This one is weird...

If I park my 1989 740 turbo wagon on steep driveway overnight, either facing up or down, it will not start in the morning, It cranks OK but it's like it isn't getting any gas. Originally I was leaving the tank with only a few gallons of gas since I thought it had to do with the fuel pump. BUT, when I filled the tank to the top, the problem got worse.

If I let it roll back onto the street and park it on the relatively level street, it still won't start. BUT, if I let it sit for a few hours, it starts normally. It acts like it was flooded. I never have any problems starting the car at any other times.

Replacing the intank fuel pump had no effect.

Ideas?

 

did you replace the sock and little piece of hose that also goes inside hte tank with the tank pump?

if it does it both parked nose UP or DOWN, then my other ideas dont make sense. if it was just one or the other, I'd suspect an issue with an injector or fuel pressure regulator.

I suppose it could also be an issue with the main pump.

 

All I can think of is the fuel pump check valve doing something unusual, and/or the main pump in conjunction with it. 700/900 won't run with low gas if pointed down hill, but both ways?

 

My friend and I pushed the Volvo to a fairly level spot and it would only "pop" but not actually start. We pulled off the gas supply tube that goes to the injector rail, cranked it over, and there was no gas.

At that point, I gave up and my fantastic Volvo mechanic came to my house and went thru all the standard "why won't it start" tests. Everything was with the ignition so he replaced the main fuel pump relay and bingo, good as new.

We don't know why the slope appeared to affect the car starting, but it was obvious that when you leveled the car out, it would start and run fine. Maybe the main pump was never running and the tank pre-pump alone just couldn't supply enough pressure when the car was on a steep angle.

Thanks to those who offered their inputs!