QuestionI have a 91', 4 cyl., Non turbo Volvo 740. I recently encountered difficulties starting the car after it has warmed up. At times I could run the car for days , sometimes weeks with no problem.
1 - After I shut the engine down It would not start up. I might just shut it down to purchase gas....for instance. Them as I go to start it up, it wouldn't restart.
2 - Other instances the vehicle would start and restart numerous times with no problem.
3 - There is no gas reaching my fuel injectors,I have been told by other 'joe' mechanics...who are not familiar with the Bosch fuel injection system or Volvos for the matter.
4 - I am permanently disabled, on a set "never have enough to pays bills" income, and I need some, kind and knowledgeable, expert, who can steer me in the right direction and give me detailed and precise steps to get this car going. Its my wife and she feels lost without her car.
Thank You, Sirs
and God Bless You!
Answer Ok, I would start with putting a set of mechanical fuel pressure guage on the vehicle. Observe the readings during no start. If there is indeed no or low pressure, try jumping the fuel pump manually at the relay pins. If pressure returns and the vehicle starts, try a new fuel pump relay. If pressure does not return, look at the fuel pumps. One in tank, one underneath the vehicle.
Be careful here. You need to check when in failure mode to see if you have no spark. The fuel pump relay will not close/latch, if it sees no spark signal from the ignition module through the computer. It will not close fooling you that the relay is bad. No spark may be the cause with no fuel pressure being the effect. Make sense?
With a schematic and a DVOM you can test for signal(s) presences to help you sort it out. Otherwise, you are just guessing.
If you want to "shot gun" this, I would go with fuel pump relay or ignition module first. Throw the dice, both are common. If you have and can test for spark during failure. That will get you down to fuel pump relay.
Mark
