QuestionQUESTION: I have a Series 3 XJ6 and it wont start, the negative battery terminal gets hot when I hold the key. The starter doesnt turn the engine when I put the key on and the voltage across the starter is 6V under load. I am guessing there is a short but not sure where to check or if one of the relays is the culprit then how do I check that. Also where is the ignition protection relay? It sounds to me like I have too high of a resistance somewhere but I cant find the voltage drop. Also when I hook the battery up the battery indicator on the dash stays on. I have a brand new deep cycle battery and brand new starter and solenoid on the car. When I turn the key I get one click from the solenoid and then nothing and like stated before the voltage is low only 6V. Thanks in advance for the help!!!
ANSWER: Hi Jamie,
When a battery post gets hot it is a clear indication of resistance and a poor connection. That must be corrected before you can do anything else. Heat is generated at any point that has high resistance.
After you correct that use a heavy jumper cable and jump from the battery to the starter directly and bypassing the starter solenoid. If the starter still does not spin the engine make sure the engine is not locked up and then do voltage drop tests of the whole circuit, battery + to starter solenoid connection, then engine to frame drop test and body to (-) post of the battery. If you are not familiar with "voltage drop" tests let me know and I will detail it for you.
It is almost impossible to have a short anywhere that can stop a starter from spinning with a fully charged battery. You problem is most likely poor connection or connections in the starter circuit.
Howard
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QUESTION: Since this post I have rewired the battery wire to the solenoid and the wire from the starter relay to the solenoid and the actual battery cables. I am not very familiar with voltage drop tests as most of my experience is with mechanical issues. Is it possible that this new starter I have is bad? Since I have replaced theose wires both posts warm up now but they do not get as hot as before. Obviously still a short somewhere. Also how do you bypass the solenoid? Thanks again!!
ANSWER: To bypass the solenoid just disconnect the (+) battery cable first, then on the solenoid move the battery cable to the wrong large post on the solenoid (which is the starter motor.) Then at the battery just touch the cable to the battery post. The starter motor should spin like an electric motor but not connect to the engine. You never did tell me if you confirmed that the engine is not locked up????
A voltage drop test can be run on any cable or wire. The readings will be different depending on the load and the size of the wire. A positive or a negative wire can be tested while under load.
Put your volt meter on a low volt scale DC and connect the negative test lead to the negative post on the battery, now connect the positive test lead to the engine itself (any bare metal) and hit the starter as it is when connected up correctly. You will read a small amount of voltage but it should be very small like under .5v. A higher voltage may indicate a poor connection on any ground wire (engine to frame or frame to battery) In your case you may see a little higher readings but it should not be much higher.
You said your wires get warm. That means a lot of current is going through the wires. Current always has to make a loop from battery to load back to battery. What ever current is traveling in the positive cable, the same amount of current is traveling in the negative cable. If the cables are getting warm then there is a massive amount of current moving. A starter does draw a lot of current when it is operating normally and the only way a massive amount of current can be traveling and the starter is not spinning is for either the engine is locked up or the starter motor is no good. (unless you have the (+) cable bolted to the engine block instead of the solenoid)
Howard
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QUESTION: Okay so I have tried to turn the crank by hand and I am not getting anywhere. I put the car in neutral and attempted to turn the crank with a half inch breaker bar. By the way what is the correct size socket for the balancer nut? The engine and transmission fluid levels are and have been fine. The car was running and parked for maybe 15 minutes and when we came out it didn't start. What could cause the engine to seize like that? I thought maybe if teeth broke off of the flywheel and jammed it but the teeth I can see look fine. I am not sure what to do at this point. Any help would be appreciated!!! Should I pull the tranny and check the flywheel or try penetrating oil in the combustion chambers? Thanks again!!!!
AnswerI wouldn't go as far as to think about removing anything yet until you know what is wrong. The crank does not turn very easily on a 4.2 engine. Did you test the starter motor like I said. It will test the starter motor itself without engaging the engine. When you bypass the solenoid you also bypass the starter bendix.
Blow all the dirt out of the spark plug wells and remove all the plugs and just use a box end on the small bolts as it is difficult to get a big socket in on the crank bolt anyway. I have many times used a large channel lock pliers on the water pump pulley hub and just push on the belt to keep it tight to turn the crank with the plugs out. Some mechanics just remove one of the screens on the bell housing and use a large screw driver to move the crank.
Howard
