewhere in search of an answer. Lots of interesting discussion, but precious little practical steps he can take to fix his truck.

I fully agree that too much ignition advance can cause the symptoms he has experienced, so you're not wrong to suggest it. So can many other things, too. It's super quick to rule out the ignition timing. as previously mentioned, duplicate the fault by letting the truck sit for half an hour after getting good and warm. If the slow cranking is now present, pull and ground the center lead at the distributor cap. And if cranking speed returns to normal, you've found the culprit. Can't get any simpler than that. It's an important preliminary step in a systematic troubleshooting approach.

Looking back at other posts by the OP, it looks like slow cranking has been an ongoing issue. LOTS of new parts have been installed, including a Chinese starter relay, a (Chinese?) starter, new cables, etc. There's a very good chance one or more of those parts is failing when hot, and coming back to life when cool. That's why I keep harping to run the voltage drop test. (Heck, I even modified it to include your suggestion to check the timing.) If the fault is active, that simple test will isolate the fault in minutes. No wrenches. No wire brushes. No parts catapult...

We good? No slight intended, just trying to help the poor OP stay on track.

 

Changing the dwell does not affect the timing in an electronic ignition this was one of the advantages of electronic ignition systems that could change the dwell without impacting ignition timing. This is not points where dwell is mechanical and fixed, and where changes to the dwell directly affect ignition timing just like how 4 6 and 8 cylinders motors ALL have different dwell settings with a points dist due to to the differing lobe profiles but use the SAME dwell with electronic ignition. A DS II module has no idea if it is driving a 4 banger 6 or an 8 or even a 12 for that matter and uses the same dwell for all.

To much dwell time will increase the load (amp draw) on the ignition system and may overheat the coil and cause it to fail eventually. By reducing the dwell time during start the DS II system can run the coil at a full 12V for a hotter spark with no concerns of overloading the coil or the ignition system. Also reducing dwell in a points dist ADVANCES the timing not exactly what you want to do for starting. Most electronic ignition and basically all HEI systems can adjust the dwell independently of ignition timing.

 

I learn things from these debates. If the original thread starter wants to jump in and ask a question or get us back on track, he certainly can. Like you said, he hasn't checked back in so I am not too worried about it. And you are certainly welcome to get us back on track and or give your 2 cents anytime.

 

OK I got around to running this test, seems something is amiss, here are the readings I got (I list 2 numbers for each scenario, the first is when I start cranking, the second is for just before I stop after the specified amount of time)

Step 4)Connect your voltmeter (+) lead to the battery (+) post

10.2 / 9.6

Step 5)Keep the voltmeter (+) lead on the battery (+) post. Move the (-) lead to the big electrical stud on the starter

1.25 / 0.8

Step 6)Keep the ignition disabled. Move the voltmeter (+) lead to the starter case. Move the voltmeter's (-) lead to the battery (-) post

3.5 / 2.4

 

Thank you, thank you, thank you for running the test!!!

Of the three results, the last one (2.4V drop under load between the starter case and the (-) battery post) is WAY out of limits.

The second one (0.8 v) on the positive side of the starter circuit isn't healthy, either. Remember, in both cases, you want as close to 0.00 as possible. That's not really practical, but 0.5V is possible.

The combination of those two reduces available power to the starter by almost as third. Remember the see-saw analogy? You want every possible advantage on the supply side of the equation, versus taking away a huge chunk.

The battery itself? 9.6V after 15 seconds of cranking is barely, barely adequate, depending what limit you want to use. (Some sources say 9.5, others say 10.0).

To continue testing, make sure to fully recharge the battery. Then concentrate on the negative side of the starter circuit, since it was the worst. Give the ground cables a good visual inspection for any signs of corrosion, loose crimps, etc. Try cranking the engine again, and the bad spot(s) should feel warm, and possibly hot. Be careful not to burn your hand.

If you don't find anything obvious, test the negative side of the starter circuit in segments by moving one of the meter leads. For example, leave the positive lead on the starter case, and move the negative lead to the flag terminal in the middle of the long ground cable, where it attaches to the frame. Crank the starter again for five seconds. If the reading UNDER LOAD is less than 0.5V, that portion of the circuit is good. Test the other half of the circuit by moving the negative lead to the negative battery post, and moving the positive lead to the same flag terminal in the middle. Crank the starter again for five seconds. If this value is above 0.5V, the fault is between those points. Remember, the higher the voltage drop, the worse the restriction. When you find a fault between two points, you can further isolate the exact location by moving the test leads closer together along the conductor.

Once you find and repair the fault in the negative side of the starter circuit, repeat the other two steps. After you remove one restriction, this increases current flow through the rest of the circuit. A marginal restriction elsewhere may have been masked by the huge restriction you just fixed, but if you don't repeat all three steps of the test, you may miss them.

Somewhere about now, somebody may suggest simply replacing all of the cables. This is a very spendy option, but it's your call. A conductor doesn't really wear out, unless it is severely corroded the whole way. If there is enough slack, I've had good results trimming a cable end and crimping on new terminals. Saves a lot of money that way, but you'd have to factor in any crimping tools required.

If you want to shotgun and replace the cables, don't forget to test them after installation. Some cheaper brands have marginally sized conductors that can't really carry the massive flow of the electrons in the starter circuit. "The part is new, so it must be good" goes the thinking, and before you know it, you replace a bunch of other perfectly good parts.