Dear Volvo enthusiasts, Help needed

i recently bought a volvo 1988 740 gle for 600 euros and the car was not in working condition. The car engine is B230E with K- jetronic cis injection. The previous owner had the car sitting for long time. He tried to start it up and run it a little with bad fuel and the engine after initial run stopped working.
When i bought the car we removed the old fuel and added fresh,. Serviced the car i.e changed oil (which was mixed with fuel probably because he kept cranking the car) new battery new oil filter, fresh oil, new sparkplugs new timing belt and new water pump. Serviced the engine breather as the hose was disintegrated. also replaced the air intake flow divider hose as it was torn and in general whatever hose we had been visibly disintegrated. Wouldnt start up until we checked the fuel pump there was no power supply so we checked the relay and it was disconnected. We inserted the relay and the car started up. Run roughly 2-3 minutes relatively ok then again the car started idling very rough the engine vibrated a lot and died again on us. We seen that there was smoke puffed from the injectors so we changed the injectors as they were in bad shape and also new injector seals. The engine started up but the idle is still not good and without pressing the accelarator it dies off... After replacing the injectors (with new seals as well) and air flow rubber the engine did improve a litle and could rev up even slowly since before it couldnt.
We clearly have a bad fuel pressure accumulator as it is leaking so we bypassed the fuel line to ''cancel'' the acumulator until the new parts arrive but to my understanding the car should idle at least until warm normally even without the accumulator. Maybe we suspect that we might have a malfuncioning in tank fuel pump as well but we didnt dig into it yet.
Now, i was reading some threads about the fuel pump relay and how it could cause some startup issues so i thought i should try installing a new one. so i purchased a new aftermarket fuel pump relay and installed it and when i turned the ignition on the fuel pump started working continuously (not just prepping the fuel) and very noisy and the engine wouldnt startup. removed the new fuel pump relay and inserted the old one but now the car wont start up at al... :/
I am an amateur with just basic knowledge on mechanics. I know for a fact that we need a new fuel pressure accumulator and i suspect that we have a non working in-tank fuel pump.
Please advise on how to proceed further on so that we can put another classic Volvo back on the road. Your advise is much appreciated on what it might be wrong...

Ps. I have a few videos, From the initial startup by the previous owner before it died out, from my initial startup before the idling problem and with the idle problem (before the injectors and air flow rubber was replaced...

Thank you all in advance and i hope you take some time to help a fellow volvo amateur enthusiast...

 

Sounds like you did most of the proper things. Did you happen to change the fuel filter yet? If not that is one of the first things I would do. It is connected to the in-tank pump so you should change both if you suspect they are bad. Also, check all the fuses to make sure the fuel pump fuse is not blown (or missing)

 

CIS fuel injection
Rough idle - do you have even compression?
Have you compared the fuel flow from the injectors at idle speed?
Pull all injectors out and lay them on the valve cover. (hoses connected). Hot wire the pumps to run all the time. Lift fuel metering plate slightly and watch injectors spray evenly (hopefully) If not push fuel plate up as far as possible to possibly clear the injectors and maybe help them produce a better spray pattern.

If fuel sits in the system, the fragile valves in the fuel distributor and control pressure regulator can become corroded and not meter fuel evenly between cylinders - which would require a replacement new/remanufactured fuel distributor to solve.

A compatible fuel pressure gauge is needed to determine any other useful information about the system and I trust you have a suitable 3mm allen wrench to adjust the fuel mixture.

 

The injectors and seals were replaced with brand new ones so i can assume that these would work correctly... the injectors were visibly leaking and the seals were very bad creating visible vacuum leaks with smoke puffing smoke after the engine died. so we replaced them without testing pressure. We haven't used a pressure gauge since what we have available doesn't have the appropriate fittings to use on this system and we are trying to make a working adjustment. Surely we have a broken fuel pressure accumulator that is leaking and we "cancelled" it to avoid fuel spilling and loss of pressure and will be replaced once we receive the part. I want to ask what are the symptoms of a malfunctioning fuel distributor and warmup regulator? how many bar measurements should be from fuel pump to fuel distributor and from warm up regulator so that we can assume that are ok? Is there a thread with instructions on pressure testing with gauge? Once we will manage to fit the pressure gauge i will let you know. In the meantime i am worried about the relay because for some reason after using a brand new fuel pump relay the main fuel pump was working continuously once you turn the ignition switch and the engine wouldn't fire up. After refitting the old relay the engine wouldn't fire up at all...

I am wondering...Is it possible that we might have piston compression issues? Maybe stuck piston rings? Would that contribute to the car not idling?

 

1. Check compression, make sure ignition is in good condition also.
2. as described earlier - check injector flow
3. Google is your friend for CIS info - I've seen lots of stuff mentioned/copied to this site and swedespeed.