Starter issue

Ok so in the last couple of days my starter has been acting up. My XJ is a 97 4.0L auto 4x4. When I go to start it up I hear the start try to start the engine but it sounds like it "lets go" and just free spins. When I let off and let the key drop back to the "on" position it stops and I hear a pop sound. Now I was an automotive student and a local tech school for a while before I transferred to a big University and I learned how a starter works and got to take one apart and everything so I know that the gear extends out and engages the flex plate and then it turns and starts the engine. Now it seems like it is turning but not extending out and engaging the flex plate. Would this be a solenoid issue or the whole starter itself? I know I can take it to autozone and have it tested but that takes time to take the starter out and get it over there. I do plan on doing this but I am just curious as to what i should expect the verdict should be. Any thoughts?

Sounds like loose starter bolts. Second guess, is your Bendix is full of garbage. Third guess, is your solenoid has a torn seal and is full of rust. Possible it's your overrunning clutch, but unlikely.
Could also be a cable/clamp problem, starter needs all the juice it can get to work right.

Once again:

Life begins with the Battery.

Clean battery posts/clean cable ends/clean connections at the starter, and just for practice check/renew the other system grounds. Check the connections at the starter relay.

Is the battery fully charged, and will it pass a load test? If you haven't done these things yet, nothing else matters.

You can not, repeat, can not diagnose a starter or starter solenoid problem without having a fully charged battery that will pass a load test and has all connections clean and tight.

It is unlikely that is is just the solenoid, because that is also what engages the contacts in the starter to make it spin after it pushes out the gear. The one way over-running clutch could be shot, or possibly you are missing a tooth on the flywheel. Sometimes you can rotate the engine with a wrench or pulling on belts to move the flywheel (flexplate) to another position to try starting there. You could pull the starter, check out the flywheel teeth and see what happens if you run the starter from the battery with jumper cables where you can see what's happening..

winterbeater said:

It is unlikely that is is just the solenoid, because that is also what engages the contacts in the starter to make it spin after it pushes out the gear. The one way over-running clutch could be shot, or possibly you are missing a tooth on the flywheel. Sometimes you can rotate the engine with a wrench or pulling on belts to move the flywheel (flexplate) to another position to try starting there. You could pull the starter, check out the flywheel teeth and see what happens if you run the starter from the battery with jumper cables where you can see what's happening..

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x2 on that

The battery is definitely good since its a 2 year old optima yellow top king of batteries. The factory connections were ditched a long time ago and the wires were striped and refitted with some replacements from autozone and no I didn't buy the cheapest ones I bought the ones right before you step up to the gold plated ones and I put the dielectric grease all over the bare wires and clamped them down good and used those little felt things you can buy to hinder corrosion which I thought were a load of crap but when I first did the connections I didn't use the felt things and they would corrode and I would have to clean them every other month but since I put those felt things on there I never have to fool with them. I do check them often when I pop the hood to inspect everything and make sure nothing is out of the ordinary. I will check everything at the starter though since I have never fooled with it before. I really hope its not a missing tooth on the flexplate cuz that will be a b*tch to change. Guess I'm just gonna have to pull it and check things out.

Life begins at the battery.

1. Batteries fail--even Optimas.

2. Is the battery fully charged?

3. Will the battery pass a load test?

If the answers to 2 and 3 are not "YES", then I wish you would confirm those before going to the trouble of pulling the starter.

However, it is your time and trouble, so do as you will.

Ben824 said:

I put the dielectric grease all over the bare wires and clamped them down good

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I really don't think it's an issue in this case, but someone please confirm for me, because I've seen different ideas on this: I think that dielectric grease is an insulator. I think you put it on where you don't want electricity to flow and to stop moisture which can make current flow. So wouldn't the course of action be to clean the connections good, mechanically complete the connections, and then put dielectric grease over the top to seal out moisture. I've seen people say, when completing other connections, such as the dashboard plugs, to put in dielectric grease. So are we counting on the scraping of the plug to get through the insulating grease? DO I HAVE THE WRONG IDEA ABOUT THIS?:huh:

I use the felt doughnuts, or a commercial spray, on battery cables.

After cleaning contacts I do cover them with dielectric grease and count on the contacts making contact (boy, does that sound retarded), and the dielectric is for anti-corrosion and water resistance.

Stuffs too expensive to use on battery terminals.

winterbeater said:

I really don't think it's an issue in this case, but someone please confirm for me, because I've seen different ideas on this: I think that dielectric grease is an insulator. I think you put it on where you don't want electricity to flow and to stop moisture which can make current flow. So wouldn't the course of action be to clean the connections good, mechanically complete the connections, and then put dielectric grease over the top to seal out moisture. I've seen people say, when completing other connections, such as the dashboard plugs, to put in dielectric grease. So are we counting on the scraping of the plug to get through the insulating grease? DO I HAVE THE WRONG IDEA ABOUT THIS?:huh:

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I read someplace many years ago that if the coating of di-electric grease is thin enough (like a few molecules) it stops being an insulator or has very little resistance. But I don't use it on sensor plugs, for the simple reason the voltage is usually very low and even a little resistance may be too much..

Dielectric grease is an insulator plain and simple. Because it does not conduct electricity, it is useful to insulate multi-wire terminal connectors from moisture. I personally would not use it on battery connections because it serves no purpose and certainly does not increase conductivity. 5-90 suggests using a mixture of Vaseline and baking soda on the outside of battery terminals to reduce corrosion which sounds like a good idea. There are recent posts on this.

To increase conductivity use a product such as GB Ox-Gard available where home wiring products are sold. A small tube lasts a long time. A tiny bit is normally adequate -- I use a flat toothpick as an applicator (probably a hint from old_man). You obviously have to use caution in using this in multi-wire connectors since it is a conductor. It is good for ground connections to help reduce corrosion where paint is scraped off the body.

It seems counter-intuitive to use dielectric grease in plugs but an otherwise good connection simply cuts through the grease, thick or thin, with metal to metal contact. I know that some people slather this stuff on anything but I personally would not use it on in-cab connectors such as dashboard plugs, if for no other reason that it is such a damn mess to clean off the next time you have to work on the circuit. Again, it's to exclude moisture and in the case of spark plug boots perhaps, to ease removal.

I guess with sensor connections where moisture is a potential problem, you just decide which is more important, but a poor connection is a problem with or without dielectric grease and a good connection will not be affected by the presence of the grease -- at least that seems to be the OEM design concept. I agree with 8Mud in that I would not use it on delicate electronic connections except perhaps carefully around the edge of the connector in high moisture situations.

Quote Pelican: I guess with sensor connections where moisture is a potential problem, you just decide which is more important, but a poor connection is a problem with or without dielectric grease and a good connection will not be affected by the presence of the grease -- at least that seems to be the OEM design concept. I agree with 8Mud in that I would not use it on delicate electronic connections except perhaps carefully around the edge of the connector in high moisture situations.

Yes. And be careful with the Oxygen sensor connector!!
Dielectricgrease is mostly based on silicone and it will kill the sensor. :spin1:

Good point.