jumping speedometer?
1 - 15 of 15 Posts
Joined
·
79 Posts
This has happened periodically with my '74 Spider (manual)...mostly around the time I had some ground issues (inconsistent starting, speedo jumping...sudden failure of throttle cable and hood release cable). Cleaning and tightening the various grounds seemed to alleviate the problem...could be a coincidence though...as a good car wash also seemed to fix things!
I was wondering if you would mind sharing a copy of the solution to this problem. I just purchased a 1991 Spider Veloce Automatic and I have this problem. Would like to know how to repair myself.
Thanks,
Dan
Joined
·
13,131 Posts
It's one of the Alfa published TSBs. You can get all the TSBs as well as the service manual from cardisc: CarDisc International Ltd. - Home Page It's well worth the $50.
Joined
·
612 Posts
Correct me if im wrong, but in your `74 speedometer is mechanic not electronic, and to its functionality you dont need to have any power, unless yours is modified. So in this case I cant imagine how bad ground can couse jumping effect in speedo?
If you go to where the cable connects at the firewall next to the master cylinder and unscrew it you can pull the inner cable out and lubricate it, found that wd40 works better than graphite in this car.
Uh yea, improving the ground on a mechanical speedomenter isn't going to solve much. Replacing the hood cable will though...
But seriously, bad grounds and a throttle cable failure MIGHT be related. If your engine ground strap isn't present or tight, then guess what grounds the engine? The throttle linkage! All that current running through your Spica throttle cable will heat it up, change its heat treatment, and cause it to die. Yea, the throttle shaft is electrically isolated by its two bushings. But at rest, it contacts the stop, which grounds it to the body.
Joined
·
79 Posts
Well gentlemen, I hope you've had a little fun at my expense! But, it's amazing what happens when one gets into one of these cars...cleaning a little of this, tightening a little of that...heck, even just bumping something, then, voila! Something totally unrelated suddenly works (or doesn't!). I stand by my suggestion...waste a little time, and clean those ground contacts. Your throttle cable will last longer, your car will start more reliably, heck, maybe your hood latch won't give out, or your trunk lever...and, while you are doing that, you might just knock a kink out of the speedometer cable!
Joined
·
2,830 Posts
The Series 4 Spider instrument cluster is all electric.
On my 1991 Spider, after pulling the cluster, inspecting and cleaning harnesses and connectors fuses and solder joints and pins and removing hot glue from variable resistor pots and turning adjuster screws, I put it all back together and implemented the referenced SB in an attempt to fix my speedometer, which has randomly varied from smooth to erratic operation to nonoperational since I bought the car several weeks ago. For about six miles on the first test drive after complying with the SB, the speedometer worked as designed, then abruptly went dead.
The tach however, completely inoperative since I bought the car, decided to briefly work shortly after the speedo went back to sleep. Then it too became tired and fell lifelessly to the resting peg. I suppose it's one or the other, but not both. If I allow the car time to rest, the speedometer will operate for a few minutes. Or a few miles. Whichever comes first. Then it takes a nap again. The tach remains listless, immobile only until I give it a few solid pod whacks. It jumps a bit in fright with each whack, then cowers against its rest peg, trembling and wondering why I'm abusing it.
Jaeger, a decidedly Teutonic name, does not live up to the myth of German excellence in engineering. The car has been well cared for and the pod, connectors, and harnesses all appear nearly new. The Jaeger family obviously lived in Italy for too many generations prior to deciding to manufacture electronic components for the automotive industry.
On my 1991 Spider, after pulling the cluster, inspecting and cleaning harnesses and connectors fuses and solder joints and pins and removing hot glue from variable resistor pots and turning adjuster screws, I put it all back together and implemented the referenced SB in an attempt to fix my speedometer, which has randomly varied from smooth to erratic operation to nonoperational since I bought the car several weeks ago. For about six miles on the first test drive after complying with the SB, the speedometer worked as designed, then abruptly went dead.
The tach however, completely inoperative since I bought the car, decided to briefly work shortly after the speedo went back to sleep. Then it too became tired and fell lifelessly to the resting peg. I suppose it's one or the other, but not both. If I allow the car time to rest, the speedometer will operate for a few minutes. Or a few miles. Whichever comes first. Then it takes a nap again. The tach remains listless, immobile only until I give it a few solid pod whacks. It jumps a bit in fright with each whack, then cowers against its rest peg, trembling and wondering why I'm abusing it.
Jaeger, a decidedly Teutonic name, does not live up to the myth of German excellence in engineering. The car has been well cared for and the pod, connectors, and harnesses all appear nearly new. The Jaeger family obviously lived in Italy for too many generations prior to deciding to manufacture electronic components for the automotive industry.
Joined
·
2,830 Posts
I wish I knew. I pulled the tach from the cluster, it looked good. All solder joints, pins, etc. look almost new. After installing the speedometer SB, there was a noticeable change in operation. It now operates smoothly from first pull away until it quits in a few miles- no erratic jumping. It's consistent too- after five to six miles of driving, it fails completely and will not return to operation until a good night's sleep in the garage. Then it works smoothly again for five to six miles, then fails. Before installing the SB I had also removed the sending unit and wires on the transmission and cleaned all that thoroughly.
So if we've cleaned all electrical connections, checked harness continuity, replaced any applicable fuses, verified the sending source is functional, really all that I can come up with is to replace an individual gauge or send the entire cluster off to a professional rebuild shop. The annoying thing is my cluster and the gauges within, all in great condition, at least upon visual inspection.
Ah well.
So if we've cleaned all electrical connections, checked harness continuity, replaced any applicable fuses, verified the sending source is functional, really all that I can come up with is to replace an individual gauge or send the entire cluster off to a professional rebuild shop. The annoying thing is my cluster and the gauges within, all in great condition, at least upon visual inspection.
Ah well.
1 - 15 of 15 Posts
Join the discussion
