couple guage issues, new to Fieros

[egagnon086]

Hi all,

I recently bought a 1988 Fiero with the L4. I have the following issues:

The tach pegs on start up, so does the temp guage sometimes.
The trip meter does not function.

Been reading through posts, have an idea on the temp guage, but at a loss on the others.

Any help would he greatly appreciated.

[Fierofool]

Welcome to Fiero ownership and the Georgia Fiero forum.  I can't help with all the issues but maybe I can be for a couple.

The trip odometer problem could be either the meter itself or the stepper motor that drives it.  The meter can be replaced with any other Fiero odometer.  Even though the stepper motors are the same, the electric plugs are different on some.  I heard someone say you could even use the motor that drives the regular odometer, since they both have to register the exact same mileage.  Find an instrument pod in a junk yard and get the motors, or put an ad in The Market section to see if any of our people have a spare.  Aerodonamic usually has a good supply of spare parts.  Email him. 

Pegging of the gauges occurs because full power is applied to them on startup.  The tach pegging is unusual.  I've heard of the temp gauge pegging, but that's not normal. 

[TopNotch]

The tachometers in  88 4-cylinder cars seem to be notorious for failures. I'm not sure why -- maybe it's because they don't have a tach filter like other Fieros. Mine read high when I got the car, but I got a good one from Ebay. Our club has a "club car" that's also an 88 4-cylinder, and it reads high.

[Fierofool]

Go back to the home page of the website.  In the left column is a tab "Tech Tips".  Click on it and you will find a fix for pegging temp gauges. 

[egagnon086]

I got the temp guage figured out. Thanks

Any idea on why the tach would peg on start and never come back down?

[TopNotch]

I'm not sure why it pegs, but maybe the meter driver chip is bad. You can read about it here, and what to use as a replacement.

[egagnon086]

Got the temp guage fixed with,  wiring fix and a new sender.

The pegging tach was replaces and it works now.

Thanks

[Fierofool]

Where did you find your replacement tach?  They are specific to 4 or 6 cylinder car.  A 4 cylinder tch installed in a V6 will read 50% higher.  A V6 tach installed in a Duke will read 33% lower. 

The trip odometer can be changed out with any other Fiero trip odometer if you're careful about opening up the plastic retainers.  Sometimes it's the driver motor that goes bad.  They are all interchageable, except that they have different harness plugs.  Speedo can interchange with trip odometer motors, because they both clock the same exact mileage off the same VSS signal.

[egagnon086]

I found a lightly used L4 Tach on ebay for $30.

The trip meter is broken, the gear that drives the trip meter on the little motor is not attached. I'm still looking for one.

Im having a strange issue were the oil pressure gauge will fluctuate when I have the blinker on. And will read lower when the brights are on.
Any ideas, this did not happen on the old guage but then again the tach didn't work on that on.

[Fierofool]

The fluctuations sound like they may be the result of a poor ground or weak connection.  There may be some minor fluctuation, but it shouldn't be really noticeable.

If you have the gear, you can LocTite it back on to the motor.  Be sure you clean out the teeth well or it will bind.