25 replies to this topic

[D-DAWG83]

Still got issues with my speedo, though now starting to think its a connector issue rather than a cable issue. Iv replaced the rear hub, the wiring into the main loom, as well as the fuses, and still sometimes get a dead speedo. There is a road to work that is pretty bad, and when i go over it, the speedo flickers into life again. It is also the same after intense rain, its works fine, then when it dries out, it dont work again. Just wondering if there are any connectors that also power the speedo that could be a little loose and need cleaning and connecting properly. When the speedo is not working, when i depress the clutch to change to first, the revs die a little, like the car is about to stall,then it picks back up again.

[fezzasus]

Could be an issue with the stack. There are new ones for sale in the Lotus auctions.

[D-DAWG83]

Iv tried banging the stack, and it has no effect. Though that is no sure way of testing it. Everything else is working fine on the Stack. Would a MAP sensor have anything to do with it? Lee VX replaced mine a while back, as my one failed, or are there any other parts of the looms that would affect it? The looms around the engine look fine and healthy, not crispy at all. Thats why im wondering if iv just got a dodgy connection some where. But dont know of any other connectors that could affect the speedo.

[fezzasus]

Might be time to do some resistance testing on each pin. Painful, but better than simply splicing in a new connector

[D-DAWG83]

Have no idea where id even start doing that, or even how to. When it comes to electrics, you may aswell be talking Japanese. Ha ha

[Bargi]

Not 100 percent sure but doesn't the rear hub centre go to the ABS unit first then to the stack or is that might be for the ECU

[D-DAWG83]

Il have a look aroubd that area and see if i can see any damaged wires or anything

[peteslag]

I seem to remember you had an ABS issue. If that is the case it won't be an issue with the stack. It must be related to the rear left ABS sensor/wiring as it has an input into the speedo and ABS system. You need to find something that is common to both systems otherwise you'll be chasing a a big fat red herring. Don't forget, the ABS worked perfectly when I had the car (yes folks, 2 channel ABS that works!!!).

[D-DAWG83]

Just had a look at the ABS module, and noticed that there is some marks on the plug that look like scortching, wondering if this is normal or not.


Also, noticed after driving, that if i brake, ie shift the balance forward, then the speedo seems to work, then under load,leaning back, it sometimes kills the speedo.

[peteslag]

When your abs is disconnected, the fault is still there so i'm not sure that would be the cause.  This really sounds like a wiring fault. Exactly what wiring have you replaced?

[Exmantaa]

According wiring scheme, the rear left (wheelspeed) sensor is connected to pin 22 & 23. So (let someone...) measure Ohm resistance with a multimeter accross these 2 pins:

Edited by Exmantaa, 28 June 2015 - 03:57 PM.

[leevx2.2]

If your speedo is not working the engine will try to stall when coming to a standstill . I have a spare abs unit you could check

[D-DAWG83]

Replaced the rear hub,the connector and the wiring all the way to an inch of where it goes into the main loom. Seems odd that when i brake it works again, like a dodgy connector or something.

[D-DAWG83]

If your speedo is not working the engine will try to stall when coming to a standstill . I have a spare abs unit you could check

Thanks Lee, sounds like a start. Will drop you a message and sort something out

[peteslag]

Replaced the rear hub,the connector and the wiring all the way to an inch of where it goes into the main loom. Seems odd that when i brake it works again, like a dodgy connector or something.

 

Whenever you have replaced wiring it is good practice to con check it.  I would do continuity checks from the abs unit to the sensor, as exmantaa suggested. Get some one to wiggle the wires by the sensor while you're doing it. Otherwise you could be chasing your head up your arse for no good reason! 

[D-DAWG83]

Checked the restistance across the pins yesterday, and got 1490ish ohm's, so iv ruled that out now. Iv bought a pair of front hubs, so will replace them, and see how i get on. The hubs look original, so its worth replacing them even if it dont fix the problem, will have fresh hubs all round then

[fezzasus]

I have a spare 2 channel ABS controller if you'd like to give that a go. My parents are in MK so i'm there periodically. 

[peteslag]

Checked the restistance across the pins yesterday, and got 1490ish ohm's, so iv ruled that out now. Iv bought a pair of front hubs, so will replace them, and see how i get on. The hubs look original, so its worth replacing them even if it dont fix the problem, will have fresh hubs all round then

 

Seems a shame to replace hubs that have covered less than 50,000 miles, your choice I suppose.  A wire brush and a lick of paint will work just as well! Your front hub sensors have absolutely bugger all input into your speedo by the way.

 

Is 1490 ohms normal? Seems a bit high to me. Disconnect the connector at the hub then short the pins out with a bit cable. Re-check at the ABS controller connector, you should see almost zero ohms. Anything more than that, you still have a wiring fault.

[Exmantaa]

Checked the restistance across the pins yesterday, and got 1490ish ohm's, so iv ruled that out now. Iv bought a pair of front hubs, so will replace them, and see how i get on. The hubs look original, so its worth replacing them even if it dont fix the problem, will have fresh hubs all round then

 

That sounds as a reasonable value. I just checked and both my 2 (front) hubs measure 1452 and 1460Ohm, directly on the ABS sensor connector.

 

Your Speedo problem is not the rear ABS sensor/wiring...

[peteslag]

 

Checked the restistance across the pins yesterday, and got 1490ish ohm's, so iv ruled that out now. Iv bought a pair of front hubs, so will replace them, and see how i get on. The hubs look original, so its worth replacing them even if it dont fix the problem, will have fresh hubs all round then

 

That sounds as a reasonable value. I just checked and both my 2 (front) hubs measure 1452 and 1460Ohm, directly on the ABS sensor connector.

 

Your Speedo problem is not the rear ABS sensor/wiring...

 

 

This is very odd. It is still worth baring in mind that your speedo fault and abs fault both seemed to manifest themselves at the same time. Maybe it is worth looking at the wiring diagrams and try to see if anything else that is common to both systems. 

 

I'd still short out the cable and do a resistance check of the rear left abs loom, it will take you about 5 minutes to do and would rule it out once and for all. There is a difference of 30/38 ohms between your readings and exmantaa's after all.