Severly Bouncing Speedometer

[kings1527]

So my problem seems to be a little different compared to the standard speedo problems. I left my car out overnight where it got into the low-mid 30's. I started driving and the speedo worked fine for about a mile and then it started jumping around wildly. If I were driving 60 on the freeway and then hit the accelerator suddenly, it'd bounce to 85, 75, 70, 80, 85, 75, etc. Randomly all over the place. This whole time, the odometer still worked perfectly.

As soon as things warmed up and I got out of the valley and into a slightly warmer climate (maybe about mid 40's at that point), the problem started to correct itself. By the time I got to work, the speedo was just about back to normal. This has never happened before but this is easily the coldest I've driven the car. Here's my service history with the angle drive and all ancillary components:

-original angle drive
-AD lubricated with gear oil at least every oil change (about every 3 months or so)
-DMCNW teflon lower speedo cable
-upper speedo cable is original
-lambda counter was reset about a couple years ago and was fine

I need to pull the wheel off today and look at the dust cap but like I said, the odometer never gave me problems that I could see. I thought maybe some linkage for the speedo needle had broken internally due to the cold the but the speedo started working again normally as I drove to a warmer area.

Has anyone ever had their speedo get all funky in very cold weather?

[DMCMW Dave]

That's when the grease gets hard and things go bad.

Could be in the lambda box, could be the upper cable, could be water in the lower cable etc. When it's jumpy like that it is usually the plastic cap slipping in the hub, but look at that as an indicator that something is not right.

[kings1527]

Thanks Dave. I'll take a look at the plastic cap and look at the hole and start from there.

[Jonathan]

If I were driving 60 on the freeway and then hit the accelerator suddenly, it'd bounce to 85, 75, 70, 80, 85, 75, etc. Randomly all over the place. This whole time, the odometer still worked perfectly.

Just food for thought here, and not trying to argue, but I don't expect the odometer was still working perfectly throughout this cold weather problem with your speedo.

Reason being is they are tied together and unless the speedo problem had somehow been related to only the actual needle on your gauge, they would both misbehave together.

If you drove a couple miles and it bounced a little high for a while and then a little low, it might come out to average the same distance driven and give you the impression it is still working. Or if it only bounced higher than it should have been, if you travelled 2 miles it might have recorded 2.5 miles perhaps.

You can see very quickly if your needle on the speedo isn't reading the exact speed you know your car is travelling at (verified by a GPS unit perhaps) but to know whether the odo is recording miles accurately you need to do it over an extended period of time or distance. Your speedo might have been bouncing in the cold only enough to make you believe the odo was working ok when it really wasn't.

Like I said, not trying to be argumentative. And luckily regardless of whether it was or wasn't working perfectly, it will be back on track once the speedo needle is back on track.

[kings1527]

Hi Jonathan,

No, I hear what you're saying. I appreciate the input. That didn't make any sense to me either. I kept as close of an eye on my odometer as I could safely do so and the "speed" of the numbers turning was the same. But like you said, for a split second or for however long the needle was severely bouncing, that could throw the odometer off. But there were periods where it was bouncing all over the place for 20-30 sec and I could swear the odometer was still consistent. I'd have to see that again just to be sure and I know it doesn't make sense but I was looking specifically at the odometer because my first thought was either the dust cap square hole became ground out or the angle drive took a dump. When I saw everything was working as it should with the odo, then I became really confused.

I'll know more tomorrow when I drive home and I'll pull the wheel here in a bit.

[TTait]

To expand on Dave's post - Also understand that the dust cap is similar to a fuse in some ways. It can eventually just get old and start to slip a little, but its as likely that there is other friction in the system that is making it harder to turn the dust cap.

Check the stuff he called out as the cause, and the dust cap spinning as the effect. You may well have to replace the dust cap, but address any underlying friction before you do.

[kings1527]

Thanks. So I pulled the wheel off and the dust cap itself looks good. There didn't look to be any damage to the square hole. I've pulled it off and replaced it so many times that it just kind of rests in its place. I twisted the angle drive cable for about 20 revolutions and it moved perfectly without any resistance. Just like it always has. :dunno:

I'll drive it home tomorrow and see how it works. I have a GPS speedo app on my phone so I'll test it that way but coming in to work I did just that, and it was about as accurate as it always has been. Maybe +/- 2mph or so. Strange. I've never seen it bounce so wildly as this morning...25-30 mph swings at times.

[kings1527]

And for what it's worth, I always lubricate the AD during every oil change with 80W gear oil. I would think that would stay more liquid than grease when it gets very cold. Although I'd expect it to get very viscous at 35 degrees as compared to 50 degrees.

[DMCMW Dave]

Wrap a turn of electrIcal tape around the outside of the cap and it will stop slipping.


Sent from phone

[hmcelraft]

Somewhere I remember reading that the OEM angle drives have a propensity to wear (if not lubricated regularly) or, they were already loosely meshed, and allowed the gears to slip when things got a little "tight" on up the line - like cold grease in a cable, lambda counter, etc.? It may be time to replace the angle drive. You might be able to test for that symptom but it would probably take two people - one turning the wheel the other applying some limited resistance to the cable as it turns.

I had a similar pulsing issue but turned out to be the lower cable got dry and eventually froze - taking the angle drive with it. It happened quickly, too. Shaking of needle started - 15 minutes of driving later the speedometer went dead.

[kings1527]

Somewhere I remember reading that the OEM angle drives have a propensity to wear (if not lubricated regularly) or, they were already loosely meshed, and allowed the gears to slip when things got a little "tight" on up the line - like cold grease in a cable, lambda counter, etc.? It may be time to replace the angle drive. You might be able to test for that symptom but it would probably take two people - one turning the wheel the other applying some limited resistance to the cable as it turns.

I had a similar pulsing issue but turned out to be the lower cable got dry and eventually froze - taking the angle drive with it. It happened quickly, too. Shaking of needle started - 15 minutes of driving later the speedometer went dead.

I hope it's not time to replace it. I was very lucky with my car since the AD was in great shape when I bought it and I put it on a strict diet of gear oil lubricant at every oil change which is very frequent; about every 3 months.

So I drove home yesterday and checked everything with an odometer and speedometer app and everything seems to be working as normal. Like I mentioned before, there was zero resistance on the AD when I manipulated it the other day. Whatever it was, it had to have been related to the very cold weather and hopefully the resistance met during the cold didn't harm anything internally. And it's quite possible that my speedo was slightly more bouncy than normal after this incident. Or maybe I'm being very paranoid right now. Don't know. But just like I am with my car in general: drive it until it dies.