I'm going to throw out some details on this one. I decided to give my 1985 740 to my girlfriends 18 year old daughter for a Christmas/birthday gift, since she has never had a car. It had been sitting in my driveway for 3 weeks since it was driven, but prior to sitting it was my commuter car and driven on a daily basis. There was some very slight intermittent hesitation while commuting home in 3rd gear @ 35 mph, but not enough for concern. I only started it up twice since it sat, and ran it briefly in that time. Both times after the weather dipped into the twenties for a couple days, to make sure it didn't drain the battery.
The daughter came over yesterday to get the car, all excited. She started it up and it idled for about 10 minutes after a slightly hard start. She started to pull away and it stalled. I tried to restart the car for several minutes with no luck. It sputtered and tried to fire on almost every occasion.
So...I'm asking if anybody knows what slots in the fuse box to use a jumper wire to test the fuel pumps and relay ? The main pump on the drivers side was replaced about 20 months ago just prior to me buying the car, and I can hear it running when the car is sputtering and trying to start. But the in tank pump, has not been replaced in my knowledge any time recently. I cannot hear it prime from inside the car when I turn the ignition to the on position. Which leads me to think using a jump wire to test the pump and relay would be a good start.
I'll keep snooping online for other info until I hear back. THX !

 

Doesn't sound like fuel pumps... More like hall sensor. Make sure the wiring is not falling apart as '85 are prone to that.

 

Lev..It could be the Hall sensor, but I figure it doesn't cost money to use a jumper wire to test the fuel pumps and relay first. I'm just starting with the basics. I know on my '84 245 I used to have to test the fuel pumps with a jumper wire was from the #5 fuse slot to #7 slot. But I'm not sure on my '85 740, or how to use a jumper wire to check if the relay is working.

 

the 740 fuses aren't nearly as easy to jump that way. its easier to pull the relay and jumper the relay socket. but I'm with lev, check the wiring on the hall sensor on the side of the distributor.

 

There isn't a distributor....it looks like dual coil packs on the back end of the cylinder head up by the valve cover. But I'll check online for a schematics to find out where it is. Thank you guys.

 

Nice....I found a pic of the distributor taken off the cylinder head. Now I know why I thought it was coil packs. It also shows the plug to the Hall sensor.
Ahhhhh....I see, said the blind man.

 

The 740 has a cam driven distributor and it only has a rotor in it. The firing of the coil is done with the crank position sensor mounted over the flywheel in the rear top of the engine. Timing is done through the ECU. Check for fuel and spark and based on which you don't have we can go from there.

 

no-no-no-no. LH2.2 740's (non-turbo up through 1988 and turbo to 1989) use a hall sensor int he distributor and ARE timed by rotating the distributor.

LH2.4 740's and all 940s use the crank position sensor.

 

I would try to start the car on ether to rule out the hall sender. You can jumper the fuel pumps on #30 to #87/2 on the pump relay socket. To run each pump individually, pull fuse 1 or 11; also check the fuses. I think 1 is the main and 11 the tank pump. Listen at the gas filler tube for in tank pump. Make sure the battery has a full charge.

 

only the tank pump is separately fused, the main pump is on the same fuse as the injection system, so if you pull that NO pumps will run.