I just purchased a 96 850 Turbo wagon. I live in Canada and when it is cold the car will turn over and catch for an instant but not start. I can keep the starter running but it will not start. Some times after an extended period it will catch.

I have found that if I turn the engine over for a few seconds. Then remove the fuel pump fuse, it will immediately start - run for a few seconds and then stop - I assume running out of gas. If I replace the fuel pump fuse it will start right up.

I cannot figure out why. Any suggestions?

For background here are the things I have investigated / changed which have not solved the problem to-date.

- New spark plugs - no effect
- New cap and rotor - no effect
- Then I used an obd2 reader to collect any codes. - found no codes.
- Reviewed Volvo technical - procedures published on the web for 850's giving instructions on how to trouble shot conditions - when there are no codes present.
- Other than the obvious = this document points in the direction of - potential fuel injector leaking, or faulty pressure in the system. - However, the car runs fine and starts fine after it is started once ... so it seems to me it is likely an intermittent problem. (However, this my be the next place to investigate if all else fails)
- Repaired leaking - vent pipe attached to turbo - no effect
- Purchased a subscription to Alldata - found a technical service bulletin - (Engine Ignition Conditions and Starting Difficulties) - which required checking the coil resistance and grounding of the coil, connections and battery terminal. Looked promising but - after a few hours of work had no effect.
- Further investigated Alldata and found that - a defective engine temperature sensor could cause the computer to alter the fuel injector timing. I.e. if it were defective the computer assumes a 68F temperature - felt that might be the problem starting at 32F. However, after confirming the temperature gauge on the dash works (and is powered by the sensor), and then confirmed the resistance of the sensor when cold and when hot was to spec. gave up on this idea.
- Exhaustively reviewed the wiring diagrams and component repair and operation data for a hint of why - so far to no avail.
- One form respondent speculated that this problem may be due to flooding. I.e. the fuel leaks into the head and washes the cyl reducing compression. In my case it does start after the removal of the fuse. Hence I believe my compression is ok. Might be flooding, however, but seems to start quickly after the above mentioned sequence (removing fuel pump fuse).
- Removed the main relay for the fuel system (located on the radiator cowling) and inspected and cleaned the connections - seem fine - coil resistance seemed fine as well. Also the fuel injectors do work so the relay must work as well. Could be sticking however, removing the fuel pump fuse to un-stick it sees like a stretch ...
- checked cam shaft position sensor - connections as per Alldata - found ok
- Did inadvertently touch the rubber boot on the high tension cable on the coil and got shocked (garage floor was wet from melting snow)

Why removing the fuel pump fuse - 15 amp #2 and replacing it allows the engine to start - has baffled me -HELP