Hot start problem

Hot start problem

Author
Discussion

QBee

19,276 posts

126 months

Thursday 27th April 2017
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Bought my car when it was 13 years and 67,000 miles young.

Day one I collected it and drove it 10 miles to visit the recommended TVR specialist. After an hour with him I drove it one mile, parked in the town centre, popped into a shop, came back.......and it wouldn't start. 15 minutes later the said TVR specialist arrived and it started first time.

I had the same problem several times that summer, and quickly realised that if I dared to turn the engine off when the car was hot, it wouldn't restart for 15 minutes. So no illegal parking while popping into shops for me, but lots of embarrassment in petrol stations.

I did the Dave Beer mod, which worked for a while, but then had more alarm/immobiliser issues. A discussion with Carl Baker resulted in a replacement, updated, alarm immobiliser. Never had the problem again in 30,000 miles of happy motoring.

So yes, many of these cars run faultlessly, as yours have, particularly if you protect the incorrectly wired immobiliser circuit, but quite a number of us do suffer this irritating problem, and the accompanying jests from other motorists who all think that misquoting Jeremy Clarkson is hilarious. I have to say, my TVR has been the most reliable car I have owned.

Ribol

9,927 posts

240 months

Thursday 27th April 2017
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QBee said:
I had the same problem several times that summer, and quickly realised that if I dared to turn the engine off when the car was hot, it wouldn't restart for 15 minutes. So no illegal parking while popping into shops for me, but lots of embarrassment in petrol stations.

I did the Dave Beer mod, which worked for a while, but then had more alarm/immobiliser issues. A discussion with Carl Baker resulted in a replacement, updated, alarm immobiliser. Never had the problem again in 30,000 miles of happy motoring.

So yes, many of these cars run faultlessly, as yours have, particularly if you protect the incorrectly wired immobiliser circuit, but quite a number of us do suffer this irritating problem, and the accompanying jests from other motorists who all think that misquoting Jeremy Clarkson is hilarious. I have to say, my TVR has been the most reliable car I have owned.
All very easily explained ..........

Starter drawing more current than it should, damages the contacts inside the immobiliser. The DB mod allows those same contacts to work a bit longer due to how little current they carry post mod. Eventually they give up, new immobiliser required. Was the original problem with the starter ever looked at, probably not, the cycle starts again. If during that cycle the starter dies a death through natural causes the problem is then resolved, if not it carries on.

It is very easy to draw the wrong conclusions, but the good news is it did stop you parking illegally, at least for a while cop

QBee

19,276 posts

126 months

Thursday 27th April 2017
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Starter was checked and was working fine.

bobfather

11,119 posts

237 months

Thursday 27th April 2017
quotequote all
Ribol said:
ll very easily explained ..........

Starter drawing more current than it should, damages the contacts inside the immobiliser. The DB mod allows those same contacts to work a bit longer due to how little current they carry post mod. Eventually they give up, new immobiliser required. Was the original problem with the starter ever looked at, probably not, the cycle starts again. If during that cycle the starter dies a death through natural causes the problem is then resolved, if not it carries on.

It is very easy to draw the wrong conclusions, but the good news is it did stop you parking illegally, at least for a while cop
I'm not sure this is entirely correct, it is correct that increasing available contact switching current overcomes the problem of stiction generated within the starter solenoid. There is an assumption here that the stiction will continue to increase over time thus requiring ever greater current and therefore eventually burning out the bypass relay contacts. That may be true for you but I suggest it isn't true for everyone, in my case I assume the stiction has reached a plateau, greater current is required and provided by the DB mod but the amount of required current is no longer increasing. My DB mod has been working for many years without any sign of failure.

These engines operate in many other cars without this hot start problem, this is likely to be due to those solenoids being supplied via better relay contacts. Those solenoids stiffens over time but never gets stiff enough to burn out relay contacts. The issue here is that the TVR solenoid switching system was weak resulting in owners detecting an increasing current level. If the system had been more robust in the first place then one or two of us would have discovered a problem but it would not have become such a big TVR issue. Those problems would have been solved by replacing the starter motors

Cider Andy

1,880 posts

207 months

Thursday 27th April 2017
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There is doubtless not just one cause, as has been discussed. There are also other factors, not least the quality of the starter motor fitted. Mine had a replacement genuine Land Rover part fitted and it's performed faultlessly, unlike the aftermarket unit previously fitted. nb. it wasn't replaced because of this problem although I had suffered one instance of having to wait at a motorway petrol station prior to wiring in a Modwise-style relay.

Others have avoided the problem by fitting a heat shield against the starter motor although I'm not convinced most of the heat is conducted rather than radiated.

Thirdly, others have measured a discernible voltage drop in the Vauxhall wiring connecting the ignition switch to the TVR loom.

So we have:

1. Immobiliser relay.
2. Solenoid wiring.
3. Heat.
4. Ignition switch wiring.
5. Condition of starter motor.

If the set-up is already marginal by design it's likely that any one (or more) of the above factors may conspire to produce the symptom of a starter motor that doesn't turn, hence the different reports of how individual owners effected a cure.

Sardonicus

18,520 posts

203 months

Thursday 27th April 2017
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Other vehicles i.e Range Rover may use the same engine but unlike TVR they do not get cooked by poor airflow and exhaust temps the bane of an electric motors life frown dont to a dirty or gummed solenoid any favours either hence not so much as a click when the condition arrives (dreaded hot start) as it dont shunt

Cider Andy

1,880 posts

207 months

Thursday 27th April 2017
quotequote all
Sardonicus said:
...hence not so much as a click when the condition arrives (dreaded hot start) as it dont shunt
Exactly, and that is an important point: I guess any of these motors would turn the engine if the solenoid actually pulled the contacts in.

Sardonicus

18,520 posts

203 months

Thursday 27th April 2017
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Cider Andy said:
Exactly, and that is an important point: I guess any of these motors would turn the engine if the solenoid actually pulled the contacts in.
Pretty much yes

mk1fan

10,108 posts

207 months

Thursday 27th April 2017
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My take in no particular order of importance;

1. Upgrade wiring circuit to starter. Larger cables, relays and connectors.
2. Heat management. Ceramic coating the manifolds and Y piece.
3. Sorting out the TVR 'modded' immobiliser.
4. Good quality battery (or batteries).

I suspect that if 1. and 2. had been done in the factory then the issue would not exist.

Ribol

9,927 posts

240 months

Thursday 27th April 2017
quotequote all
bobfather said:
These engines operate in many other cars without this hot start problem,
Sardonicus said:
Other vehicles i.e Range Rover may use the same engine but unlike TVR they do not get cooked by poor airflow and exhaust temps the bane of an electric motors life
There is your answer.

Ribol

9,927 posts

240 months

Thursday 27th April 2017
quotequote all
QBee said:
Starter was checked and was working fine.
How many times was the starter checked the exact moment it failed to crank (not after it had cooled down)?

TJC46

2,106 posts

188 months

Thursday 27th April 2017
quotequote all
Ribol said:
Clean and lube up the solenoid, which as you have already worked out yourself is the real problem.

.
THIS.....yes............................oh and fit a heat shield above the starter to protect from the heat given off by the manifold, and you should have no more problems.

People call it the "hot start problem" because that's when it usually happens.

I would rather call it the "starter motor solenoid problem" general cause of which is heat from the manifold and high under bonnet temps.

Clean and lube the starter and solenoid and fit a heat shield.......job done.

Englishman

2,159 posts

192 months

Thursday 27th April 2017
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The 'hot start' problem was also present on the more highly tuned wedges due to heat soak from the manifolds. When delivered new from the factory the TVR Centre wrapped the starter motor with heat shield prior to delivery to customers to get over the issue.

bobfather

11,119 posts

237 months

Thursday 27th April 2017
quotequote all
If you wrap the starter motor be sure you don't use the foil backed heat wrap, there is an uninsulated high current power connection on the solenoid directly connected to the battery

citizen smith

717 posts

163 months

Thursday 27th April 2017
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I had a similar hot start problem with a Griff (always tended to happen when filling up with Fuel - what an embarrassment!) a few years ago. What would happen, is after long drive where the car got hot, I would stop for fuel or whatever, then go back to the car and hey presto NOTHING for 15 minutes.

Hence, my solution was to take the starter off the car, strip it down - clean all the muck and grime off after 10 years of abuse, then reassemble using high melting point grease. After that ,the starter worked perfectly and I saved myself a wedge of money.

It would be very difficult to replicate the heat soak conditions, that the starter motor has to operate under. Hence when it's Cold it will always function O.K.

But I may have been just lucky.

SILICONEKID345HP

14,997 posts

213 months

Thursday 27th April 2017
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I would rather rip th lot out and just have a hiddwn switch somewhere.

Then have a remote just to open and close the doors .

bobfather

11,119 posts

237 months

Thursday 27th April 2017
quotequote all
SILICONEKID345HP said:
I would rather rip th lot out and just have a hiddwn switch somewhere.

Then have a remote just to open and close the doors .
Go for the old Fiat 500 method, a piece of bike brake cable connected to the starter motor contacts and secured between the seats, pull the wire and the high current circuit switch is made. Not low current circuit to worry about

Ian Abel

100 posts

124 months

Thursday 27th April 2017
quotequote all
Hi All
I must admit I had the very same problem. Drive for a while, stop, normally for petrol. and yes won't start for a while. Goggled the problem and "hot start" pops up. Saw / read about the kit so fitted one. Must say for the last 2 years or so seems to be starting ok. Any reason why this might be, given that the kit seems to be a temporary fix. Am I going to get caught out sometime soon?
Cheers

Ribol

9,927 posts

240 months

Friday 28th April 2017
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SILICONEKID345HP said:
I would rather rip th lot out and just have a hiddwn switch somewhere.

Then have a remote just to open and close the doors .
That won't solve the starter problem, but it will invalidate your car insurance if that matters to you at all.

erichowden

1 posts

1 month

Monday 5th September
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Hi does anyone have a diagram of how to bypass the immobilizer on TVR Chimaera please