Starter solenoid issues

[dhaumann69166]

I was wondering if anyone else has had an issue with the starter solenoid not working when the engine is warm? It starts every time when it’s cool but once the engine hits 120° or so it won’t start again. I have power everywhere I should and when I turn the ignition I get 24v to the started solenoid but nothing happens. Grounds have been checked and cleaned and I have the aftermarket ground harness installed. I have bypassed the control box just to make sure that wasn’t the issue and got the same results. Any help would be appreciated!

 

[Action]

Did you read my reply on that 17 year old post on the other site?

Why does hitting my truck's starter with a hammer make it work again? - General Questions - Straight Dope Message Board

 

[Retiredwarhorses]

It cranks or won’t crank at 120 degrees?

 

[dhaumann69166]

It cranks or won’t crank at 120 degrees?

Won’t crank above 120° or so. Last week it was over 100° outside and the black Humvee was sitting in the sun all afternoon and wouldn’t start when I went to leave. Trailered it home and still wouldn’t start. Walked out about 11pm when the temp was down around 80° and it fired right up.
This morning it started fine. Shut it off and it started back up fine. Let it run about 3 minutes and shut it off and fired right back up. Let it run till the temp gauge started climbing toward operating temp and shut it off. No start when I tried to immediately restart it. Crawled underneath with a meter and confirmed that I was getting power to the solenoid when the ignition was turned. Don’t want to spend the money on a new one if possible.

 

[Retiredwarhorses]

Sounds like your solenoid is bad…you own a hmmwv, get used to spending money.
HMMWV=High maintenance money wasting vehicle

 

[frank8003]

What is the current draw of starter on startup?
It is listed. use an amp meter.
What is the current draw of starter on startup?
Solenoid is weak usually
Pull it and put NEW in there.
This had been a very common problem going way back to even before I was born.

 

[Action]

Carry a bottle of water and pour some on the GPC or TSU when it wont start. That may get you home if need be.

 

[TOBASH]

Guys. It’s is either a bad starter solenoid getting heat soaked or a bad starter that is getting heat soaked.

 

[Milcommoguy]

Guys. It’s is either a bad starter solenoid getting heat soaked or a bad starter that is getting heat soaked.

ACTION say's soak the GPC / TSU. TOBASH say's it's heat soaked.

Give the rig a good hosing down, CAMO

Love ya guy's. OP stated had voltage to the solenoid control lead??? OK.......... Check the solenoid resistance. Should be very low value ohms <12 +/-.

Listen up, here's how it works. Little "CLICK followed by a bigger "CLUNK" with a BIG electric motor turning over the engine. Happens REAL fast. No "CLICK" no workie.

Check it over real good. Simple circuit and could have open / loose connection inside solenoid or ?? bad luck times ahead.

The old screw driver to the "HOT STUD" connected over the the "Control / start" contact and NOT to the "Motor stud" trick. It will test AND scare the poop out of first timers LOL. That's my free guess.

 

[TOBASH]

I have less experience with HMMWV’s than Cam, but I have huge experience with heat soaked starters.

Heat shield +/- new or rebuilt starter should fix. Only problem with that is a PCB issue where the glow plug sensor is somehow farked and preventing start when warm.

Heat soak is not uncommon with GM starters.

 

[Milcommoguy]

I have less experience with HMMWV’s than Cam, but I have huge experience with heat soaked starters.

Heat shield +/- new or rebuilt starter should fix. Only problem with that is a PCB issue where the glow plug sensor is somehow farked and preventing start when warm.

Heat soak is not uncommon with GM starters.

Yes ... it could be heat related. Could be this or that too. What's interesting is with many of the symptoms, observations, real testing done to "zero in" on problems... turns into a guessing game AND that OK and fun to play. If "ON SITE" most here could get right to it. As more data is received from the OP, it will be interesting to see just what the problem is. From that we all learn of another HumV back on the road.

So here in the Steel Soldier Shop... I was just poking a little fun as we all go to the next round of "FIX THAT HumV" I gave my guess so I'am out.

Think I will give the Humv a bath, soaking in the 115 degree Mojave Desert. CAMO

 

[Milcommoguy]

Yes ... it could be heat related. Could be this or that too. What's interesting is with many of the symptoms, observations, real testing done to "zero in" on problems... turns into a guessing game AND that OK and fun to play. If "ON SITE" most here could get right to it. As more data is received from the OP, it will be interesting to see just what the problem is. From that we all learn of another HumV back on the road.

So here in the Steel Soldier Shop... I was just poking a little fun as we all go to the next round of "FIX THAT HumV" I gave my guess so I'am out.

Think I will give the Humv a bath, soaking in the 115 degree Mojave Desert. CAMO

 

[Mullaney]

Yes ... it could be heat related. Could be this or that too. What's interesting is with many of the symptoms, observations, real testing done to "zero in" on problems... turns into a guessing game AND that OK and fun to play. If "ON SITE" most here could get right to it. As more data is received from the OP, it will be interesting to see just what the problem is. From that we all learn of another HumV back on the road.

So here in the Steel Soldier Shop... I was just poking a little fun as we all go to the next round of "FIX THAT HumV" I gave my guess so I'am out.

Think I will give the Humv a bath, soaking in the 115 degree Mojave Desert. CAMO

.
At 29 Palms they always told everybody that it was "a dry heat".
After about a week or so, when you come back and hit the showers - the funk that comes off of you...

 

[Glider]

Just throwing this out, but I thought my starter was going bad. Sometimes just wouldn't work, sometimes would work normal. Turns out the one of the switches in shift/parking brake safety is getting old. I have to pull my t case shifter slightly towards driver side(or wiggle around a little) to get a good connection. I haven't fixed yet because it is kind of antitheft aid. Might be worth a shot. When mine isn't working it doesn't make a sound when start command is given.

 

[papakb]

Gentlemen, if there's 24v to the starter solenoid then the GPC or TSU is doing it's job and chances are the solenoid itself is the issue. If your at home spray it with your hose to cool it down and if it starts then you'll know what you need to replace. Replacing it you definitely want to disconnect the batteries first and then get ready to do some heavy lifting. That monstrosity is a bugger and because of where it is in the frame it's a one handed job.

Getting the solenoid off isn't much fun either. There is a good writeup in the manual on how to disassemble it.

 

[dhaumann69166]

Well so far I have it fixed. I took the starter off and tore the solenoid down and cleaned and greased everything inside. It had a very small amount of corrosion in there that I cleaned off with a wire brush. Put the starter back on (nightmare project by yourself that ended up with the ground post stuck in my arm at one point) and still no go. The very first response I got to my question was hit it with a hammer...so I did. Hit it hard about three times and it fired right up. Shut it off and wouldn’t start again. Crawled underneath and whacked it a couple more times and it fired right up. Repeated this process 4 times in a row until the 5th time it started without being assaulted. So far it has started every time since. Guessing it just took a minute to get all the grease worked in to where it was grabbing. Much thanks to Action for the advice and sorry I ignored you twice. Hopefully this fix will keep the old rig going a while.

 

[Action]

The hammer is usually just a temporary fix. It can knock rust loose.

 

[Mullaney]

Well so far I have it fixed. I took the starter off and tore the solenoid down and cleaned and greased everything inside. It had a very small amount of corrosion in there that I cleaned off with a wire brush. Put the starter back on (nightmare project by yourself that ended up with the ground post stuck in my arm at one point) and still no go. The very first response I got to my question was hit it with a hammer...so I did. Hit it hard about three times and it fired right up. Shut it off and wouldn’t start again. Crawled underneath and whacked it a couple more times and it fired right up. Repeated this process 4 times in a row until the 5th time it started without being assaulted. So far it has started every time since. Guessing it just took a minute to get all the grease worked in to where it was grabbing. Much thanks to Action for the advice and sorry I ignored you twice. Hopefully this fix will keep the old rig going a while.

.
Could also be worn bearings in the starter motor.
Or there might be a dead spot on the big chunk of metal "rotor" that rotates inside the "fields".

If the hammer solved it, that will be temporary

Those bushings are pretty thin, and when they wear , they have to be replaced before you wear out the really expensive parts.

 

[Milcommoguy]

The "wack a mole starter" Not wishing any bad luck here,

Coffee and a donut... (doesn't have to be Starbucks) it will come back to bite ya in the butt... when you most need to get somewhere. Having it out on the bench was the perfect time to give it a GOOD check up or better refresh all the wear parts, pinion, brushes, bearings, contacts, etc. and bench check a couple of 30+ times without the hammer. Going to all that trouble pulling it, one could cancel the membership at the gym.

Now that its back on, check the mounting bolts for proper torque. Here some notes to read for next time> https://www.flashoffroad.com/electrical/Starter/starter.htm

Keep that hammer handy, CAMO

 

[Glider]

I was told by my local starter shop none of the repair parts were available for starters or alternators. Do you guys know of a source? I have a brand new starter that I had purchased only to realize later it was a loose safety switch. If I could find the rebuild parts I would go that route when necessary and sale the new starter.