old problem again - any ideas please?

[paulr]

some of you may have read my post from 2011 (france trip) when Ruby - our midas coupe mk3 had power loss on an exceptionally hot day when cruising along a french motorway - power faded and engine stuttered until speed dropped from c 65 to c 50 then ran smoothly - happened a couple of time and we decided symptoms were consistent with fuel starvation (engine never died) and we decided most likely problem was excessive heat under the bonnet and fuel lines (which on Ruby are rubber and ran very very close to exhaust downpipe) gettting too hot - fuel vapourising and reduced supply hence power loss.

Following advice we bought a rather neat polished stainless steel heat shield which we bolted on and which sits under the carb and we ran the fuel pipe between (above ) the heat shield thinking this would prevent it getting too hot.

All since been fine - hurrah - until past fortnight.

Have twice in recent very hot weekends - taken Ruby for a run and each time recurrence of the French problem - once Ruby is upto temperature (and by that I mean warmed up not overheating ) and cruising on dual carriageway - had same loss of power and stuttering engine and speed dropped off then at lower speed ran smoothly .

Have replaced fuel in line filter - in case this was restricting flow (but why only on very hot days?) and bought new (rubber again) fuel pile which I have run from engine mounted fuel pump -back away from exhaust down pipe and circuitous route away from exhaust to carb- problem still there on very hot days so puzzled as to what it is?

Have bought exhaust heat wrap which I will fit in next day or so round downpipe (and perhaps also wrap around fuel pipe where closest to exhaust) in hope that cures it .

So problem only has ever occured on really hot days- no excess temp on gauge - hoping that exhaust wrap will cure it but any ideas appreciated

one bit of good news is that in UK exceptionally hot days truly are exceptional and rare!

thanks all

[Rich]

I used to get this, the only thing that fixed it was blanking off the engine heated mechanical fuel pump and replacing it with an electric pump and filter king fuel pressure regulator/filter.

[DavidL]

I did too, and removed the mechanical pump. However, I used a small Facet pump mounted near the tank but didn't use a fuel regulator, because I didn't realise I might need one!
It might have been that the pump only operated on demand, but that was back in the 1980s/90s so I don't remember much about it, but I can't remember any problems with excess fuel supply.

Ignorance is bliss...

[Rich]

I did too, and removed the mechanical pump. However, I used a small Facet pump mounted near the tank but didn't use a fuel regulator, because I didn't realise I might need one!
It might have been that the pump only operated on demand, but that was back in the 1980s/90s so I don't remember much about it, but I can't remember any problems with excess fuel supply.

Ignorance is bliss...

My facet is sat on the rear subframe, you can manage without a regulator if the float valve is tip top. For me it gave me a decent filter and a consistent pressure at the float valve which from (very dim) memory needs to be around 3psi.

[Hans Efde]

In my turbo days with lots of heating problems I eventually cut a hole in the bumper and except for an oilcooler also installed 2 large flexible hoses (around 8cm in diameter). One ran to the airfilter under the headlamp, the other around the engine towards the turbo and carburettor. Never had a problem again at motorway speeds. Even the bonnet felt cool.
Also to consider is an overheating coil. I had power cutting out a year ago. After cooling down it would start again. The coil was too hot to touch. I moved it away from the engine and haven't had a problem with it since. But I have to say I haven't used it on hot days this year.

[Hans Efde]

I forogt to mention. On my first Midas Gold (now in Sweden) the first owner had cut back the lip of the bonnet. This creates an airslot sucking out the hot air. Very clever. I might do that with my present car as well. It's hardly noticable.

[streetsy]

When I had a seven replica on hot days the fuel used to evaporate from the fuel pump, facet in the boot cured it. Thermal wrap on the exhaust manifold may also help, makes a massive difference to under bonnet temperature.

[mikeeskriett]

Hi

Are you sure it's fuel and not the ignition module, the symptom you have is identical to the fault you get when you use factory electronic ignition with the wrong coil or that the module is breaking down due to heat soak.

I've had both issues on my Mk3 notably on a hot day on the way down to Brighton loss of power at high speed and when in traffic sputtering to a halt and refusing to start until the engine had cooled a bit.

Cheers,

Mike

[paulr]

thanks everyone- fitted the heat wrap last night so will have to wait now for a hot day to see if problem gone or not . Mike re the module - where is it and is it a straightforward click out click in replacement - not sure exactly what the module is - do I get replacements from ordinary motor factors or minispares etc ? thanks

[Stuart]

the plastic box on the side of the distributor, picture off ebay.