won't start when hot
Discussion
citizen smith said:
Had the same problem a few years ago. My solution was to take the starter motor off, stip it down and give it a total clean - regrease required components and refit. Problem solved for me.
The only other thing to do is too clean the terminals on both the solenoid and starter motor with some emery, since there could be some corrosion on them causing a poor contact. You should also consider replacing the low tension wire Terminal, since this wire can give problems at point of contact. 
storm grey said:
hi second problem this weekend as the title says starts no problem when cold but when it gets hot wont star till it cools down a bit.i think it has a modwize kit on it as i have a receipt in my file.(it will start if i bump start it)
This is a very common problem on these cars, the underlying reason is the TVR wiring was already rather marginal from new, so any of the following fundamentals or more likely a combination of them all will create a critical mass failure.1. A tired starter motor solenoid and or the motor itself
2. Corrosion in the already marginal TVR wiring
3. Poor/corroded earth points
As already suggested you need to use a multi meter to establish the true origins of your problem, guessing and replacing components in the blind hope you'll stumble on a fix is not the way to approach the problem. You need to approach this with an open mind and accept that it may actually be the accumulation of a series of marginal elements all adding up to give you the failure.
Remember, resistance in a wire will increase with heat, this rule equally applies to an electric motor as it's windings are just a series of wires, so with everything right on the edge of functional when cold it only takes a small increase in heat to reach the the tipping point that pushes your starting system into failure
This is why your car starts when cold, fails to start when hot, and then starts again when you let it cool.
The ModWise Hot Start kit is just a relay, the idea is it delivers more amps to your starter solenoid, this in itself is not a bad idea as TVR never fitted a dedicated starter relay which is automotive wiring best practice, although the real reason a relay is used by car makers is to protect the contacts in the ignition switch and not strictly speaking as a way of delivering more amps to the starter solenoid. The issue with the Hot Start kit is it doesn't really address the problem in a holistic way, it takes a one dimensional look at the hot start issue and making the assumption the problem is solely that insufficient amps are getting to your starter solenoid, it attempts to address that one area in isolation.
Because the Hot Start relay is sold as a magic bullet easy fix kit, people are understandably drawn to it as the 'be all and end all' solution to the problem, this is misleading at best, worse still it may help initially which tends to fool people into thinking it is indeed the magic bullet solution it promotes itself to be. The reality of the Hot Start Kit is all it's doing is addressing one element in a long chain or marginals that all add up to the hot start issue, adding the relay may be enough to temporarily take the stater system out of failure... but because it hasn't addressed all the other marginal elements the problem is very likely to return as all those other marginals slowly get worse, and this is exactly where the OP is at right now!
So to fix this common problem as a whole, TVR owners need to take a holistic approach, rather than just fitting the Hot Start Kit which addresses one element they need to test each element systematically with a multimeter and address the marginal nature of everything in the chain of wiring and components that make up your starting system, and to do this the process must start some voltage and amp drop tests at a number of strategic points along the chain of elements that forms the complete starter system.
One often overlooked and misunderstood element in this chain of components is the immobiliser which is just an interrupter switch you control (switch on & off) with your IR fob, the starter solenoid trigger circuit passes through the immobiliser so if this is all or part of the issue it doesn't matter if you have the Hot Start Kit (just a relay) it's not going to help. The immobiliser's part in the hot start problem should not be underestimated, this is because within it Meta provided a number of switching circuits to be immobilised which are run through internal switching relays, these little internal relays are rated appropriately for the various different amp rated components being switched/immobilised.
Sadly TVR wired the immobiliser incorrectly, essentially they used the higher amp Meta internal relay for switching the low amp ECU circuit and the low amp Meta internal relay for the far higher amp starter solenoid circuit. The relay responsible for the ECU therefore rarely gives trouble, but that low amp Meta internal relay really suffers a hard life as it must take all that current from the starter solenoid, a level of amps it was never designed for. Over time the contacts on this lower amp relay become pitted and eroded increasing resistance across them, add in the increase in resistance in the wiring itself that always comes with heat and the end result is the system reaches a tipping point and the starter fails to crank.
What you really need to do is replace the faulty relay inside the immobiliser with one that is designed to carry the amount of amps drawn by the starter solenoid, however this approach is not particularly practical as the relays are potted inside the Meta unit. The solution is either to replace the entire security system which is expensive, or bypass the system on the problematic starter circuit, if you find the immobiliser is your issue and decide a bypass is for you I can help with instructions if you PM me. At this point its worth pointing out if you bypass the starter solenoid circuit only, the car will still be secure as the system will still be controlling the live feed to the ECU.
The most important message in all this is... Do Not Make Assumptions'!, by this I mean do not assume the problem is one thing or another IE, the immobiliser, your starter solenoid, the starter motor itself, the wiring ect ect ect ect. Instead of making assumptions test the entire system and everything in the chain that makes up your starter system.
What you will almost certainly find is the problem is an accumulation of a number of marginal elements that by themselves do not give you the failure, it's only when you add them all together do you reach critical mass. Fixing one of these elements like replacing a tired or gummed up starter solenoid for example may be enough to solve the problem, but while you will be left feeling smug you fixed the issue the truth is all the other marginals remain and wait to catch you our another day.
The solution therefore is not to address one marginal element in the system (a failing or gummed up starter motor and or solenoid, the poorly executed TVR wiring, the badly installed immobiliser, the very long string thin starter cable used by TVR, poor earthing, lose terminals/connectors, corrosion at earthing points and or terminals, ect ect ect)..... but to eliminate them all...
Finally, always keep in mind the catalyst that pushes the marginal TVR Chim/Griff starting system and all it's elements to a point of failure is nearly always the introduction of heat, this is why your car starts fine when cold, fails to start when hot, then starts reliably again when it cools down
"An electric current flows when electrons move through a conductor, such as a metal wire. These moving electrons can collide with the ions in the wire. ... As temperature increases, the metal ions vibrate more so there are more collisions with the electrons.... and so the resistance in the wire will increase."
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