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Temp Gauge Entertainment

scam75

Active member
Greetings chaps

Mentioned this on my build thread once or twice but merits its own thread now I think!

My temp gauge is causing me grief! To start the gauge was erratic and flicking upwards sometimes to max, always above the temp it should be. A flick on the clock pod would sort it out for a bit, then it would go daft again soon. Cleaned up and swapped rugby balls (I have a spare complete clock pod) and was ok for a few days, then went worse than ever. Tried a different rugby ball, again ok for a few days then bonkers again. So, I swapped out the temp/fuel gauge from my other pod. Perfect for a week or so. Then noticed the other day I had no temp after driving for a bit, flicked the pod and it sorted itself. Then yesterday I noticed it was starting to be a bit erratic again, but this time going lower than the actual temp. Again, flicking the pod offers a temporary fix!

So, my thoughts are, it can't be wiring, sender (been replaced before chasing this issue, made no difference), or the dash cluster itself (can it?), as one gauge causes/can cause an erratic over-read, and the other gauge causes/can cause an erratic under-read, or even a no read? I'm mostly ruling out rugby balls as well due to multiple swaps, and pretty much at the stage I think I have 2 x faulty gauges. I could swap over the full PCB from the other pod (only thing I've not tried), but I don't think its the issue given 2 different types of fault with the 2 gauges?

So questions would be:
  • Can you actually obtain the rugby ball thingys anywhere without buying a full binnacle? Suppose it would do no harm to acquire some new ones.
  • Can the gauge itself be cleaned up in any way to help the issues, or be repaired?
  • Do you agree my gauges are faulty (fuel side is fine on both)?
  • Any other suggestions?

Probably hard to find 2nd hand without paying £300+ for a full clock pod. I'm not doing that. There is one on eBay just now for £40, I'm not convinced the temp needle is sitting where it should be though in the picture, it seems to be touching the start of the white markings, whereas my 2 gauges sit a couple of mm away from the start of the scale, when powered off.

Thanks as ever in advance

Stuart


 
Mine was also doing this last time I drove it, something to deal with when it eventually goes back on the road. Are there any capacitors on the cluster? could it be failing components? If so this should be easy to replace?

How are your grounds? are you still using the original engine ground strap and battery ground strap? (did a search on rennlist - this is a VERY common topic on there) from the threads I've read, most common fix is grounds or sensor / sender. Someone also mentioned the diodes on the cluster could be bad, or the ground behind the cluster.

Found this as well - Pelican Parts Technical Article: Solving Strange 944 Gauge Problems...

You can test the sender and wiring with a multimeter - Sensors and Gauges - Information, Troubleshooting, and Testing (clarks-garage.com)

 
So, thanks for all your replies on this matter.....................:ROFLMAO:

Spent a day on this today. It may be fixed or it may not. To be fair I wouldn't offer any advice on this subject either!

So today took the clocks out, took out the low error gauge and cleaned it all up best I could. Put it back together and it worked.......for 5 mins......then literally died. So, I got the clocks back out and whipped out the spare binnacle, which happens to look in much better shape then the original one, and decided I would plug in this binnacle, as it was, and see how the temp gauge was (this had the high error gauge at this point). It seemed to work fine, so I took the decision it could be the pod or PCB and went about swapping everything over. This meant the rev counter, speedo and oil pressure/voltage gauges would need swapped over as they all have some sort of issue. The rev counter is bouncy and the needle slightly bent, the speedo obviously had the wrong mileage, and the voltage gauge was badly out of calibration.

First up, had to carefully swap over all the bulbs as I had been robbing this binnacle for years for spares. This is not easy in daylight going back and forward, in and out the car, to check all the bulbs are correctly located and working. Then crack open the binnacles and swap the oil pressure/voltage gauge, easy enough. Then the rev counter, a bit trickier but had done it before so not too bad, 3 screws and 5 nuts/washers and it comes out. Then the speedo, hadn't done this swap before, very fiddly, but got there in the end, unsure it would work though (see later on..). The speedo has 4 screws holding it, but when you start to remove it you see that it has a PCB underneath, that locates over pins (which doesn't move with the gauge, and is connected by wires, quite short, and routed round screw lugs for extra inconvenience!), that needs prized off with one hand as you hold the speedo with the other. A couple of rubber seating washers to deal with, and a black plunger thingy that sits on a slidey pole and locates into another device, no idea what it does. So, it's very tricky to remove and even trickier to refit. A three hand job if ever there was one! Thankfully, could play about with the other binnacle a bit to fumble my way through it. Of course, the removed incorrect speedo, reseated into the now reserve clock pod quite easily (luckily it turns out!) and of course the correct speedo, did not reseat very easily at all into the "live" binnacle. Anyway, much fiddling later it was in!

Bolted it all back together and re-assembled into car, all working including speedo, trip reset and odometer, result! Out for a test drive, 5 mins later we got the sky high temp again. FFS.

So it wasn't the binnacle itself. Clocks out again, split both pods and got back out the low error gauge, that had previously died earlier in the day. Swapped this back in and found the best rugby ball out my collection, back in the car and it worked fine surprisingly. Let it run up to temp, a few fan on and off cycles, and all was well. End of play after that so no test drive as had had quite enough of removing pods and swapping gauges back and forward by then! Was best to chuck it with it working and cling to the hope it would keep working I thought!

Remains to be seen if it will continue to work, fingers crossed. So I may well still have 2 x faulty gauges, or it could be rugby ball related (less likely I think) but I do have a much nicer binnacle than I did now installed! Will get another gauge if it plays up again.

Word of warning for any future clock pod dismantlers, the little orange needles on the gauges are so delicate and can be bent or twisted by breathing too hard! I don't know what they are made of but to the untrained eye it seems to be folded rice paper painted orange! Bare this in mind when you are trying to eradicate bits of dust on the gauge faces before you whack on the plastic cover and button it up! I tried using a hairdryer for this purpose and it looked like I had turned the ignition on!

Feel free to give me a shout on any binnacle related matters, apart from the f'kin temp gauge!

Cheers

Stuart
 
dlknight said:
Mine was also doing this last time I drove it, something to deal with when it eventually goes back on the road. Are there any capacitors on the cluster? could it be failing components? If so this should be easy to replace?

How are your grounds? are you still using the original engine ground strap and battery ground strap? (did a search on rennlist - this is a VERY common topic on there) from the threads I've read, most common fix is grounds or sensor / sender. Someone also mentioned the diodes on the cluster could be bad, or the ground behind the cluster.

Found this as well - Pelican Parts Technical Article: Solving Strange 944 Gauge Problems...

You can test the sender and wiring with a multimeter - Sensors and Gauges - Information, Troubleshooting, and Testing (clarks-garage.com)


Sorry Dave, never seen this reply, must have been while I was writing my post!

There are stacks of diodes, resistors and some capacitors exposed on the rear of the cluster. I've mostly ruled these out in my case as per my post, as same results with 2 x clusters, displaying exact same issue, would be most unlikely IMO.

Yes, still got the original engine ground and battery straps, couldn't rule this out, however all my other gauges are spot on and unwavering so I tend to think this is also not my issue.

Many thanks for the links!

Stuart
 
Stuart,
I have exactly the same issue. I've had it on and off since I bought the car many years ago.
I've had about 4 different temp/fuel gauges in it over the years and it seems to sort it out for a while and then it will, randomly, hop up and down and then be fine for months.
I've had it all out and cleaned it many times and it makes it different but not really properly fixed.
A tap on the dash usually fixes it so it must be electrical and in the dash but exactly what I haven't found it.
As you say spares are getting hard and expensive to find although I feel I should have sufficient to find one that works!
If you find a fix let me know!
 
Thanks David.

Yeah sounds exact same (and Dave K as well). With you guys saying that it sways me back to rugby balls. Although I have swapped known "good" rugby balls over to the temp gauge, then like you say, can be good for days or months before the symptoms return. I've definitely ruled out the PCB/binnacle with my testing. Between us we have possibly ruled out the gauges, though I did read today on Pelican link that a gauge going skywards is usually a faulty gauge. But between us we are talking 6 or 7 gauges all doing the same (though I have one gauge doing opposite!), bad batch, bad design? Who knows. Just noticed I think our 3 cars are all MY90, could point to bad batch? (Although chances of all your replacements being from MY90's is slim!)

It could well be that the temp gauge is more sensitive than the other gauges causing it to misbehave with a rugby ball that seemed fine on another dial? Just a pure guess.

On the rugby ball front, someone must surely sell replacements? Can't be that hard to knock a batch up, can't believe nobody has done this at any point. Also, they do not like de-oxidising contact cleaner, I find they get worse after using that. Once my gauge inevitably plays up again, I will try cleaning with metal polish (as Paragon recommends) and cleaning up residue with alcohol. That's about the only thing I've not tried.

I will keep the updates coming!

Cheers

Stuart


 
I had a problem with my last Turbo. The usual issue with the disintegrating 'cork' gear wheel.
After I replaced it the odometer was running about 30% high. cut a long story short I sent it to an outfit in Holland who were recommended from a number of sources. The guy specialises in PCB restoration. It was a costly exercise and basically he didn't fix the problem.
He made the point however that the components on PCB 's are getting very old and will inevitably deteriorate. I'm a retired Electrical Engineer and spent some time working on industrial Capacitors. These are reckon to last about 7 years at best!
I've always left the rugby balls untouched as they are pretty sensitive.
BTW when the Odometer gear fails does it stop the trip meter AND the overall odometer from working?
Eddie
 
g59tester said:
I had a problem with my last Turbo. The usual issue with the disintegrating 'cork' gear wheel.
After I replaced it the odometer was running about 30% high. cut a long story short I sent it to an outfit in Holland who were recommended from a number of sources. The guy specialises in PCB restoration. It was a costly exercise and basically he didn't fix the problem.
He made the point however that the components on PCB 's are getting very old and will inevitably deteriorate. I'm a retired Electrical Engineer and spent some time working on industrial Capacitors. These are reckon to last about 7 years at best!
I've always left the rugby balls untouched as they are pretty sensitive.
BTW when the Odometer gear fails does it stop the trip meter AND the overall odometer from working?
Eddie


Eddie is spot on regarding capacitors, I know tapping sometimes gets the gauges to work again, but capacitors can also display strange quirks when they are on the way out. One moment they will work perfectly fine and the next they won't. I don't claim to be an electronics engineer but my other interest is repairing broken audio equipment and I usually find power supply capacitors can create all sorts of problems when they drop slightly below their specification. If I still have the issue with mine when it is eventually running again I will start by replacing the caps.
 
Interesting stuff guys, thanks, definitely stands to reason, for all the skywards gauges anyway. I have an outlier gauge though which error reads low and has never flicked skywards, you would assume any capacitor fault would make it flick skywards at some point (in common with our know other failures). This gauge is currently in the car and behaving. I will keep this gauge in for a while and see if it ever does the skyward flick in the name of research! If it does I think we are onto something with capacitors.

So, for my 2 x binnacles, David L x 1 and David K x 1, should it be a capacitor fault, I'll bet replacing the same capacitor will fix all of them.

Cheers

Stuart


 
Got stuck in a rather lengthy tailback due to a smash this evening. The gauge was rock solid the whole time.

On a slightly different note, I've noticed since post engine build, my temp stays a lot more consistent. Used to be quite erratic. If sitting in traffic it would quickly get up to 92 degrees and the fans would kick in. You could see the gauge move downwards and within 5 mins the temp would be back at 80 degrees and the fans would go off. This cycle would repeat till in clear air. Now I know my engine circulates better (was gummed up a bit previously as the tear down showed), and I have an aluminium (bigger capacity) rad, new water pump and a fully clear system. Temp takes longer to build from cold, and takes much longer for the fans to come on in traffic. The fans kick in same at 92 degrees when it eventually gets there, then it pretty much stays on that mark, or just below, if you are not moving. As soon as you get going and get some airflow, it will drop quite quickly back to 85 ish. I'm sure this is much closer to how it should be than it was before.

For reference, according to clarks, the 2nd line represents 80 degrees and the 3rd line 100 degrees on the gauge. 92 degrees is the designated fan cut in point. This also shows me my gauge is quite accurate, as I have fan cut it when it rises just past the mid point of the 2 lines. I wasn't out with a thermometer in traffic in case anyone was wondering...........

Be interested to hear of other folks experiences. (Yes, I need to get out more, and this is firmly on a par with my previous oil pressure monitoring antics...........:ROFLMAO:)

Stuart
 
So, the low read gauge decided yesterday that enough was enough, not even a flick would bring it alive, stone dead. It had done this before but a different rugby ball brought it back to life.

Haven't pulled the binnacle out yet, next moves are either replace it with the other working, but flicky skywards gauge, try to clean the rugby ball with metal polish as per Paragon write-up, or both.

Will have a think after a coffee. Tools will be out one way or another!

Stuart
 
More fun today! Got a rugby ball off my spare binnacle and set about it with metal polish, then removing any residue with alcohol. What a difference it made, very shiny now. I swapped it over leaving the "low read (dead)" gauge in place out of curiosity. It started to work right away. Did notice that despite it was working, it was taking sometimes a few seconds to move when the ignition switched on (when hot obviously), it did this before. This is not right (should be instant on ignition) and decided that the gauge is definitely faulty and would probably die again at some point.

So swapped back in the "high read flicky up" gauge, mated to the shiny cleaned rugby ball. It springs into life immediately like it should when ignition switched on. Let it run up to temp and a few fan cycles, all good. Took it for a spin for 20 mins, all good. Let's see how it goes now. If it indeed cures it, its most likely the most sensitive gauge (like I mentioned before) and rugby ball related. If it goes flicky skyward again, like the other known gauges we have between us, then the problem must lie in the cluster.

I bought another cluster plastic body and PCB there on eBay, £25 seemed a bargain (was £30, free delivery but best offered £25). No instruments, or front cover, same circuit board and VDO part number as my 2 binnacles, does have a few bulbs but not a full compliment. These are always handy. This will give me more to play with if need be, if not it's there for a rainy day. Incidentally, the seller "luxury car spares" has absolutely stacks of split binnacle stuff, he has at least 50 temp/fuel gauges amongst other things! Nobody else seems to split them and it seems a complete turbo binnacle on eBay will now set you back over £500! Madness. I paid £40 quid for my complete spare turbo (180mph) binnacle about 13 years ago on eBay.

On the subject of binnacle PCB's there looks to be at least 2 types, so look out if you are after one from this guy or anywhere else. Slightly different lay out and different VDO number on the other one. Some capacitors, resistors or diodes in different places.

Cheers

Stuart
 
I might have a really good go at cleaning the rugby ball then as mine is being a bit of a pita currently. I don't think I've had it out for a little while so it wouldn't hurt. I haven't ever gone to those extents before so maybe that's (part maybe) of the answer.
I'll let you know. David
 
Worth a go David. For what it's worth mine is still behaving well after a few days.

As well as the rugby ball itself, clean up the threaded post, washer and nut as well. Won't take you long when its apart.

Interested to hear your updates!

Stuart
 
Another week of faultless operation including sitting in traffic jams a few times. Always found when it was playing up it would be fine up to the quarter mark, then get flaky once it was above that. So the only upside to hideous traffic jams was a chance to check gauge operation!

Anyway, all still good, fingers crossed it continues!

Stuart
 
Glad yours works! I had mine out on Friday night, cleaned the rugby ball posts up and the threaded post to a nice shine and cleaned everything afterwards with contact cleaner and put it all back together. I took the car to work on Saturday and whilst getting warm it was fine but once warm it was dreadful, worse than before I started! I even had it stuck at 0 a couple of times which is a new one to me. Still a sharp tap moves the needle, sometimes back to just over 80 where it should be and sometimes not. But it must be electrical in the dash pod. It's the original pod but not the original temp gauge. It's been fine for a good while, years maybe, until a few months ago and it's been getting slowly worse. Anyway I have taken the pod out again and given it all a good wiggle, reseated etc (very scientific) and I'll see how it is this week. I didn't bother putting the oval dash surround back this time as something tells me I will need access again. I even put the steering wheel back on straight the second time!
 
Hi David

Sorry to hear that hasn't worked as expected. Pre engine rebuild mine had worked faultlessly for years. It was after I put contact cleaner on the multi-plugs for the binnacle, chasing an oil pressure reading problem, it started to play up again, so I've disturbed something! Can't remember if I cleaned all the rugby balls at that point also with contact cleaner, if I did, all my other thoughts make sense!! Contact cleaner seems to make it worse, not better.

Obviously I've documented here what I've done so far, did 80 odd miles and some stop-start for roadworks today, and all is still good.

I have a spare PCB, and another PCB I purchased being delivered to me. I kind of ruled out PCB after a swap over, but I can send you one if it gets to that stage. I thought I had cracked it though with the metal polish (without contact cleaner)! And for me, so far so good.

I have a gauge that "zero" reads sometimes, it never over reads. Unusual you have had both phenomenons with the same gauge. I went back to my over read (but never zero read) gauge when I did my polishing and its been all good.

I still think your problem is rugby ball (and use of contact cleaner) related, as your symptoms changed when you cleaned it. I would be moving that rugby ball to a different gauge, and then doing the metal polishing with the other rugby ball, and see how you go? But avoid contact cleaner this time.

I think it all still points to the sensitivity of the temp gauge (more input sensitive than the other 3), makes it more susceptible to issues. A rugby ball that makes a temp gauge play up, always works ok on any of the other 3 gauges (fuel, oil, volts). And swapping over a rugby ball, almost always changes the symptoms for the temp gauge, but the other gauge it was swapped over from, always remains working.

Let me know if you have any luck with my suggestion.

Stuart
 
Thanks Stuart. I have various spare rugby balls so I'll try and clean one of those up without contact cleaner and see how we get on.
David
 
I had it all apart again and took some brasso to the rugby ball posts and cleaned that up with some alcohol and didn't touch it afterwards.
I ran it for about a 20 min run and it seemed better, no hopping about and appropriate movement as it got warm. Sadly the run was to the workshop as it's sprung a power steering leak so I shan't see it for a few days. They really can lose fluid quite quickly! Anyway I'm hoping it isn't anything too drastic.
 

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