FreFro

Hi,

New to the forum and 1st post.... I'm almost ready to give up and part out. I have a 1980 Euro 928S automatic with K-Jetronic CIS and I'm having trouble diagnosing a control pressure issue. I've bought a gauge set and both books. Here are the details:

-I'm measuring no control or system pressure at the WUR. I've cleaned and blown out all hard fuel lines, cleaned fuel injectors, and verified fuel pump operation and volume (at dizzy and tank).
-The Fuel Distributor was rebuilt by the previous owner and appears to be in working condition. The control plunger moves freely and I can hear the injectors spray when I push down the Sensor Plate
-I have disassembled the control pressure regulatory, cleaned and verified that all orifices are clear.
-Verified all internal filters (dizzy and WUR) are clean. I've been circulating 1/4 tank of fuel with Berryman B12 to see if there's some "crud" I've missed in the system.
-Car has started without starter fluid, but I'm unable to keep it running ( ).

Driver Side of the engine


Picture showing control pressure regulatory location on fuel distributor


Fuel pressure gauge hook up to WUR


Passenger Side of the engine

-I've attached pictures, video link and hope this is enough information for the group to help with my frustration.

I look forward to your suggestions and am happy to answers questions or provide more details.

Fred

Mrmerlin

NOTE your tester lines are reversed., so, reverse the gauge lines.

With the way they are routed now you will see exactly what you report.

NOW With them reversed and valve shut you can read system pressure.

and with it open the WUR pressure increase. as it warms up.

based on how its running its lean try turning the distributor mixture screw about 1/8 of a turn.
See note.

NOTE if you have any old hoses connected to the intake,
it would be wise to replace them so to remove any vacuum leaks .
including making sure the center collars clamps are tight.
and the spider tube clamps are snugged

jpitman2

I didnt see any report of pressures here, which is whats essential IMHO. Also with the open/closed tap where it is the pic, as Stan says, you will see control pressure, but not system pressure. Reconnect with tap on the other side of the gauge leg, then with tap open you will see control pressure (~20 cold, 45psi hot), with tap closed, system pressure (75psi).
jp 83 Euro S AT 57k

FreFro

Thanks for the review and suggestions. Unfortunately, I got the same result when I switch the lines. I measured zero system and control pressure with the WUR cold and warm. Pictures of these results are below. Does anyone have a suggestion on how to verify proper control pressure regulator operation? I have verified fuel flow at the fuel distributor, injectors and back to the tank. Thanks for reviewing my issue.


Reversed connections per feedback


0 psi System Pressure Cold


0 psi Control Pressure Cold


Verified WUR voltage (a little low)


0 psi System Pressure Warm (after 10 mins)


0 psi Control Pressure Warm (after 10 mins)

STRIKEMASTER

Do you have fuel flow both into and out of the WUR?? A K-Jet F.D. has a VERY SMALL (.004") port in the steel plate between top and bottom halves of the F.D. If this port is blocked or miss aligned you get no control pressure Some pressure gauges have one way 'schrader valves' that you have to remove to make them work... The H.F. gauge set is like that.

Mrmerlin

OK what does your fuel pump jumper look like? what size fues are you using.?
I use a set of wires about 5 feet long with two female ends on one side,
and two male ends on the other.

The males get plugged into the CE relay position and the then a 10 amp blade fuse is placed in one of the female connectors,
when your ready join the fuse to the other female end. This will run the pump.

I use a 2 pin AMP connector with jumpers to the ground and the hot post to run the WUR.

jpitman2

have you checked fuel flow rate - remove the hose from the gauge back to the WUR, from the WUR, and run it into a container (fire extinguisher handy), turn on the pump - should get ~1350ml in 30 secs. If you get none, pump wiring is suspect, or pump itself, or filter. If you have good flow rate, and still see zero pressure (with hose connected to WUR), the gauge is suspect - check other ideas above on this. Can you hear the pump running up the back, when it should be ? A noisy pump is suspicious.
jp 83 Euro S AT 57k

FreFro

I have good fuel flow at the fuel distributor (1800ml in 30 sec) and return to the fuel tank (1300ml in 30 sec). I have not yet measured fuel flow at the WUR. I found this fuel/vacuum diagram on the forum and added the blue fuel flow direction arrows. Do I have this correct? Thanks, again for everyone's the input.


1980 fuel and vacuum lines with fuel flow direction

karl ruiter

If you don't have fuel flow into the WUR it is very likely the small hole in the metal gasket in the FD. It could be blocked with some crud, or if the PO rebuilt the FD the gasket could mis-aligned, or plugged with Indian Head shellac. Before you dig into the FD, though, check that you don't have flow into the WUR by doing a drip test, and if not, pull the WUR feed line from the FD, and check there. The WUR feed line could be plugged.
Repairing a broken CIS system can be very frustrating. Not everybody can be patient or methodical enough to get it done. I believe there is someone on here to whom you can send the whole system and get it back fully checked out and ready to install.

jpitman2

Your flow diagram is slightly wrong, but it doesnt change anything really. The left side loop shows flow into the FD, from the WUR, but it flows the other way - out of centre of FD , to WUR, then out of the regulator back to the FD pressure regulator, and out the return line. See if you have any fuel flow out of the line from the pressure gauge first - it sounds like NO if you are not seeing pressure there, unless there is a problem with the gauge, of the supply pipe from the FD - remove this one and clean it out.
jp 83 Euro S AT 57k

FreFro

Thanks for everyone's input.... I believe I have isolated my issue as blockage of the small control pressure channel within the fuel distributor. I measured 0 psi at the top port on the fuel distributor and no flow with fuel pump running (see picture below). I verified that my S&G gauge does not have a check valve that is keeping it from working properly. When I push the sensor plate down I can hear the injectors spray. Is it possible to clean this small channel within the fuel distributor without taking it completely apart?



fuel pump running with no flow from the top port on the fuel distributor.

karl ruiter

First, double check there really is no fluid coming out of the WUR port on the FD. It looks like you are expecting it to be a lot of fluid, but it is a really small stream or even just kind of a drip, drip drip sort of deal.
You could certainly try back flushing it. As a guess I would remove the pressure regulator bits from the FD then try to force fuel or something backwards through the WUR port.
But......
Has the car ever run correctly for you? Do you know for sure it has run correctly since the PO rebuilt the FD? If no, there is a pretty good chance the gasket is in the FD in the wrong orientation. Super easy mistake to make.
Going through the FD is not really that hard. It looks a lot worse than it is. You mostly need to be careful not to drop the piston or get the gasket in the wrong way or lose any springs. For me, it is perhaps a 2 to 4 hour job from start to finish. Of course if you have never done it before it will be a bit longer. You don't actually need any parts. You can use Indian Head Shellac on the metal gasket, leave the O rings alone, and lightly sand down the copper washers that seal the fuel lines. Or you can get a kit with the gasket, washers, and O rings for $100 ish, I think. I got mine off ebay last time.
I think you could easily spend more time trying to rig up the fittings to try back flushing that it would take to do the rebuild.

If you know for sure the car ran since the FD was rebuilt, I would give the back flush a quick try. Just remove the regulator parts, remove the WUR line, and fill a syringe with fuel or some other reasonable fluid and perhaps put some rubber hose over the tip of the syringe to try to give it a little bit a a seal to the FD body where the WUR line has been removed and try the back flush. Or maybe just an air-hose? Then, when that does not work, move forward to the FD rebuild. Make sure you put a paper towel or something where the regulator parts were removed so you can see if any crud comes out, and remember you will have to get all the crud out, or you will quickly be back in the same position. If there is crud in there, make sure the filter screen that is in the FD inlet banjo fitting is intact. There is lots of opportunity for rust and crud to form in the lines between the fuel filter (way at the back of the car) and the FD, that screen is your only defense against it, it is not at all well documented, and it is often defeated or ignored.

Also, be careful about pressing the control plate and making the injectors squirt. All that fuel will seep past your rings and end up in your oil. If you have a silicon pan gasket too much fuel will quickly eat it. If not, you will want to think about changing your oil immediately after you get the car to run.

FreFro

Thanks for your detailed response, Karl. I verified with a clear tube that there is no fuel coming from the WUR port on the FD. I have a setup for cleaning fuel injectors that I can use to back flush the FD. I will try this first and then decide if I want to disassemble the FD to check the diaphragm orientation. Thanks for the advice on the control plate. After making the injectors spray, I did turn the engine over with the fuel jumper off to clear the cylinders. I will still change the oil once I get it running.