[joe]

I just sent out my meters pod to Palo Alto Speedometers to fix it all up. They sent it back, saying that it was all fixed. But when I put it back in the car the speedometer, odometer, and trip calculator all still don't work. I was thinking maybe there might be a problem with the wires that plug into the pod, and run to other areas in the car.
~Any ideas what's wrong with my meters?

Thanks
Joe

 

[John M]

What year car? Reason asking...some are cable driven to the head unit....some are electonically driven at the head unit.

All of the manual spiders have a speedo cable of some sort. A mechanical cable connects the tranny drive to either the head unit or a pulse generator that feeds the head unit an electrical signal.

On some Ljets and all motronics a rare but common failure is the pulse generator. The spica cars were all mechanical as far as I know in regards to the speedo.

Best Regards,
John M

 

[artart]

My 88 Grad did same thing until I replaced a bad fuse

check those fuses, sorry I can't remember which one it was and I don't think it was listed.... My tach would work fine but even trying a manual run of pulse generator with a drill wouldn't show anything on speedo or odometers. New fuse did it.
artart

 

[Gubi]

a rare but common failure is the pulse generator

Does that failure happen often but infrequently, John?

Quick thing to check is the connector to the pulse generator...sometimes the connectors get corroded. If you have an S4 it's a three-wire connector on the firewall near the brake MC, for post-'86 S3 it's over in the driver's side corner.

 

[joe]

Reply

It's a 1989 Spider Veloce

 

[joe]

No, the meters don't ever move. I'll try to check out that pulse generator. What did you mean by "rare, but common problem"?

 

[John M]

Well boys what I meant to imply.....

The failure is rare.....

But the most likely failure is the pulse generator....

And check the fuse for the pulse generator. Should have three wires. The grey is signal. Then I believe..think...if I remember correctly...that it gets 12V from white and ground is black.

Best Regards,
John M

 

[joe]

Checked the fuse, need another idea

I checked the fuse and it was fine. I took the pulse generator off the car, but don't know how to test it. Need some help.

Thanks,
joe

 

[Motovagrant]

I have an 91 Spider and I have the same problem. My Speedo Cable is fried. Don't know why, but it is totally frayed. May want to check the cable. Just a thought...

 

[Gubi]

You can plug in the generator, turn the key to on, and drive it with a power drill and square drive. If the speedo works with that then it's the cable.

If that doesn't work, I think you can check the output between the gray wire and ground with a multimeter while you drive the sender. Should be something like a 12V square wave. No signal = bad sender, good signal = bad speedo head.

 

[Tifosi]

If using a drill to spin it up, which way does it need to rotate? (I wrecked a Smiths speedo by going the wrong direction years ago)

 

[Gubi]

Good question, and Mongo dunno. Since it's an electrical sender (I'm guessing Hall effect with a magnet on a rotating arm) it probably doesn't care, so you won't trash it like you would with a mechanical speedo.

That being said, I'm not absolutely certain of this so it might be best to check.

 

[joe]

1989 spider veloce, speedometer

Do I need to drive the car and spin the drill at the same time.

 

[Paradiso]

It may be rare but it happened to my car last year (or maybe the year before?) I replaced the speedo cable but that didn't help. I ended up getting the sender from APE, they were NLA when I was looking and I checked all the US suppliers.
The sender for S3 and S4 spiders are identical but the wire lengths are different. The S4 has longer wires.
I used the sender from an S3 and spliced on the connector from my original one.

 

[ossesso]

my 88 veloce tachometer never goes over 3000, and now suddenly, odo & speedo are totally dead! So now she truly is a "time machine"