Ahmeter not working! Marking in the middle

[jalexquijano]

My 240z has an alternator has a 60 amp alternator upgrade. The ahmeter is not working, it dials in the middle. The fuel gauge does work. Where do i need to check? do i really need to take down the full dashboard to sort this out?

Another thing i have read is that the ammeter shunt could be faulty? How do i check this? where is it located? I dont want to keep on spending money on second hand gauges if i can find the solution immediately.

Anyone with this problem?

[peng155]

You need to do some simple troubleshooting first, and provide some information... Where is the amp meter needle pointing in the following situations, also what year is your 'Z'?

1) Engine OFF, NO accessories ON (Amp Meter needle should be in the MIDDLE of the gauge, No current flow, electrical system not charging, or dis-charging)

2) Engine OFF, Headlights ON (Amp Meter needle should move to the LEFT of the middle of the gauge, Current flow, electrical system is dis-charging)

3) Engine ON, NO accessories ON (Amp Meter needle should move to the RIGHT of the middle of the gauge, electrical system is charging)

4) Engine ON, Headlights ON (Amp Meter needle should move further to the RIGHT of the middle of the gauge, electrical system is charging at a higher output)

Also what does the amp needle do with the engine OFF, and you have the turn signal ON, either LEFT, or RIGHT (Amp Meter needle should move move back, and forth)

Just trying to determine if your amp meter is indeed not working or not....

Your statement " The ahmeter is not working, it dials in the middle" isn't really saying much.. If you have an early 'Z', your amp/fuel meter should look like this..

To a certain extent it doesn't matter if your fuel gauge works or not... they are two separate gauges in the same housing

Edited September 22, 2014 by peng155

[beermanpete]

Perhaps this thread will help you interpret the ammeter reading (or lack thereof):

http://forums.hybridz.org/topic/114701-how-do-i-interpret-the-amp-meter/

[jalexquijano]

You need to do some simple troubleshooting first, and provide some information... Where is the amp meter needle pointing in the following situations, also what year is your 'Z'?

1) Engine OFF, NO accessories ON (Amp Meter needle should be in the MIDDLE of the gauge, No current flow, electrical system not charging, or dis-charging)

2) Engine OFF, Headlights ON (Amp Meter needle should move to the LEFT of the middle of the gauge, Current flow, electrical system is dis-charging)

3) Engine ON, NO accessories ON (Amp Meter needle should move to the RIGHT of the middle of the gauge, electrical system is charging)

4) Engine ON, Headlights ON (Amp Meter needle should move further to the RIGHT of the middle of the gauge, electrical system is charging at a higher output)

Also what does the amp needle do with the engine OFF, and you have the turn signal ON, either LEFT, or RIGHT (Amp Meter needle should move move back, and forth)

Just trying to determine if your amp meter is indeed not working or not....

Your statement " The ahmeter is not working, it dials in the middle" isn't really saying much.. If you have an early 'Z', your amp/fuel meter should look like this..

68795.attach

To a certain extent it doesn't matter if your fuel gauge works or not... they are two separate gauges in the same housing

Okay. Question: Engine on, air conditioner on. Does it need to move to the right and oscillate or should it remain steady at the right?? Mine moves to the right and oscillates at idle but keeps to the right! 60 amp alternator and original 45 amp ahmeter

[zKars]

You care only about one thing. With the engine running, the ammeter should be one the + side (right). It will wiggle and wander in response to many things that draw current and control it, but it must be on the right (+).

Being on the plus (+) side means the alternator can push current into the battery, which is a good thing as it means that the alternator voltage is higher than the battery voltage. On the left side means its discharging, which is a bad thing. With the engine off, turning on ANYTHING should make it go left of center as the battery is supplying the current.

The ammeter then tells you if the battery is charging (+ good) or discharging (- bad).

[jwtaylor]

Temporary swings to the - side are normal, such as when at a stop light with the brakes on.  After the engine speed is increased and brakes off it should swing positive + to recharge the battery.   If your not seeing any movement it's either been removed from the circuit (bypassed) or is bad.  On the 240s the shunt is in the meter.  First thing I would do is check the connections to the amp meter, it should have a large wire to each of the shunt studs.