I have a 1989 Volvo 240 DL. It's been siiting in my driveway for two years. It would not start. Did a lot of work on it. Replaced both fuel pumps and fuel filter. Checked everything related to ignition and starting. Finally got the car to start after cleaning the terminals of the ignition coil. BUT now I have run into another problem. To make the long story short... I can get the car to start but it stalls within few seconds of starting. Checked the voltages at both fuel pumps. The supply to in-tank fuel pump is at 10.3 V even without the load (i.e., when disconnected from the pump. When I check for short the supply line to the in tank fuel pump appears to have very low resistance (3 to 4 Ohms, almost a short). I checked for short upstream towards the engine I still see the low resistance (almost a short) at the fuse and at fuel pump relay. When I remove the fuse for the intank fuel pump (disconnecting the in-tank pump) the car starts and does not stall. The only problem is that the main pump seems to be noisier. What do you think is the problem? What should the resistance of the in tank fuel pump line be? What is the voltage at fuse #4 when the car is running normally (intank fuel pump connected)? Pls help!!!!

I should also mention that I replaced the fuel pump relay also.

The voltage at fuse #4 should be about 14v with the engine running. On my car it's 13.6v, and at the battery it's 14.2v (engine running).

Could you tell me what the resistance is at fuse 4 to ground with and without the engine running? This will help me do one to one comparison. Thanks for your quick reply!

Engine off. Resistance fuse #4 to ground is practically infinite, over 1 Meg. That's with the fuse in so it's measuring both ways.

Engine on. I don't try to measure the resistance of a live circuit.

Check the crank position sensor. Or, if it's original, replace it.

Have you tested the fuel pressure? Is the regulator working right? resistance of a 10A rated copper wire abt 2.5M long ==0.2 ohms effectively-I'd suggest that the connections are dirty, if not a damaged wire. Accurate readings less than abt 10 Ohms, where precision is required, are next to impossible without a home made wein bridge using appropriate multipliers and a piece of piano wire with a sliding contact, and measuring system. Because the pump draws so much current, ANY resistance in the wire/connection system is going to be significant, and reduce the available power. In such circuits, HEAT is a dead give away of localized trouble. The pump is cooled by the continuous fuel flowing thru the system. See my coming post on fuel relays for cheaper substitute to OEM.

Measured the resistance on either side of fuse #4 (fuse for intank pump, of course with fuse removed). Saw low resistance, about 4 to 6 Ohm. Unplugged the intank pump at the connector in the trunk. Still saw low resistance at the two terminals of fuse 4 (with fuse removed). Removed the fuel relay and measeured the resistance. Same story. Low resistance at the two terminals of the fuse (fuse still removed). I don't think there is anything between the fuel relay and fuse 4. Should only be a wire. Why am I seeing short in that line. Same on the other side of fuse 4. When fuse is removed there should be nothing between the terminal of the fuse to the connector in the trunk. Plain wire. Why am I seeing short on this wire?

Plugged the fuel relay back on ( fuse 4 still removed) and started the engine. Engine started and did not stall. Plugged the fuse and the intank connector in the trunk back on (now everything plugged as it should be). Started the engine. No problem. No stall. Measured the voltage at fuse 4. Saw 13.5 V. Tried to start multiple times and each time car started fine and stayed on without any problem. That was last night. Again tried to start the engine this morning, the problem came back. Car starts but stalls right away. When the fuse is removed (no supply to intank pump) then the car starts and stays on. If I leave it on for a while (about 5 mts or so) and stop the engine and start again with the fuse on then the car starts and does not stall. I wonder if the problem is related to temperature. Any correlation between the voltage supply to intank pump and temperature?

As to the crank position sensor, I tried to find the darn thing, but could not. I have a service manual but could not find anything on the crankcase position sensor. Where is it located?

As for fuel pressure, no I have not tested for the fuel pressure. I assume I have to get a special tool for that. Is the sysmptoms described above consistent with fuel pressure or regulator probelms?

Thanks for chiming in on this.

does sound like the fuel relay/pump dropping out whilst battery voltage is low (on cranking). How big/good is your battery, BTW?, do you have good battery connections? Clean all fuses and fuseholders-even the one near the L front suspension tower-a sealed unit. Replace all Aluminium fuses with copper/brass-they corrode less. clean burn marks from fuseholders in door pillar.

The wire with short:
I don't understand where you're measuring. The power wire to the pump goes via the fuel relay contacts, & it must be operated to get a thru' connection. Then you should have an effective short circuit back to the fuse output. The fuse input will be live as the ignition will need to be on for the relay to operate. BE VERY CAREFUL and do NOT put the meter on the fuse INPUT! --Boom! Your few Ohms reading is probably just the resistance of your fuel pump motor, and you're measuring on the earth lead, not the power one.

With wiring probs, colour code references always help diagnosis. I will reload my CD's and have colour references for you tonight., my time.

The crankshaft position sensor (RPM sensor) is located on the top side of the bell housing for the flywheel. You can either see it or feel it from the passenger side. Not both at the same time. It helps to have a skinny left arm. One bolt holds it to a bracket. If you replace it, and I recommend it be replaced if it's original, take care not to break the bolt or the bracket. If so, you'll be looking at dropping the tranny to get at it.

Figured I would try out the easiest option which was to replace the fuse (#4). Looks like that did the trick. So far no failure on multiple tries. Thanks to 'Maxman' for his suggestion.

As to crankshaft position sensor, I have not been able to locate it and if the car stalls again, that's the first thing I will have to focus on. Thanks to 'nice86' for his helpful suggestions.

This is a great forum to trade ideas in! I am a novice do-it-yourselfer and without the forum like the Volvo forum working on cars would not be as fun.

I have another question about transmission fluid leak, but will start another inquiry chain. Hope you will respond. Thanks everyone!

David