tlsmith1999

My 79 EURO is very difficult to start, it will sputter and die many times until it will finally idle very rough. I you let it idle until it warms up, it will restart with no problem.


I have connected my CIS gauges and found that I have over 9bars cold pressure at the WUR. I have found many posts that explain how to adjust the warm pressure with the bar inside the WUR, but how do you adjust the cold pressure?

jpitman2

9 bar? Hard to believe that, when system pressure is only supposed to be ~5bar. Cant see how that could run. Sure you dont mean 9psi? Couple of things could be wrong here. The aux air valve is upposed be fully open stone cold (well, depends on ambient temp) so there is enough air to lift the cold idle, the cold start injector (front of spider body) is supposed to give some extra fuel to get the fire lit. This last depends on circuit through the thermotime switch to open it, and fuel getting to it. Thermotime is a brass thing facing front, near the thermostat housing - do a search for item by WallyP on how to test this with a multimeter.
You might pull the cold start injector, face it into a container (extinguisher handy), crank some and check for gas.
Mine had a rough cold idle and occasionally stalled on me a while ago. I found the aux air valve was not open much, so I pulled it, opened it up (drill out rivets), and fixed it- now cold idles ~1100rpm for a few minutes then comes down . do a search for items on this - access to a freezer, a bit of spring bending, 4 M6 bolts you can be in business. If you full the front hose of the valve, when its fully cold, you should be able to get at least a pencil right through - shine a torch in and should will see the moving plate. You may have to adjust idle screw afterwards when fully hot.
jp 83 Euro S AT 53k

tlsmith1999

It has 9 bar. I have removed the gauge, cleaned the WUR, and re-connected it and it has 9 bar again.

I have recently cleaned the cold start injector, verified the AAV is open. The car starts, but dies after a second, so I believe the cold start injector is firing.

I believe the cold start pressure is regulated at the fuel distributor, but do not know how to adjust it.

Luis_M

Wow, 9 bar! What is your system pressure? SP is supposed to be 5.2 bar or so but yours must be much higher, since control pressure can never be higher than system pressure. Your pressure regulator on the distributor might be shot, if that gauge is accurate. Also, it's quite possible that your WUR inlet is plugged up. After I clean out the inlet on my 81 Euro S, I have normal control pressures hot and cold for a while, but they slowly creep up, probably from some stray crud in the fuel system plugging up the fine screens. Once the CP gets high enough, I have exactly the symptoms you describe, telling me it's time to clean the WUR again! I'd try cleaning that out before messing with the hot and cold pressure adjustments. I found that my control pressures fell exactly back into spec after cleaning out the inlet. For completeness, you should also jumper the fuel pump relay at some point and disconnect the WUR return line (with the engine stopped) and check the control pressure that way. If CP suddenly drops, you must have some kind of block in the return line to the distributor or the fuel tank.

Luis
81 Euro S 5sp

jpitman2

The whole system pressure is set in a regulator on the fuel distributor. Its adjusted by shims, but if you are seeing 9 bar I think something is blocked. Are you seeing the 9bar with the valve at the gauge open or closed? The fuel that passes through the WUR goes back to the return line at the distributor. Can you check that there is fuel returning to the tank at the line going into the gauge sensor? If there is little or none, that line or the regulator can be the issue. Do this test with the pump relay jumpered. Watson suggests following to find blockages...
-crack open outlet of WUR - if pressure drops, problem is further along; if no drop, WUR is problem.
-crack open return line at distributor - if pressure drops, problem is further along, else dist regulator.
- check return entry at tank- SAFELY! Its faintly possible the return tube into tank might be blocked - remove sensor unit and check.
My money is on blocked return or regulator in distributor.
jp 83 Euro S AT 53k

jpitman2

Luis,
Yours sounds like its not getting enough use to keep the lines clean...My initial WUR was like this, then Erik donated one to me, and its been great ever since. Some have had good results from loading the tank with a cleaner like Berrymans, and bridging the relay for an hour or two, to slowly disolve crud and deliver it the filter. Mind you I havent checked my pressures for a long time now, but while it starts first try stone cold, warms up smoothly, and doesnt misbehave or use excessive gas(last run got 26mi/imp gal), what can be wrong?
jp 83 Euro S AT 53k

Luis_M

jpitman2: I agree my CIS trouble is from not enough regular use of the car. The car sat a while, and I've just recently finished an intake refresh, fuel tank cleanout, fuel pump/filter change, and clean out (best I could without disassembling distrubutor) of the distributor, WUR, and engine bay fuel system lines. The WUR is functioning longer and longer between plugging up (was minutes, then hours, now days) so I think any residual junk I couldn't get to will hopefully work itself out completely soon and then I'll be relatively free of trouble for a while. I've thought about putting an in-line filter at the WUR inlet.... any comment on this idea?

WallyP

I would worry a lot about finding a fuel filter that was rated for a working pressure of 9 bar - you need a pressure rating quite a bit higher than that to have a safety margin.

Of course, I would also worry about the rest of the system as well, especially the flexible lines...

tlsmith1999

While checking the fuel dist, I found a crack in the distr body near the return line. It was not leaking, but I am going to replace dist, clean all the lines and injectors and reassemble. Hopefully this will help.

karl ruiter

I think you are on the right path. Start by getting the system pressure into spec. I will never work right without that. The WUR pressure is regulated down from it. You can remove the guts of the system pressure regulator without removing the fuel distributor...As I recall it is one of the easiest parts of the system to get at. I also think i can be adjusted, although I would guess that the return line from your regulator might be blocked. I would:
1) remove the return line for the system fuel distuributor that goes back to the tank. Make sure you can move fuel or air or something through it back to the tank.
2) remove the guts to the system pressure regulator and inspect.

blown 87

As would I, 9 bar is 130 PSI.

Dennis Wilson

I've never seen or heard of a CIS pump putting out more than 6.5 bar. Are you sure it is a CIS test gauge with the valve in the proper position?

Dennis

jpitman2

Luis, Many WUR have fine brass gauze filters in the inlet, under the banjo bolt - mine actually had FIVE layers of these in the hole. They can clog very easily, and the only reliable way i have found of cleaning these is to remove them (frequently destroys them), and burn them over a lighter flame to get rid of all the fine lint and rubbish. I doubt you will find a small filter that would carry the 4-5 bar involved.
jp 83 Euro S AT 53k

tlsmith1999

I agree that 9bar seems way too high, I have removed and reinstalled the gauges, got 9 bar again. Then I let the system pressure bleed off over night to about 2 bars. With the gauges connected and the valve closed (no fuel to WUR), jumper the fuel pump and it jumps right back to 9 bar. Open the valve and it fluctuates a little and settle right back at 9.
These are the same gauges I used to set my 78 2 years ago, Unless it went bad sitting, I am guessing the gauge is correct.

My plan:
I have two spare fuel dist that are just as old. I am going to attempt to rebuild one per the write I saw floating around.
I am also going to remove and clean all of the fuel components in the engine bay. The pumps/filter/accumulator/tank were done a few months ago.
Reassemble and test fuel quantity at the return line. I might even test it at the sender unit also to insure no blockage all the way back.
Re-test cold pressure at WUR, and see if I have improved it.
Then go from there.

GlenL

The cold pressure is set using the pressure relief valve on the fuel distributor. Your's may be sticking closed. Generally, people are advised to not mess with it. In your case I'd try making an adjustment. Just might come loose and perform correctly without a full rebuild.

Rebuilding is doable. There are instructions aplenty out there. Disassemble carefully to make sure it goes back right. Clean everything both thoroughly and gently. The tolerances are tight and need to stay that way. Sealing the block halves requires the right treatment to the thin diaphragm. I used Indian Head Shellac and had no problems.