After having got the car up and running on Sunday morning I decided to drive along to the S.E. meet and along the way my fuel pump started making a load whining / humming noise.
This is accompanied by a massive fluctuation in fuel pressure withn the gauge reading second by second changes of 60 psi dropping to 40-50-60-30.
I'm unsure whether its the fuel pump itself or anything else that may be causing it, i.e. relay or wiring.
If I start the engine and test the voltage at the pump I assume I should get a constant reading. If I'm testing the pump and the voltage is fluctuating at the same time as the pump is whining then can I assume that it is related to the power the pump is receiving?
I also want to rule out a crushed return line, if I disconnect the return line to the tank and feed it straight out the of FPR into a can then if the pump stops screaming I know this could be the cause.
I know I could run wires straight from the battery to the pump but I am hard pushed to find any that are long enough and meaty enough. I suppose I could always disconnect the power line from the amp in the back and use the body as an earth couldn't I?
either pump not getting a constant petrol flow or......
not sure but what rgulates the 12v output from the relay? i know sometimes alts send out too much voltage when the regulator goes, could this send a higher voltage to the pump?
The problem stems from a bracket I made for the FPR. Basically due to the FPR's position on the bracket the fuel line out of the return end of the rail had a sharp bend in it. It wasn't kinked but it was far from "straight through". Therefore I reckon the pressure would build up in the line and force some through to the FPR while putting additional strain on the pump.
BTW I checked the relay there is definately no switched +'ve, only a switched earth and the relay is off when the ignition is off.
ts all but cut up now matey! engine is yet to be opened up, but the cam belt has jumped a few teeth so fingers crossed, think i'll be ok though as omegas have mighty deep pockets in the pistons, gonna do the head while its out, oh and solid lifters
havent told steveg yet, i'll have to mail him some pics, let me know how you get on down there mate