Skip to main content
Topic: 88 bird 5.0 amp guage (Read 1046 times) previous topic - next topic

88 bird 5.0 amp guage

We have one last thing that needs repair on the car since we got it for mason a year or so ago.

the amp guage needle sets dead center and never moves.
In light of my know to ask the right question~
-can someone post the 88evtm page for the shunt lead that is tied to the guage.

I will gander through my 87shop manuals and evtm in advance but i have a couple questions...

What size shunt is it?
100mv, 50mv, 25mv or what?

Tom Rezon~you may chime in on this ,, i asked you this a while back and cant remember if you found the info on the shunt lead or not, either way if you do have info, i appreciate it.


I am speculating now that the one harness i took apart that leads down to the 2 large connectors at the base of the battery , within this harness i found a couple of conductors bonded together with a fuse link which i believe is my shunt for the ammeter..again just speculation at this time but it makes sense. (blue in color).

thats it for now,, we want to get this working soon.

88 bird 5.0 amp guage

Reply #1
The circuitry for the Sport gauge cluster isn't shown in the '88 EVTM, only for the Turbo Coupe(I'd guess they are similar)...

That said, the problem is most likely the gauge it's self, problem is likely the small "C" magnet inside the gauge is dead, I've never seen one work in a TC either...  I've opened a gauge, "re-charged" the magnet with a large one and it worked for a couple weeks before it went numb again...

My recommendation is install a volt meter and forget the original gauge...

88 bird 5.0 amp guage

Reply #2
CONVENTIONAL AMMETER
A conventional ammeter must be connected between the battery and alternator in order to indicate current flow. This type ammeter, Fig. 1, consists of a frame to which a permanent magnet is attached. The frame also supports an armature and pointer assembly. Current in this system flows from the alternator through the ammeter, then to the battery or from the battery through the ammeter into the vehicle electrical system, depending on vehicle operating conditions.
When no current flows through the ammeter, the magnet holds the pointer armature so that the pointer stands at the center of the dial. When current passes in either direction through the ammeter, the resulting magnetic field attracts the armature away from the effect of the permanent magnet, thus giving a reading proportional to the strength of the current flowing.
Troubleshooting
When the ammeter apparently fails to register correctly, there may be trouble in the wiring which connects the ammeter to the alternator and battery or in the alternator or battery itself. To check the connections, first tighten the two terminal posts on the back of the ammeter. Then, following each wire from the ammeter, tighten all connections on the ignition switch, battery and alternator. Chafed, burned or broken insulation can be found by following each ammeter wire from end to end.All wires with chafed, burned or broken insulation should be repaired or replaced. After this is done, and all connections are tightened, connect the battery cable and turn on the ignition switch. The needle should point slightly to the discharge ( - ) side.
Start the engine and speed it up a little above idling speed. The needle should then move to the charge side (+), and its movement should be smooth.If the pointer does not behave correctly, the ammeter itself is out of order and a new one should be installed.

SHUNT TYPE AMMETER
The shunt type ammeter is actually a specially calibrated voltmeter. It is connected to read voltage drop across a resistance wire (shunt) between the battery and alternator. The shunt is located either in the vehicle wiring or within the ammeter itself.When voltage is higher at the alternator end of the shunt, the meter indicates a charge (+) condition. When voltage is higher at the battery end of the shunt, the meter indicates a discharge ( - ) condition. When voltage is equal at both ends of the shunt, the meter reads zero.
Troubleshooting
Ammeter accuracy can be determined by comparing reading with an ammeter of known accuracy.

    With engine stopped and ignition switch in RUN position, switch on headlamps and heater fan. Meter should indicate a discharge ( - ) condition.
    If ammeter pointer does not move, check ammeter terminals for proper connection and check for open circuit in wiring harness. If connections and wiring harness are satisfactory, ammeter is defective.
    If ammeter indicates a charge (+) condition, wiring harness connections are reversed at ammeter.
I spend money I don't have, To build  cars I don't need, To impress people I don't know

HAVE YOU DRIVEN A FORD LATELY!!

88 bird 5.0 amp guage

Reply #3
The dash gauge is a shunt unit. The shunt is incorporated in the wiring harness. I think it only shows a charge rate according to the print. Not 100% on this!!  Reason i say this is because it is in the alternators heavy charge wire. It is not wired in to the cars battery supply side. This is according to the print i am looking at. Either way you can test the gauge portion with an OHM meter. The gauge is a micro volt meter of sorts and measures the voltage drop across the shunt. If you hook an OHM meter across it out of the car you should get it to move with the shunt now not in the circuit and i would think the battery from an buttstuffog meter should have enough battery on the low OHM scale to move the needle. I have several turbo coupe and mustang gauge clusters i will test one tonight. That is as simple as i can explain it. It looks like the entire load does not come through the wiring as i see it. Could be wrong but that is what i see. Hope this helps.
I spend money I don't have, To build  cars I don't need, To impress people I don't know

HAVE YOU DRIVEN A FORD LATELY!!

88 bird 5.0 amp guage

Reply #4
looking throught 33-05-13 shop manual now,, which are posted on photobucket for viewing per my link below
going to dig in also after i straighten the shop out of all the mess we've collected over the past couple days.

thunderchicken
if you've got a visio or pdf or whatever of what you did in the past,,, jcassity@alpha.com

The other tom would know this stuff like the back of his hand ~ turbocoupe50

88 bird 5.0 amp guage

Reply #5
The best I can do is the 88 TC diagram. As I understand it, they are mostly the same as the 5.0 Sport cluster (and if you have an ammeter, that's what you must logically have).  Don't expect much, there aren't any details given other than it's supposed to connect between the fuse link you kept and the fuse links you didn't keep.  If you swapped the cluster in, odds are that the gauge isn't connected, as you can see in the diagram the ammeter connections are in the engine bay.  Check that the pins on the cluster connector (harness side) are populated.  If not, well, you're sharp, so I expect you to know what to do about that.


X

88 bird 5.0 amp guage

Reply #6
Yes this print shows the gauge in the entire load system. My print showed it in the charge circuit only. Some manuals have known to be wrong. I never pay any attention to my AMP METER on my coupe. A volt meter is what you want. So with this print it would sense both charge and discharge issues. But who cares an alternator is not current regulated. It is voltage regulated.  Basically an amp meter is useless. But i always like my gauges to work if they are in the car. Notice the SHUNT in the wiring harness. So if the gauge does not work and the car functions properly and not modified the gauge is KAPUT!!! I would think?? Also with the 3G conversions and people installing new charge wires to the solenoid. Well think about it the amp meter is on the wrong side with that setup!!
I spend money I don't have, To build  cars I don't need, To impress people I don't know

HAVE YOU DRIVEN A FORD LATELY!!

 

88 bird 5.0 amp guage

Reply #7
FOE i got it now i have the right print??? You posted a 1988 TC right ?? I looked up a cougar. Different print. I stand corrected. The gauge in the print you posted is set up to ssense both charge and discharge. Sorry should have checked further. Some of these services i pay an arm and a leg for are incorrect some times. Thanks for the proper print. Thanks Tom
I spend money I don't have, To build  cars I don't need, To impress people I don't know

HAVE YOU DRIVEN A FORD LATELY!!