Ideas on problems starting?
Lead Driver
Joined: Nov 2013
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I'm not 100% convinced. If the starter relay base was not fully grounded, that would reduce the current flow to the relay coil. That would reduce the clamping force on the main contacts feeding the starter and cause extra resistance. Under the heavy current flow of the starter, even miniscule amounts of resistance would have readily shown up in the voltage drop test of the positive side of the starter circuit.
Or has it been a while since you did the complete voltage drop test from end to end?
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Elder User
Joined: Aug 2009
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It's .2 milivolts. The confusion on my part was that I turned the dial too far on the dvm and was reading a different unit.....
im not convinced either, the fender is bolted to the firewall which is grounded....I dunno, but it seemed like a problem at the time.
maybe the chassis ground helped too, I'm embarrassed to take a picture of it cause it looks like medusas head with 2 gauge ground wires going everywhere.... one of them seemed to make a difference.
and yes, it's been a week or so since I did voltage drop testing on the entire circuit, I was going through tonight and starting a little more methodically, battery to chassis, battery to block, battery to body, battery to solenoid etc....that's when I noticed the difference . I didn't get much testing done after that, I didn't even get from battery to starter yet, I was hoping the new one showed up and I was going to replace it....
im not convinced either, the fender is bolted to the firewall which is grounded....I dunno, but it seemed like a problem at the time.
maybe the chassis ground helped too, I'm embarrassed to take a picture of it cause it looks like medusas head with 2 gauge ground wires going everywhere.... one of them seemed to make a difference.
and yes, it's been a week or so since I did voltage drop testing on the entire circuit, I was going through tonight and starting a little more methodically, battery to chassis, battery to block, battery to body, battery to solenoid etc....that's when I noticed the difference . I didn't get much testing done after that, I didn't even get from battery to starter yet, I was hoping the new one showed up and I was going to replace it....
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Elder User
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Hold that thought.. I had sort of a slow crank this morning. Definitely faster than slow, slower than fast. I'll get into testing some more today.
my plan today is to curse the mail for not delivering my starter, and do all this drop testing again, methodically.
my plan today is to curse the mail for not delivering my starter, and do all this drop testing again, methodically.
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Elder User
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This is what my dvm is set to so there is no mistaking. I did my grounding voltage drop testing, fully charged battery, engine off, key off. This is the end all be all for voltage testing on the negative side, if I still have problems, I'm ruling it out once and for all!
battery negative terminal to block .1-.2
block to ear of solenoid .1
starter to block .0
starter to chassis (new this morning) .1
starter to ear of solenoid .0
starter to negative side of battery .1
firewall ground stud to negative side of the battery .0
i added ground wire from starter bolt to chassis after I found the negative side of the battery to a bolt on the starter to be .4, I only had 4" of wire left over so I went straight over to the frame and ground down a nice spot.
battery negative terminal to block .1-.2
block to ear of solenoid .1
starter to block .0
starter to chassis (new this morning) .1
starter to ear of solenoid .0
starter to negative side of battery .1
firewall ground stud to negative side of the battery .0
i added ground wire from starter bolt to chassis after I found the negative side of the battery to a bolt on the starter to be .4, I only had 4" of wire left over so I went straight over to the frame and ground down a nice spot.
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Elder User
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Now, I wanted to test the wire going from the ignition to the solenoid. I unhooked it attached a meter lead to it and to the negative side of the battery, on a 20 scale,I turned the key over 3 times
first time initial 10.96 to 12.39
second time 10.81 to 12.38
third time 11.91 to 12.36
notice my 2 numbers, as fast as my dvm could record the first number was basically the initial hit of voltage and a millisecond later recorded that higher number. I had to record it with my camera to catch it.
just for fun, I repeated the first test without depressing the clutch, that time I recorded 3 "sweeps" like above from .26-.30. Again that was done on a 20 volt scale.
first time initial 10.96 to 12.39
second time 10.81 to 12.38
third time 11.91 to 12.36
notice my 2 numbers, as fast as my dvm could record the first number was basically the initial hit of voltage and a millisecond later recorded that higher number. I had to record it with my camera to catch it.
just for fun, I repeated the first test without depressing the clutch, that time I recorded 3 "sweeps" like above from .26-.30. Again that was done on a 20 volt scale.
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Elder User
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I next disconnected the bottom lead wire to starter on the solenoid, and put the other lead on the battery negative terminal. I didn't want the truck to start, I just wanted to see if all voltage was passing through the solenoid.
12.47
12.89
12.47
12.89
12.42
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Elder User
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Next I put my dvm back on 200m scale, connected one lead to the bottom solenoid stud to starter(starter lead still disconnected) and the positive lead to positive terminal connection on battery.
3 tests
5.1 to 4.7
6.7 to 4.7
6.0 to 4.6
3 tests
5.1 to 4.7
6.7 to 4.7
6.0 to 4.6
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Elder User
Joined: Aug 2009
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That is all the testing I have time for right now before work. Hopefully that shows something. If there are any questions or concerns please let me know. Also like to note, this is normally the time the truck has no problem starting, I.e. Cold engine etc. I would like to test again after a drive when the engine is warm and seems to be more problematic, such as when I park it at the gas station. Maybe I'll be able to do that on the way home and it may show diminished performance as starter gets warm, compression is up, cables and connections get warm. I'm also going to try and warm it up, pop out number 1 spark plug, put in my compression tester, disable the coil lead and crank it over to get static compression.
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Elder User
Joined: Aug 2009
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Distributor cap adapter had a little more play than I liked, so I took it back off and bent down the retainer springs some more. No more wobble there.
warmed up the engine, shut it off, disabled the spark and plugged cylinder one in to the compression tester, I was getting around 150-155 psi.
warmed up the engine, shut it off, disabled the spark and plugged cylinder one in to the compression tester, I was getting around 150-155 psi.
Lead Driver
Joined: Nov 2013
Posts: 7,173
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Danger, Will Robinson, danger!
This test can give very misleading results because the circuit is unloaded. You have confirmed the starter relay is closing, but that's about it. Please see the section here with the damaged wire, with only a single strand intact. It's about one third of the way down:
https://www.ford-trucks.com/forums/1...w-starter.html
Now with a new starter relay, it's not super likely to be bad, but who knows, or maybe it got damaged fighting with your Chinese starter. Just be aware if the contacts were damaged by arcing, for example, you might still get enough current through when unloaded so a simple voltage test looks good. Try to spin the starter, though, and that arcing damage becomes a huge restriction that slows the starter. This will quickly show up in a loaded voltage drop test, but not if simply checking for voltage unloaded.
Post Fiend
Joined: Feb 2008
Posts: 5,831
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From: St Albert, Alberta
Danger, Will Robinson, danger!
Now with a new starter relay, it's not super likely to be bad, but who knows, or maybe it got damaged fighting with your Chinese starter. Just be aware if the contacts were damaged by arcing, for example, you might still get enough current through when unloaded so a simple voltage test looks good. Try to spin the starter, though, and that arcing damage becomes a huge restriction that slows the starter. This will quickly show up in a loaded voltage drop test, but not if simply checking for voltage unloaded.
Now with a new starter relay, it's not super likely to be bad, but who knows, or maybe it got damaged fighting with your Chinese starter. Just be aware if the contacts were damaged by arcing, for example, you might still get enough current through when unloaded so a simple voltage test looks good. Try to spin the starter, though, and that arcing damage becomes a huge restriction that slows the starter. This will quickly show up in a loaded voltage drop test, but not if simply checking for voltage unloaded.
This is a very real possibility. Your Voltage through the starter relay should be constant. But as noted previously due to the nature of the design of these units unless they have a significant load on them they may not make clean electrical contact.
Lead Driver
Joined: Nov 2013
Posts: 7,173
Likes: 1,173
I'm sensing you're making this way more complicated than it has to be. The voltage drop test I wrote is actually a hybrid of two tests, but the entire thing can be done in less than five minutes. Three meter lead setups, that's it. This tests the starter circuit loaded, which is very important.
If they pass, you don't have to do anything else for electrical testing. The problem is elsewhere. Passing all three tests indicates a marginal starter, internal engine binding, or too much ignition advance.
Shame you didn't live closer. This long distance diagnosis stuff can get very tricky.
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Elder User
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I just found out today my starter is delayed and will be here tomorrow. That would have been nice to know a little sooner!
yes, I am going overkill on the testing, maybe, but I don't want no "what ifs" the only what if I have now is testing maybe with a hot engine, where wires degradate and starter draws more current.
my gut tells me not to twist the distributor, and I see no reason to believe if any binding. It does however make a very strong argument about testing with the coil lead disconnected...
With the recurved distributor, I would see how it doesn't like lesser timing, and I do have the stock distributor I can always throw back in it and try to retard it, but it seems that would be against basically the cam and degrade performance. She runs like a scalded dog when it starts.....
And to make matters worse, I still can't seem to replicate it at any given time, with a hot engine today, I was able to still start fine with no slow crank multiple times.
I'll test tomorrow with new starter I guess. I'm dwindling down my options here....
yes, I am going overkill on the testing, maybe, but I don't want no "what ifs" the only what if I have now is testing maybe with a hot engine, where wires degradate and starter draws more current.
my gut tells me not to twist the distributor, and I see no reason to believe if any binding. It does however make a very strong argument about testing with the coil lead disconnected...
With the recurved distributor, I would see how it doesn't like lesser timing, and I do have the stock distributor I can always throw back in it and try to retard it, but it seems that would be against basically the cam and degrade performance. She runs like a scalded dog when it starts.....
And to make matters worse, I still can't seem to replicate it at any given time, with a hot engine today, I was able to still start fine with no slow crank multiple times.
I'll test tomorrow with new starter I guess. I'm dwindling down my options here....