What’s happened here then?
Discussion
Went out to fire up the Chim which has been laid up and I’ve given a run periodically to keep oil moving around etc.
Not enough oomph in the battery, so I’ve jumped it using one of the spare race car batteries and she fired into life- all good, all normal.
5-10 mins of happy idling later I’m pottering around checking and doing things, I notice the Rev counter has died. Bit odd! I take a seat and give it a rev to probably 2000rpm-ish which barely registers a movement on the needle, it did move but maybe from 0 to 100rpm. Odd!
Carry on doing some other bits, she splutters and dies. Put it down to s
tty running having been laid up, go to fire her up again- nothing. With ignition on I have dash lights, gauges and fuel pump, all normal, but go to fire the starter and it all dies- no lights, no gauges, not a click, silence.
Am I looking at an alternator problem? Symptoms of low voltage, seems odd that all the lights and gauges come up as normal if there’s not even enough voltage to fire the ignition relay! If it was the BIG fuse I’d have a full open circuit and no power to anything at all.. riiiiiiiight?
Should add... issue is slightly complicated by the fact that ALL my tools are in my race rig 20-odd miles away. So I put her back to bed, grumbled to myself and tried to forget about it
Any thoughts? Can rev counter death and lack of starter power be related in any way or is this a red herring? I’ve not had either issue in 4 years, but then I suppose being laid up out in the weather is likely to cause various problems.
Not enough oomph in the battery, so I’ve jumped it using one of the spare race car batteries and she fired into life- all good, all normal.
5-10 mins of happy idling later I’m pottering around checking and doing things, I notice the Rev counter has died. Bit odd! I take a seat and give it a rev to probably 2000rpm-ish which barely registers a movement on the needle, it did move but maybe from 0 to 100rpm. Odd!
Carry on doing some other bits, she splutters and dies. Put it down to s
tty running having been laid up, go to fire her up again- nothing. With ignition on I have dash lights, gauges and fuel pump, all normal, but go to fire the starter and it all dies- no lights, no gauges, not a click, silence.Am I looking at an alternator problem? Symptoms of low voltage, seems odd that all the lights and gauges come up as normal if there’s not even enough voltage to fire the ignition relay! If it was the BIG fuse I’d have a full open circuit and no power to anything at all.. riiiiiiiight?
Should add... issue is slightly complicated by the fact that ALL my tools are in my race rig 20-odd miles away. So I put her back to bed, grumbled to myself and tried to forget about it
Any thoughts? Can rev counter death and lack of starter power be related in any way or is this a red herring? I’ve not had either issue in 4 years, but then I suppose being laid up out in the weather is likely to cause various problems.
Charge/or swap battery 
once running check voltage and battery terminals is over 13.5 + volts if not and showing 12 volts or under main fuse as probably blown under O/S engine mounting or alternator failed etc, you may find the flat fuse strip was on the turn and the duty of passing current to charge a partially discharged battery was all too much a common woe , if so replace with a more robust 100A midi fuse
once running check voltage and battery terminals is over 13.5 + volts if not and showing 12 volts or under main fuse as probably blown under O/S engine mounting or alternator failed etc, you may find the flat fuse strip was on the turn and the duty of passing current to charge a partially discharged battery was all too much a common woe , if so replace with a more robust 100A midi fuse Zener said:
Charge/or swap battery once running check voltage and battery terminals is over 13.5 + volts if not and showing 12 volts or under main fuse as probably blown under O/S engine mounting or alternator failed etc, you may find the flat fuse strip was on the turn and the duty of passing current to charge a partially discharged battery was all too much a common woe , if so replace with a more robust 100A midi fuse
Fuse strip on the turn once running check voltage and battery terminals is over 13.5 + volts if not and showing 12 volts or under main fuse as probably blown under O/S engine mounting or alternator failed etc, you may find the flat fuse strip was on the turn and the duty of passing current to charge a partially discharged battery was all too much a common woe , if so replace with a more robust 100A midi fuse 
What’s your thoughts on using a 120A main fuse Zen.
rev counter is powered by the pulsed earth side of the ignition coil.
if you had no tacho, and then the engine spluttered and died, I'd look at your coil and the feeds to the coil.
next pull the instument cluster - lots of tachos/fuel gauges etc need a regulated 5v feed - google L7810 and replace the 5v regulator if oyu havent already done so.
if you had no tacho, and then the engine spluttered and died, I'd look at your coil and the feeds to the coil.
next pull the instument cluster - lots of tachos/fuel gauges etc need a regulated 5v feed - google L7810 and replace the 5v regulator if oyu havent already done so.
But you said your battery was low and you had to jump it.
No other issue before it was parked? Charge the battery would be the first thing to do as it causes allsorts of anomalies. Ticking over what little charge your battery had simply drained away leaving not enough power for coil would be my guess.
100A fuse blown stops alt charging so I thought.
No other issue before it was parked? Charge the battery would be the first thing to do as it causes allsorts of anomalies. Ticking over what little charge your battery had simply drained away leaving not enough power for coil would be my guess.
100A fuse blown stops alt charging so I thought.
Classic Chim said:
But you said your battery was low and you had to jump it.
No other issue before it was parked? Charge the battery would be the first thing to do as it causes allsorts of anomalies. Ticking over what little charge your battery had simply drained away leaving not enough power for coil would be my guess.
100A fuse blown stops alt charging so I thought.
All of this ^ No other issue before it was parked? Charge the battery would be the first thing to do as it causes allsorts of anomalies. Ticking over what little charge your battery had simply drained away leaving not enough power for coil would be my guess.
100A fuse blown stops alt charging so I thought.
Battery was low but I’ve not had an alternator/charging problem before once running, I put it down to it being a matter of months since the car last ran (battery charger not installed in meantime due to location of car).
No battery light when car was running, just died. It could be alternator/100A fuse but the tacho dying a death was strangely convenient. I’ll take the battery out and charge it and see how my luck is.
No battery light when car was running, just died. It could be alternator/100A fuse but the tacho dying a death was strangely convenient. I’ll take the battery out and charge it and see how my luck is.
Get it running and check your alternator output at the alternator, then check your alternator output at the battery. Any voltage drop recorded is going to be somewhere in the circuit between the alternator the battery and or the earth return, ie a loss down the string thin and probably corroded 20 plus year old main charge cable, the 100amp fuse, or a bad earth path.
On a Chimaera the engine block and so the alternator is earthed to the chassis at a stud on the O/S front outrigger diagonal, the only other earth on the engine block is a stud on the back of the N/S cylinder head which is responsible for the lambda sensors and possibly other engine sensors too. The main earth cable from a bolt in the block in the area of the oil pressure switch runs to that outrigger stud, from here the chassis itself becomes part of the earth connection to the battery which isn't a great idea. A second cable from the chassis on the passenger side of the transmission tunnel is used to complete the final connection run from the chassis to the battery negative terminal, so as we can see there are lots of connections and so points of potential resistance in this main and highly critical earth circuit.
The full live and earth high amp loop is very long, also if you count up all the connections there are 9 in total in this critical circuit which are all potential points resistance due to corrosion, loose security of the connections or a fuse failure, the 100amp fuse being a particularly physically weak link in the chain as it's prone to cracking through vibration, if nothing else you are well advised to replaced this vulnerable strip fuse with a physically far stronger midi type fuse.
The starter/charge cable used by TVR was also of a rather thin gauge for it's considerable length, even when new it was rather marginal but add 20 plus years of internal corrosion and the resistance in that very long cable can become huge, and often is! The condition of this long and rather thin gauge main charge cable (also doubles as the starter cable) and the earth path is all critical to ensure you're getting the 14v produced by your alternator back to the battery, keep in mind the correct functioning of everything electrical on the car depends on it.
Common problems with the critical high amp charge/starter circuit on a Chimaera are:
1. An internally corroded main charge/starter cable, which as already covered is already a rather thin gauge for it's considerable length
2. A cracked 100amp fuse
3. Loose terminal connections at the 100a fuse holder
4. A poor connection at the positive battery clamp/terminal
5. An internally corroded earth cable from the engine block to the earth stud on the O/S outrigger
6. A bad/corroded earth connection at the engine block and or earth stud on the O/S outrigger
7. A bad earth connection at the transmission tunnel, a lose bolt here is common
8. An internally corroded earth cable from trans tunnel to battery
9. A poor connection at the negative battery clamp/terminal
The fuse box is fed directly from the battery via a short run of twined brown cable, while this main fuse box feed is short it also has a strip fuse in it between the battery and fuse box, loose terminal nuts at the fuse holder are common just as they are on the 100a fuse holder under the car, look for signs of melting of the plastic fuse holder cover.
As everything electrical on the car is fed from the fuse box if the battery is not showing the same 14v you record at the alternator, or the fuse box is not receiving the full 14v, you're going to suffer issues.
Going right back to the beginning you must start by checking your alternator output at the back on the alternator itself, if your alternator shoves out 14v it's working correctly, if there is less than the same 14v at the battery you need to find out where the loss is occurring. A quick and highly effective earthing test is to run a long jump lead from the battery negative terminal and clamp it to the alternator bracket or a stout bolt on the engine block, if the loss is eliminated you know the issue is in the earth path.
TVR definitely could have done things better, as a consequence there is significant scope for improvement that everyone with a Chimaera should consider.
1. Upgrade the string thing and almost certainly internally corroded starter/charge cable with a new high quality heavier gauge marine tinned cable
2. Replace the physically weak and crack prone 100a fuse with a stronger 100a midi fuse
3. Check the terminal nuts at the 100a fuse holder are nice and tight
4. Replace the TVR idea of using the chassis as the earth return with a high quality heavy gauge marine tinned cable
5. Fit better battery clamps, quality tinned brass stud type are best, now use a proper hydraulic crimping tool to fit ring terminals to your main earth and starter/charge cables so you can firmly bolt them to your new tinned brass stud type battery clamps which in turn should be nice and tightly clamped to the battery terminals
6. Replace the physically weak and crack prone 80a fuse in the main fuse box twin brown feed cable with a stronger 80a midi fuse
7. Check the terminal nuts at the 80a fuse holder are nice and tight
All Chimaera owners should consider the above as these upgrades can make a huge improvement to the way everything electrical on the car performs, common results after making these improvements are:
On a Chimaera the engine block and so the alternator is earthed to the chassis at a stud on the O/S front outrigger diagonal, the only other earth on the engine block is a stud on the back of the N/S cylinder head which is responsible for the lambda sensors and possibly other engine sensors too. The main earth cable from a bolt in the block in the area of the oil pressure switch runs to that outrigger stud, from here the chassis itself becomes part of the earth connection to the battery which isn't a great idea. A second cable from the chassis on the passenger side of the transmission tunnel is used to complete the final connection run from the chassis to the battery negative terminal, so as we can see there are lots of connections and so points of potential resistance in this main and highly critical earth circuit.
The full live and earth high amp loop is very long, also if you count up all the connections there are 9 in total in this critical circuit which are all potential points resistance due to corrosion, loose security of the connections or a fuse failure, the 100amp fuse being a particularly physically weak link in the chain as it's prone to cracking through vibration, if nothing else you are well advised to replaced this vulnerable strip fuse with a physically far stronger midi type fuse.
The starter/charge cable used by TVR was also of a rather thin gauge for it's considerable length, even when new it was rather marginal but add 20 plus years of internal corrosion and the resistance in that very long cable can become huge, and often is! The condition of this long and rather thin gauge main charge cable (also doubles as the starter cable) and the earth path is all critical to ensure you're getting the 14v produced by your alternator back to the battery, keep in mind the correct functioning of everything electrical on the car depends on it.
Common problems with the critical high amp charge/starter circuit on a Chimaera are:
1. An internally corroded main charge/starter cable, which as already covered is already a rather thin gauge for it's considerable length
2. A cracked 100amp fuse
3. Loose terminal connections at the 100a fuse holder
4. A poor connection at the positive battery clamp/terminal
5. An internally corroded earth cable from the engine block to the earth stud on the O/S outrigger
6. A bad/corroded earth connection at the engine block and or earth stud on the O/S outrigger
7. A bad earth connection at the transmission tunnel, a lose bolt here is common
8. An internally corroded earth cable from trans tunnel to battery
9. A poor connection at the negative battery clamp/terminal
The fuse box is fed directly from the battery via a short run of twined brown cable, while this main fuse box feed is short it also has a strip fuse in it between the battery and fuse box, loose terminal nuts at the fuse holder are common just as they are on the 100a fuse holder under the car, look for signs of melting of the plastic fuse holder cover.
As everything electrical on the car is fed from the fuse box if the battery is not showing the same 14v you record at the alternator, or the fuse box is not receiving the full 14v, you're going to suffer issues.
Going right back to the beginning you must start by checking your alternator output at the back on the alternator itself, if your alternator shoves out 14v it's working correctly, if there is less than the same 14v at the battery you need to find out where the loss is occurring. A quick and highly effective earthing test is to run a long jump lead from the battery negative terminal and clamp it to the alternator bracket or a stout bolt on the engine block, if the loss is eliminated you know the issue is in the earth path.
TVR definitely could have done things better, as a consequence there is significant scope for improvement that everyone with a Chimaera should consider.
1. Upgrade the string thing and almost certainly internally corroded starter/charge cable with a new high quality heavier gauge marine tinned cable
2. Replace the physically weak and crack prone 100a fuse with a stronger 100a midi fuse
3. Check the terminal nuts at the 100a fuse holder are nice and tight
4. Replace the TVR idea of using the chassis as the earth return with a high quality heavy gauge marine tinned cable
5. Fit better battery clamps, quality tinned brass stud type are best, now use a proper hydraulic crimping tool to fit ring terminals to your main earth and starter/charge cables so you can firmly bolt them to your new tinned brass stud type battery clamps which in turn should be nice and tightly clamped to the battery terminals
6. Replace the physically weak and crack prone 80a fuse in the main fuse box twin brown feed cable with a stronger 80a midi fuse
7. Check the terminal nuts at the 80a fuse holder are nice and tight
All Chimaera owners should consider the above as these upgrades can make a huge improvement to the way everything electrical on the car performs, common results after making these improvements are:
- Much stronger engine cranking giving better and more reliable starts especially when hot
- A longer lasting battery that gets charged properly
- A better more consistent supply to the ignition coil and earthing of the plugs giving stronger spark for improved combustion and so better starts, improved fuel economy, and a smoother driving car
- A more consistent and solid current supply to the ECU and so a smoother driving car
- Better earthing of all engine sensors (coolant temp, fuel temp, AFM, Lambdas ect) giving more consistent readings for the ECU to work with and so a smoother driving car
- More consistent and accurate fuel injector durations and so a smoother driving car
- Brighter headlights
- Brighter instrument illumination
- More accurate and reliable instrument readings
- A louder horn
- More powerful radiator fans with less on time
Zener said:
Charge/or swap battery once running check voltage and battery terminals is over 13.5 + volts if not and showing 12 volts or under main fuse as probably blown under O/S engine mounting or alternator failed etc, you may find the flat fuse strip was on the turn and the duty of passing current to charge a partially discharged battery was all too much a common woe , if so replace with a more robust 100A midi fuse
As above, it's meter out time once running check voltage and battery terminals is over 13.5 + volts if not and showing 12 volts or under main fuse as probably blown under O/S engine mounting or alternator failed etc, you may find the flat fuse strip was on the turn and the duty of passing current to charge a partially discharged battery was all too much a common woe , if so replace with a more robust 100A midi fuse Been a while! But I’ve attacked the car with a multimeter and yes, it’s not charging. I haven’t actually tested the alternator, just the full circuit- so it’s alternator or big fuse. Instead I’m going for the big fuse straight away, I figure it’s at least 4 years since it’s been touched so it’s probably gunked up and nasty and could do with a clean and removal even if it’s intact.
If it is the big fuse at fault, is it that big a no-no just to bypass it? All the ones I’ve ever seen break have been through cracking or corrosion so unless this one has actually popped in a ‘fuse’ fashion then it’s not really that risky is it?
Anyway, it may be the alternator yet- I’m just typing this whilst making a brew and mentally preparing for getting mucky and nasty under the car. Thought I’d bump the thread to summon help if (when) I screw something else up
Oh, when car started I have my tacho back- so whichever clever soul suggested that it’s fired off the coil, car not charging so battery died until it couldn’t power the coil any more- you win a mars bar
If it is the big fuse at fault, is it that big a no-no just to bypass it? All the ones I’ve ever seen break have been through cracking or corrosion so unless this one has actually popped in a ‘fuse’ fashion then it’s not really that risky is it?
Anyway, it may be the alternator yet- I’m just typing this whilst making a brew and mentally preparing for getting mucky and nasty under the car. Thought I’d bump the thread to summon help if (when) I screw something else up
Oh, when car started I have my tacho back- so whichever clever soul suggested that it’s fired off the coil, car not charging so battery died until it couldn’t power the coil any more- you win a mars bar
Yes do get rid of the alternator main fuse
Surprised at the number of people that fit a new fuse rather than rewiring the main alternator supply
Purchase or find a long enough length of cable heavy enough for the job and run it through good quality conduit/sleeving from starter motor main positive to alternator main positive, a nice safe cable run is what makes all the difference
Keep well
Surprised at the number of people that fit a new fuse rather than rewiring the main alternator supply
Purchase or find a long enough length of cable heavy enough for the job and run it through good quality conduit/sleeving from starter motor main positive to alternator main positive, a nice safe cable run is what makes all the difference
Keep well
Okay, so I have found no fuse... I have only the one cable on the offside chassis rail, pictured- which runs from the starter motor along the rail (two tell-tale zip ties there ) and up towards the bulkhead. Is this the cable run where one would expect to find the 100a fuse, is it reasonable to assume it’s already been removed?
(Yes it was red once upon a time)
) and up towards the bulkhead. Is this the cable run where one would expect to find the 100a fuse, is it reasonable to assume it’s already been removed?(Yes it was red once upon a time)
Third of the way down this page shows one
http://www.chimaerapages.com/technical-info.html
Likely plenty of topics here that show it
http://www.chimaerapages.com/technical-info.html
Likely plenty of topics here that show it
Ok then, fuse-less is goodness
Once you're sure that she's alternating fuse-less, which you do come across as being
Sleeve the supply, better to be safe than sorry
If you don't fancy dragging the cable out to protect it, good split sleeving or that horrible plastic spiral wrap will do the job with most of the cable in place, simply get it on where you can get to it and push it along the cable, obviously the cable ties would need to be removed
Keep well
Once you're sure that she's alternating fuse-less, which you do come across as being
Sleeve the supply, better to be safe than sorry
If you don't fancy dragging the cable out to protect it, good split sleeving or that horrible plastic spiral wrap will do the job with most of the cable in place, simply get it on where you can get to it and push it along the cable, obviously the cable ties would need to be removed
Keep well
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