Need advice with 1999 V70 Petrol without ETM
which fires but after running for short time dies.
Have tested fuel pressure which I believe should be 55 psi? but compound meter I used only measures fuel pressure up to 10 psi.
Nevertheless the following may give a clue to what could be the fault.

When the motor cranks and fires the meter needle showing the fuel pressure shoots way past the 10psi max and sticks there while motor is running.
When the motor starts to die and the idle speed drops the needle showing fuel pressure begins falling to a much lower pressure and the first time it will drop to around 5psi, then the dying motor suddenly recovers and the idle speed increases again and the pressure needle shoots back up to ​over 10psi (10psi is max fuel pressure on meter) then after running normally again for only a short time the motor begins to die again, and the idle speed drops again, and as the idle speed drops the fuel pressure needle drops back below 10psi, but unlike the first time it does not suddenly recover at 5psi but instead keeps dropping until by 3psi or before, the motor has completely died.

After motor has died, while the ignition is switched on, the fuel pressure needle very slowly climbs back up to just after 10psi and stops there (see photo below), then when motor is cranked and fires again the needle shoots up even higher while motor is running normally.

In photo below the 10psi mark is shown immediately to the right side of needle when looking at photo. The 25 visible to the left of needle is not part of the fuel pressure section of meter, but it is where the fuel pressure needle shoots to when the motor is cranking and after motor has fired and is running normally.

 

check out RobertDIY's vids on Youtube - he has one for measuring fuel pressure for the 850/V70s (pre-ETM) that may give you some ideas.

 

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Thanks. Will check the vids to see if there's anything that will help.

 

You have not tested fuel pressure - you have pegged a vacuum tester that can test fuel pressure on a low pressure fuel system, perhaps a carbureted engine. You need to use a fuel pressure gauge like the one I suggested 6 months ago. A gauge that will measure the fuel pressure exactly. Once again you are guessing at solutions without valid data to based those guesses on. (you questioned a cam sensor and antenna ring last time, with weird test techniques) Use the correct tool to get valid data, and then you can make an informed diagnosis.

It's entirely possible the fuel pump is not delivering the correct pressure - due to old age. Your last post about this same issue was over 6 months ago - so if you are still trying to run the car with the same gas in the tank - that could be a problem also. (like how hard it is to start your lawn mover after sitting for 6 months unused with the old gas in it)

 

Thanks for explaining. I'll get the right tool and see what pressure it reads.

 

The fault has finally been identified.
A failing fuel-pump controller.
To help anyone in the future who has this problem who finds their way to the end of this thread.
The controller is located in the left rear corner of engine bay (on a RHD model) when viewed from front looking under the hood. It is under the cover that houses the fuse box. To remove the cover unscrew the 4 torx screws then lift it off. The fuel-pump controller can then be seen. It is salmon pink with the number 103 on the top (see picture below) It will feel tight like it may not pull out but it will.

After removing it, you can test that it has a fault by connecting a short jump wire between terminal 15 and terminal 87 in the connection that the controller plugs into. If the vehicle then starts and runs normally it means the controller is faulty (often intermittently, so sometimes by
unplugging it, then reinserting it, it will start to work again albeit temporarily)

My thanks to everyone on this thread who gave advice to try to help me find the motor killing fault