(formally known as russell booth)
Are these symptoms of a dying fuel pressure regulator
Some of you may know I have had a pinging problem with my RB30DE motor,last weekend when the pump primed up it fell straight back to zero PSI,now it isn't as bad but it still loses pressure almost down to zero PSI in 10 minutes instead of overnight.
The fuel pressure seems o.k. at idle,it reads 35 PSI with the vacuum line connected and 42 PSI with the line disconnected (no vacuum),the motor tend to ping when I come into a slight corner and I have to accelerate after I have backed off the throttle and it starts pinging,under heavy load I have tested the O2 sensor voltage (it is a new sensor) and the volts drop to zero,but just on cruising a stab of the accelerator sees it shoot up to 0.7-0.9 volts which is running rich.
On cruise it cycles like it is supposed to (rich to lean and vice versa)
Someone told me that I am supposed to be getting a constant rich reading (1 volt) when the engine is under load and not zero (very lean),with the old O2 sensor it wasn't even cycling and the reading remained between 0.2 - 0.5 volts (lean) when stabbing the throttle under no load.
Could this be the fuel pressure regulator not holding pressure under high loads?,could it be letting too much fuel back to tank and not supplying enough for the injectors?
It wasn't the fuel pump non return valve as crimping the return line maintained fuel pressure,I think i may have stuffed the reg up when putting the fuel hoses on when I first fitted the motor,I connected the hoses up back to front and switched the ignition on and the fuel pump just stalled under load,reversing thelines fixed the problem.
I think the fuel reg could be dodgy as I gave the motor a total rev out while stopped and it started to misfire,it was a typical miss you get when the engine is starved for fuel,someone said it could be the rev limiter cutting the motor out but I thought that was removed by cutting wire No 53 which on my car is disconnected.