M52 Stalling problem

Post Mon Jul 27, 2015 2:43 pm

Recently completed My M52 conversion into the E30, all perfect for the first 3-4 weeks.l.

I was happily driving in normal conditions at normal speed and all of a sudden the rev counter dropped off completely and the car stalled. So i pulled over and it sounded as if the fuel pump wasn't priming. Gave it 5-10 seconds in-between flicks of the ignition and i could hear it prime.

Replaced the fuel pump on the weekend with a replica of the Bosch LPH 5 bar pump. New Mann fuel filter, but still i have the same issue, if i hold the bleed valve on the end of the rail and prime the pump it sprays out of the bleed at a really high pressure, If i let the pump prime, then hold the bleed fuel just trickles out.

I'm thinking this may be related to the fuel pressure regulator sticking open and causing the fuel to not build pressure and flow back down the return.

Anyone ever experienced this?

Post Mon Jul 27, 2015 5:54 pm

If the rev. counter drops suddenly, it's an electrical fault. Badly made connection, DME relay, crank position sensor, etc.

Post Tue Jul 28, 2015 8:12 am

Thanks for your response, i'll be buying a cps and a new relay today.

The only thing that pointed me in the direction of the regulator is the rail not holding it's pressure after priming.