Speedo Diagnosis

[dwise]

My Speedo was bouncing around for a bit and finally stopped. Thus far I bought and replaced: 1. The angle drive (it was bad) 2. The dust cap (it was worn) 3. The lower cable (Recommended by John Hervey)

We replaced all of those parts and the speedo still is not working. Yesterday we took the old lower cable and connected it to the bottom of the LAMBDA and did the drill test, the speedo does not spin thru the LAMBDA.

When I take the Upper cable loose from the lamda I can hand spin it and see the speedo moving.

Would this mean the LAMBDA unit is bad? Anything else anyone can recommend before either buying a new/rebuilt LAMBDA or buying that bypass long cable available for $89.95?

[Andrew]

A few years ago I took a Lambda counter apart to add some grease while trying to dx a similar speedometer issue. IIRC, the Lambda counter uses a pass-through sleeve which connects the upper and lower cables. The sleeve turns a gear assembly which turns the counter itself. Thus, absent a failure of the sleeve, I think it would be pretty difficult to have a speedometer failure resulting from the Lambda counter. Before going any further, I would recommend making sure that the upper cable is fully engaged in the speedometer assembly. This can be confirmed (with the binnacle in place) by gently pushing the cable housing upward toward the speedometer.

I may have an extra Lambda counter on my shelf that I removed when I installed a speedometer cable driven cruise control speed sensor in 5052. I don't think the counter itself works, but the speedometer worked fine. If I can find it and you want it, you're welcome to have it for the cost of shipping.

Good luck,

Andrew
4194
5052

[Jonathan]

Your speedo problems sound similar to the ones I had. I too replaced pieces in the chain and a couple of them more than once. I took the guts out of my Lambda counter at one point and that worked for a while. Andrew is right about it having a pin that spins inside between the upper and lower cable. It likely shouldn't matter whether the gears are still in there, but maybe it does. Eventually, I went with the one piece speedo cable (and new angle drive and dust cap at the same time) and eliminated the Lambda counter and it has been fine ever since (KOW).

I don't think it would hurt for you to open up your Lambda counter and at least look and see what is going on inside it. Mine had a ton of goober in it that I can't imagine was helping it turn smoothly. It squeaked a few times when it was still in the car and maybe that was a sign it was on its way out. Who knows. My speedo works now with the one piece cable and so long as it keeps working, I don't much care about the why's or how's. That damned speedo was my nemesis for the first few years I had the car.

55694

[dwise]

A few years ago I took a Lambda counter apart to add some grease while trying to dx a similar speedometer issue. IIRC, the Lambda counter uses a pass-through sleeve which connects the upper and lower cables. The sleeve turns a gear assembly which turns the counter itself. Thus, absent a failure of the sleeve, I think it would be pretty difficult to have a speedometer failure resulting from the Lambda counter. Before going any further, I would recommend making sure that the upper cable is fully engaged in the speedometer assembly. This can be confirmed (with the binnacle in place) by gently pushing the cable housing upward toward the speedometer.

I may have an extra Lambda counter on my shelf that I removed when I installed a speedometer cable driven cruise control speed sensor in 5052. I don't think the counter itself works, but the speedometer worked fine. If I can find it and you want it, you're welcome to have it for the cost of shipping.

Good luck,

Andrew
4194
5052
This can be confirmed (with the binnacle in place) by gently pushing the cable housing upward toward the speedometer.
Andrew ,
Forgive my ignorance but what is the "Binnacle".
And what would I be looking for by gently pushing the cable housing upward?

As I mentioned, if I remove the upper cable from the LAMBDA I can hand spin it and see the speedo moving.

Thanks for the help!

[Andrew]

This can be confirmed (with the binnacle in place) by gently pushing the cable housing upward toward the speedometer.
Andrew ,
Forgive my ignorance but what is the "Binnacle".
And what would I be looking for by gently pushing the cable housing upward?

As I mentioned, if I remove the upper cable from the LAMBDA I can hand spin it and see the speedo moving.

Thanks for the help!

The binnacle is the housing on the dash that holds the gauge cluster. Removal the binnacle isn't too bad, aside from turning yourself upside down in the footwell...not recommended if you have neck, back or shoulder problems! IIRC correctly you need to remove the binnacle to access the release tab on the upper cable at the speedometer head. If the cable housing is pulled down enough it could cause the cable end to disengage from the speedometer head when the cable is attached to the Lambda counter. Thus, before anything else, I would try pushing the cable housing up a little and then reconnect it to the Lambda counter. Maybe that will fix it.

While the single-piece speedometer cable is a nice upgrade, if you ever want to install cruise control retaining the two-piece cable provides the option of a speedometer cable driven speed sensor as opposed to messing around with the driveshaft magnets. However, the cable sensor requires a fitting swap on the upper cable to a GM style fitting.

[dwise]

The binnacle is the housing on the dash that holds the gauge cluster. Removal the binnacle isn't too bad, aside from turning yourself upside down in the footwell...not recommended if you have neck, back or shoulder problems! IIRC correctly you need to remove the binnacle to access the release tab on the upper cable at the speedometer head. If the cable housing is pulled down enough it could cause the cable end to disengage from the speedometer head when the cable is attached to the Lambda counter. Thus, before anything else, I would try pushing the cable housing up a little and then reconnect it to the Lambda counter. Maybe that will fix it.

While the single-piece speedometer cable is a nice upgrade, if you ever want to install cruise control retaining the two-piece cable provides the option of a speedometer cable driven speed sensor as opposed to messing around with the driveshaft magnets. However, the cable sensor requires a fitting swap on the upper cable to a GM style fitting.

Luckily I'm a Yoga teacher so I think I can squeeze under the footwell. Lol. Thanks for the great guidance.

[dwise]

Re the Speedo issue. Just to bring you up to speed. I bought and replaced:

1. The angle drive
2. The dust cap
3. The lower cable.
4. Long bypass cable (bypassing the Lambda completely)

We replaced all of those parts and the speedo still is not working.

It was quite the reach to get the long bypass cable snapped into the back of the speedo. Removing the clip and releasing the old one. The cable end did look somewhat worn and frayed compared to the new long bypass cable. I was able to snap the new one in place (it seemed like it only had one way to attach and the clip went back in. )

I am paying a guy to come over this weekend and help me spin test the cables from the bottom to the top.

Do you have any other specific advice to offer?

[David T]

The only thing left to replace is the speedo itself. That is assuming all of the parts you replaced are working and were correctly installed. Do the "spin test". Raise the front, left wheel and see if the cable end going into the head spins when you spin the wheel.

[PJ Grady Inc.]

Re the Speedo issue. Just to bring you up to speed. I bought and replaced:

1. The angle drive
2. The dust cap
3. The lower cable.
4. Long bypass cable (bypassing the Lambda completely)

We replaced all of those parts and the speedo still is not working.

It was quite the reach to get the long bypass cable snapped into the back of the speedo. Removing the clip and releasing the old one. The cable end did look somewhat worn and frayed compared to the new long bypass cable. I was able to snap the new one in place (it seemed like it only had one way to attach and the clip went back in. )

I am paying a guy to come over this weekend and help me spin test the cables from the bottom to the top.

Do you have any other specific advice to offer?

The company you bought your parts from should be willing to assist in diagnossing what is wrong.
Rob Grady

[dwise]

The only thing left to replace is the speedo itself. That is assuming all of the parts you replaced are working and were correctly installed. Do the "spin test". Raise the front, left wheel and see if the cable end going into the head spins when you spin the wheel.

So we were able to spin the wheel but felt a little tension somewhere in the length.

Just a reminder, I am working with new angle drive, brand new hub plastic thing, extra long cable going directly from angle drive all the way to speedo.

Take a look at this video clip to see what the speedo is doing now. https://youtu.be/fmVBT5sGTyI

[dwise]

The company you bought your parts from should be willing to assist in diagnossing what is wrong.
Rob Grady

John Hervey did indeed take the angle drive back and made an adjustment. We were able to install today, but there is still some tension in the speedo system. Check out this video to see what the speedo is doing now. (Jumping around and making a serious clicking sound) https://youtu.be/fmVBT5sGTyI

[David T]

Is the odometer moving? Does the noise stop if you disconnect the speedo head? I suspect a problem inside the speedometer.

[DMC-Ron]

John Hervey did indeed take the angle drive back and made an adjustment. We were able to install today, but there is still some tension in the speedo system. Check out this video to see what the speedo is doing now. (Jumping around and making a serious clicking sound) https://youtu.be/fmVBT5sGTyI

This video shows symptoms like a speedometer I had (not in the DeLorean, but another classic car). It turned out to be the speedometer cable was tight and sticking. At each rotation, the inner cable would stick at a certain spot then break loose with more twist pressure. This caused the input to the speedometer to "twitch" and the speedometer would jump just trying to follow along. I ended up pulling out the inner cable and lubing it. I Know this is a new cable but it's worth a checking to see if they lubricated it properly from the factory.

One way to check this is to disconnect the cable from the back of the speedometer and bring it down where you can observe it. Push a small piece of card stock on the cable to act as a pointer. Have someone rotate the left front wheel while you observe the pointer as it rotates. It should turn smoothly with the wheel.

Ron

[NightRider]

I've had a lot of problems with my speedometer/odometer recently. I just had my mechanic replace the original speedometer cables on my car, and less than 50 miles later, the speedometer has stopped working properly again. It seems to work ok from a cold start until I hit maybe 20 mph, and then the needle drops to 0 or fluctuates in the 0-5 mph range. The odometer stops working properly as well when this happens.

I'm thinking about getting the one piece cable, but I'm going to have everything checked first to make sure it isn't something else or simply a lubrication issue.

[Jonathan]

I've had a lot of problems with my speedometer/odometer recently. I just had my mechanic replace the original speedometer cables on my car, and less than 50 miles later, the speedometer has stopped working properly again. It seems to work ok from a cold start until I hit maybe 20 mph, and then the needle drops to 0 or fluctuates in the 0-5 mph range. The odometer stops working properly as well when this happens.

I'm thinking about getting the one piece cable, but I'm going to have everything checked first to make sure it isn't something else or simply a lubrication issue.

If yours is only working at low speeds, it might be that the dust cap is spinning inside the hub when it shouldn't be. Wrap a thin, single layer of electrical tape on the edge of the plastic dust cap and reinstall. You are trying to get it to sit in there snug and not rotate. The dust cap is meant to turn with the wheel so that the square hole on the inside of that dust cap that the angle drive cable end sticks into spins and that translates to your speedo needle moving. Try that and also make sure that square hole in the plastic isn't rounded out.

Oh, and yes, the speedo and odo work together. Or don't work together. If something isn't right from the dust cap to angle to lower or upper cable all the way into the backside of the speedo it will show-up on both the speedo needle and odo counters. If one works and the other doesn't (which would be rare) it's a problem inside the gauge.

I personally think that some speedo troubles are a result of small pieces broken off and being left inside in the gauge when someone breaks the trip reset shaft. Nothing to prove that though, just a theory.

[NightRider]

Thanks, I will check the dust cap before I take it back to the shop. Hopefully that is all that there is to it!

[Michael]

Thanks, I will check the dust cap before I take it back to the shop. Hopefully that is all that there is to it!

Agree with Jonathan. I noticed you are in NC, your weather is probably the same as ours. In cold weather my speedo also acts up and I am positive it's a worn dustcap, I even have a new one ready to replace but haven't done so yet.

[David T]

It can also be the square shaft spinning inside the square opening in the dust cap. Or the angle drive. You can test by using a drill to spin the inner cable and see what works and what doesn't. My theory is the posts break of inside the speedometer head and the metal clip gets stuck on the spinning magnet jamming the system leading to the dust cap getting damaged, the cables getting damaged, and the angle drive getting damaged.

[Michael]

It can also be the square shaft spinning inside the square opening in the dust cap. Or the angle drive. You can test by using a drill to spin the inner cable and see what works and what doesn't. My theory is the posts break of inside the speedometer head and the metal clip gets stuck on the spinning magnet jamming the system leading to the dust cap getting damaged, the cables getting damaged, and the angle drive getting damaged.


I think I see a pattern here


The dust cap is meant to turn with the wheel so that the square hole on the inside of that dust cap that the angle drive cable end sticks into spins and that translates to your speedo needle moving. Try that and also make sure that square hole in the plastic isn't rounded out.

I personally think that some speedo troubles are a result of small pieces broken off and being left inside in the gauge when someone breaks the trip reset shaft. Nothing to prove that though, just a theory.

[Grover]

I had this exact problem in the past. Long story short, I had to replace the speedometer because it acted exactly like your video. I tried everything to get it to work and the only way was to buy a replacement speedometer. I tried looking for a shop that could repair and recalibrate the speedo but couldn't find a place that I felt confident sending it to.

[NightRider]

I finally had time to look at this problem on my car. I took the wheel off and checked the dust cap. It seems to be nice and tight. I couldn't see anything obviously wrong from spinning the wheel by hand although it did not spin as freely as I expected it to. I'm just going to take it back to the shop and have them take a look at it.

[Michael]

I finally had time to look at this problem on my car. I took the wheel off and checked the dust cap. It seems to be nice and tight. I couldn't see anything obviously wrong from spinning the wheel by hand although it did not spin as freely as I expected it to. I'm just going to take it back to the shop and have them take a look at it.

You should have pulled the cap.and checked the inside. They strip there too.

[Jonathan]

If you can look again with the dust cap removed, you can also spin the tip of the cable that's sticking out with your finger and learn a few things. You won't be able to spin it fast enough to get up to 50 mph, but you should at least see the needle move up to 10 mph or so. You can get a helper to watch for you, or do the spinning for you, or get creative with a mirror or camera and do it yourself.

The wheel being harder to spin than you thought could just be a relative thing, and nothing's wrong, or it could be telling you the brakes are sticking. That assembly is a long way from some frictionless perpetual motion device, but it still shouldn't take a ton of effort to spin it with your hands.

[David T]

For comparison you can also spin the right front tire to see how easy it or hard it is. Get a helper and try a cordless drill and see if you can get any readings bu spinning the cable. You can also try disconnecting the cable going into the angle drive and spin the inner cable there. Make sure you spin it the right direction!

[NightRider]

Yea, I knew that I should have checked the inside of the cap, but I was by myself and was rushed a bit. I'll check it again tomorrow with a helper. Thanks for all of the helpful suggestions!

[NightRider]

Update: I had time to work on this today. I took the dust cover off, and it looked stripped on the inside. I used a cordless drill to turn the system and was able to get the speedometer to register just fine even up to high speeds. Anyway, I ordered a new dust cover so hopefully I'll be back in business once that arrives. I'm wanting to sell the car and felt like I really needed the speedometer and odometer to work before showing it to any buyers. Thank you for the help!