Hot start problem

Hot start problem

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Discussion

mickh32

Original Poster:

118 posts

98 months

Sunday 5th June 2016
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Had a hot start prob today. This is not the first time but it has happened before. When I bought the car the owner said the hot start fix had been done. How do I check to see if the fix has been done or where do I start to look to remedy the prob.

Paulprior

822 posts

88 months

Sunday 5th June 2016
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There seems to be 2 types of Hot start problem, one with the engine not turning over at all, the other with a very slow turn over, which one do you have?

ChimpOnGas

9,637 posts

162 months

Monday 6th June 2016
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To locate the hot start kit you're looking for yet another relay dangling precariously in the passenger footwell, it'll be the one that looks like someone has added it.

The factory relay for the fuel pump is fitted to a blue relay holder, the factory relay for the ECU is the other one and should have a red stripe across the top of it denoting it's a diode protected relay, both were metal bodied originally but may have been changed to plastic bodied relays by now. The hot start kit relay will definitely be plastic, it will also have a fuse holder & fuse associated to it or be a fused relay.

It's actually fairly irrelevant if you have the hot start kit or not, the hot start kit is by no means a guaranteed fix for the so called hot start issue. The true problem originates inside your immobiliser and the poor way TVR wired it, adding a relay (the hot start kit) to the starter circuit is a good idea because TVR failed to do so themselves. However what the hot start kit can't do is repair the damage already present inside your immobiliser, at best it will just mask it for while.

What you need to do is replace your internally damaged immobiliser, or bypass it so its no longer part of your starter circuit. If you then fit the hot start kit (a relay) you will have a reliable starter circuit, but people don't do it this way. People add the hot start kit to their TVR after it starts exhibiting the problem, but because the internally damaged immobiliser is still part of the starter circuit they are really just storing up trouble for the future.

In summary, you may well find that hot start kit (an extra relay) in your footwell but it actually means nothing, you need to understand and address the underlying source of the hot start problem not just add a relay and hope it will fix the irreversible damage that's already taken place inside your immobiliser, because it won't!

Focus on a permanent fix to the immobiliser issue (replacement or bypass) first, then add in the starter solenoid relay TVR never fitted. Then and only then can you turn your attention to upgrading your heavy high amp starter cable that goes from your battery to the starter motor, finish off with an additional earth from your engine block to the negative terminal on your battery.

Once you've completed all of the above, and in the above order, you will have a reliable starting TVR you can trust. Do not expect adding the hot start kit (a relay) will fix anything on its own, at best just fitting the hot start kit will only serve to mask the true underlying problem and fool you into a false sense of security only to find (as you have) that the car continues to suffer the problem.

And the next time it fails to start could just be at a very inconvenient moment, so now is the time to fix it properly. My best advise is not to guess where the problem is but to use your test meter to conclusively prove it's source, then and only then can you be sure you're fixing the right point or points of failure.

If you find it is indeed inside the immobiliser I can help you with some simple bypass instructions that will solve the problem for nothing and still leave your car secure as the immobiliser controls the live feed to the ECU as well as the live feed to the starter solenoid circuit.

Don't guess, test.... then PM me if you need my instructions to bypass the immobiliser on the starter solenoid circuit only.

carsy

3,018 posts

148 months

Monday 6th June 2016
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Mick, have a read of this excellent thread by Dave, (Chimpongas) It covers everything you need to know about the hot start problem.

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

zacherynuk

353 posts

116 months

Monday 6th June 2016
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I took a picture of mine this morning for you... red wires, little sugar cube sized black cube and a 20AMP fuse...
If you don't have this, then I don't think you will have the kit installed. It's cheap and even I can do it - took me about 20 minutes.


Smokey Boyer

503 posts

114 months

Monday 6th June 2016
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My 'hot start' issues were solved by replacing the car battery. The old one was already tired when I brought the car, and before swapping the battery I had investigated most of the common hot start causes and possible solutions.

I suspect that many people fit various fixes to their car which have short term benefit, rather than fixing the underlying fault (and I too may be guilty of that with the new battery)

Belle427

6,808 posts

216 months

Monday 6th June 2016
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The best modification anyone can do to these cars is tidy up that birds nest of wiring by the battery and mount the relays securely so they don't rattle around.

mickh32

Original Poster:

118 posts

98 months

Monday 6th June 2016
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Firstly I should say the problem when the car refuses to start is it makes no noises apart from the petrol pump priming. Had a look and found 2 grey/silver relays both of which have a stripe on. There is a black oblong multi plug with 7or 8 black wires and plugged into it a plug that simply links the wires back together again. There is also 2 yellow and one green and black relay plugs with nothing in. Back to you guys.

Edited by mickh32 on Monday 6th June 14:54

ChimpOnGas

9,637 posts

162 months

Monday 6th June 2016
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Stop looking for the hot start kit, it doesn't fix the real problem.

Read my above post and the link provided by carsy, understand what's going on and use your multimeter to test the system.

Its not at all complicated, the problem is people are seduced by the idea of buying a kit that solves the problem, it doesn't.


bobfather

11,132 posts

238 months

Monday 6th June 2016
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ChimpOnGas said:
Stop looking for the hot start kit, it doesn't fix the real problem.

Read my above post and the link provided by carsy, understand what's going on and use your multimeter to test the system.

Its not at all complicated, the problem is people are seduced by the idea of buying a kit that solves the problem, it doesn't.
I do have difficulty with this. My understanding is that the operation of the starter motor solenoid gets stiff or sticky after years of sitting in a hot environment. This, combined with low current due to the Meta alarm link means that when heat further reduces the current we end up with too little energy to fire the solenoid. I had this problem and 6 years ago I fitted the 'hot start kit'. I have never suffered hot start problems since fitting the kit. Therefore, in my experience the hot start kit gets around the issue, sure the right answer should include freeing up the starter solenoid but with the extra current delivered through the kit the stickier solenoid is no longer an issue.

I do intend to replace the motor feed cable and earth next winter but that's an entirely separate issue

ChimpOnGas

9,637 posts

162 months

Monday 6th June 2016
quotequote all
bobfather said:
I do have difficulty with this. My understanding is that the operation of the starter motor solenoid gets stiff or sticky after years of sitting in a hot environment. This, combined with low current due to the Meta alarm link means that when heat further reduces the current we end up with too little energy to fire the solenoid. I had this problem and 6 years ago I fitted the 'hot start kit'. I have never suffered hot start problems since fitting the kit. Therefore, in my experience the hot start kit gets around the issue, sure the right answer should include freeing up the starter solenoid but with the extra current delivered through the kit the stickier solenoid is no longer an issue.

I do intend to replace the motor feed cable and earth next winter but that's an entirely separate issue
It may help to understand the immobiliser is just a switch, the only difference between it and a traditional switch is you turn the immobiliser switch on and off with your IR fob, but its definitely switch and like any other switch it has contacts that are subject to wear/erosion. Actually there are two switches inside the immobiliser and they come in the form of two little relays, if you understand the operational function of a relay you'll know it's just a switch, a switch that allows a low amp trigger to switch on a higher amp circuit.

The two little relays inside the immobiliser are a low amp one designed for the low amp ECU circuit and a higher amp one intended for the starter solenoid, sadly TVR wired the low amp ECU through the high amp relay and the higher load starter solenoid circuit through the low amp immobiliser relay. The results of this wiring mistake were that the low amp immobiliser relay had a rather short life, this is the hot start problem so called because resistance in any circuit increases with heat, so the problem mostly (but not always) first appears when restarting the car hot and so all it's wiring is hot too.

After fitting the hot start kit the immobiliser remains a switch on the starter solenoid circuit, nothing changes here, so what happens if damage has already been inflicted on the little immobiliser relay in the starter solenoid circuit? Does the hot start kit in some way miraculously repair this damage, or does it remain? I'll let you digest the above before you answer but I think you'll agree the answer is pretty obvious... the existing damage remains. Now, the reason your problem disappeared after fitting the hot start kit was because it helped take a bit of load of the immobiliser relay, but it most definitely didn't fix any existing damage to the immobiliser relay on your starter solenoid circuit, it just helped to mask the true problem.

I have nothing against the hot start kit, indeed if people had fitted it early enough before the damage to immobiliser relay had taken place it would have more or less been a permanent fix, the problem is people didn't do this, they fitted the hot start kit after they started experiencing the hot start issue. Actually it's always a good idea to add a relay to the starter solenoid circuit because for some unfathomable reason TVR never fitted one. It's very much automotive best practice to fit such a relay to the starter solenoid circuit on any car, but it actually has nothing to do with immobilisers, its used to protect and extend the life of the contacts on the ignition switch. But because the immobiliser is on the same circuit it can also help there too, what it clearly can't do it fix any existing damage.

If TVR had just wired the immobiliser correctly in the first place there would be little or no need for the hot start kit, if they had also used a heavier gauge and better quality starter cable and fitted the extra earth I've recommended then they would have introduced further reliability improvements, finally if TVR had also fitted a dedicated relay to the starter circuit the ignition switch and immobiliser would have been belt and braces protected.

My post on upgrading the heavy battery to starter motor cable should be seen in complete isolation to the above immobiliser issue, if you already have internal immobiliser damage you could fit the worlds heaviest starter cable and it wont help a jot. The immobiliser starter solenoid circuit is a different circuit to the very high amp starter motor circuit, try not to confuse the two. Saying that once the immobiliser controlled starter solenoid circuit has been PROPERLY sorted it is indeed a very good idea to upgrade the starter motor cable with something of heavier gauge because what TVR used was rather feeble.

People need to completely separate in their minds the immobiliser starter solenoid circuit from the high amp starter motor circuit (big red cable from battery to starter), they are both involved in the process of starting the car but they are completely separate circuits with unique and separate issues but both were the result of the poor TVR wiring practice.

Sadly the wiring practice adopted by TVR was shockingly bad, this poor wiring was/is responsible for 90% of Chimaera & Griffith no starts and the car's reputation for disappointing reliability, the key mechanical components TVR used were actually very robust so it's a crying shame they didn't make a better job of wiring the car.... and the real sad fact is it wouldn't have cost them that much more to get it right cry

The good news is you can sort the key issues easily and fairly cheaply, you don't need to fit a complete new loom, just sort the immobiliser issue with a simple bypass or better still a new system wired properly then resolve a few of the other TVR school boy wiring errors and use heavier cable in places.

It'll definitely be the best thing you can do to improve the overall reliability of your Chimaera.

Edited by ChimpOnGas on Monday 6th June 21:03

David Beer

3,982 posts

250 months

Monday 6th June 2016
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There are of course three relays, circuits to the immobiliser. Just a small point !

bobfather

11,132 posts

238 months

Monday 6th June 2016
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Thanks ChimpOnGas, that makes more sense now. I am a qualified electrical engineer, so the basic circuitry is simple for me, it was just the interaction within the immobiliser that I hadn't got my head around. I'm moving my battery to the boot, this is principally why I'll be replacing the power cables.

BTW, although there is no direct electrical connectivity between the motor power and the solenoid signal there is an advantage in increasing current to the motor with bigger gauge cable. A faster motor will start the engine quicker and therefore reduce the amount of time that the solenoid needs to be held in

bobfather

11,132 posts

238 months

Monday 6th June 2016
quotequote all
Thanks ChimpOnGas, that makes more sense now. I am a qualified electrical engineer, so the basic circuitry is simple for me, it was just the interaction within the immobiliser that I hadn't got my head around. I'm moving my battery to the boot, this is principally why I'll be replacing the power cables.

BTW, although there is no direct electrical connectivity between the motor power and the solenoid signal there is an advantage in increasing current to the motor with bigger gauge cable. A faster motor will start the engine quicker and therefore reduce the amount of time that the solenoid needs to be held in

ChimpOnGas

9,637 posts

162 months

Tuesday 7th June 2016
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bobfather said:
Thanks ChimpOnGas, that makes more sense now. I am a qualified electrical engineer, so the basic circuitry is simple for me, it was just the interaction within the immobiliser that I hadn't got my head around. I'm moving my battery to the boot, this is principally why I'll be replacing the power cables.

BTW, although there is no direct electrical connectivity between the motor power and the solenoid signal there is an advantage in increasing current to the motor with bigger gauge cable. A faster motor will start the engine quicker and therefore reduce the amount of time that the solenoid needs to be held in
Cool, the heavier starter cable and additional earth I recommended back in 2012 will certainly make a big difference on the high amp starter motor circuit because what TVR used was a very feeble cable especially given its over 7ft long. What it won't do is repair any damage to the little switching relay responsible for the low amp starter solenoid circuit because its a completely different and separate circuit, and the same very much applies to the hot start kit.

Years ago I had a long chat with Carl Baker about the original wiring error made by TVR in the 90's, Carl was trained at the Meta factory in Italy, he explained the Meta engineers knew all about the mistake TVR were making and while they were making it. Apparently Meta sent a number of memos to TVR highlighting their mistake and how to correct it, and apparently TVR arrogantly ignored them all.

So was formed a little business opportunity for Carl who must have corrected the situation on literally hundreds of TVRs over the years, his approach being the correct one of replacing the security system and wiring it correctly. Carl then explained to me he would then remove the ModWise hot start kit if the owner had fitted one, in his words "with the true problem now properly rectified the hot start kit only served to introduce another amateurish wired in point of potential failure".

He was also quite vocal about the way the the hot start kit was being marketed as a solution to the common immobiliser fault introduced by TVR that presents itself as the hot start issue, his position was that at best it was only a sticking plaster that masked the true issue and actually served to lull people into thinking they had sorted the problem permanently, which of course they hadn't. After being educated by the expert in the true reason for the hot start problem it comes as no surprise that people often still complain of suffering the hot start issue after fitting the ModWise kit some years ago.

I've now sent my immobiliser bypass instructions to over 100 TVR owners who have approached me directly themselves requesting them, what this tells us is there are still a lot of cars out there that have the issue that the likes of Carl Baker & David of HF solutions haven't fitted a new security system to. And you'd be amazed by how many of the TVR owners who contact me for the bypass instructions telling me they already have the hot start kit, typically they approach me totally confused as to why the problem mysteriously returned a few years after fitting the kit from ModWise.

I understand how attractive it must be to buy an inexpensive and easy to fit kit that claims to solve the problem, but the truth is its completely impossible for for the kit (which is just adding a relay) to fix damage that has very likely already occurred inside your immobiliser, as such and being charitable the way the hot start kit is marketed as a solution to the hot start problem is rather misleading. The seller of the kit isn't trying to mislead, he just hasn't properly understood the the true issue resides inside the immobiliser, caused by the fact TVR wired it incorrectly.

I think understandably what he's done is look at the fact TVR never fitted a dedicated starter relay which was indeed a failing, then offered a simple to fit kit that allows people to add one back in, by luck it then had the effect of taking a bit of load of that little overloaded switching relay inside the immobiliser so it very often effected a temporary cure. Sadly the starter solenoid circuit still passed through the immobiliser, and it did nothing to correct the TVR wiring mistake, so while it may mask the symptom for a while it most certainly is not a permanent fix to the true underlying fault and really shouldn't be sold as such.





Belle427

6,808 posts

216 months

Tuesday 7th June 2016
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It would be nice to create a sticky in this forum entitled "hot start issues look here" to save people repeating themselves.
I wold happily do it if it could be done.
chimpongas explanations are clear and concise and could be used with his permission.


taylormj4

1,547 posts

249 months

Tuesday 7th June 2016
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I have the hot start problem but last week it became a cold start problem. I never fitted the hot start kit as I couldn't get a plausible electrical explanation for how it helped resolve the problem (I am an electrical engineer).

I understand that it is the relay in the immobiliser that is the problem.
Has anyone tried opening up the immobiliser and replacing the faulty relay with a new, higher current component ?

I am going to try this myself this weekend but not sure if it is possible to get into the immobiliser as yet.
I also want to check that all of these circuits are fused as well.

I've already added a fuse to the PCB in the other box for the lights as that wasn't protected and when the headlamp switch shorted out to the back panel the only thing that stopped a fire was the PCB track which acted like a fuse and blew itself apart.

Funny what Chimpongas said about Carl talking to the factory. I called TVR about the headlamp issue and spoke to the guy responsible for electrics. He wasn't interested in what I had found either. Seemed more concerned I was going to try and sue him or something. They did send me a new switch though, which I modified slightly to prevent the fault happening again.

David Beer

3,982 posts

250 months

Tuesday 7th June 2016
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The solenoid draws around 13 amps, the wiring is loosing 6. So even if you Replace the immobiliser you still loose 6 amps. Don't buy the kit but fit the relay. Details on the griff and chim pages.

Edited by David Beer on Tuesday 7th June 19:19

ChimpOnGas

9,637 posts

162 months

Tuesday 7th June 2016
quotequote all
David Beer said:
The solenoid draws around 13 amps, the wiring is loosing 6. So even if you Replace the immobiliser you still loose 6 amps.
The circuit passes through the immobiliser, we know this because the immobiliser's function is to act as a switch on that circuit. And its the immobiliser, or the at least the poor way TVR wired the immobiliser that's the true issue here.

As I've continually been very clear to point it is indeed best practice to fit a relay to the starter solenoid circuit, like I've said countless times TVR never fitted a starter circuit relay which was a significant oversight. But with the problem now properly understood my concern is the ModWise hot start kit may not be the best way to add that missing relay and it certainly should not be considered or sold as a comprehensive "cure" for the hot start issue. If there is already internal damage to the switching relay inside the immobiliser and you are leaving the immobiliser part of that circuit (as you do with the ModWise kit)... the kit will not and can not resolve that issue.

While it's true in the short term the ModWise kit may well help to take some load off the little switching relay inside the immobiliser, because some current is still passing through it the ModWise kit may very well be just masking the fundamental issue, IE the potentially damage inside your immobiliser. This is why its not uncommon to hear of people who have fitted the hot start kit only to suffer the same problem a few years later, if the damage is already done no relay not even the ModWise kit will remove it.

Actually rather than adopting the ModWise method of splicing into TVRs existing rat's nest of wiring in the passenger footwell and adding yet another dangling digelberry relay, the better way to install a starter relay would be to take a good live feed directly from the battery, ideally you'd also look to mount your new relay as close as possible to the component its switching (the solenoid) rather than right over on the other side of the car in the passenger footwell as with the spliced in hot start kit. A good option therefore would be to take your high amp feed from the main battery to starter cable right at the starter motor then mount your relay somewhere dry and protected that you can also access easily.

But the facts remain that the biggest amperage drop takes place right at/in the immobiliser itself so relay or no relay bypassing the immobiliser (or fitting a new correctly wired one) will deliver the biggest benefit by far. Indeed the simplest form of bypass would be to take a new length of suitable gauge wire (with an in line fuse for safety) from the sprung start position terminal on your ignition switch straight down to the starter solenoid terminal, no relay... just a straight run from key to solenoid. Such a simple bypass without the relay may not be 100% best practice but it will most definitely deliver an immediate cure to the hot start issue, and for no other reason than you are immediately eliminating the biggest amp thief in the circuit, the immobiliser, especially if its internal relay is past its best.

Then and only then can you set about removing the feeble battery cable used by TVR and replacing it with something new and of a more appropriate gauge, finish off with a nice direct earth from the battery negative terminal to starter motor mounting bolt or engine block using the same heavy gauge cable and all your Chimaera starting woes will be banished for good. On the other hand just fit the ModWise kit in the belief it's a catch all fix for the hot start problem and one dark night you may well regret you believed the "cure" statement made on David Beer's ModWise website.






Edited by ChimpOnGas on Tuesday 7th June 20:33

David Beer

3,982 posts

250 months

Wednesday 8th June 2016
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You have only recently agreed about fitting the relay! thanks for the advert though.