Jonathan_bell Posted September 27, 2014 Report Share Posted September 27, 2014 Hi, Still trying to resolve my issue with the TR, When I open the throttles fully and inlet manifold Vacuum drops to 0 the engine feels light it is not getting enough fuel, so this morning I thought to check a few things over. Fuel pump delivery is this weekends focus, I have measured the pressure and getting the specified 106PSI so no issues there. Next task I measured the flow at the metering unit, I got 350mltrs / min, which sound a bit low to me. Next I checked the spill return from the regulator back to the tank and it is as per the manual recommends 1ltr/min. So my question is, what should be the flow be on the input side of the metering unit? I guess the pressure regulator will reduce the flow but how much should it be? Quote Link to post Share on other sites
Peter Cobbold Posted September 27, 2014 Report Share Posted September 27, 2014 (edited) If the 350ml/min flow was measured by catching the fuel with the hose to the MU disconnected, pumping to atmopshere, then its almost certainly too low. Because the back pressure (105psi) will reduce the flow "quite a lot". Fuel flow for 150 hp needs to be about 700ml per min.** So you are indeed a loong way down on flow. Even If the flow you measured were valid at 105psi you only have enough for 75 hp. When you are catching the flow from the MU hose the PRV wont be open at all - it opens at pressures around 100psi. So with the MU hose emptying to atmosphere you can ignore the prv flow - there is none. ( Unless its stuck open, but thats unlikely as its regulating at 105psi OK.) If you clamp off the PRV return to the tank you can remeasure the flow at the hose to confirm this. -- BUT dont run the pump with the PRV clamped and the hose on the MU!!! PRV seems to be setting the psi correct, so .......weak pump? or low voltage at pump? Peter ** http://www.hyperflite.co.uk/fuel-consumption.html gives 0.270 L/hp/h which for 150hp is: (0.27 x 150)/60 litre per min SO: 150hp needs 675 ml per minute Edited September 27, 2014 by Peter Cobbold Quote Link to post Share on other sites
Jonathan_bell Posted September 27, 2014 Author Report Share Posted September 27, 2014 Hi Peter, thanks for your advice I thought as much, I have checked the voltage at the pump some time back and even put a dedicated line and relay. I have a Bosch pump in there at the moment I guess it's a little tired, it's been on the car some time before I purchase it, car was laid up for many years so I think it's time to admit it needs to be replaced. Thanks again for your advice. Jon Quote Link to post Share on other sites
Steves_TR6 Posted September 27, 2014 Report Share Posted September 27, 2014 Before replacing the pump I'd check for a blocked fuel filter, would give these symptoms? Quote Link to post Share on other sites
Peter Cobbold Posted September 27, 2014 Report Share Posted September 27, 2014 Before replacing the pump I'd check for a blocked fuel filter, would give these symptoms? Yes ! that's the wisest next step. Peter Quote Link to post Share on other sites
Jonathan_bell Posted October 4, 2014 Author Report Share Posted October 4, 2014 Hi Pete, Just thought to let know the problem has now been resolved, the short flex pipe before the metering unit was the culprit, I replaced it lasts year and at first it seemed fine, anyway took it off the car yesterday and I could hardly blow through it, guess the rubber inside had reacted with the fuel and swollen to cause the restriction. Fitted a replacment this morning and it certainly has a few more horses available now. Regards Jon Quote Link to post Share on other sites
ijonsson Posted October 4, 2014 Report Share Posted October 4, 2014 Hi Pete, Just thought to let know the problem has now been resolved, the short flex pipe before the metering unit was the culprit, I replaced it lasts year and at first it seemed fine, anyway took it off the car yesterday and I could hardly blow through it, guess the rubber inside had reacted with the fuel and swollen to cause the restriction. Fitted a replacment this morning and it certainly has a few more horses available now. Regards Jon Should I be worried? I recently replaced this tube with a steel reinforced tube from Rimmers, where did you purchase yours? /Inge Quote Link to post Share on other sites
Peter Cobbold Posted October 4, 2014 Report Share Posted October 4, 2014 (edited) Hi Pete, Just thought to let know the problem has now been resolved, the short flex pipe before the metering unit was the culprit, I replaced it lasts year and at first it seemed fine, anyway took it off the car yesterday and I could hardly blow through it, guess the rubber inside had reacted with the fuel and swollen to cause the restriction. Fitted a replacment this morning and it certainly has a few more horses available now. Regards Jon Hi Jon, I am shocked. Who sold it? Its not fit for purpose, we need to know. Also pls fill in a PQI form: http://www.tr-register.co.uk/pqi/ Pls dont throw away the faulty one. Are you using UK fuel? Hoses with teflon lining are safe with ethanol fuels. Peter Peter Edited October 4, 2014 by Peter Cobbold Quote Link to post Share on other sites
Jonathan_bell Posted October 4, 2014 Author Report Share Posted October 4, 2014 No need to panick, I purchased this at a local marine store where they are considered to be experts hose manufactures, I would question that now. I am going to section the tube at the crimp to see what the issue is. Quote Link to post Share on other sites
Peter Cobbold Posted October 4, 2014 Report Share Posted October 4, 2014 No need to panick, I purchased this at a local marine store where they are considered to be experts hose manufactures, I would question that now. I am going to section the tube at the crimp to see what the issue is. !!! At least your TR was not out of sight of land when the hose failed. Quote Link to post Share on other sites
JohnC Posted October 5, 2014 Report Share Posted October 5, 2014 Almost completely off-topic, but here's a result of using the wrong spec fuel hoses. On a ship. Four sailors died in the resulting fire. BTW, the hoses were wire-braided and failed after only 40 HOURS operation. Me, I try to stick with fuel-related components from reputable suppliers. No 100% guarantee I suppose, but I feel safer. Quote Link to post Share on other sites
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