Temp Gauge Entertainment
- Thread starter scam75
- Start date
scam75
Well-known member
Well after a couple of fault free weeks my gauge had a little episode tonight, a slight quiver up the way (only maybe 5-10 degrees on the scale, not full scale point to the sky!) and back down for a few mins, not terribly bad but enough to tell me the fault is still at large! Parked up (cooled a bit obviously) and when drove home later is was fine.
I'm pretty puffed out with this nonsense now, will probably just live with it and see how it behaves. My third PCB I bought has arrived, although I have managed to replicate the fault with both PCB's I already had (and kinda ruled them out), so I may swap it all over but I fear it will make no difference. The rugby balls almost certainly have a bearing on it, it could also be diode related, or both.
Dave - I'd be happy to send you this latest bare PCB board if you wanted to run some diode tests on it? (even fire in some new ones and see how it goes?) I think that might be the next step in this operation. Let me know. I am a disaster zone with a soldering iron or i'd do it myself!!
Cheers
Stuart
I'm pretty puffed out with this nonsense now, will probably just live with it and see how it behaves. My third PCB I bought has arrived, although I have managed to replicate the fault with both PCB's I already had (and kinda ruled them out), so I may swap it all over but I fear it will make no difference. The rugby balls almost certainly have a bearing on it, it could also be diode related, or both.
Dave - I'd be happy to send you this latest bare PCB board if you wanted to run some diode tests on it? (even fire in some new ones and see how it goes?) I think that might be the next step in this operation. Let me know. I am a disaster zone with a soldering iron or i'd do it myself!!
Cheers
Stuart
scam75 said:
Hi Stuart - I'd be happy to run some tests on the board, I'm not a professional electrician but I've mended a few electrical circuits now. A linear power supply on my Otari reel-to-reel machine was the most difficult. Most recently I repaired a fault on a DVD player where the 2nd laser wasn't receiving the correct voltage and reporting "no disc".
I've also just got myself a new temperature controlled iron from ali-express which comes with glowing reviews from the youtube.
DavidL
Active member
I'm still waiting for the car to return currently. No doubt expensive power steering bits are coming but there can't be many places you can drop the car off at 6pm on a Bank holiday Saturday!
Which is this pcb you are talking about? I haven't changed anything out other than gauges themselves. I did try a whole cluster once but the speedo is in km so wasn't quite so easy. Actually I might have naother whole cluster somewhere. I've had that so long someon gave it to me, not so sought after then.
I'll update once it's back.
I see what you did there
Which is this pcb you are talking about? I haven't changed anything out other than gauges themselves. I did try a whole cluster once but the speedo is in km so wasn't quite so easy. Actually I might have naother whole cluster somewhere. I've had that so long someon gave it to me, not so sought after then.
I'll update once it's back.
dlknight said:
I see what you did there
scam75
Well-known member
Hi guys. Been busy moving house.
The PCB I'm referring to is a bare cluster, with no gauges on it, or front cover. Just the circuit board for the whole cluster.
Dave - Happy to post it to you for a play with. PM address and I'll get it sent next week at some point when I get a chance.
Stuart
The PCB I'm referring to is a bare cluster, with no gauges on it, or front cover. Just the circuit board for the whole cluster.
Dave - Happy to post it to you for a play with. PM address and I'll get it sent next week at some point when I get a chance.
Stuart
scam75
Well-known member
DavidL said:
I have done this David, and the fault persisted. I'll post this new (to me) PCB to Dave K this week for analysis!
So far the rugby balls, and gauges themselves, are the only variables that make a difference (and they obviously plug into each other), but I've a feeling that there could be a common issue we all have, PCB/diode or something related. Be interested in the PCB examination findings!
The other thing I have thought, is to try and metal polish the gauge prong holes, which would make sense, but that looks awful fiddly and nigh on impossible!
Cheers
Stuart
scam75
Well-known member
Update on this guys is that my temp gauge settled down a couple of weeks since my last post on this, with no further fiddling as I got puffed out with it , so probably about the end of May. It's been faultless since with the car used almost daily. We will see how long this lasts. I do recall having a very long spell pre-engine rebuild without fault. Cannot remember what gauge was installed at that time though.............. The fault only started again when the cluster was disturbed during my oil pressure issues (was sender, not cluster it turned out). Maybe the set-up is sensitive to wires being plugged in and out, making a fault show, then if left for a period, seems to settle down and be fine. I can report this being true now twice for me. Possibly coincidence, who knows! [8|]
Anyway, on that note, Dave, have you had a chance to experiment on the PCB yet?
Stuart
, so probably about the end of May. It's been faultless since with the car used almost daily. We will see how long this lasts. I do recall having a very long spell pre-engine rebuild without fault. Cannot remember what gauge was installed at that time though.............. The fault only started again when the cluster was disturbed during my oil pressure issues (was sender, not cluster it turned out). Maybe the set-up is sensitive to wires being plugged in and out, making a fault show, then if left for a period, seems to settle down and be fine. I can report this being true now twice for me. Possibly coincidence, who knows! [8|]Anyway, on that note, Dave, have you had a chance to experiment on the PCB yet?
Stuart
scam75 said:
Sorry, still sitting on the sideboard, I need to print out the page from the workshop manual with the wiring diagram on. I had a quick look at the diagram a couple of weeks ago and it looked very simple from what I remember with the gauge almost wired directly to the sender with little componentry inbetween.
Will let you know what I can make out from the diagram and then if there is anything that is worth testing on the cluster [s1]
scam75
Well-known member
Time for a thread resurrection!
My temp gauge had been getting worse and worse before the car went into the bodyshop, for a good few months, consistently going off it's head once it reached the quarter mark, on every drive. A new development however, which brings me back to thinking the fault lies in the gauges rather than PCB or wiring, was the gauge flicking wildly skyward and sticking in the full up position. Now I've seen this before, however this time it stayed there when the ignition was switched off. At this point surely the wiring and PCB are no longer in operation? Thoughts?
Anyway, a hefty flick on the binnacle glass saw it drop back to the off position. So, today, I decided to transplant my other gauge in, which from memory worked, never went haywire but sometimes it didn't actually move at all (inoperative). Once in the car today it was dead as a dodo, wouldn't work at all. Petrol side fine but hee haw on the temp side. So, back out it came. Whilst I had the original gauge out I gave the screw thread and the rugby ball a quick rub down with contact cleaner. Put it all back together and it has worked perfectly for the rest of the day. Now, having seen this movie many times before, I know full well this can happen and it will 100% at some point start it's flicky nonsense again.
So, what in hell is actually going on here? Can we pin this 100% on the gauge now?
Stuart
My temp gauge had been getting worse and worse before the car went into the bodyshop, for a good few months, consistently going off it's head once it reached the quarter mark, on every drive. A new development however, which brings me back to thinking the fault lies in the gauges rather than PCB or wiring, was the gauge flicking wildly skyward and sticking in the full up position. Now I've seen this before, however this time it stayed there when the ignition was switched off. At this point surely the wiring and PCB are no longer in operation? Thoughts?
Anyway, a hefty flick on the binnacle glass saw it drop back to the off position. So, today, I decided to transplant my other gauge in, which from memory worked, never went haywire but sometimes it didn't actually move at all (inoperative). Once in the car today it was dead as a dodo, wouldn't work at all. Petrol side fine but hee haw on the temp side. So, back out it came. Whilst I had the original gauge out I gave the screw thread and the rugby ball a quick rub down with contact cleaner. Put it all back together and it has worked perfectly for the rest of the day. Now, having seen this movie many times before, I know full well this can happen and it will 100% at some point start it's flicky nonsense again.
So, what in hell is actually going on here? Can we pin this 100% on the gauge now?
Stuart
DavidL
Active member
Stuart,
I still see the same issues but I have discovered that it really doesn't like contact cleaner!
I find it happens at a certain time in the journey whihc, I assume, equates to a certain engine temperature. A quick flick of the binacle fixes it and I'm not getting the erratic bouncing but that may change.
If it's engine temperature then hitting the dash shouldn't help should it so I'm still inclined to say it's dash end.
I've tried various gauges, I think I have 4, and in the end the same issues occur so I'm still inclined to say its the pcb somehow. I do have a spare pcb/clocks dash and I did try that once but I don't recall the results. I assume as I took it out again it didn't help although it was a lhd (km) s2 set so not quite what I need anyway.
I still see the same issues but I have discovered that it really doesn't like contact cleaner!
I find it happens at a certain time in the journey whihc, I assume, equates to a certain engine temperature. A quick flick of the binacle fixes it and I'm not getting the erratic bouncing but that may change.
If it's engine temperature then hitting the dash shouldn't help should it so I'm still inclined to say it's dash end.
I've tried various gauges, I think I have 4, and in the end the same issues occur so I'm still inclined to say its the pcb somehow. I do have a spare pcb/clocks dash and I did try that once but I don't recall the results. I assume as I took it out again it didn't help although it was a lhd (km) s2 set so not quite what I need anyway.
scam75
Well-known member
Hi David
I've tried 2 x clock pods and was the same. It's definitely at the dash end, not engine bay. I had same bad experience with contact cleaner before but this time is seems to have temporarily cured it (small amount applied on some kitchen towel then rubbed the thread and prongs), which helps nobody! I also bought a 3rd clock pod and sent it to David K for testing, and I think it all seemingly checked out ok? I'm sure he will confirm, in fact I'm sure he still has it!! (may be wrong lol)
I'm more convinced than ever that it is the gauge and a certain design flaw or age deterioration. Can't speak for your 4 gauges but I have 2 with 2 separate faults. Mine always works fine until it reaches quarter on the scale, then is flicks about, sometimes more erratic than other times. And occasionally it goes full skyward. Sometimes a dash flick sorts mine, other times it doesn't.
For the record mine is still behaving a few days later.
Stuart
I've tried 2 x clock pods and was the same. It's definitely at the dash end, not engine bay. I had same bad experience with contact cleaner before but this time is seems to have temporarily cured it (small amount applied on some kitchen towel then rubbed the thread and prongs), which helps nobody! I also bought a 3rd clock pod and sent it to David K for testing, and I think it all seemingly checked out ok? I'm sure he will confirm, in fact I'm sure he still has it!! (may be wrong lol)
I'm more convinced than ever that it is the gauge and a certain design flaw or age deterioration. Can't speak for your 4 gauges but I have 2 with 2 separate faults. Mine always works fine until it reaches quarter on the scale, then is flicks about, sometimes more erratic than other times. And occasionally it goes full skyward. Sometimes a dash flick sorts mine, other times it doesn't.
For the record mine is still behaving a few days later.
Stuart
AnotherPITA
Member
I'd suggest that anything intermittent or partially resolved by hitting the binnacles is either connection or earth/grounding related. Having released both of my fuse boxes and removed the centre console I've discovered a bewildering array of cables, common earthing/grounding points and a mass of cabling added for aftermarket upgrades.
scam75
Well-known member
Thanks, that makes sense. I can't help thinking it's not wiring related though, i am aware of quite a few people with this issue, and this gauge has temp on one side and fuel on the other, nobody has ever had an issue on the fuel side. It's a real head scratcher............heads are being scratched in the states too with no solutions if you look at Rennlist.
Hi Stuart,
I still have the PCB / pod, I've got your address so will pop it in the post when I have a few minutes. Here for the benefit of others was the testing I performed last year. The PCB is very simple so not much at all to go wrong as they are all passive components which can easily be tested. My guesses on the actual cause are below. Maybe an external temp gauge is required to solve it 100% or integrate into a fancy ECU like David's?
I've tested all the component I could see on the PCB (except for the bulbs).
Diodes - all measured between 500-600 ohms (which is good) and none of them were shorted in reverse.
Ceramic Resistor - measured within spec 68k +- 5%
The circuit is not complex from what I can make out the water temp sensor receives a positive voltage from the dashboard PCB (same line as some of the bulbs). It is earthed through the body of the sensor. The second wire is the signal wire which feeds directly to the gauge on the PCB. From what I can make out there are no components in the signal path.
My best guess is that the intermittent nature could be -
1. An issue with the wiring harness (wire degradation possibly)
2. An issue with the gauge itself (I think you ruled this out)
3. An earth issue, this could be the engine block or the PCB earth
4. Possible back voltage from another component on the dashboard PCB, I noticed that + and - feeds for the gauge are shared with some of the warning bulbs and other gauges. Worth making sure all the bulbs are in good condition.
5. PCB connector issue, I've seen it mentioned before that the ribbon connectors get wear points when the cable connector pins have imprinted on the PCB connector. This could possibly lead to an intermittent connection if any flex or vibration occurs.
scam75
Well-known member
Great write up David, many thanks for taking the time to do that! There is no rush, just post it whenever.
I think we have seen the problem persists for affected cars even if you interchange gauges and PCB's.
I maybe did rule out the gauges at some point, but I cannot be sure. Your analysis, theories and testing run way beyond my more rudimental swapping of gauges and PCB's and various methods of cleaning up prongs, terminals and rugby balls!
I really hoped a duff diode or resistor would raise it's head, but sadly not. What I can't get my head round, is of all the possible plausible theories mentioned, why does a dash flick sort things out, albeit mostly temporarily? This is what keeps bringing me back to the gauge itself, but there seem to be a fair few of them displaying same issues.
Could any testing be done on an actual gauge? When I initially swapped my gauge over, it gave me about 10 years with no issues. I'm guessing after that point the replacement gauge deteriorated somehow to the same condition as the previous one? Goodness knows..........
I think we have seen the problem persists for affected cars even if you interchange gauges and PCB's.
I maybe did rule out the gauges at some point, but I cannot be sure. Your analysis, theories and testing run way beyond my more rudimental swapping of gauges and PCB's and various methods of cleaning up prongs, terminals and rugby balls!
I really hoped a duff diode or resistor would raise it's head, but sadly not. What I can't get my head round, is of all the possible plausible theories mentioned, why does a dash flick sort things out, albeit mostly temporarily? This is what keeps bringing me back to the gauge itself, but there seem to be a fair few of them displaying same issues.
Could any testing be done on an actual gauge? When I initially swapped my gauge over, it gave me about 10 years with no issues. I'm guessing after that point the replacement gauge deteriorated somehow to the same condition as the previous one? Goodness knows..........
The temperature sensor with the blue plug near the front of the head is the one for the DME (and the one that my VEMS ECU uses to display temps) - I had an issue where my dash cluster temp display wasn’t working at all and I found that there was damage to the wiring on the dash temp sensor - which is the one a little further back under the manifold with two spade connector plugs on the top.
I know you’ve checked everything but just wanted to make sure that you’d checked the second temperature sensor and not just the one with the blue top?
I know you’ve checked everything but just wanted to make sure that you’d checked the second temperature sensor and not just the one with the blue top?
scam75
Well-known member
Thanks. Yes, I did check that ages ago, and I'm sure the wiring and terminals were tidied up when the engine got rebuilt. Can have another look though...or I will when the gauge f's up again, its been fine for over a week now.................
The thing is, I've found that almost any time you remove the binnacle and play with the gauge or rugby balls, it works perfectly again for a while. I can't help thinking this is not a problem at the sender end.....who knows!
The thing is, I've found that almost any time you remove the binnacle and play with the gauge or rugby balls, it works perfectly again for a while. I can't help thinking this is not a problem at the sender end.....who knows!
Could any testing be done on an actual gauge? When I initially swapped my gauge over, it gave me about 10 years with no issues. I'm guessing after that point the replacement gauge deteriorated somehow to the same condition as the previous one? Goodness knows..........
From what I understand a simple check for the gauge is to connect the signal cable to earth, that should make the gauge read full temp. I did some searching on water gauge issues and there was quite a lot of matches, most of them pointed to earth issues with either the sender or the gauge.
I'm not sure how the gauge works inside, could it be that after 30+ years something gets worn out inside.
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