I have a 99 Grand Cherokee, 4.0 bone stock...I recently rebuilt the motor and got it back in... It cranked up first few times then it won't crank at all now... Turn the key, everything comes on but nothing no click except the relays. I've changed the park/neutral switch which is the screw in type, I've tried to bump it over in the starter and it only sparks, removed the starter and tested it it works fine out it back in and it does it again... Checked grounds, when I removed the grounds and turn the key on, the fan starts running and the ASD relay goes crazy what am I doing wrong? Any help would be greatly appreciated

 

A no crank no start condition.. but, the starter solenoid operates to make the starter run like it normally should to crank the starter motor when you have it pulled testing it outside of the vehicle?

I am sure you would have said. But, have you turned on the interior lights to the Jeep when you turn the key trying to start it? Do the interior lights dim greatly when you turn the ignition key while attempting to start it? You could hook up a voltmeter to the battery to see what it is doing as you are trying to start it.. to see if there is any current being directed towards the starter as you turn the ignition key to start? This would rule out the battery as the reason for you.

I think I would want to trace the power to see if it is going to where it needs to be going after turning the ignition key, checking with a voltmeter first at the relays. Although, before the current runs into the different relays, it does get drawn through a fuse. The fuse would actually be one of the first things to check and verify that it is good. But, if you go straight to the relays and they are recieving power.. Then, you know the fuse is good. Even so, I think it would be wise to look at all of your fuses just to make sure, and see it isn't because of one of the fuses first.

 

Yes when I have it out it bumps over just fine, when I bolt it back into place, it won't do anything...I tried to jump the terminals on it and it just sparks. I even took a jumper cables connected to positive and straight to the starter terminal still just sparks. I checked the starter relay and have power there. I pulled the starter wire and tried testing there while I turned the key to start... No power at all! When I disconnected the ground and turned the key to the on position the electric fan started turning and the ASD relay went crazy. I put the motor together complete with trans connected and reinstalled so I have no pinched wires
Oh also I did look at all the fuses in the box under the hood they all look solid, haven't looked at any under the dash

 

Nothing wrong with the starter, your rebuilt engine has froze up.

 

Umm why would you say that? And why would it freeze up? As in locked up? Oil was flowing good, all new parts... Oh man I hope that's not the problem

 

Well I just rolled my engine over by hand and NO it's not froze up... You almost put a damper on my day by saying that... Where does the wires run from the ignition? Is there a panel in the passenger side that has relays? Mice found a home inside while the Jeeps been sitting. I'm kinda guessing they may have eaten up some wires hope not though... If there's something shorting out would that cause the starter to not kick in when jumped across terminals? And to answer the guys previous question about the dome lights, headlights blower motor and all, they do not die down when you turn the key to start. They start steady and bright no dimming at all...I have power at the starter relay but not getting to the starter selenoid

 

I was up earlier this morning and read this too. I was going to suggest to try and manually turn the engine over by hand to check, but I figured it sounded to me you know what you are doing enough to be able to think of doing that to check it out on your own. That is definitely really good it is not something like that.. because it does sound like it could of been a possibility.

How well did you test the starter when it was being tested and ran when you had it disconected outside of the Jeep? The starter may be able to test perfectly fine when done it like that.. when there is no load placed on it how it normally has when it is being required to turn over the engine.. That does happen like that sometimes.

You probably used jumper cables? With the positive cable connected from your Jeeps positive battery terminal and running the other end of it connected up to the large terminal on the starter? Running the black jumper cable from the battery negative side post connecting it onto the starter body metal casing for the ground? Did you do that, and then jumper it with a screw driver. That is one way to test it.

Another way, is to keep the ground connected up how mentioned. Take the positive jumper cable keeping one end connected up to the battery positive post still, and touch the other end of the positive jumper cable to the s terminal (the small one) of the starter. This should only activate the starter solenoid to see and/or hear that it is engaging to work just the solenoid.

Another way, is to keep the ground like it is. Take the positive jumper cable lead (still having it hooked up on the other end to the battery positive post), and touch it to the second largest starter terminal (not the main one normally hooked up leading to it from the battery). This should test to run only the starter motor itself.

If you only tested for the starter motor itself, as in the last testing procedure I mentioned above, you will not know if the starter solenoid is working like it should be...

You probably already know how to jumper the starter correctly how you mentioned doing with a screwdriver when it is connected up on the Jeep. But, if you did not jumper from the largest starter terminal correctly to the smallest s terminal of the starter, it ill spark like you say it has done for you, but may not operate the starter....

If the starter motor runs fine when it is outside of the vehicle like it does. It still may not be good enough to run to crank turning over the engine when it is hooked up to the Jeep.. if it is a weak and bad starter....

Which cable are you talking about that you disconnect from the starter.. for how you say you are not seeing power? That part doesn't make sense to me yet, because if you are not seeing power at the other end of the cable, then how is it able to spark when you try jumpering the starter terminals with a screwdriver?

 

It sounds to me like you are saying the starter relay terminal tests okay showing 12V when you work the ignition switch. So, this means from the ignition key being turned up to this point it is okay. That means the problem is in-between here and the starter motor itself. The starter motor runs fine when it is outside of the vehicle. So, likely what this really means is that the problem is between here and the output terminal on the starter solenoid. The neutral safety switch (nss) provides power to ground for the starter.. So, it is included as a possibility still. If the nss or its wiring is not correct and working right it will not allow the starter solenoid to engage the starter motor. This makes the nss one of the likely reasons.

I suppose I would want to check the opposite side of the equation at the starter with a voltmeter. Put one of the dvom leads onto the output (the starter motor side) of the starter solenoid and ground the other dvom lead out to earth. Work the ignition switch and see if the starter solenoid is providing current to the starter motor when you turn the key? It doesn't sound like it is... Then, check the feed terminal (battery side) of the starter solenoid next. If the feed side is getting power that means the starter solenoid is bad. If the feed side of the starter solenoid is not getting power.. it could be the nss part of this equation has a fault.. Or, it could be the wiring leading from the output side of the starter relay terminal going to the starter is the reason. I am not sure if you meant you actually tested the starter relay, or only tested at the starter relay terminal(s)? That is the other likely possibility if there is no power picked up by a dvom at the starter solenoid feed terminal, is that it could be a faulty starter relay.

Another possibility is there could be too much ground resistance. This can be tested for as well with a dvom too. Although, a testing lamp may be more preferable to do this... Connect one lead of a testing lamp to the feed terminal (battery side) of the starter solenoid and the other test lamp lead to a body ground. If there is too much resistance it will not illuminate well (if at all). After you do this.. you should repeat the test lamp testing procedure again. Except, this time you should use the metal on the engine to ground it out.. If it illuminates on one of your grounding points vs not on the other? Well, then you know which ground has too much resistance. . . the battery strap ground vs the engine ground.

 

When I tested the starter outside the Jeep it tested fine, jumped, spun, kicked out, everything... When I put it back in, it will not do any of those things when I jump it across, not a sound... Also I am getting no power whatsoever at the s terminal lead on the starter. I only tested the 2 terminals at the relay, tried the grounds jumper like everyone says and still nothing

 

I think I would have to go after the known problem at the s terminal, and try to find out why and fix it. I don't know why it won't crank for you with a screwdriver when you jump the terminals at the starter if you are doing that correctly (I am sure you are)? The only thing I can think of for that is like what I was saying above about how the starter motor can be too weak to do anything cranking when it is actually hooked up and has to turn the engine over. It could appear normal.

The s terminal is because of your nss though. That is all it can be related to right? It doesn't have to be the neutral safety switch itself though.

I think for having no power at the s terminal I would want to look at two different things at this point. The ignition switch has a wire leading from it to provide power to the nss. I believe it may be the yellow and red wire, but I am not 100% sure on that wire color? I would say to look it up. If there is no power going to the nss it is not going to work.

The FSM probably calls the nss something else along the lines of transmission range selector switch or something like that? I would have to say it is important for the ground supply for this sensor wherever that is located.. For it to be intact and correct is required for the nss to be able to work. You may find it located on the inner fender in a hard to reach spot near the PCM, but I am not 100% sure about this location? I would say to look this up, and go after it too.

I don't know about that starter though? It sounds like it should be cranking, and its not.