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On my recent trip where I was driving long hours in high temperatures, I did have a few hot-start problems - not overheating, just starting up after a 10 minute break, for example.

What I was wondering is how modern cars manage this? They have much more enclosed engine bays, with under trays, plastic engine covers, sound deadening (which must keep heat in, if anything), no heat wrap on the exhausts etc yet my tin-top has never had this problem, so how do they do it?

It can't be about airflow because there isn't any when the car is not moving...

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Going to my ex-AA days, we had circa 20-30% more breakdowns in excessive heat i.e. at the beach side in summer.

The was mostly due to two areas; general poor maintenance during service, hose inspection, seeping radiator matrix and my favourite 'I thought something was wrong because I have to top up the water every week'. Secondly the antifreeze mixture was totally wrong, especially if they have been topping up with water. A lot of people think antifreeze is to stop the coolant from freezing but it has cleaning chemicals and more importantly raises the boiling point.

Buy a coollant tester and check your mixture. Most is us would be surprised.

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Not sure what ECU you're using or if you're even on injection, but generally I've found the default maps that cars come with very rarely have had any time spent on the hot-start aspects of the map. Spending a bit of time fine-tuning the cranking enrichment settings and temperature-related enrichment settings made a massive difference for me, and my car now starts generally pretty well, hot or cold. How to do this is a topic in itself though and does take time and patience (particularly cold starts; not your problem though)...

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Is it a cranking problem or running problem with the heat? If cranking check the ground cable to/from the battery and you may want to add another ground strap to the starter.

If it is a running issue more than likely it is heat soaking of the swirl pot and HP pump in the engine bay. Tin tops do not have this setup and it is why I am in the process of moving everything to below the boot. Pumps do not like heat and we have more of it, it seems here in California (even though I'm in northern California) than in the UK.   

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Been there fixed that. If you’re on a K6 ecu it will be as Brumater says. You need to play with initial prime to help cylinder wetting and then first to tenth turn enrichment. Beyond that it a bit pointless, who turns more than ten times without a rest. Mine was woefully low on initial crank and first to third turn enrichment at all temperatures but worst when hot. 
it was Brumster who pointed me in the right direction btw so big thanks Brumster. 
 

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Ahh, that's a good call - Emerald were actually very good and told me what to do to my map for cold starts, so I'll ask them for something similar for the hot start. 

Good point about the swirl pot in the engine bay, Marlin - makes a lot of sense. 

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  • 7 months later...

So, back to this old sucker...

Emerald (actually John Lamsley, the guy who left there and started up on his own) updated my map for hot-starting but it has not fixed the problem. He reckons the problem is fuel pressure.

I don't have a fuel pressure gauge (possibly on order) but assuming it is low, what is the most likely culprit - the HP pump or the OEM Ford regulator I have fitted? Or something else...

Any way to test what it is?

 

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eBay item number:
113895639898
 
Universal Fuel Injection Gauge Pressure Tester Test Kit Car System Pump Tool
Not sure if this item will help you out for £19.99
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