Fuel Pressure, Lean mixture, pinging in Volvo 144 B20E

Hello Chris! 
Seems like a hard one to solve.
Wonder if you have checked the voltage at the fuel pump terminals exactly when fail occurs ?
Also a tip, the coolant temp sensor can short to gnd or give very faulty value when it is warmed up (even if ok at cold state), i have that experience. This can make engine run rough or even die. Exclude as failsource by putting in one resistor in the two-pin connector, simulating the temp of your engine (See manual for correct value on resistor)

Know that the last one is not related to dropping fuel pressure, but just saying.

Another tip is that the injectors and even cold start valve(leaking) may cause problem when engine hot. Have seen that. May be excluded as fal source by a plier, one and one hose blocking, monitor pressure gauge while blockin one and one hose.

Anyway, hope you and your volvo is ok

BR Terje
 

Dear All, thank you for valuable input - to help me solve the issue.
There has - finally - been time enough for some progress with the problem.
A lot of different things has been solved or remedied to better the problem. One thing I am sure off now - is that old Injection cars is not for impatient people
Problem one;
The fuel pump sound is a bit low toned buzz sound compared to what a fuel pump usually sound like, and it only primes for about ½ a second when the ignition is turned on before it stops again. A bit too short to actually get the engine to start so I have to prime it 4 times before it makes sense to turn the key to crank the engine. 
I have cleaned all fuel pump electrical supply lines and the main and fuel pump relay contacts with contact cleaner and that changed the sound of the pump - now it runs stable with a whizz sound instead. 
Problem two:
The manometer itself actually posed a problem, the damper fluid inside the instrument actually absorbs condensate while cooling down - and eventually fills the instrument completely. Result is counter pressure on the outside of the bourdon tube increasing with temperature - resulting in a lower reading when the engine was warm. The reading eventually went to zero with a running engine - which lead me to suspect the instrument. After releaving it of some of the damper fluid - the reading went up to 2 BarG rock solid regardless of temperature.

Pinging kept on - all airleak possibilities were searched out and found tight.
Problem three;
The ignition timing has been and still keeps being a mystery; The book says 10 deg BTDC with blocked vacuum line - but the engine sounds like a machinegun and bogs a lot on the slightest movement throttle at that position. And I've tried timing adjustments an endless number of times with very little luck, I have even switched distributors, and replaced the contacts with a breaker less solution, that helped a lot but did not solve the problem.
However the improved fuel pump performance actually showed a bit of sanity looking at timing again. Old school teaching - retard the timing to make the pinging disappear- the pinging finally changed from heavy to moderate reaching approx 0 deg. BTDC. But that was how far it was possible to turn the distributor body - because of the vacuum canister was touching the cylinder block at this position and the throttle response improved a bit too.
I finally reached to the conclusion that the distributor drive gear needed to be repositioned to allow for extra adjustment - it was turned one tooth clock wise (the rotor moves counter clock wise) and set back in - reassembled and adjusted a number of times iteratively to 8 deg ATDC - and whoof - pinging gone - but the car jerks and runs like it wants to be a kangaroo and the performance is poor - but the throttle response stopped bogging.
When I set it to approx 5 deg ATDC then it behaves fairly well and have a good throttle response but when it gets more than 2/3 throttle it pings slightly but nothing really bad. 
The question is now - is this "normal" and should this be accepted or have I just found a new problem? 



    



 

Hi Chris,
are you sure you used the correct marks for the adjustment?
There are marks from -30° to +30°... and the distributor-cam turns counter-clockwise.

I think, I by myself could have been errated by this, because I almost ever worked on cars with the distributor-cam turning clockwise.

Regards
Norbert