Hello, Thibaut, stuck in France here, my 240 GLT was resurrected after a long period... started with the crankshaft timing sensor replacement (easier said...), started straight away, now the issue is a no cold start at all.

Checking the fuel line, uncoupling the return line from the FPR into a jug it started staright away, I then blow the return line, reconnected, restarted and after a couple minutes it just died. Uncoupled the return line, noticed it is under some low pressure (?), attached a transparent tube to the jug, plenty of air bubble.

Reconnected the transparent tube to the return line, plenty of air bubble, and it stalled again... It seems it only works when there is no back pressure at all in the return line?

There is no gasoline leak from the FPR (standard 3.0 bar 0280 160 294) to the vacuum hose.

Question is: is it normal to have some level of back pressure in the return line?
Should I go straight and replace the FPR which should handle some back pressure?
Anything to do with the amount of bubbles in the line?
Are they an issue coming soon with the pumps/filter/lines?

Beforer investigating the tank, fuel lines and various item with poor access, I thought it might be a common issue...

Thank you for reading and some tips to avoid newbie's errors.

 

Ok, you are loosening the hose clamp and pulling the return line hose that goes from the Fuel pressure regulator to the metal return pipe - and putting that in a jar and see air bubbles. Or have replaced that hose with clear and see bubbles.

There should be only liquid (gasoline) being pumped to the injector rail with the excess being returned to the gas tank - if there is air in the line - that means you are out of gas in the tank or the feeder pump is not picking up the fuel properly. Find a picture of a 240 Volvo intank fuel pump and you will notice a small 2 inch long piece of hose connecting the pump to the fuel sender - that hose break/rots/ falls off. If so there needs to be maybe over 1/4 tank for that pipe to be covered with gas and not suck air -

That could be why the car won't stay running.

There should be no back pressure in the return line from where it's clamped to the regulator all the way to inside the tank - it's a clear unobstructed line. If air does not pass easily there could be a crimped hose near the tank.

 

Great thanks, seems the FPR is not faulty then, rather tube from the sender unit to replace and some obstruction in the return line to clear... it looks like these were never accessed before looking at the grunge and the various pipes condition, so its good timing after so many years. Thank you very much for your help to pinpoint the problem.