TVR misbehaving dials
Discussion
My fuel gauge and rev counter don't work properly.
Fuel guage reads half full when actually full, then stays there until it fuel gets low then it starts reading a bit accurate!
Rev counter bounces around and doesn't seem accurate
The speedo is a bit hit and miss but I could live with it
Specialist suggests sending off to get recalibrated/ fixed which will take 12 weeks.
I don't really want to wait that long ... anyone got any shortcut ideas? see below pic of dial type.
Fuel guage reads half full when actually full, then stays there until it fuel gets low then it starts reading a bit accurate!
Rev counter bounces around and doesn't seem accurate
The speedo is a bit hit and miss but I could live with it
Specialist suggests sending off to get recalibrated/ fixed which will take 12 weeks.
I don't really want to wait that long ... anyone got any shortcut ideas? see below pic of dial type.
I’m not sure how much work is involved, but maybe check the wiring and grounds? The fuel sender is in a place where contacts can get pretty grimy and I believe there’s a ground back there on one of the screws? The rev counter sounds like it may be missing pulses, so check coil connections and engine grounds. The speedo may have been dodgy from new? Or it could be a common issue with all gauges under the dash cover, but I’m not sure if they share a ground or not? Lots of uncertainty from me but I know I would tackle as much as I could before sending them off for an unpredictable length of time!
On a Cerbera, those symptoms can suggest a fractured "big fuse", but I don't know if that applies to a Chimaera.
Also, many of the speedos can be recalibrated by you. If you go to the Caerbont/Smiths website, there are instructions on how to set the pulse timing to a different standard, and hence re-calibrate the reading.
Also, many of the speedos can be recalibrated by you. If you go to the Caerbont/Smiths website, there are instructions on how to set the pulse timing to a different standard, and hence re-calibrate the reading.
morebeanz said:
On a Cerbera, those symptoms can suggest a fractured "big fuse", but I don't know if that applies to a Chimaera.
Also, many of the speedos can be recalibrated by you. If you go to the Caerbont/Smiths website, there are instructions on how to set the pulse timing to a different standard, and hence re-calibrate the reading.
Big fuse. There's one on the Chimaera, mounted on the chassis somewhere.Also, many of the speedos can be recalibrated by you. If you go to the Caerbont/Smiths website, there are instructions on how to set the pulse timing to a different standard, and hence re-calibrate the reading.
Are your wipers moving slower than usual as well?
Speedo - how the Chim one driven. On the cerbera it's via a sensor mounted to the rear diff, reading the cogs. The gap has to be quite exact and dirt into that gap causes the speedo to jump around. A simple 5 min cleanout using feeler gauges often works wonders.
Byker28i said:
Big fuse. There's one on the Chimaera, mounted on the chassis somewhere.
Are your wipers moving slower than usual as well?
There are 2 'big fuses'. One is below the O/S engine mount but is only the connection between the alternator and the starter motor/battery.Are your wipers moving slower than usual as well?
The second fuse is in the passenger footwell and is between the battery and pretty much everything else on the car.
However my vote goes for poor earth(s) for the dash. These are at the body securing bolts on top of the tunnel both sides.
If the body has been off or lifted then I would put money on it.
Steve
Fuel gauge:
The fuel sender is easy to remove from the tank, lift the carpet off the top of the tank and unscrew the Philips screws that hold the sender in the tank, lift out carefully to expose the long sender wand and float arrangement. With the setup extracted from the tank you can now move the wand through it's full arc and watch the gauge, this will prove if you have an issue with the potentiometer..... or more likely not.
Far more likely is it's a bit stuck and or it just needs some adjustment, based on the description of your gauge behavior you just need the float sitting a little higher, by the sound of it the mechanism may be stuck and just needs freeing so the wiper runs across the full potentiometer winding range end to end (empty to full). With everything free and tested outside the tank you can now fine tune the sender by bending the wand, the wand is made from wire of a slightly lighter gauge than that of a wire coat hanger so it's easy to bend by hand, but do be careful and only make small tweaks at a time.
Re-insert the float and your now free moving/adjusted sender assembly/wand into the tank, with the tank full of fuel you are looking for the float end of the wand to freely float on top of the fuel not held submerged under it against the winding stop. The wiper contact should be sitting at the 'full end' of the potentiometer winding but not jammed up against the stop, to test make sure your tank is full then tune your bending of the wand so the gauge reads full, now drive the car, you want the gauge needle to just start falling fractionally off the full mark after just 10-12 miles or so.
Continue the test over 260 miles of normal driving and once completed re-tune/bend the wand as required to show empty, you should only need a tiny bit of bending to achieve this. Like this you should see the gauge reading full with a full tank and showing empty with a 'safety gallon' still in reserve, you'll probably need to remove the sender a few times and make a few tweaks before you achieve perfection, every time you do so always be sure to test the mechanism runs free across its full range (ark) of movement across the entire potentiometer winding (empty to full).
Speedo:
Probably a transducer clearance issue typically mounted on the diff/prop flange, clean the transducer face and remove any road debris from the toothed trigger wheel then close the gap fractionally, this should give you a more consistent speedo reading. On earlier LT77 box cars there's a transducer on the gearbox itself which is a speed sensor for the ECU, but I believe most early cars still had the rear mounted transducer for the speedo itself?
Rev Counter:
This instrument is very sensitive to electrical magnetic interference and the biggest source of interference is your high tension ignition system, leaky old HT leads being the first place to start, it's also well known Magnecor HT leads can cause rev counter bounce. Replace your leads with new quality items, I recommend MSD Superconductors but there's nothing wrong with a set of Bosch leads for a distributor equipped 1993 Range Rover P38 which are a direct fit and are quality items. Do take time to carefully route the leads away from the engine bay loom/other wiring as best as possible and do consider ditching the dreadful plug extenders if still fitted as these are notoriously leaky.
Check you have resistor spark plugs fitted as non-resistor plugs will give similar issues, I recommend NGK BPR6ES or better still their iridium equivalent, make sure the plug number includes R for Resistor, finally if you're still on the highly inappropriate shrouded electrode No7 plugs TVR specified replace them with 6's and the car will immediately run better.
Results of the above suggestions:
An afternoon with the car adjusting the fuel sender and cleaning the speedo transducer will cost nothing and should net some good improvements, a new set of No6 Resistor spark plugs, some plug end socks to replace the extenders and a set of well routed new HT leads will finish the job for very little money.
Follow the above suggestions and you should achieve the full package of improvements you seek and potentially deliver a better running TVR too.
The fuel sender is easy to remove from the tank, lift the carpet off the top of the tank and unscrew the Philips screws that hold the sender in the tank, lift out carefully to expose the long sender wand and float arrangement. With the setup extracted from the tank you can now move the wand through it's full arc and watch the gauge, this will prove if you have an issue with the potentiometer..... or more likely not.
Far more likely is it's a bit stuck and or it just needs some adjustment, based on the description of your gauge behavior you just need the float sitting a little higher, by the sound of it the mechanism may be stuck and just needs freeing so the wiper runs across the full potentiometer winding range end to end (empty to full). With everything free and tested outside the tank you can now fine tune the sender by bending the wand, the wand is made from wire of a slightly lighter gauge than that of a wire coat hanger so it's easy to bend by hand, but do be careful and only make small tweaks at a time.
Re-insert the float and your now free moving/adjusted sender assembly/wand into the tank, with the tank full of fuel you are looking for the float end of the wand to freely float on top of the fuel not held submerged under it against the winding stop. The wiper contact should be sitting at the 'full end' of the potentiometer winding but not jammed up against the stop, to test make sure your tank is full then tune your bending of the wand so the gauge reads full, now drive the car, you want the gauge needle to just start falling fractionally off the full mark after just 10-12 miles or so.
Continue the test over 260 miles of normal driving and once completed re-tune/bend the wand as required to show empty, you should only need a tiny bit of bending to achieve this. Like this you should see the gauge reading full with a full tank and showing empty with a 'safety gallon' still in reserve, you'll probably need to remove the sender a few times and make a few tweaks before you achieve perfection, every time you do so always be sure to test the mechanism runs free across its full range (ark) of movement across the entire potentiometer winding (empty to full).
Speedo:
Probably a transducer clearance issue typically mounted on the diff/prop flange, clean the transducer face and remove any road debris from the toothed trigger wheel then close the gap fractionally, this should give you a more consistent speedo reading. On earlier LT77 box cars there's a transducer on the gearbox itself which is a speed sensor for the ECU, but I believe most early cars still had the rear mounted transducer for the speedo itself?
Rev Counter:
This instrument is very sensitive to electrical magnetic interference and the biggest source of interference is your high tension ignition system, leaky old HT leads being the first place to start, it's also well known Magnecor HT leads can cause rev counter bounce. Replace your leads with new quality items, I recommend MSD Superconductors but there's nothing wrong with a set of Bosch leads for a distributor equipped 1993 Range Rover P38 which are a direct fit and are quality items. Do take time to carefully route the leads away from the engine bay loom/other wiring as best as possible and do consider ditching the dreadful plug extenders if still fitted as these are notoriously leaky.
Check you have resistor spark plugs fitted as non-resistor plugs will give similar issues, I recommend NGK BPR6ES or better still their iridium equivalent, make sure the plug number includes R for Resistor, finally if you're still on the highly inappropriate shrouded electrode No7 plugs TVR specified replace them with 6's and the car will immediately run better.
Results of the above suggestions:
An afternoon with the car adjusting the fuel sender and cleaning the speedo transducer will cost nothing and should net some good improvements, a new set of No6 Resistor spark plugs, some plug end socks to replace the extenders and a set of well routed new HT leads will finish the job for very little money.
Follow the above suggestions and you should achieve the full package of improvements you seek and potentially deliver a better running TVR too.
ChimpOnGas said:
......Rev Counter:
This instrument is very sensitive to electrical magnetic interference and the biggest source of interference is your high tension ignition system, leaky old HT leads being the first place to start, ........
Also worth being aware that the rev counter signal lead comes away from the coil, across the front of the engine past the dizzy, along past the fuel injectors then to a single connector somewhere below the inlet hose running between MAF and throttle body.This instrument is very sensitive to electrical magnetic interference and the biggest source of interference is your high tension ignition system, leaky old HT leads being the first place to start, ........
Plenty of places for it to pick up stray signals.
Also worth checking the condition of that leads connections.
Steve
Interesting stuff as the tacho in my 430 is misbehaving again. It sort of worked when I picked her up but did not want to go over 3000 rpm. Then last summer when I replaced both regulator and rectifier in the alternator it improved but have noticed when running her up it's mucking about again and as we know she had a body off refurb I guess that I need to check the earth points on top of the tunnel.
Also a little odd is that if the headlights are switched on the reading on the oil pressure gauge drops slightly. Alternator shows it's putting out just over 14 volts but I did notice that it's giving just over 6 volts on one of the terminals and normal 14+ on the other. Some thing happened to the new Bosch battery Heath supplied and fitted as it now won't accept more than 6 volts..... weird. The battery did drain down for some reason??
Also a little odd is that if the headlights are switched on the reading on the oil pressure gauge drops slightly. Alternator shows it's putting out just over 14 volts but I did notice that it's giving just over 6 volts on one of the terminals and normal 14+ on the other. Some thing happened to the new Bosch battery Heath supplied and fitted as it now won't accept more than 6 volts..... weird. The battery did drain down for some reason??
When you say the battery drained down was the alarm armed at this point, even if it was’nt there’s likely to be parrasatic drain and this is very common with most Tvr if not used enough, it’s why many use trickle chargers at this time of year, i’d wager many many vehicles will do the same thing if not used enough, you also have the obvious loss of battery power from cold weather which compounds the batteries hard life.
I’ve elected to store my car with battery disconnected and removed a couple of connections and the battery has largely held its charge
I’m lucky as in the car is stored in a secure place with alarm systems etc
I’ve elected to store my car with battery disconnected and removed a couple of connections and the battery has largely held its charge
I’m lucky as in the car is stored in a secure place with alarm systems etc This actually happened during the end of the summer so she was in regular use at the time and not locked. She is currently plugged in to the trickle charger/conditioner.But yes we have a couple of electrical issues:-
1) Passenger window is now working, switch had power but not reaching motor, need to get door card off. trie by my forearms are too large to fit through the speaker hole. Well can just squeeze it through but then cannot turn it to reach the nuts.
2) Interior lights not working. Believe a relay was removed but cannot find it or where it was supposed to go.
3) Headlights on dip are yellowish but main beam is brilliant. headlights are new LHD ones and nea bulbs fitted.
4) Windows need lubing up as they are glacial, well the drivers on is that works!
5) Got to somehow move fog light to LH side of car. problem is that has after market rear lights and only fog light is on right and needs to be on left. Am thinking of fitting rear bulb in reverse lamp and cross wiring to fog so have 2 fogs at rear and adding reversing lights.
6) Need to adjust revering light switch as only come on when gear stick is held right over to the side. Release it and the reverse light goes out.
Oh and get and fit new water pump.
1) Passenger window is now working, switch had power but not reaching motor, need to get door card off. trie by my forearms are too large to fit through the speaker hole. Well can just squeeze it through but then cannot turn it to reach the nuts.
2) Interior lights not working. Believe a relay was removed but cannot find it or where it was supposed to go.
3) Headlights on dip are yellowish but main beam is brilliant. headlights are new LHD ones and nea bulbs fitted.
4) Windows need lubing up as they are glacial, well the drivers on is that works!
5) Got to somehow move fog light to LH side of car. problem is that has after market rear lights and only fog light is on right and needs to be on left. Am thinking of fitting rear bulb in reverse lamp and cross wiring to fog so have 2 fogs at rear and adding reversing lights.
6) Need to adjust revering light switch as only come on when gear stick is held right over to the side. Release it and the reverse light goes out.
Oh and get and fit new water pump.
I’ll re Phase that the drain happens any time of year if cars left standing, only takes about two weeks or less if battery isn’t tip top.
Windows, nothing new there, try and find a photo where someone has marked where door card nuts are situated then use a small child or skinny chap to undo them, Once they are off you have to pull cards out from bottom then up as they are hooked over a ledge at the top.
Water pump is not so bad if you follow usual procedure, the two ( SERP) not sure about pre SERP bolts that run through water jacket can be very tight, so it’s best to start with those first before releasing pressure on casing by undoing the others.
Water can and does get into doors which if weep holes at bottom of door are blocked builds up and can knacker window motor so see if there’s power to it first and work from there.
I’m no sparky so not sure about interior light wiring, maybe ask via a dedicated thread.
the drain happens any time of year if cars left standing, only takes about two weeks or less if battery isn’t tip top. Windows, nothing new there, try and find a photo where someone has marked where door card nuts are situated then use a small child or skinny chap to undo them, Once they are off you have to pull cards out from bottom then up as they are hooked over a ledge at the top.
Water pump is not so bad if you follow usual procedure, the two ( SERP) not sure about pre SERP bolts that run through water jacket can be very tight, so it’s best to start with those first before releasing pressure on casing by undoing the others.
Water can and does get into doors which if weep holes at bottom of door are blocked builds up and can knacker window motor so see if there’s power to it first and work from there.
I’m no sparky so not sure about interior light wiring, maybe ask via a dedicated thread.
I was having problems with my rev counter bouncing & finally dieing.
I had moved the king lead to prevent the first bout of hic ups but the rev counter dieing meant look again.
My cables where lagged in insulated foil. So i took it off to have a look as you do.
You lot will know, but i did not know that theres 2 fuses for the white blue & white black wires.
The black wire from the coil runs direct into the loom.
Well someone had placed the fuses into a standard spade connector.
The spade connector being a lot wider than the fuse. This was causing the poor connection.
To check before fitting a proper fuse holder i put some tape on the fuses.
Fired her up & normal service resumed.
I have attached a photo with the tapped fuses.
Might be worth checking yours.
I no longer take anything for granted with the car, who knows what has happened in the past.
I had moved the king lead to prevent the first bout of hic ups but the rev counter dieing meant look again.
My cables where lagged in insulated foil. So i took it off to have a look as you do.
You lot will know, but i did not know that theres 2 fuses for the white blue & white black wires.
The black wire from the coil runs direct into the loom.
Well someone had placed the fuses into a standard spade connector.
The spade connector being a lot wider than the fuse. This was causing the poor connection.
To check before fitting a proper fuse holder i put some tape on the fuses.
Fired her up & normal service resumed.
I have attached a photo with the tapped fuses.
Might be worth checking yours.
I no longer take anything for granted with the car, who knows what has happened in the past.
fieryfred said:
................You lot will know, but i did not know that theres 2 fuses for the white blue & white black wires.............................
Yours will be the first I have seen with fuses in those wires. However, the white/blue going to the ECU (pin 39) does have/should have a 6.8K Ohm resistor in line.Steve
Steve_D said:
Yours will be the first I have seen with fuses in those wires. However, the white/blue going to the ECU (pin 39) does have/should have a 6.8K Ohm resistor in line.
Steve
Thanks Steve.Steve
So a previous owner has had a problem & someone has added the blue terminals instead of the standard black & added loose fit fuses.
Mmm. Wonder what i will find next, hopefully that was the only bodge.
Rev counter now works, saves a trip to speedy cables who took 3 months & a phone call after 2 months to get my Moto Guzzi clocks back.
I will leave my new fuse holders in place untill i tackle a few other jobs.
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