Volts jump up and down. Bad ground?

beemrmem3

Founding Member
Jan 8, 2002
831
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Washington
So when im driving and I hit a bump sometime the volts will drop wayyy down and the engine will even cut out briefly. Then if I hit a few more bumps it will jump back up to almost normal levels and run fine. Now if i shut it off when then volts are down it will crank really slow and not start sometimes. Sometimes it will even just give me the clicking noise. So obviously there isn't enough voltage going to the starter. When the volts are up, it starts fine.

Something is loose right? I checked the battery to block ground to make sure it was tight, and also the block to chassis ground. I cleaned the chassis to block ground terminals and made sure they were tight, but the wire looked in not so good shape.

Any Ideas guys?
 
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A new ground wire is less than $10, so replace any ground wire that looks suspicious. You can never have too much money or too many good grounds.

Here's a checklist:

Since some of the tests will bypass the safety interlocks, make sure that the car is in neutral and the parking brake is set. Becoming a pancake isn’t part of the repair process…

Check battery, terminal connections, ground, starter relay switch (also known as solenoid) and starter in that order.

A voltmeter is handy if you are familiar with how to use it to find bad connections. Measure the voltage drop across a connection: more than .5 volts across a connection indicates a problem.
See http://www.fluke.com/application_notes/automotive/circuit.asp?AGID=1&SID=103 for help
fig-7.gif


1.) Will the car start if it is jumped? Then clean battery terminals and check battery.

2.) Check the battery to engine block ground, and the ground behind the engine to the firewall.

3.) Jump the big terminals on the starter relay next to the battery with a screwdriver - watch out for the sparks! If the engine cranks, the starter and power wiring is good. The starter relay is also known as a starter solenoid.

4.) Then pull the small push on connector (red wire) off the starter relay (Looks like it is stuck on a screw). Then jump between the screw and the terminal that is connected to the battery. If it starts, the relay is good and your problem is in the rest of the circuit.

5.) Remember to check the ignition switch, neutral safety switch on auto trans and the clutch safety switch on manual trans cars. If they are good, then you have wiring problems. See http://www.autozone.com/images/cds/gif/large/0900823d80195963.gif for 88-90 year cars .OR see http://www.autozone.com/images/cds/gif/large/0900823d80195964.gif for 91-93 year cars. See http://www.autozone.com/servlet/UiB..._us/0900823d/80/1d/db/3c/0900823d801ddb3c.jsp for 94-95 model cars.

6.) The starter may be hung, loosen up the bolts that hold it on, and give it a good whack with a big hammer. Tighten up the bolts and try again.

7.) If that doesn't work, use a jumper cable from the positive lead on the battery direct to the starter post where the big wire from the relay connects. If it cranks then, it is the power wire from the relay gone bad. This will be hard to do, since there isn't much room to do it.

8.) Pull the starter and take it to Autozone or Pep Boys and have them test it. Starter fails test, then replace it. If you got this far, the starter is probably bad.
 
In addition, check the power distribution block. It's prone to corrosion and has caused many issues for folks.

Good luck.