Volvo: 1990 Volvo 240DL not starting in extreme temperatures, fuel pump relay, fuel pumps

Question
hey,
I've got my good ol golden box giving me problems. I came back from work today (I carpool)it wouldn't start. The engine would turn over but it would not fire. It was upwards of 102 degrees today and it was just left idle sitting all day. After I tried to start it a few times, I got a ride back and waited a few hours. I came back at about 9:30 when it was much cooler and the car fired without a hitch. Can high temps be an explanation for this? How do you think I could prevent it? I have had electrical problems with the car concerning the feul pumps but I got those replaced a year ago. Anyway, any help will be appreciated.

Answer
Marcus,
When it will not start see if there is power to the fuel pumps, both main and pre pump. If no power then look at the fuel pump relay see if power is leaving the relay on the larger yellow/red wire. Read the codes in the system. If there is one for the flywheel pick up, replace it. Check to see that all the power wires at the battery are good and solid. Test the fuses for the main and pre pump make sure that they are tight and have good clean fuses installed.
If there is power to the pumps, test to see what the fuel pressure is. It should be 42 psi.
A couple of other thing you might try to substitute a known good air mass meter and power stage to see if that helps. Some of those parts there is not a good test other than a known good unit. I have tested many MAF and they test good, but replace it and all problems are gone. Used MAF is about $100.00 and power stage is $40.00. Eliminate the first things before throwing parts at it.