Rob, I have been working on this for months. The car has always started at the first hit until this summer when it took 2 or 3 trys to start when the car is cold or has been parked for several hours. Then after the second or third try it starts readily.When hot as always it starts on the first try. After running for a few seconds it will start each time on the first try like it always did. Fuel pressure is good, fuel pump check valve is good. I swapped in the original pump and that didn't change anything. I swapped out the pressure regulator and that made no difference. The fuel filter is less than a year old. I replaced the cam sensor and the crank sensor in the spring. I lifted the injector rail and with the pump on there is no fuel leakage past the injectors. There is no smell of gas in the car. I will change out the injector o rings and filters next, on the grounds of why not. Being retired is nice, no rush. The car runs nicely, good gas mileage and smooth. Any thoughts? This is the only issue with the car. I enjoyed the 2002 brake fluid story. Ned Monaghan. emonaghan@snet.net
Does the vehicle when started after the cranks give any smoke out the tail pipe? Also how did you test the fuel pump check valve?
I had replaced the original working fuel pump last year with a new one and put the original pump back in to see if there was a change in the starting problem. It didn't change. Before this I clamped the fuel line. The car uses little oil and there is no smoke.
If there are no other symptoms you should check the cold start sensor. I'm sure there is a better name for it, but it enriches the fuel mixture when cold. Performs the function of a choke. Not terribly expensive.
I released fuel pressure this am at the Schraeder valve on the fuel line after the car had sat for a couple of days. No fuel came out!. I then switched on the ignition several times to get fuel pressure up and checked the valve again. A good flow this time. Then I tried to start the car and It fired but did not start after about a 2 second crank, After cranking a second time it fired up. I ran it for a few seconds and then checked the Schrader again. This time it was a proper spray. There was no smoke at the tailpipe after starting . I checked this on several cold starts. So I'm losing pressure/fuel while shut down. We are getting close. I do have a pressure gage but it has SAE threads and I need a metric to SAE adapter to make it work Re the cold start sensor, the DME does not have a separate cold start enrichment injector. The mixture is modulated by the DME controlled gas volume passed by the injectors. Thanks guys, Ned
I know you have replaced the fuel pump but you might need to replace again and the fuel filter as well.
Right now I have the return line from the pressure regulator clamped. We will see if that holds the pressure. Ned
No time to finish this as we are off for a week. When I return I will disconnect the pressure regulator return line from the fuel tank and see if the leakage while shut down is via this line. A regulator with a bad seat could be the cause of the problem. Ned
Sorry for the delay. Thanks to other folks for chiming in on this one. I'm a bit out of my depth on E39s, only had one.
I finally got it. The indie had incorrectly plugged a 6 prong light green relay instead of the correct 4 prong blue DME relay and this prevented the fuel pump from running with the key in position 2.The car started this morning on the first hit!!! Ned
