Humvee Starter / Flexplate Teeth

[jake20]

That was in fact the ticket, got it all apart now.

Is it possible that my fork could be the issue? There is a rather large flat spot on one side of it compared to the other. I haven't noticed anything else that's too drastic yet.

 

[gringeltaube]

Is it possible that my fork could be the issue?

I don't think so; the solenoid core spring will absorb much more than that wear.

During operation, while engaged, the bendix pinion will rest against the stop collar, held there by the (spring-loaded) fork. Some wear at those fork knobs is inevitable. That's why we put some moly grease in that area, when reassembling.

 

[Mogman]

It looks symmetrical, that means you can install it the other way around and start with a virgin surface

 

[Mogman]

You may have to buy a new solenoid to get the seal, not a bad idea anyway.

 

[jake20]

It looks symmetrical, that means you can install it the other way around and start with a virgin surface

Was thinking the same thing actually I can't see any differences between either side.

I gave Mac Motors a call, they've got a pretty hard to beat price on DLA reman starters.

Haven't had luck with finding the seals either, and new solenoids don't seem to come with that main outer rubber seal either for some reason Going to try a few other vendors.

 

[Milcommoguy]

Was thinking the same thing actually I can't see any differences between either side.

I gave Mac Motors a call, they've got a pretty hard to beat price on DLA reman starters.

Haven't had luck with finding the seals either, and new solenoids don't seem to come with that main outer rubber seal either for some reason Going to try a few other vendors.

Whatever you do... Keep taking GREAT pictures.

Smile and say GREASE, CAMO

 

[Mogman]

Actually after thinking about it, I would replace that fork, it is just as important to pull the bendix back as it is to push it forward and any wear limits the overall travel.

 

[Mogman]

I was having problems finding the core nut tool, looks like they expect you to make one.

 

[jake20]

Whatever you do... Keep taking GREAT pictures.

Smile and say GREASE, CAMO

The amount of threads and questions I've seen with this:


So yep, I'll continue to take pictures for all the other souls that will inevitably venture onto this thread and others seeking the same help I did haha

 

[jake20]

I was having problems finding the core nut tool, looks like they expect you to make one.

Sounds like a 13MM socket wrapped in a rag being held by channel locks while sticking a hex key through it will remain my preferred method then

 

[Mogman]

Sounds like a 13MM socket wrapped in a rag being held by channel locks while sticking a hex key through it will remain my preferred method then

I ordered enough stock to make a ton of them, you need to be able to tighten that nut while holding the key, tight enough that it will not get loose.
I sent you a PM

 

[jake20]

Random thought, I feel like that worn fork surface could absolutely be the issue? Since the TM calls for a specific amount of endplay when the solenoid is engaged? Even though it looks like it fully engages when I bench test it, I feel like this could be causing partial engagement when under load axial load.

So theoretically, adjusting that endplay using the nut on the solenoid with the existing components could be a ghetto field fix? I’ve got a few new parts on order (bendix and fork, still trying to find the solenoid seal), so not that I plan on trying a questionable field fix in any case. Also have another starter coming in to get me running for now.

Anyway… just a random sleepy thought lol, off to get some zzzz

Pic of TM specs attached

 

[jake20]

Welp it looks like I’m unfortunately back to the drawing board. New starter came in and it’s still doin the same thing.

What I did after attempting the first start is rig my phone to record the action. On the bright side, it doesn’t look like it’s grinding against the edge of the teeth. What it does look like however is a meshing issue. It seems like it could be meshing too tight?

Start attempt at 22 seconds:

Going to do some more googling and see what I can come up with.

 

[Mogman]

The starter is engaging that is not the problem, something else is wrong, not enough juice or an engine problem.
Measure the voltage AT the starter (pos and neg) when trying to start.
IS that the same sound/symptom as before?

 

[Coug]

might be a stupid question, but are you sure the flex plate is installed the correct direction?
I don't know if it's possible to do that or not, but it might explain why the starter gear isn't fully engaging if the flex plate has the teeth offset from center and in the wrong direction..

I'd also agree with Mogman that the power just doesn't seem to be there, so measure for voltage drop to the starter (and measure voltage at batteries when cranking)
(if you aren't familiar with voltage drop test, put one multimeter lead on the positive post of the battery, and the other on the positive post of the starter. You are looking to see how many volts difference there are between the two points. If it's more than 1V in a 24V system you have a bad connection.

 

[Mogman]

Or possibly a bad starter but I would look at everything else really close

 

[Mogman]

That amount of engagement is perfectly normal, would be very difficult to install the flex plate backwards.

 

[Mogman]

The "shimming" is also not an issue, when there is an interference issue on a GM starter the bendix will tend to not retract.
There is a large solenoid shoving the bendix into the flex plate but only a spring pulling it back, that is what gives the awful screeching on an improperly shimmed GM starter as/after the engine starts, the bendix stays engaged after the key is released until the engine gets up enough speed to force it out, you do not want to be "that guy" at a car show, heard it a hundred times at least

 

[jake20]

It is in fact the same sound / symptom. I did just check the voltage drop from positive battery to positive starter lead, 0.00

Meanwhile positive battery to negative starter yields high 25v as expected.

The only variable that I changed recently was my repair of the thick cable coming from the engine harness to the starter positive (the one I’m holding in the attached pic). It’s not the best solder job like I said before, but from my understanding, that cable isn’t the one providing the bulk of the start current? I’ll try to get large crimp connectors instead and go that route. That’s the only electrical related thing that comes to mind at the moment.

I’ll try again shortly and measure the voltage at the starter while cranking.

The shimming example and the fact that it does engage and not grind the edges does make sense, so lemme chase some electrical gremlins and see what I can come up with.

 

[Mogman]

The last time it ran,,, was there anything unusual about the way it ran or when it was shut off? I would say 25V at the starter would be pretty good, in fact maybe too good like the starter is not loaded as you would expect, of course as Coug pointed out do a voltage drop on the negative side anyway.
That lead is to the alt. output, not likely the problem.