I cant be sure about the auto, as far as temps and pressures are concerned. Too date i have never owned an auto car, so never had to work on one. You may have to look elsewhere for that info. As far as pressures, i would tend to agree with delcos comments above. 4.8 is alot smaller then 7-8mm. Smaller diameter tubes have a much smaller flow compared to bigger ones.....like the reduction in size is not linear to volume flow, it has a multiplying effect.
Electronics is fairly resilliant to heat, but to a certain degree. i would think the ecu would handle temps around 50 degrees, if your mounting it direct on the firewall, i would put some heat insulation betwen it and the wall, or even better have some insulation material on the wall then mount the ecu slightly off it on some sort of stand off so air can flow under it, if heat is a serious problem there. You wouldnt want it in the glove box, it would be in the way there.
Fuel pump, what i would do possibly is buy one of those little line taps at the auto shop. Use it to rig a light bulb(or even just a flying lead to wrap around your volt meter probes) from the violet fuel pump wire, through the bulb or volt meter, then to earth. This will light-up then when ever there is power on the pump. This will let you see when you are losing the power. From that point you should be able to make some deductions for fault finding. I very much doubt its the ecu. Very few propblems are ecu related. They are generally very reliable and dont do "odd" things like that, unless someone fugged the program. They will die altogether usually if they fail.
