Intermittent 308 Speedometer

When the speedo goes out, does the odometer also quit advancing?

-matt

 

If the 76 models are the same as the injected cars you either have a bad sending unit or connections to it. It is VERY VERY common and not a very expensive part that you can replace in your driveway.
This is common enough that I rarely believe the milage on 308's (also because it so easy to unplug the thing)

It screws in down by your right rear wheel

 

Two years ago mine had the same symptoms and I found it was working loose. It screws in and the body of the sender seems to make the earth connection. Screwed it back in and luckily it has been fine since.

 

I'll bet anything that it is the sending unit. They are notorious on these cars for going bad. Located on the transaxle it merely unscrews and is easily replaced.

 

I had to replace the one on my car also. It is called the speedometer impulse generator and is easiest to access if you take the right rear wheel off. I think I paid around $150 for a new one.

 

The odo and speedo run off the same signal....so if the speedo is acting up, the odo will too. You can try removing the sender (unscrew it) and cleaning it with a can of aerosol electrical contact cleaner, using the nozzle to spray into all the openings and electrical connector. Reconnect and cross fingers. That seems to have worked for one or two people. Most just end up buying a new one (I did).

 

If you need the sender, I've got it in stock here in my hot little hands... p/n 124146

http://ricambiamerica.com/product_info.php?products_id=213529


-daniel

 

I just replaced mine. I think yours is identical to mine. That said, it is on your transaxle/tramsmission, driver's side and is relatively easy to get to once you pull the right rear wheel off (I suspect you could get to it without removing the wheel if you have a stand. You can plainly see the electrical connector if you look under the right rear of your 308. Follow the lead to the large brass "bolt" head and unscrew. Taking the wheel off/replacing took the most time. I think it took 20 minutes to replace mine including head scratching time needed to figure out how to heck to get my wrench in there.

Mine bounced like crazy then went dead.

 

See how many so far have had a problem? NEVER believe what you see on the odometer on these cars. I can tell you at least another dozen or so stories.

Be careful when buying one

 

Mike, help me locate. I had the wheel off yesterday and was looking for the sender, I could not find what your talking about. Yours is '85 right?

Right now my speedo is about 15 MPH fast and the odometer is doubling the milage on the trip meter. I was able to determine that by driving my Suv around the block. The 308 registered doble the actual. I really need to get this sorted out.

Thanks for the help

 

See below. It's part 59 with a wire/pigtail coming off the top.
Image Unavailable, Please Login

 

Thanks Daniel, ill be calling if I need the part, I appreciate your help!

 

I too had the same problem last year. Speedo sending unit was the problem. As mentioned, very easy fix...as long as the pin that connects from the sending unit is not seized in the little pinion gear that sticks out of the transaxle.

Try and guess who that happened to.

 

Thats too bad, how were you able to fix it? Im hoping that mine goes the easy route.

Thanks for the input!

 

I removed the little pinion gear that sticks out of the axle housing and went down to my local garage. There, the mechanic heated the gear and quickly cooled it off. Afterwhich, the pin slid right out.

 

Somebody above said this sender is on driver's side, then somebody else said remove the right rear wheel. That person must be in England!

So, the sender appears to be on the clutch side, right?

My speedo is suffering from the same problem every so often, so I figure I'll get in there and try to clean mine..

Thanks,
Greg
77 308 GTB USA

 

An intermittant speedo is usually the dash unit failing, if everything is working ..then it quits (odo also)

The sender can fail...

The dash unit can fail.

or you can have a pinched wire at the metal frame loops, in between.

I've never heard of "cleaning" anything making a difference, the pulse generator at the tranny either works...or not.

The signal reaches the dash via wiring.....or not.

The dash unit works.........or not.

HTH

 

Thanks BT. Post #8 said cleaning may work, so I guess I'm guilty of wishful thinking. Plus, mine is very rarely intermittent, seemingly only so at high speeds for a length of time, i.e.; on the highway. Hard to pinpoint why...
Plus, it's only non-functional for about a mile or so, then it kicks back in. Weird, huh?

Thanks,
Greg

 

No...that's the failure mode of the dash unit..

Somebody here is deep into one, repairing it with a new IC chip........I'm no good with solder at that scale so it's Palo Alto Speedo for me......

 

Oh great......

 

Disagree, the sender can go intermittent (did on my 308 and also on a friend's, though on my 355 it just completely crapped out). They are inexpensive enough, and easy enough to replace that I would go with that assumption first. IF it ends up it is the speedo, you now have a spare sender (they do fail every few years).

 

Thanks Hugh G.!



Here's hoping a little TLC will fix my sender.....

 

+1