intermittent speedo
12-13-2003, 10:59 AM
#1
Drifting
Thread Starter
intermittent speedo
anyone have some advice as to what to look for in the 1988 car? this is like an intermittent connection. sometimes the speedo works and then it just quits. maybe later it will start again.
its getting to be a real pain as im not sure how fast im going when i see speed cameras and the like!
its getting to be a real pain as im not sure how fast im going when i see speed cameras and the like!
12-13-2003, 11:56 AM
#4
Rennlist Member
Drnick,
I have the exact same thing going on in my 82. Does your odometer and trip meter stop working as well? mine stop working when the speedometer does. It works for a few miles then decides to stop for a few miles than works again. very random. started about a month ago.
I have the exact same thing going on in my 82. Does your odometer and trip meter stop working as well? mine stop working when the speedometer does. It works for a few miles then decides to stop for a few miles than works again. very random. started about a month ago.
12-13-2003, 12:10 PM
#6
Nordschleife Master
drnick: Sounds like something in the pod, then. There's just one connection to the pod. Maybe a new flexible circuit is needed. You'd have a good chance to clean all the connections at that time.
There's a connection at the right-front of the spare tire well that causes problems. That'd drop both spedo and odo.
There's a connection at the right-front of the spare tire well that causes problems. That'd drop both spedo and odo.
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12-13-2003, 12:43 PM
#8
Nordschleife Master
I have the problem that it takes a few sec sometimes for the signal to register while the odo and trip are working the speedo sits on 0 for a few sec then jumps up to speed, I had just assumed as the signal is getting to the computer it is just a loose/corroded connection, I was just going to be replacing the printed circuit and cleaning the connectors, but the printed circuit is my gues as to what it is
12-13-2003, 01:58 PM
#10
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Originally posted by Lizard931
I have the problem that it takes a few sec sometimes for the signal to register while the odo and trip are working the speedo sits on 0 for a few sec then jumps up to speed, I had just assumed as the signal is getting to the computer it is just a loose/corroded connection
I have the problem that it takes a few sec sometimes for the signal to register while the odo and trip are working the speedo sits on 0 for a few sec then jumps up to speed, I had just assumed as the signal is getting to the computer it is just a loose/corroded connection
12-13-2003, 02:52 PM
#11
Nordschleife Master
The connector in the spare tire well is for speedo pick-up and back-up light switch. I use fine sandpaper on the plugs and inside of the sockets.
The flexible circuits get really stiff and fragile with age. New ones to replace them are still available. Not a tough job in itself, but getting the pod out and the edge connectors back on right ain't easy unless you're a Chinese circus contortionist.
The flexible circuits get really stiff and fragile with age. New ones to replace them are still available. Not a tough job in itself, but getting the pod out and the edge connectors back on right ain't easy unless you're a Chinese circus contortionist.
12-13-2003, 03:48 PM
#12
Nordschleife Master
I was just going to call/contact 1 of the big 3 to see if they had 1 or I was just going to remove it and then clean all the connections, and check for breaks,
12-14-2003, 06:03 AM
#13
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I have found that a good old whack on the pod usually gets the instruments going again when this happens to me. May want to try that when you're speed camera dodging, drnick, until you get a permanent fix (i.e the courage/time to clean pod connectors). Also, best to make sure nobody sees you doing this on the highway 
12-14-2003, 06:15 PM
#14
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As outlined above, the speedo sender is connected in the spare tire well and that connector needs to be cleaned occasionally. The sender delivers signals to the spedometer and odometer as well as the cruise control. If you cruise still works, then the sender and rear connector are ok.
The speedo signal reaches the pod through the lower left connector. You may be able to get at it and at least make sure it is seated well by removing the lower plastic cover plate (if you have small hands). Really, most anything you do back there requires pulling the pod. Once you have done it a few times, it is a 15 minute job which includes removing the steering wheel. It is not as daunting as it seems.
The cause of my intermittent speedo was the flexible printed circuit card. If you look at the card and trace the speedo signals, you will find that they wind up at 4 prominent grommets that are in the center of the board in a line. The job of those grommets is to carry the signal from the back of the card to the front of the card where they can be plugged into the speedometer housing. The grommet connection on mine had become intermittent with age, so the signal was lost every time the board flexed.
A new circuit card is cheap and will possible help with other things. For instance, my voltmeter picked up 1/2 a volt with the new card. While you are in there you can replace the bulbs as well.
Good luck
The speedo signal reaches the pod through the lower left connector. You may be able to get at it and at least make sure it is seated well by removing the lower plastic cover plate (if you have small hands). Really, most anything you do back there requires pulling the pod. Once you have done it a few times, it is a 15 minute job which includes removing the steering wheel. It is not as daunting as it seems.
The cause of my intermittent speedo was the flexible printed circuit card. If you look at the card and trace the speedo signals, you will find that they wind up at 4 prominent grommets that are in the center of the board in a line. The job of those grommets is to carry the signal from the back of the card to the front of the card where they can be plugged into the speedometer housing. The grommet connection on mine had become intermittent with age, so the signal was lost every time the board flexed.
A new circuit card is cheap and will possible help with other things. For instance, my voltmeter picked up 1/2 a volt with the new card. While you are in there you can replace the bulbs as well.
Good luck
12-14-2003, 07:24 PM
#15
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On the earlier (non-digital dash) cars, if the odo/trip odo still work but the speedometer doesn't, the problem is inside the speedometer head itself. There is only one connection for the pulse from the sending unit for everything.
If both the odo/trip odo and the speedometer stop, first suspect is the connector in the spare tire well, second suspect is the connections to the flexible printer circuit board, third is everything else. We (and the other vendors) sell the flexible printed circuits.
If both the odo/trip odo and the speedometer stop, first suspect is the connector in the spare tire well, second suspect is the connections to the flexible printer circuit board, third is everything else. We (and the other vendors) sell the flexible printed circuits.