85fortheDrive

Halfway to work this morning, the speedometer needle dropped to zero and stayed there for twenty minutes. Meanwhile the odometer stopped turning. ( I replaced the crummy ODO gear a coupla months ago, so I'm not suspicious of that). After twenty minutes, the speedo started to climb again, but showed 40 MPH when I think I was doing about 65 (2000 rpm in 5th).

Might this be a relay problem?
Any BTDT tips?

Thanks folks.
Tim

Rod Underwood

Check the left connector under the access panel under the pod. I've had similar problems and it was associated with this connection. You may also need to clean the connections in the spare compartment.

Rod

j.kenzie@sbcglobal.net

Tim,
Check to see if odometer and speedometer are failing at the same time. If so, the problem is probably bad connection anywhere from connector at right front corner of spare tire well to left pod connector as Rod points out to circuit foil on back of instrument cluster. If odometer works but speedometer doesn't then the problem is probably internal to speedometer.
Good luck. I had both problems in my 84S.
Dave McK.

Rod Underwood

You can actually leave the cover off under the pod and reach up under the pod to the connector while driving and see if that's the problem.

Rod

85fortheDrive

Dave and Rod:

Thanks for both suggestions. I'm no stranger to the instrument pod, so I will check those bunched connectors. So too, the spare tire connector is any easy check and a likely suspect.

New clue: the car alarm has been going on intermittently this morning, much to the delight of my fellow employees. Might this be related? I've left the car unlocked in the hopes that it will stay quiet for the remains of the work day.

928s are fun, aren't they?

j.kenzie@sbcglobal.net

Tim,
My guess is the alarm is different problem unfortunately. On our cars (84S) alarm can be disabled by pulling Z-plug at CE panel an jumping Z4 to Z6 (not what is often described). That does not fix anything except keep the alarm from going off.
Dave

hacker-pschorr

Spare tire - there is a plastic 4-pin plug that feeds the speedo in this area, front most portion of the spare tire area.

I cut off the plug, replaced with 4 individual connectors. I haven't had any speedo issues since. Before I had to tighten that platic plug a few times a week to turn my speedo back on.

My car in an 81, so not 100% sure the 84's are the same.

Big Dave

I had that happen to me. It was a short in the interior lights. The alarm system will be triggered if the alarm is armed and the interior lights come on. In my case, it was the lower rear hatch assembly. It had broken and was intermittantly shorting out, fooling the car that the rear hatch was being opened.

85fortheDrive

Hacker:

Is this the wiring connection you're talking about? If so, I'll go ahead and swap it out for individual connections.

Dave:

My back hatch light assembly is indeed a major suspect. I can't have it in the triggered-on position or fuse 28 pops immediately. Something funky going on there. I will check the wiring and see what the problem might be.

Thanks and Peace,
Tim

Rod Underwood

That's the one. Good luck.
Rod