hupp

John,

I would recommend diagnosing entire system per the WSM to ensure you are headed in the right direction. One thing I've learned is that one's imagination can run wild when trying to chase CIS gremlins. What follows is a summary of what I would do (please pardon me if you have already proceeded down this path.)

After completely cold - sitting over night:

- Bridge the fuel pump safety circuit - this allows the fuel pump to run indefinately without starting the car.
- Unplug the WUR connector.
- Remove vacuum line on the side of the WUR and replace with Mighty Vac
- Install CIS pressure gages to WUR and pump the mighty vac to proper vacuum
- Turn key to on
- Bleed the pressure gage and then observe cold control pressure. Compare to WSM tolerances
- With fuel pump running, check for leaky injectors by listening with stethiscope or screwdriver (metal end on injector handle to ear). You should abserve no clicking/whirling sound. If you do the injector is leaking.
- Turn key off and plug WUR connector then turn key on.
- Observe gage - pressure should rise slowly as the element inside the WUR is heated. Observe pressure once steady - this is warm control pressure.
- Turn key off and observe gage for fuel pressure leak down. Should have very little leak down for 30 min.

jtrygstad

Thanks Scott & JP. I'm on the road this week, but give me some things to research & think about. I really like the connection between CIS and "imangination runs wild"! Lars (my son & owner) has ordered a few injectors anticipating some leakers.

JP, what did you do to your WUR to get the pressure corrected?

jpitman2

John, Initially I opened up the WUR completely and flushed brake cleaner back and forth through the inlet port (with the presure regulating valve dismantled), and this helped for a while. Next time control started to rise (probably due to more crud and shellac being washed through by usage) I found there is a !@#$%^&*( very fine brass gauze filter in the inlet port that cannot readily be removed without destruction, so it got destroyed.....if you can get it out in one piece (maybe blow it out from the inside port with air?), burning the crap off it is the best way to clean it - just hit it with a cigarette lighter flame. I have heard of others removing these filters both in the WUR and in the distributor connections as well. At one stage I was also able to reduce control pressure by inserting a thick gasket between the base and the body of the WUR. Also its worth finding a shop that can clean (ie back flush properly) and test the injectors - my local guy does them for A$12 each - four came back recommend replace due to leakdown or poor spray pattern. FWIW, they are the same Bosch part no as late Peugeot 505 injected cars. If you remove and refit, get new rubber seals - use vaseline to lube to enable fitting, mine were very tough to do.
HTH
jp 83 Euro S AT 49k

jtrygstad

It's finally Saturday, so once again I'll try to get the beast running.

jtrygstad

Pulled out injectors 5 through 8 (still attached to fuel lines) and bagged each with a zip-lock sandwich bag.

Turned on the fuel pump and three of the four were spraying fuel. I changed out number 8 with a new injector and tested again. Still spraying which seams to indicate that the fuel distributor plunger is slightly up allowing plus 50 psi fuel flow to the injectors. Could this be occuring because I don't have the A/F screw turned far enough ccw? Or do I need to pull the fuel distributor off yet another time and do who knows what to it another time?


Control pressure w/o vacuum 53 psi (cold; the engine hasn't run in weeks)
Control pressure with 400mm vacuum 58 psi (cold, of course)
System pressure 78 psi.

Dennis Wilson

John,

Adjust it ccw until the injectors stop spraying. Make sure you aren't pushing down on the plate when you make the adjustment. If they won't stop spraying when adjusted ccw then the problem is due to too little control pressure (WUR) or leaking o rings in the distributor.

Dennis

jtrygstad

Dennis,

Thanks for the independent input. I've gone all the way ccw. The pressure from the WUR is a bit high, so therefore, it's probably leaking o-rings in the distributor. As I recall, the "new" 8 o-rings on the cylinder "didn't quite look right" when I pressed it into the top part of the distributor body. Are these the o-rings you are referring to?

Dennis Wilson

John,

Had the same problem when I rebuilt the distributor on the euro. Was finally able to find 8 "fat" small (all I remember of the size) at the local Autozone. You may also want to try adjusting your control pressure before tearing the distributor back down.

Dennis

jtrygstad

Re-built the fuel distributor again (actually twice for a total of 4 times). Who out there says keep fixing it until it is broke?

So far only have had time to run the pump and tweak the A/F until the injectors just start to spray. A major acomplishment not having the injectors flooding everything in an uncontrolled manner. Next will be to put the plugs back in and tighten up the injectors.

The cold tests are:
Control pressure nearing 60 psi and
System pressure 85 psi.

Looks like I will need to tackle the WUR next to get that control pressure down.

Thanks to everyone for their help so far. I'm sure I'll be back with more questions since I won't be able to crank it over until next week sometime.

Dennis Wilson

John,

Agree the control pressure is too high. Systems pressure is within specs. BTW you will have to lean up your AF mixture when you get the control pressure within spec. If you plugged the 8 decoupler holes between the two halves of the distributor, that could account for the high control pressure.

Dennis

jpitman2

Dennis, I would have though the 25psi difference between control and system would be enough....mine didnt give me problems until control got to 60, with a system of 75. SI it related to being too close to (or above?) injector opening pressure?
Can you explain 'decouple' to me please. I have seen it several places, but not sure I understand its meaning. I suspect it means the hole joining two fluid spaces is small enough to prevent pressure changes on one side from being rapidly communicated/transferred to the other side? But the hole is needed to allow the fluid to fill both spaces for the system to function.....
jp 83 Euro S AT 49k

Dennis Wilson

Jay,

The system pressure should be between 5.2 and 5.8 bar hot or cold. The control pressure should be between 1 and 3 bars dependent upon temp (50 to 104 F). His cold control pressure of 60 psi is a minimum of 15 psi too high. I would guess it is possible to richen the AF mixture enough to compensate for cold or hot running but not sure about both. The decouplers (Bosch term) are basically bleed off orifices from the top of the distributor (control pressure from the WUR) to the bottom of the differential pressure valves (system pressure). If these are plugged with gasket cement, dirt or shellac the control pressure will stay too high regardless of the valve position in the WUR.

Dennis

jtrygstad

It runs!

Finally got home long enough to get the fuel distributor rebuilt properly. Most of my troubles with rebuilding (many times ) were the result of improper o-rings (or not being able to find them locally). I finally did what I should have done to begin with - type in "o-rings" on Google. Bought all of them at:

AOP Technology
http://www.air-oil.com

This is a very complete site for every conceivable size of o-ring.

Also, just to be sure on the 8 o-rings on the distributor barrel, I purchased a set of 7.5mm (id) rings, too - these seem to fit better than the 8mm originally prescribed.

Thanks for everybody's help. Now I have to get back to solving the original problem with too much system pressure.

heinrich

Nice! Now on to the a/f ... makes a huge difference. I found the Bentley manual for the 911SC reasonably helpful when I did my 911 CIS. So much so it pulls harder than ever and has ultra-low emissions.