Starter not engaging

[6T7Merc]

So i had it tested this morning and my starter is bad. Something with the coil or contacts. Hopefully picking up a new one will fix my problem

[FLATBEDFORD]

When I put the new starter in mine, I couldn't belive how much better it cranked than the old one (when it was working at all). You should be happy with the new one.

[6T7Merc]

Ok so a little has changed since the last time i posted.
I installed a new starter today. I took off the inspection plate under the flywheel and i can see the new one spinning slowly but not engaging with the flywheel. Along with that im still getting a chattering noise from my starter relay switch(which is also new). Ive inspected my wiring and its exactly the same as the 67 wiring diagram.
The only thing i can think of is the battery. Ive tried 2 new 650 cranking amp batteries. Should i try i higher cranking amp? I took my starter to canadian tire for testing and they used a portable boosting box and it engaged and span like mad so im wondering if i need a more powerful battery...

[seattle67]

No, any car battery would crank that starter. A larger battery will just let you crank for a longer amount of time before being discharged.

If you are sure that the batteries you were using were good and charged up then I would suspect something else.

Two things will slow down a DC motor, mechanical load and low voltage. You say that the motor is turning, but slowly, not even engaging the fly wheel. So for now, lets assume that its not a mechanical problem.

Here is a test you can try for checking voltage drop, you're going to need two people.

1. Pull your coil wire so the truck doesn't start while you're doing this.

2. Put your meter leads on the battery posts and read what the voltage is while someone is cranking, or attempting to crank the engine. Make sure you have the leads on the posts themselves, not the battery clamps. Once you have that voltage reading, stop cranking and go to the next step.

3. Now, put your meter leads on the positive post of the starter and the negative lead of your meter to the case (ground) of the starter itself. Same deal, have someone crank the engine and record the voltage.

The reading you get at the starter will probably be lower, but if it is much more then 1 volt less, then I would suspect that there is a point of excessive resistance.

If the voltage drop is more then a volt or two, then you can try to find the bad spot in the same manner. Leave the positive lead of your test meter on the positive battery post, follow the negative cable from your battery and do the cranking test at each connection point, such as the frame, engine block, and the starter itself. This will check for a voltage drop on the negative side. If the voltage stays consistent, then do the same for the positive side of things. Leave the negative lead of your meter on the negative battery post, then follow the path of the positive cable. Battery side of start solenoid, starter side of start solenoid, etc.....

One thing, and I know you have done this already, but you should check the circuit one more time, just to make sure everything is hooked up correct. Even better, have a friend double check it. This is not a reflection on you, it's just human nature to miss things, and a second pair of eyes can often see what we are missing.

There is more we can check, but this is enough for now
If you go through these steps and nothing shows up, we'll go on from there.

[6T7Merc]

The reading you get at the starter will probably be lower, but if it is much more then 1 volt less, then I would suspect that there is a point of excessive resistance.

If the voltage drop is more then a volt or two, then you can try to find the bad spot in the same manner. Leave the positive lead of your test meter on the positive battery post, follow the negative cable from your battery and do the cranking test at each connection point, such as the frame, engine block, and the starter itself. This will check for a voltage drop on the negative side. If the voltage stays consistent, then do the same for the positive side of things. Leave the negative lead of your meter on the negative battery post, then follow the path of the positive cable. Battery side of start solenoid, starter side of start solenoid, etc.....

thanks! ill give it a shot!
also, just a shot in the dark here, i have summit batter cable on my truck but the batter is located on the frame under the bed. would this cause excessive resistance even with the smaller gauge wire?

[Thunderfoot]

if you have the battery in the back of the truck and Looong cable running to the front you have to have Large battery cable or you will have voltage loss, which sounds like what you have...
Try taking and hook up another battery using jumper cables, hook the ground to the chasse of the truck and hook the positive to the positive terminal on the starter relay on the fender and try to start it.

[seattle67]

if you have the battery in the back of the truck and Looong cable running to the front you have to have Large battery cable or you will have voltage loss, which sounds like what you have...
Try taking and hook up another battery using jumper cables, hook the ground to the chasse of the truck and hook the positive to the positive terminal on the starter relay on the fender and try to start it.

[6T7Merc]

So i put my new starter in and everything and it still did the same thing but then for some weird reason when i jumped the starter and then put it back on the battery it engaged and turned the flywheel. my only issue now is that when it turns over it will only turn over a little bit but then will stop. Ive had my engine rebuilt so when it tries to crank over it seems like so much compression is built up for it to turn over continuously. after it stops theres hissing out of my valves so im wondering if maybe im not getting enough power to the starter to get it to turn over continuously or would be that theres so much compression in my engine?

[seattle67]

Any idea what size the battery cable is? Also, how is the negative hooked up? Is it a jumper that goes from the battery to the frame? Is there a ground strap going to the engine block?

We may be getting to the point were some pictures would come in handy.

Sorry that this has turned into such a pain, but from your descriptions I'm just not coming up with the smoking gun.

[rjewkes]

any chance there is a chunk of old starter nosecone in there grinding the flywheel to a stop?

or a bad rebuild?

[QC]

I'm guessing that with the battery in the back you have it grounded to the frame, or did you run a cable to the engine block? If it is grounded to the frame do you have a cable from the block to the frame?
Has the truck ever started with the battery back there?

[6T7Merc]

negative on the cable from the frame to block.
i do have it grounded to the frame. i never thought of that and i can see that now.
ill run a cable next time im down there. thanks!
the cable im using is about a 1 gauge.

[6T7Merc]

Problem solved! Thanks guys so much!

[seattle67]

Good deal!