Immobiliser & Heat
Discussion
Hi, this is my first post as I have just bought my first TVR, a Chimaera 400 (1997). It is in great condition and the everything seems to work well.
I have the hot start issue though and have been looking at fitting a relay in the passenger foot well as suggested in many of the posts. I just wondered though if anybody has just swapped over the connections on the immobiliser from the 10A & 25A relay so that they are the correct way round, i.e starter on the 25A relay ?. Is a cable gauge issue the reason it is not recommended, is the cable too thin a gauge as well as the wrong relay wiring. ?
I also have another quick question if I may. The engine temperature runs about 70 on the motorway and in heavy traffic gets to about 95 before the fans kick in (both work) and can creep a little higher and it just sits there until free running traffic. I know the gauges probably have a few degree tolerance, but what should I be looking for as a max temperature. The car is fitted with a Racetech alloy rad.
It seems the fans kick in after a lot of heat has probably built up and I wonder what it would be like in summer. Should I buy the two stage fan kit from Mod Wise, fit a manual switch or swap the otter switch for one which kicks in earlier and for a longer period. There is also a fan switch hole in the new radiator, so I could add a second switch there and wire in parallel as a back up or to run at a lower temperature.
Any advice would be great.
Thanks
Andy
I have the hot start issue though and have been looking at fitting a relay in the passenger foot well as suggested in many of the posts. I just wondered though if anybody has just swapped over the connections on the immobiliser from the 10A & 25A relay so that they are the correct way round, i.e starter on the 25A relay ?. Is a cable gauge issue the reason it is not recommended, is the cable too thin a gauge as well as the wrong relay wiring. ?
I also have another quick question if I may. The engine temperature runs about 70 on the motorway and in heavy traffic gets to about 95 before the fans kick in (both work) and can creep a little higher and it just sits there until free running traffic. I know the gauges probably have a few degree tolerance, but what should I be looking for as a max temperature. The car is fitted with a Racetech alloy rad.
It seems the fans kick in after a lot of heat has probably built up and I wonder what it would be like in summer. Should I buy the two stage fan kit from Mod Wise, fit a manual switch or swap the otter switch for one which kicks in earlier and for a longer period. There is also a fan switch hole in the new radiator, so I could add a second switch there and wire in parallel as a back up or to run at a lower temperature.
Any advice would be great.
Thanks
Andy
Not all cars were wired to the immobiliser incorrectly. My 1996 Griffith certainly was not.
The problem with swapping over the contacts is that if you have the hot start problem then assuming that your car was incorrectly wired then the lower rated immobiliser contacts will be knackered. So transferring these to the ignition circuit could well cause issues there.
If you suspect the immobiliser, better to update to something like a Toad which several owners including myself have done. A far better package well engineered. Mine cost under £100 but I was able to fit, labour to fit one will be quite hefty as its a longish job.
Best of luck.
The problem with swapping over the contacts is that if you have the hot start problem then assuming that your car was incorrectly wired then the lower rated immobiliser contacts will be knackered. So transferring these to the ignition circuit could well cause issues there.
If you suspect the immobiliser, better to update to something like a Toad which several owners including myself have done. A far better package well engineered. Mine cost under £100 but I was able to fit, labour to fit one will be quite hefty as its a longish job.
Best of luck.
Thanks for the reply. I didn't realise they weren't all wired wrong so thanks for the heads up.
I might look for a replacement instead as you suggest.
It is nice to work on the TVR as it is not a ECU for every little thing. Having come from a Boxster, it is much easier and to be honest more fun. People generally seem to like the car more as well.
I might look for a replacement instead as you suggest.
It is nice to work on the TVR as it is not a ECU for every little thing. Having come from a Boxster, it is much easier and to be honest more fun. People generally seem to like the car more as well.
Hi and welcome to the wonderful world of TVR ownership, it sounds like you've done your research already which shows intelligence and an understanding these great cars require a little tweaking from time to time, it's all very much part of the TVR ownership experience. If you're a hands on guy the pleasure you'll get from improving and maintaining your TVR will help you form an inseparable bond with the car, if fettling and spannering isn't your thing then frustration with the car may quickly follow.
A Chimaera is a hobby car for a certain type of person, it's most definitely not for everyone
, however, if you like a challenge and relish problem solving all the information you need is contained within these pages, the PH TVR forum is an invaluable source of knowledge supported by a fantastic community of dedicated enthusiasts, so please read on......
You could switch the circuits running through the Meta immobiliser so they're correct but the problem you've got is TVR wired it incorrectly years ago so the damage caused by running the high amp starter solenoid circuit through the inadequate 10A relay potted inside the Meta unit has almost certainly already taken place, in the same way this is why the Hot Start kit is a solution that locks the door after the horse has bolted.
Saying that its always good automotive wiring practice to fit a relay in the starter circuit, but for no other reason than to reduce the load on the ignition switch which will greatly extend the life of its contacts. TVR chose not to fit a starter solenoid relay, they probably mistakenly thought the Meta relay covered it, worse still they wired the low amp ECU through the higher rated 25A relay and the much higher amp starter solenoid circuit through the feeble 10A relay.
Add in some 1990's Italian electronics from Meta and you have the perfect recipe for starting issues that plagued these cars very early on in their life, if you go way back to when PH started you'll find lots of posts from people with starting issues, the cars were quite new back then and already throwing up staring issues that we now know were almost certainly Meta/TVR wiring related. Very few people at that time knew the true source of the problem so they typically guessed and fitted new starter motors ect. Interestingly I'm reliably informed Meta knew the mistake TVR were making when wiring their system on Griffs & Chimaera, Meta desperately tried to help TVR by informing them of their wiring error, Meta sent memos to TVR and TVR simply ignored them
Obviously replacing an ancient, failing and incorrectly wired by TVR security system is the best option by far, but it is costly, options range from a plug & play DIY solution from Abacus Alarms for roughly £300 or having a TVR alarm specialist replace the whole system for you for more or less double that figure. Another cost effective option (read free) many have chosen to implement is simply to bypass the failing immobiliser on the problematic starter solenoid circuit, this still keeps one line of defense against theft because the immobiliser is still controlling the ECU. This circuit seldom gives trouble because the Meta 25A relay TVR wrongly ran the ECU through is way over specified for the work it's doing, if you'd like detailed instructions on how to bypass your immobiliser just send me a PM and I'll be pleased to help.
Keep in mind TVR also designed in another starting fault, if your battery is healthy and you're finding your Chimaera cranks slow you should consider replacing the very long and inadequate gauge starter cable TVR used, indeed anyone still on the string thin original starter cable should consider replacing it with a superior quality and thicker gauge cable.
You can read about how I uprated my starter cable some six years ago here:
https://www.pistonheads.com/gassing/topic.asp?t=11...
On the subject of temperature you need to accept the TVR gauges are not especially accurate, the car does not need a radiator upgrade either as the original cooling system is perfectly capable of managing coolant temps. The original radiator had a copper core and brass tanks, radiator manufacturers have used these metals since the dawn of time because they are far superior at transferring heat than anything else. Aluminum radiators are lighter so they are used in race cars, but the weight reduction benefit is the one and only reason they exist, an aluminum radiator of the same size as the one TVR fitted most definitely does not offer better cooling and the car doesn't demand better cooling anyway. In terms of performance (removing heat from the coolant) the uncomfortable truth people who've invested heavily in an aluminum radiator must accept is a radiator with a copper core and brass tanks will always be the far superior performer. Brazed or soldered brass tanks are also infinitely more flexible than aluminum, in a TVR the radiator is fixed to the fiberglass body which in turn is bolted to the car's separate tubular chassis, flex is inevitable!
So do keep an eye on that aluminum radiator as cracks, especially around their TiG welded seams, are common.
If you want to move away from the TVR otter switched fan setup your best bet is to buy something from a large trusted manufacturer of quality automotive components, I would avoid the ModWise kit as it's a rather errrr 'Made In a Shed' looking thing, I'm not even sure you can buy it anymore so people who bought one may now have zero after sales support. If you buy something from a reputable manufacturer you'll be getting a better quality and rigorously tested product made by professionals, as such I would recommend the excellent Davies Craig fan controller.
https://www.demon-tweeks.co.uk/Product.do?method=v...
This is a quality kit that has a number of advantages over other fan controllers, firstly it's an all in one design that comes supplied with two standard 40A automotive relays, if you consider the cost of two quality relays alone the kit is clearly superb value indeed. This kit also has a digital temp gauge so you can actually see what the coolant temp really is and tune when the fans come on with complete confidence, finally it has an internal delay circuit for phased fan operation which is a very useful feature indeed. When the system triggers it will first only turn on fan one, it will then wait 10 seconds before switching on fan two, this staged fan effect takes 50% of the very high amp fan startup load off the alternator and so provides a smoother idle at point of fan activation.
I fitted one of these Davis Craig fan controller kits last year and it's worked flawlessly, I also added their top hose sensor kit which is a far superior, more accurate and neater solution than just jamming the sensor in the rad fins. This top hose kit uses a brass compression olive to seal the sensor in the hose adapter so there are zero leaks, and placing the sensor in the water flow ensures you see the true coolant tempts on the controller's digital readout.
https://www.demon-tweeks.co.uk/motorsport/fan-cont...
Tuning the fan on time is easy, I have a Canems ECU so I was able to double check the true coolant temps at the cylinder head on my laptop against what the Davies Craig digital readout was showing at the top hose, you could do the same using the Rover Gauge software. As you might imagine initially the cylinder head shows a reading that's a few degrees hotter the top hose but the two numbers are very consistent with each other all the time proving the Davies Craig kit is an accurate thing, I set my on temp at 88 degrees at the top hose on the Davies Craig Fan Controller which equates to 90 degrees at the cylinder head. This works perfectly, my head temps rise to a maximum of 92 degrees and fall to a minimum of 85 degrees at idle, it's a super reliable and super safe system while maintaining a nice tight operating temp window of just 7 degrees.
You can read more about how and why I fitted this fan controller here:
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Hope all this helps?
Dave.
A Chimaera is a hobby car for a certain type of person, it's most definitely not for everyone
, however, if you like a challenge and relish problem solving all the information you need is contained within these pages, the PH TVR forum is an invaluable source of knowledge supported by a fantastic community of dedicated enthusiasts, so please read on......You could switch the circuits running through the Meta immobiliser so they're correct but the problem you've got is TVR wired it incorrectly years ago so the damage caused by running the high amp starter solenoid circuit through the inadequate 10A relay potted inside the Meta unit has almost certainly already taken place, in the same way this is why the Hot Start kit is a solution that locks the door after the horse has bolted.
Saying that its always good automotive wiring practice to fit a relay in the starter circuit, but for no other reason than to reduce the load on the ignition switch which will greatly extend the life of its contacts. TVR chose not to fit a starter solenoid relay, they probably mistakenly thought the Meta relay covered it, worse still they wired the low amp ECU through the higher rated 25A relay and the much higher amp starter solenoid circuit through the feeble 10A relay.
Add in some 1990's Italian electronics from Meta and you have the perfect recipe for starting issues that plagued these cars very early on in their life, if you go way back to when PH started you'll find lots of posts from people with starting issues, the cars were quite new back then and already throwing up staring issues that we now know were almost certainly Meta/TVR wiring related. Very few people at that time knew the true source of the problem so they typically guessed and fitted new starter motors ect. Interestingly I'm reliably informed Meta knew the mistake TVR were making when wiring their system on Griffs & Chimaera, Meta desperately tried to help TVR by informing them of their wiring error, Meta sent memos to TVR and TVR simply ignored them
Obviously replacing an ancient, failing and incorrectly wired by TVR security system is the best option by far, but it is costly, options range from a plug & play DIY solution from Abacus Alarms for roughly £300 or having a TVR alarm specialist replace the whole system for you for more or less double that figure. Another cost effective option (read free) many have chosen to implement is simply to bypass the failing immobiliser on the problematic starter solenoid circuit, this still keeps one line of defense against theft because the immobiliser is still controlling the ECU. This circuit seldom gives trouble because the Meta 25A relay TVR wrongly ran the ECU through is way over specified for the work it's doing, if you'd like detailed instructions on how to bypass your immobiliser just send me a PM and I'll be pleased to help.
Keep in mind TVR also designed in another starting fault, if your battery is healthy and you're finding your Chimaera cranks slow you should consider replacing the very long and inadequate gauge starter cable TVR used, indeed anyone still on the string thin original starter cable should consider replacing it with a superior quality and thicker gauge cable.
You can read about how I uprated my starter cable some six years ago here:
https://www.pistonheads.com/gassing/topic.asp?t=11...
On the subject of temperature you need to accept the TVR gauges are not especially accurate, the car does not need a radiator upgrade either as the original cooling system is perfectly capable of managing coolant temps. The original radiator had a copper core and brass tanks, radiator manufacturers have used these metals since the dawn of time because they are far superior at transferring heat than anything else. Aluminum radiators are lighter so they are used in race cars, but the weight reduction benefit is the one and only reason they exist, an aluminum radiator of the same size as the one TVR fitted most definitely does not offer better cooling and the car doesn't demand better cooling anyway. In terms of performance (removing heat from the coolant) the uncomfortable truth people who've invested heavily in an aluminum radiator must accept is a radiator with a copper core and brass tanks will always be the far superior performer. Brazed or soldered brass tanks are also infinitely more flexible than aluminum, in a TVR the radiator is fixed to the fiberglass body which in turn is bolted to the car's separate tubular chassis, flex is inevitable!
So do keep an eye on that aluminum radiator as cracks, especially around their TiG welded seams, are common.
If you want to move away from the TVR otter switched fan setup your best bet is to buy something from a large trusted manufacturer of quality automotive components, I would avoid the ModWise kit as it's a rather errrr 'Made In a Shed' looking thing, I'm not even sure you can buy it anymore so people who bought one may now have zero after sales support. If you buy something from a reputable manufacturer you'll be getting a better quality and rigorously tested product made by professionals, as such I would recommend the excellent Davies Craig fan controller.
https://www.demon-tweeks.co.uk/Product.do?method=v...
This is a quality kit that has a number of advantages over other fan controllers, firstly it's an all in one design that comes supplied with two standard 40A automotive relays, if you consider the cost of two quality relays alone the kit is clearly superb value indeed. This kit also has a digital temp gauge so you can actually see what the coolant temp really is and tune when the fans come on with complete confidence, finally it has an internal delay circuit for phased fan operation which is a very useful feature indeed. When the system triggers it will first only turn on fan one, it will then wait 10 seconds before switching on fan two, this staged fan effect takes 50% of the very high amp fan startup load off the alternator and so provides a smoother idle at point of fan activation.
I fitted one of these Davis Craig fan controller kits last year and it's worked flawlessly, I also added their top hose sensor kit which is a far superior, more accurate and neater solution than just jamming the sensor in the rad fins. This top hose kit uses a brass compression olive to seal the sensor in the hose adapter so there are zero leaks, and placing the sensor in the water flow ensures you see the true coolant tempts on the controller's digital readout.
https://www.demon-tweeks.co.uk/motorsport/fan-cont...
Tuning the fan on time is easy, I have a Canems ECU so I was able to double check the true coolant temps at the cylinder head on my laptop against what the Davies Craig digital readout was showing at the top hose, you could do the same using the Rover Gauge software. As you might imagine initially the cylinder head shows a reading that's a few degrees hotter the top hose but the two numbers are very consistent with each other all the time proving the Davies Craig kit is an accurate thing, I set my on temp at 88 degrees at the top hose on the Davies Craig Fan Controller which equates to 90 degrees at the cylinder head. This works perfectly, my head temps rise to a maximum of 92 degrees and fall to a minimum of 85 degrees at idle, it's a super reliable and super safe system while maintaining a nice tight operating temp window of just 7 degrees.
You can read more about how and why I fitted this fan controller here:
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Hope all this helps?
Dave.
Hi Dave, Thanks for all the info, very useful. I am expecting to have to do a few things on the TVR, but it's also something I enjoy doing to be honest. It also gives my son a chance to learn about cars.
I do like that fan controller, especially the inline coolant hose sensor option. I did see some adjustable stats where you put the sensor in the hose and use PTFE around where the jubilee clip was. It didn't look too robust to me if I am honest, so your solution is very neat. The digital system also gives me a chance to monitor temps accurately.
I put a relay in for the moment this evening on the immobiliser just as a interim solution, but I am conscious I will probably need a long term solution. I opted against swapping the circuits after you mentioned the possibility the 10A relay is already damaged. I would rather it didn't start than the engine cut out while driving due to the 10A relay being previously damaged.
I have several diagnostic cables for mostly modern OBD cars, where is the best place to get Rovergauge software ?
When I bought the car I asked Southways to have a look just to see if the chassis was reasonable. What a great garage, really enthusiastic and happy to share a lot of useful information. I'll be going there again when I need a service.
Thanks again.
I do like that fan controller, especially the inline coolant hose sensor option. I did see some adjustable stats where you put the sensor in the hose and use PTFE around where the jubilee clip was. It didn't look too robust to me if I am honest, so your solution is very neat. The digital system also gives me a chance to monitor temps accurately.
I put a relay in for the moment this evening on the immobiliser just as a interim solution, but I am conscious I will probably need a long term solution. I opted against swapping the circuits after you mentioned the possibility the 10A relay is already damaged. I would rather it didn't start than the engine cut out while driving due to the 10A relay being previously damaged.
I have several diagnostic cables for mostly modern OBD cars, where is the best place to get Rovergauge software ?
When I bought the car I asked Southways to have a look just to see if the chassis was reasonable. What a great garage, really enthusiastic and happy to share a lot of useful information. I'll be going there again when I need a service.
Thanks again.
Edited by ahpboxster on Thursday 18th January 19:50
Great stuff and glad to help, its what this slightly illogical TVR ownership thing is all about.
It sounds to me like you've done your research and connected with the right people already, so unlike many you've already started your TVR ownership from the right place.
Remember there's no such thing as a daft question, share your experiences, I'm sure we can learn from you too.
Welcome and enjoy
It sounds to me like you've done your research and connected with the right people already, so unlike many you've already started your TVR ownership from the right place.
Remember there's no such thing as a daft question, share your experiences, I'm sure we can learn from you too.
Welcome and enjoy
ahpboxster said:
..........I have several diagnostic cables for mostly modern OBD cars, where is the best place to get Rovergauge software ?..........
None of your OBD cables will do the job.The software is free but if you buy the cable here https://www.pistonheads.com/classifieds/parts-and-... it will come with the software and some instructions.
Steve
Gassing Station | Chimaera | Top of Page | What's New | My Stuff