At the top of all of this, sparks + fuel + oxygen = Boom.
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Originally Posted by macdoe
Thank you, 97 SL320.
So, is it possible that one of the fuel pumps is working enough to cause an audible fuel swishing sound at the fuel distributor....but, because the OTHER (2nd) fuel pump is not working and therefore not building up enough pressure (100 psi) to reach the proper psi to fire the injectors?
I get a small squirt of fuel when the fuel-line fitting is cracked, after presurization, but not much.
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Dig around for a "How Bosch CIS / K Jet works" manual. Some of the Bosch factory sites have these for free. It will answer lots of questions.
Quote:
Originally Posted by macdoe
I guess that might mean that at least the accumulator is working then?
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Accumulator is just there to hold pressure during hot soak / allow for quick starts. The only failure mode is the diagram fails allowing fuel to leak to the rubber hose side ( it is "t" ed into the rubber hose leading to the fuel tank.
Car should at least start even with a leaking accumulator.
Quote:
Originally Posted by macdoe
And maybe one fuel pump is bad? ...then...,one pump is good, which is why it sounds like it's working? I can test them individually,now that they are out of the car. I will wait until some of the fuel fumes clear before sparking up the battery charger. Stale fuel really stinks!
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Old fuel can lock up a pump, how long was this car sitting? You can pull the pumps and test each one for operation without hooking up a fuel supply, just be ready for fuel to squirt out. Running for a few seconds is OK.
Quote:
Originally Posted by macdoe
I can see now how each post on the pump is marked pos. and neg.
So, 12 volts to the pos. post.?
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+ 12 V to the + Pos post , ground to the - Neg post
Quote:
Originally Posted by macdoe
Does that fuel distributor need to be at a constant pressurization to work, then? Is that right? I don't know?
Does the accumulator keep the pressure constant during the pulsing from the injectors constantly firing off some of the pressure?
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Fuel dist needs pressure to work, see the Bosch book. Injectors on a CIS system don't pulse, they constantly spray with volume adjusted by air flow flap / fuel distributor.
Quote:
Originally Posted by macdoe
Then would the fuel pressure regulator keep certain that only 100psi goes to the distributor?
Is the f.p regulator the small can (similar to the accumulator, but smaller) up next to the fuel distributor itself?
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See Bosch book.
Quote:
Originally Posted by macdoe
I was also reading about these check-valves located at each end of the pumps....I wonder what would happen, if one of those check valves stuck closed? How are they tested?
What is the purpose of the check-valves at the fuel pumps?
Is there suppossed to be 2 of those c\valves then?
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Check valves are there to prevent fuel pressure loss when engine is off. They could stick closed but I've never encountered that, they can leak and lose pressure with engine off.
Quote:
Originally Posted by macdoe
I can see how they are piggybacking one pump, to the other, "supercharging the psi, as you said above". It is obvious the way they are plumbed, makes sense, now that you mentioned it.
What are the insides of these fuel pumps made of? Could we bench test them and run some marvel mystery oil through to wash the varnishy fuel out of them?
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In general, fuel pumps are made many ways, roller vane , flat vane , geo rotor, screw, turbine. Late 60's Bosch D jets were usually roller vane. The 97 E320 pump I tried to rescue was a rotary screw.
Old fuel is a mess, you might have to rig up a external fuel tank, fresh fuel mixed with carb cleaner and hot wire the pump to let things circulate for a while. ( engine off ) just be sure to disconnect injector lines and route them to a can so you don't hydra lock the engine. You can also blow air through the injectors then use spray carb cleaner in the inlet to let them soak.
Lastly, the diagram in the fuel distributor fails, someone on e bay is making rebuild kits with detailed instructions.