Starter not engaging and cranking the engine - need help please!

[JKlein]

I need help with my 1996 K3500 GMC 202K miles & 5 speed. Problem: Starter fails to turn the engine over. Here is the breakdown of what happened and what I have done so far:
- The truck right now is not a daily driver as I am waiting to install either remain or new injectors & glow plugs.
- I last drove it on Saturday May 23rd with no issues at all. About a 1 ½ hour each way trip. Once I arrived it sat for about 5 hours and then I loaded up and drove home. No problems.
- In all the time I have had the truck it has never failed to start or in this case the starter has never failed to engage (turn the engine over) and start the truck.
- On Sunday, May 31st I went to start it and after the start engine light cycled on & off as usual (I can also hear the lift pump working) I depressed the clutch and turned the key to crank the truck and nothing! I tried again same result. I only had limited time so I checked the batteries with cables removed and they were around 12.6 volts each. I cleaned the terminals and reinstalled the batteries. No cranking of the engine!
- I went under the truck and found the starter. Not having much time at all I lightly tapped the starter and the starter solenoid with the handle of a long flat blade screwdriver. (That has worked for me in the past on other vehicles) I got in the truck and the first turn of the key and nothing. Then I tried a few more times and after a few tries it clicked and cranked wright up. I drove around the neighborhood and it ran great, shifted fine etc. Parked it and let it run for a bit. Then shut it down.
- So just yesterday, June 7th, I went out to crank it up and again, after the cycle of the wait to start light was done, when the key is turned nothing. The radio clock and the “Water in fuel” lights go off as you turn the key to crank – but no starter engagement.
- I had a bit more time so I decided to get the passenger side up on a jack stand to get a better look at the starter. Thinking I might have a loose cable or wire. Well I could not find a good angle to actually see the front of the starter solenoid where I could get a good look. I managed to get my hand up to the front of the solenoid and the cables/wires seemed tight. I wiggled them some and tried to start. No cranking/turning over of the engine. I tried again some light hitting on the starter and the solenoid and then tried to crank it and nothing.
I am at a loss as to what to try next. It is not a fail to start – it is a fail to crank. The starter has always (in the time I have owned it) cranked fast and hard and never once acted like it would not crank or turn the engine over.
Any thoughts? Ideas to try?

All help is appreciated. I need to get it started so I can pull it inside to start working on it……
Thank you!

~GOD BLESS~

John

[DmaxMaverick]

Simple to diagnose. During a failed start attempt, have a helper sit behind the wheel and turn the key while you use a VOM or test light (take proper safety precautions to prevent vehicle movement) on the S pole of the solenoid (small pole). If it has power and the solenoid doesn't engage, either it is bad, or is getting too little power (batteries, terminals, cables, grounds, etc.). If it doesn't have power, suspect the ignition switch or clutch disconnect. You can also watch the voltage at the batteries while the key is turned to start. If there is no change, or the voltage increases (accessories disabled), the solenoid isn't getting power.

In any case, a solenoid failure at any time wouldn't be uncommon.

[JKlein]

I can not get enough time to run the tests until this weekend - but thank you very much for the helpful tips on what to check. I got the truck with about 196K miles and do not know how old the starter and the solenoid is so I wil test to see.

Question - Can you please tell me about how many volts I am looking for that would indicate good /proper power getting to the S pole on the solenoid?

Thank you!

~GOD BLESS~

john

[DmaxMaverick]

The actual voltage is not really relevant, on an otherwise healthy system. Most common inexpensive/off-brand VOM's are only calibrated within 10%, anyway (really cheap imports, even greater). It's the differential you are looking at. System voltage should be greater than 12V with key on, but it can vary more or less depending on what draws power (accessories, GP's, etc.) at the time. For the most accurate tests, unnecessary fuses should be pulled (all but necessary engine/start). Failed/failing battery(ies) can also cause intermittent issues, but most often it's grounds and/or connections.

[JKlein]

OK - Thank you. I will get time this weekend to get inside the passenger fender wheel well and get a good look at the starter and the solenoid. Will look to test as you described.

I appreciate the help.

~GOD BLESS~

john

[JKlein]

UPDATE – Currently I can only work on my truck on the weekends. Armed with all the great tips and suggestions I went to work yesterday after church and here is what I found:

- Pulled each battery from truck and tested using a load tester. They tested fine. Also just a regular voltage check and they had proper voltage. So that told me the batteries were good and also that I do not have a parasitic voltage drain to track down.
- Removed both battery ground connections and cleaned them and reinstalled cables. Checked ground at rear of truck and cleaned and reinstalled it. All grounds were tight and looked clean to begin with.
- Fuse box inside truck for IGN has voltage when key in crank position
- Under hood fuse box I installed a new relay
- Under hood fuse box I pulled the relay and checked the terminals for that relay for voltage when key is in crank position
- Back inside cab checked and verified clutch/neutral safety switch is working correctly
- At the starter under the truck I checked for voltage at the small pole (purple wire from truck) on the solenoid when key is in crank position. It has voltage. Tried that test multiple times and got positive results each time.

Final test was to test the starter – I clamped one end of my extra heavy gauge single line jumper cable onto the starter where the wire/cable attachment from the solenoid power goes into the starter. I then had my wife turn the key to on. When she told me that the start engine light was no longer on I asked her to turn key to crank and depress clutch. I touched the other end of the jumper cable to the positive terminal of the passenger side battery and it cranked immediately. Started right up.

Rolled under the truck and removed the jumper cable from the starter. Jacked up the passenger side – removed the jack stand and the jack. Put the 3500 back on the ground running like a champ. Went for a nice long drive – even hit the car wash. I just kept it running the whole time.

So armed with all this test information I determined the ignition is working fine and that the starter solenoid is the culprit. It does not even click or clank or anything.

I did find one issue that I need help with please.

I am missing the bracket that mounts to the engine block and then you mount your starter to it. I can see that the heat shield is missing the bolt from the end that is closest to the front of the engine. I assume that is where the bracket mounts to?

Where can I get a new bracket to properly mount my new starter/solenoid?
Any help is appreciated!

Thank you,

~GOD BLESS~

john