Hey guys update to my project resto in progress.
ok so I found out that I have a 82 euro gray market 928 that has a analog box with a frequency injector on the fuel return and a weird pressure regulator and some valve that comes off the pressure regulator.
the valve has a switch that Has wires that runs to what looks like a temp Switch. I did some preliminary gauge readings and with the gauge bypassing pressure regulator from FD to WUR I got 40 to 45 psi and the gauge was fluctuating up and down.
from some info on here I was told this set up was added to the car when it was federalized and it works with o2 sensor reading. It looks like the analog box is working from voltage reading on the box going up and down when I play with the adjustments on the box. I have changed and cleaned everything except that pressure regulator and can’t get the car to stay running to get any gauge reading because I have to have the car running with this set up to get running pressure.
does anyone have any info on how to check what’s wrong without the car running.



This is the box to make adjustments to the o2 sensor


#13 is the pressure regulator and #1 is the 3way valve that has a switch with a wire that runs to what looks like a temp switch.

Not sure what this round and black plug is ?

 

Because you have th WUR in the control pressure circuit, you don't really have KE-Jetronic CIS. It's an, um, illegitimate-child hybrid system. Would be interetd in the WUR part number to contrast its pressure curve with the factory piece. As it is now, you should be able to see both system and WUR-generated control pressure with the gauges hooked up the "normal" way.

Unless there's a serious objection, this thread will be merged with your original since it's a logical continuation.


dr bob

 

I hooked up the gauge from FD to the wur bypassing the pressure regulator and the valve block and I only got 40 psi. That won’t even trigger the injectors to fire. The only thing I can think of is that my FD rebuild that I did myself was put together wrong.
I have replaced everything else
Fuel pump
tank flush and strainer
fuel filter, accumulator, fuel lines,injectors,FD rebuild
blew out all injector lines.

 

This is what my pressure gauge did when the pressure regulator in my fuel distributor was stuck. The last one also shows the AFR gauge in the car jumping around as the pressure changes.

 

I have to get it to idle first. It won’t stay running

 

Ok I made some progress my line pressure and system pressure is holding at 35 psi with the fuel pump on jumped. When I turn the key to the off position the gauge goes to 45psi. I think I have adjusted the pressure regulator in the dist by adding or taking away shims

 

The system pressure should be normal with the fuel pump relay jumpered. Engine doesn't have to be running, and in fact shouldn't be for that test. If you are just seeing 40 PSI, you should look carefully at the detail that Pete shares regarding the actual bypass part of the regulator. It takes just the tiniest bit of crud there or a sticking needle to give the results you see. The line to the WUR runs at system pressure, same as what's applied to sides of the pistons in the metering unit/FD. That circuit goes in parallel to the WUR, the top chamber in the FD, and any cold-start valve. Get that working before you mess with anything else. The FPR screw is accessible without pulling the whole metering unit, just put a towel underneath to catch fuel and the pieces when they fall out. IIRC there's a screen there in the inlet port that tends to self-destruct. Needs to be there but new, to keep crud from the system from interfering with the FPR needle/piston function.

 

i just removed and cleaned out the regulator on the side of the FD and no change. 35 psi line and system pressure. It has to be 2 things either pull the FDA d make sure i didn’t screw anything up on the rebuild or shim fpr for more pressure because the injectors won’t come on until 50 psi I believe if that’s correct. When I pull the jumper off the panel it goes to 43 psi.
any thoughts on what to look for I really don’t what to pull the FD off the car again unless I have to

 

see what you have for return-line flow to the tank from the FD. At the low pressure, the FPR should be blocking return flow. If you do find flow, you may want to try gently squeezing the return line while you watch the gauge, and see if the pressure comes up. If it does, you're chasing the FPR. If it doesn't, the pump capacity may be low.

 

To make sure I took the fuel dist off and disassembled it to make sure I put it together correctly and reassembled it. I found some debris clogging the line that has a screen in the fitting. It was the big fuel line to the far left of the FD. I put all the lines back together and finally after 4weeks of smelling like fuel and all hard work I got it to stay running but ran like crap but it was music to my ears.Lots of gray smoke I guess from not running for 10 plus years.i have to do a few things tomorrow to undo some stuff I did like reset the wur because I pushed in the round plate to see if that would work and reset the FD co adjustment.
i have a few questions how do I know if I have the correct wur on my car. The one on my car has a vacuum line coming off the side that goes nowhere.
i will throw my gauge on it tomorrow and see what readings I have.
i appreciate all guys input and help to get me this far and didn’t go unnoticed in my book
thanks again john
i will post tomorrow for updates in my progress

 

I have an 83 Euro CIS. I find that jumpered pump, closed gauge I see 75psi system. Control maxes out fully hot at 45psi, pulls like a train, starts cold very well, idles well. The35-40psi you saw above (early in post) might be the control figure. Tell us the pressures you see now that its running. Why did you include the page from PET above? It shows a control lowering addition (item 1) for starting when half hot, fitted over cylinder 3, triggered by a temp sensor on the heater water outlet. If this temp sensor doesnt close properly you can have starting issues when its stopped for < 10 mins. I would see if you can remove all that extra stuff, but keep the car running well - if there is no documentation it will be hard to diagnose. Worst thing a CIS car can do is be unused for long periods. I loaded my fuel tank with cleaning oil (Marvel, Beryymans), and left the pump jumpered for several hours, and changed the filter to try to flush debris out. Also got the injectors tested, cleaned, or replaced with the cheap short MB version, they work fine.
jp 83 Euro S AT 57k

 

I have replaced almost everything new on the car
new fuel pump,filter,tank strainer,accumulator,new main fuel lines,new Mercedes 047 injectors, rebuilt FD. Cleaned all injector fuel rails.
i will attach gauges today and see what I get but I’m still trying to wrap my head how the system works.
FD main line goes to FPR then a 3way valve which has a switch that has 2 wires that runs to what looks like a temp sensor. The fuel line continues to the WUR and there are 2 lines that return to the FD and the 1 line with the bango fitting is the line with the injector looking thing that is connected to the tan box which is actually working.my question is what does the injector on the return line play in the warm up process if any and can I make adjustments on that tan box to make it run better. the car doesn’t have any exhaust after the cats and not sure if that plays a role in how it runs but it sounds mean and the neighbors hate it lol
I ordered the Ben Watson book hoping that should have good information on the system I have

 

Does your fuel distributor have flow adjustment screws at each exit point (8) like this one?

?

 

No it has no adjustments for each injector it only has the one where the plunger is. There’s adjustment Allen type adjustment on top of the main lines but that’s it.
i took a pic

 

The Merc head is handy IF you have a native airflow imbalance among cylinders. Setting one up on a test bench for flow balancing isn't worth the aggravation, in my experience.