Well I finally finished installing the rebuilt 102 engine in my 88 190e today. The moment of truth ....checked and double checked all connections, vacuum lines, etc. Turned the key on, heard the fuel pump come on briefly (normally)...good. Tried to start the engine and it ran GREAT...for 5 seconds. Turned the key off...waited another minute...runs great for 5 seconds...well at least I know the igniotn/timing is OK.

I suspect that the car runs OK for 5 seconds due to the cold start valve dumping a bit of raw fuel into the intake manifold. This tells me that I'm getting fuel into the fuel distributor OK...so what next? I cracked one of the lines on the fuel distributor going to the injectors...and cranked engine again....NO fuel...dry as a bone.

This is strange. The engine was getting fuel before the rebuild (it was rebuilt due to a burned piston of #4 cyl...whole other story)..and all I did was take the intake manifold off the head before I took the head to the machine shop. The intake manifold, complete with the fuel distributor was stored in the shop. I DID remove all the injectors and replace the seals ..and the lines were removed from the fuel distributor for that time. Is it possible that dust or dirt entered the outlets of the fuel distributor and now it won't "distribute"?

Any ideas why I'm not getting any fuel out to the injectors, but the cold start valve works? BTW I can get the engine to run a little longer if I dump a little gas in the intake, but holding the air flap (is that what it's called) down does not make any difference..it still dies after that fuel is gone.

Help! This is the only thing standing between my wife and her car.


Thanks

Check your fuel pressure and make sure the return line and pressure regulator are correct and unblocked -- too high a pressure on the bottom chamber will result in no fuel deliver.

Also make sure the plunger on the bottom didn't fall out!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

The reason the cold start valve works, and not the distributor, is that these are separate systems..........am I correct in assuming you have a K-Jetronic type system? The missing plunger, suggested earlier, is a real possibility.

I just spent this whole weekend testing my K-Jetronic FI system.

I have what's known as CIS injection I believe. On this system the cold start valve gets its fuel from the fuel distributor as well as the injectors, or so it looks like.

As for this plunger falling out of the bottom. where would I see this? Did it fall right out onto the floor? Or is it still inside the body of the unit? What /where am I looking? Is it easy to re install if I do find it? Could having the unit stored upside down have caused this plunger to fall out?

CIS is a general form of FI........included in this group are; K-Jetronic, K-Jetronic with lambda and KE-Jetronic. If you have a warm up regulator, than yours is one of the first two.

Yes, both the cold start, and the injectors get their fuel from the fuel distributor (FD)......both share the same fuel pressure. But, their operation is different. The cold start system is electrically triggered on and off. The fuel going to the injectors is run strictly by hydraulic pressure, and mechanical activation by the plunger, which is pushed by the sensor plate.

Plungers don't just fall out, even if the unit is upside down.......at least they shouldn't.

Try this: remove the air filter.......this exposed the sensor plate......there are two kinds; one where the sensor plate functions upward (you will need a magnet), and the other, where the plate funtions in a downward direction. Run the fuel pump and lift, or push, on the sensor plate.......you should get fuel to the injectors.

If not, then you will have to check the plunger. To see it, one has to remove the FD from it's base. It is held in with 3 srews, and lifts right off. The plunger in on the bottom, in the center. Be careful.......while most plungers will remain, in some early systems, the plunger could fall out.

Another thing to try, before taking things apart: With the engine cold, best overnight, push/pull the sensor plate and note the ease by which it moves........this is due to no pressure in the fuel system. Next, run the fuel pump, and push/pull on the sensor plate. It should be harder to move, since there is pressure in the system. In both cases, the sensor plate should move smoothly, and pressure should be even throughout the movement.

up

Henryk, I tried the resistance test on the plate, and yes, with no fuel pressure it was quite a bit easier to push down (in my case) that it was with full system pressure applied...so I know I'm getting fuel at pressure into the distributor. Does this system have to be "bled" like brake kines when run dry after uninstalling and installing? I'm baffrled.

Also, when I cracked all the nuts on the top of the FD, pressed the plate down all the way and had a helper crank the engine, there was a flow (slight) of fuel out all four holes...not a pressurised stream that would shoot into theair...more like a dribble..significant?

sonny: No need to bleed the system........it self-bleeds the air out, as the pressure increases.

You seem to be getting fuel to the injectors........so, no need to check the plunger, however, I wonder if it is under enough pressure, to open the fuel injectors...........they won't work unless the pressure is high enough. When fuel, from the fuel pump (FP), enters the fuel distributor (FD), let say it enters "chamber A". There are two outlets in A; one to the cold start injector, and one into "chamber B". The fuel from chamber B then goes to the regular injectors..........this is regulated by the fuel pressure regulator (FPR), and the warm up regulator (WUR). Hence, the cold start injector is receiveing full FP pressure.........that is why it works.

The regular injectors receive a different pressure, regulated by the FPR and the WUR. The FPR is located within the FD, and the WUR is a seperate unit found near-by. The only way to test these would be to do fuel pressure tests, requiring a fuel pressure gauge, which will show what the fuel pressure is as it leaves the FPR. A "special" valve is needed, on the fuel pressure gauge, that can tell if the WUR is bad.

The fuel from the open banjo fittings should come out as a steady stream, not a dribble.

I hope this helps.

sonny: There is another at-home test that you can do. But, first I have to know if the fuel pump runs with the ignition only in the "on" position, and not the start. I would assume not. Then, see if you see a 2-wire connector plug at the base of the FD. If so, turn the ignition on, and remove the connector........the FP should run. This allows one to run the fuel pump, for tests, without cranking the engine over. If so, we can then do another test.

Well I have a three wire connector at the base of the FD...but I think that's for the wide open throttle switch. If I need to run the fuel pump, I can just jump connections 7 and 8 on the fuel pump relay connector. I assume that the test we are about to perform is a fuel delivery quantity test?

Yes, it would be the fuel delivery test. This will tell if: fuel filter, or fuel lines are clogged; and whether the fuel pump is not operating properly.

Your would take the return line, going back to the fuel tank........remove a connection and run the fuel pumps for 30 seconds, while you collect the fuel in a container. I look for a rubber hose connection to remove, install a union to a longer hose, and run this hose into a clean gallon container. The fuel accumulated should be about 750 cc/ 30 sec.

Well we don't need to go any further now. I found the problem. I had the plug for the EHA plugged into the Aux Air valve and vuice versa. Putting these connections on the proper components helped a LOT! But why would MB put the same exact size style of connector on two very close components like that? I'm just glad I didn't do any damage to the "brain" ( I don't think I did, but now the Engine will not start when it's warm)...one thing after another...but that's a new thread...

Glad to hear you solved this problem............will await the new thread.

Sonny:

That model EHA uses 8 mV as "zero" current, I believe, with 0 being full fuel cutoff and 16 being full rich. When the cold start shut off, so did the fuel.

MB tends to use the same plug for everything, so if the wires reach, watch out! Seems silly to me, but hey, I only work on them!

Set the idle mixture to cure the hot start problem -- you are too lean. Use a digital VOM that reads duty cycle (not frequency) connnected to the #3 (red lead) and #2 (black lead) sockets in the round diagnostics connector. Set to 50%, or as close as you can get. The adjuster is under the "tower" on the fuel distributor, 3mm allen wrench. Insert wrench into fitting, then press down to engage the actual adjuster. Turn a small amount and lift wrench back up and let the number stabilize -- takes about 20 sec at idle for the O23 sensor to settle down.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!