I was driving in traffic and my 93 RR County LWB 4,2 just died on me. First I heard a noise like a flat tire from the rear (i was going 70mph and it was a somewhat faint sound that lasted only a few seconds) then it hesitated/bucked a couple times, drove ok for 1 minute and just cut out. All electrical was there but no motor. I coasted to a stop and got a tow.

I have spark at the spark plug lead, new coil, all coil, pickup and amplifier tests per the RR shop manual test ok. I have fuel in the fuel rail but I can't test pressure because the fittings are pretty rusty and i've been turning wrenches long enough to know i'll need to replace the lines at the filter if I turn the fittings. I have power at the injector. When i crank it it just cranks...no attempt at all to turn over and no signs of combustion.

Because i have spark i'm thinking the injectors are not opening. Is there some sort of crank timing sensor or something that may be telling the ecu to not open the injectors. I'm pretty good at FI diagnostics but this one has me stumped. I tested the voltage at the fuel pump. I don't remember the exact voltage but it was between 4.5 and 6v. I would think it needs to be 12v. Am I wrong? Should I be suspecting the fuel pump or power to it?

 

Start with the basics, Compression, fuel, and ignition. You obviously know this ( for others ). Unlikely that compression would give out that quickly. You have spark @ the plugs. Fuel, The ECU grounds the injectors to fire them. You really need to measure fuel pressure. LR has a fuel filter kit that includes the necessary lines to replace those rusted ones.

4 wires to the fuel pump assembly. Two small ones for the level and two big for the pump. Yes, it should get 12V. If not, check the connector in the L/R wheel well to start.