Running out of ideas MFI

[dtw]

Ed, pull that pump off the engine already. Your back will thank me.

[356RS]

Ed, Doesn't look as bad as I thought it would. Cylinder/plunger tops of the ones I can see in the picture look good. There is some evidence of dirt/corrosion on the pressure valves. Wash and clean in solvent then with something like a wooden cotton swab stick, check to make sure the ball & spring move. Spring is in the threaded section and ball is in the flat sealing end. Push ball in toward the spring gently a few times and make sure it clean inside and returns to the seated position.

[Eddyvdw]

Thanks Mark, done that as well. Also thought the pistons looked okay (although didn't understand the little dent in the piston). Well, hopefully the drive tomorrow will clear some last dirt. Otherwise I'm out of ideas and will it be over to the pro's.

[Eddyvdw]

To complete the picture, the HC values are extremely high.

Ed

[Eddyvdw]

Bad news... Today tried the car on the road. Lots of (blue) smoke and lack of power. Puller the injectors one by one, no spray just some (minor) dripping.
Pump is next.
Ed

[Rusty 356]

Ed, I know I asked before, what have you gotten regarding fuel flow and pressure to the MFI pump. Trying to remember if there is a system pressure valve on the return from the pump.
Again, there is on the BMW, kugelfischer pump.
you may be able to borrow a pump from one of your Porsche mates just to isolate.
Good luck with getting her screaming again

[Eddyvdw]

Looks good also given the fact that 2 of the injectors have a nice spray!
Ed

[356RS]

Sorry to hear that Ed. You said that you pulled the injectors one by one and checked for spray. I assume the engine was idling when you did the spray check?

[Eddyvdw]

That's correct, the engine was idle. BTW, replaced all the injectors, no change...
Strange enough motor kept idle when removing one of 4, with 2 it stopped.

Mark, send you an email as well.

Ed

[Eddyvdw]

Can it be the pressure of the fuel pump? It works but will it loose pressure when broken (the fuel lines are all renewed as the solenoid and filter)

[356RS]

Ed, I thought you checked the electric fuel pump pressure? If not, you should. If you have the Porsche P233 pressure test gauge or equivalent, install it at the filter console where the MFI pump return line (left side of MFI pump) is connected to the upper side (closest to the rear of the car, easiest one to get to) of the fuel console (has an arrow pointing inward). You should have about 1 bar of pressure with the engine at idle. You should also check the fuel pump delivery. With that same fuel line coming from the MFI pump and a 1000 cc or more measuring beaker, engine off, but ign. switch on, the electric fuel pump should deliver 900 to 1000 cc of fuel into the beaker in 30 seconds.

[Eddyvdw]

Thanks, will check just to be sure. Isn't it strange that 2 of the injectors have a good spray? When the fuel pump is not good, one would expect all the injectors to have a limited or no spray at all.
Ed

[Rusty 356]

Ed, I worked with a Czech in Sweden when I was with Volvo. He always referred to himself as the cancelled czech.
Back to the electric fuel pump, you can take them apart and clean all the little rollers and check valves and give it a whirl. Keep us posted.

[356RS]

Your right Ed. I'm not saying the electric fuel pump is the reason some of the injectors are not working, but it just makes sense to check all the related components of the MFI system. Might as well make sure everything else is working properly before you install another pump. Your doing a great job.

[Eddyvdw]

Thanks all. Mark will send a calibrated and checked pump, confident the pump will solve the problem.
Still puzzled by the smoke when driving (not so much at idle or at higher revs when not driving). Is that related to the not proper working fuel intake? Remember, leakage test was good and no oil spills.

[Eddyvdw]

Could it be the valve seals? Can remove those without removing the cylinder heads right?

[Eddyvdw]

Just checked the electrical fuel pump. Pressure is 1.1 Bar, fuel delivery is (after 2 checks) 600cc/30 sec. Filter already renewed.

What does this mean? New pump or should the engine also work fine at 600cc. At idel the engine runs fine, lot's of smoke when reving up.

Ed

[356RS]

Check inside your fuel tank for any sediments that could be on the bottom around the tank filter screen. If the screen is obstructed this would cause the low fuel delivery. The engine will still run at low to mid rpm's but could cause the MFI pump to run out of enough fuel at high loads and rpm's while driving.

[Eddyvdw]

Thanks, will check tomorrow. Looking forward to the MFI pump!
Ed

[Eddyvdw]

Hello, a quick update.
Received the pump from Mark. Installed and must say, what a difference!
The engine runs smoothly and strong!
Went for a short test drive (first time since 1992 that this 72 was back on the road). The engine still smokes but a bit less then before. Smoke mainly when aggressively accelerating. Nevertheless is was still at an embarrassing level, hopefully it goes away after a longer drive.
Had to abandon the test drive because changing gears was really difficult. Turned out the shift coupler to be completely worn and broken. Ordered a new one, next attempt this Friday!
Keep you posted.
Ed