View Full Version : Trouble Starting - but runs perfect. Fuel pump?

03-25-2005, 06:46 PM
My '93 740i just started to cause some trouble. In the morning (Ca weather = not too cold) it failed to start with repeated crankings (10 or so bursts). Then suddenly starts and runs strong all day - with repeated restarts. This continued for 3 days... until it faltered a bit while driving (a burp) and then stalled out at a light several miles down the road. Same issue with the restart - got it going - running fine - stalled out and coasted home. And there she sits.
Any ideas? Fuel or spark related?

03-26-2005, 01:16 AM
I assume.
Do one thing: set ignition to position 2. Then the fuel pump starts running till the required pressure is there. Then start the engine. If that is alright, check the check valve in the fuel tank. This might be leaking and the fuel goes back into the tank. There are separate fuel check valves available for installing on top of the fuel tank. You can access this from the trunk.
Have you checked for air leaks in the suction system of the intakes? That could be another reason. When car is running, spray for example brake cleaner fluid around the intake system and see if the RPM is changing.
Do you have a PEAKE tester? That is a good investment. www.peakeresearch.com
Did you do a stomp test? Stomp test only works on US spec cars.
Stomp test is described on my website below.