andrewsjwg Posted June 25, 2017 Report Share Posted June 25, 2017 I appreciate this must be a regular and ask if there is any new ideas on this. Our TR5 stopped several times in the hot weather recently. We have replaced the pump and filters with new kit from Prestige. We have also replaced the fuel tank and flushed this out well. I see the fuel lines from the tank to the metering unit run on the inside of the chassis rails and very close to the exhaust pipes and wonder if heat from the exhaust is boiling the fuel and causing this issue? Has anyone tried lagging the exhaust pipes with silica tape or similar heat resistant tape to try and reduce this heat source. I have heard that putting a small electrically operated fan to cool the pump could also help??? Quote Link to post Share on other sites
barkerwilliams Posted June 25, 2017 Report Share Posted June 25, 2017 Also ensure the pipie from the tank to pre-fiilter then to pump has no kinks to restrict the fuel flow. The pump does not have much suction and any restriction on the supply side causes it to struggle and draw more power and hence generate more heat. For the same reason ensure the pre-filter is large enough and its filter is clear. Not the only reason but every little helps. Alan Quote Link to post Share on other sites
andrewsjwg Posted June 25, 2017 Author Report Share Posted June 25, 2017 Thanks Alan, I have just replaced the paper filter element in the pre-filter to a sintered glass type - looks very free flowing. There are no kinks in the pipework and the return line is flowing well. Quote Link to post Share on other sites
carld Posted June 25, 2017 Report Share Posted June 25, 2017 Andrew, one year at the Le Mans Classic, it was unbelievablely hot and suffered your issues, couldn't find a shop on the motorways selling frozen peas, but they did have a 12v fan, like you would find in a tower pc, worked a treat. Never heard of anyone lagging the exhaust and my issue was definitely around the pump itself Cheers Carl Quote Link to post Share on other sites
andrewsjwg Posted June 25, 2017 Author Report Share Posted June 25, 2017 Many thanks Carl, I wondered if putting a wet towel on the pump might help too? We want to go down to the Classic next year and hope we may get another spell of hot weather to test this out. As you say, it can get incredibly hot at Le Mans or very wet. Quote Link to post Share on other sites
openroad Posted June 25, 2017 Report Share Posted June 25, 2017 Hi Andrew, so is it a Lucas Pump, if so have you put your hand on it when this happens , mine sometimes gets very hot and needs the damp cloth treatment. I have been thinking about Carl's remedy too, because there is not always water about to dampen the cloth ! Good luck , Conrad. Quote Link to post Share on other sites
ianhoward Posted June 25, 2017 Report Share Posted June 25, 2017 Hi Andrew I first suffered problems you describe in hot weather and with low fuel - although it was running it certainly wasn't at all happy. Once I filled up with cool fuel it was back too normal. It occurred once again with low fuel, hot weather and very slow traffic allowing the fuel to heat and vaporise. The car stopped. I had to park up in the shade and wait about 20 mins for the fuel to cool off sufficiently. Moral is if you can't keep running at a reasonable speed (letting air over the metering unit) don't let the fuel go below around 1/4 in hot weather and especially if encountering slow traffic as there doesn't appear to be sufficient 'heat sink' cooling of the petrol in the tank. Cheers Ian Quote Link to post Share on other sites
andrewsjwg Posted June 25, 2017 Author Report Share Posted June 25, 2017 Thanks Ian and Conrad, we had 3/4 of a tank full and it is a Bosch pump. We may have solved this with the new hi flow inlet filter and guess we have to bit the bullet and find a hot day and try this out. We going to the .International, does it get hot a Malvern I wonder? Quote Link to post Share on other sites
andrewsjwg Posted June 25, 2017 Author Report Share Posted June 25, 2017 I have seen that Holden's supply a 50 cm wide tape. I am going to "lag" the manifold and exhaust pipe next. Quote Link to post Share on other sites
barkerwilliams Posted June 25, 2017 Report Share Posted June 25, 2017 Andrew, Why not invest(?) £9 in something like this http://www.ebay.co.uk/itm/DIGITAL-MAX-MIN-THERMOMETER-IN-OUT-GARDEN-GREENHOUSE-WITH-3M-CABLE-14-437-3-/322283686741?hash=item4b099acb55:g:wBcAAMXQDnpTXhY2 You will be able to attach the probe on, for example, the outlet from the fuel filter tape it over and run the cable temporarily to the cabin and fit the thermometer to the dash so you can glance at it. Drive for say 30 minutes and compare the starting temp and the finish temp. Then wet rag or whatever and compare the results then you will have something concrete to work with. If you just lag the pipes you will never know if it makes a difference as there are too many variables such as humidity, air temp etc. that skew everything. Alan Quote Link to post Share on other sites
andrewsjwg Posted June 25, 2017 Author Report Share Posted June 25, 2017 Gosh thanks Alan that sounds a great idea, I think a trip out tomorrow, thanks again everyone, lots of great ideas Quote Link to post Share on other sites
barkerwilliams Posted June 25, 2017 Report Share Posted June 25, 2017 (edited) Would also have the advantage that if you find the car cuts out when the fuel reaches say 50'C, then when you are driving and the temp reaches 48' its time to stop for an ice-cream and a couple of gallons of nice cold petrol for the car. Alan Edited June 25, 2017 by barkerwilliams Quote Link to post Share on other sites
macs6 Posted June 25, 2017 Report Share Posted June 25, 2017 Had this issue on my 6, thought it was fuel cavitation,tried lagging etc,turned out intermitent problem on fuel return line,renewed front to back,hey presto. Malcolm. Quote Link to post Share on other sites
HSM Posted June 26, 2017 Report Share Posted June 26, 2017 Just a tip for emergency fuel pump cooling, carry an aerosol of skin coolant available from any chemist ( used for treating burns ) Harvey S. Maitland Quote Link to post Share on other sites
andrewsjwg Posted June 26, 2017 Author Report Share Posted June 26, 2017 That's a idea, yes, will do this, many thanks Quote Link to post Share on other sites
HSM Posted June 26, 2017 Report Share Posted June 26, 2017 Some important health & safety advise i should have mentioned these cooling products are extremely flammable. Take great care to avoid any ignition sauce. Harvey S.Maitland Quote Link to post Share on other sites
Topoff Posted June 26, 2017 Report Share Posted June 26, 2017 Hi Andrew I first suffered problems you describe in hot weather and with low fuel - although it was running it certainly wasn't at all happy. Once I filled up with cool fuel it was back too normal. It occurred once again with low fuel, hot weather and very slow traffic allowing the fuel to heat and vaporise. The car stopped. I had to park up in the shade and wait about 20 mins for the fuel to cool off sufficiently. Moral is if you can't keep running at a reasonable speed (letting air over the metering unit) don't let the fuel go below around 1/4 in hot weather and especially if encountering slow traffic as there doesn't appear to be sufficient 'heat sink' cooling of the petrol in the tank. Cheers Ian Plus one for Ian's reply. The metering unit is the culprit. I now carry a 10 litre can of Shell V Power to fix the problem until the next garage. Also think lower octane fuel burns hotter and adds to the problem. Laurence. Quote Link to post Share on other sites
Nick Jones Posted June 26, 2017 Report Share Posted June 26, 2017 When talking about vaporisation in injection systems, bear in mind that while fuel vaporises/boils all too readily at atmospheric pressures and is even worse at the sub-atmospheric pressures that might occur on the pump suction side, it does not vaporise readily at high pressures and the PI system runs at very high pressures. 105 psi to the metering unit and still >50psi (injector break pressure) thereafter. That is not where vaporisation is happening. While I can see possible issues with hot starting if the the injector lines (especially braided ones) have heat soaked, and perhaps a leaky injector or MU non-return valve have allowed pressure in some of the injector lines to drop, I can't see this happening while the engine is running and pressures are being maintained. IMO it's all down to what is happening on the pump suction side as neither the Lucas or Bosch pumps are much good at pumping vapour. Risk factors are: - Warm fuel. This heat mostly comes from ambient and the energy lost by recirculating relatively large volumes through the PRV. It mostly does NOT come from the engine bay as the PI only recirculates a trickle unless the MU is knackered. The Bosch pumps are potentially worse in this respect as they pump more volume and thus waste more energy, putting more heat in the fuel. - Hot pump - a uniquely Lucas affliction where motor heat conducts to the pumping head tipping the balance into cavitation. But the motor heat is probably down to volt drop either in the marginal supply line or poor earth contact. Ensuring a solid supply voltage and earth will almost certainly solve the motor heating problem. The infamous "cooling coil" adds more heat to the fuel, which is ultimately unhelpful. - Low tank level. The slight extra head pressure from higher fuel levels can be enough to tip the balance between cavitation and not. - Suction line restriction. Reducing pressure on a liquid increases the boiling risk in just the same way as increasing the temperature. A kinked or flattened pipe, partially blocked filter or restricted tank outlet can all contribute to friction losses which reduce the pressure at the pump inlet. Bosch pumps again could be worse afflicted due to their higher flows, thus suffering greater fiction losses. Standard suction pipework is marginally sized even for the Lucas pump. If your pump sounds like it's pumping gravel, its not, it's pumping (or trying to pump) vapour and cavitating. It's not good at it and if it can't maintain enough flow, the pressure will drop and the engine will run rough and eventually stop. - Ethanol content. Although ethanol is not especially volatile itself, as part of the witches brew that is modern E5 (or E10) it promotes volatility. Low/no ethanol fuels will generally perform better in this respect. I think V-Power falls into this category. Food for thought Nick Quote Link to post Share on other sites
andrewsjwg Posted June 27, 2017 Author Report Share Posted June 27, 2017 Hi .Nick, many thanks for your comments, these are really helpful and they gel with my thoughts about the problem too. i'm going to keep a wet towel and bottle of water handy if ever we get hot days. I have also changed the coil as this was suspect. I've not had any problems so far. Quote Link to post Share on other sites
openroad Posted June 28, 2017 Report Share Posted June 28, 2017 Morning Andrew , I have previously sent you a PM. Top right of the page near your user name, envelope with a red number next to it ! Cheers, Conrad. Quote Link to post Share on other sites
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