Fuel Pressure, Lean mixture, pinging in Volvo 144 B20E

Hello,
the pump must deliver a higher pressure than the working pressure.
Nobody inflates a tire that requires 2.5 bar with a compressor that delivers a maximum of 2.5 bar. There has to be a reserve.

A pump whose working pressure is 3 bar has to regulate down above 3 bar, for example at 5 bar. This is just for security-reasons, the FPR regulates in normal operation.
What you are observing and measuring is completely normal.

But the pump shouldn't deliver much more pressure - there are pumps that deliver 6 bar or even 8 bar, which is too much.
The L-Jetronic pumps designed for 3 bar are the best replacement because the D-Jetronic pumps are no longer available.

Regards
Norbert

Thank you Volker & Norbert. The pump is a Bosch 0580464007 - and to the best of my knowledge correct for the system in a Volvo. I have installed this pump recently - replacing an unoriginal pump because I thought that caused the pinging problem - but there are no change in the condition - that is why I believe the problem might located in the fuel pressure valve. BR Chris

What CR ?

Gone throught the pages
I see you cleaned the tank
I see the fault beginning from the pick-up in the tank till FPR.
in my case (Opel) I found a little filter mesh inside the fuel delivery tube was clogged.
blow air into the delivery line at the FPR up to the pump (tube removed)

Hi - i finally got around to measure the delivery rate from the return line. I have checked it both with a cold engine and a warm.
Cold it produces approx 700 ml/30 sec at 2 BarG
Warm it produces approx 750 ml/30 Sec at 1 BarG
The pressure drops once the engine gets Warm and that's where the pinging starts - It pulls and runs fantastic when it's cold and operates around the 2 BarG

Hi Chris,
I don't think the FPR causes the problem. Such a device isn't known for such a behaviour.
Some warming up cannot be the reason for the effect.

I think something in the fuel delivery line is the problem.
Mud sitting in a filter or strainer gets compressed by the flowing fuel,
the delivery line gets clogged more and more.

This is not related to the engine running, but to the fuel pump's running time and the amount of fuel running through the mud..

Try it out. Let the pump take the fuel directly out of a cannister.

Regards
Norbert

As fuel pressure drops with time, you should check electric consumption in cold condition and during warm-up, for example with a clamp ammeter. My point is that maybe a component in the electric harness of the fuel pump has its resistance that increase with time, so that fuel pump power decrease.