CIS pressure table....
 

Can anyone post info or specs in a table, graph, or other form on what my fuel pressure should be at various ambient temps from cold up to normal operating temperature. I am trying to figure out if I have a bad WUR or not.

Thanks in advance for any advice here.

I can post the factory graph if you supply the engine type number and WUR part number.

without being at home all I can say right now is that the car is a 1977 3 Litre 930 Turbo. It is a euro car. Does that get us anywhere?

Cant see numbers accept for a set of three numbers on the WUR body without removal and I would rather not disturb the system until I get finished checking pressures and confirm that it is actually the issue.

Engine number is 930 101 104 . 3R

Any other ideas?

It gets us started.

The Euro WUR had a suffix of 112. The graph shown below is for a 930/66 which is an '83-'86 ROW. Your engine should be a 930/52 which is a '77 ROW. I do not know if the pre-78 Euro WURs were 112s.

The way I understand it is OK to post this graph as taken from the Porsche factory manual dated 1989. If I am incorrect in this assumption I apologize.


http://forums.pelicanparts.com/uploa...1177642221.jpg

My brother in law is the one helping me with this. He is the one asking for the data as he does not have it. I will see if I can somehow get a number off the WUR and go from there.

Stay tuned and thanks for the help! :)

There is actually very little difference in the charts for all the 930s. I think it is safe to say that the mean of all combined ranges would be in spec for any given 930.

Go ahead and check your system, cold, and warm pressures. I assume your engine is modified which can make some or all of these stock ranges less than optimal for your application.

Here are the graphs for the 930/51 and 930/53 which I think are the '76 and '77 US models, they're actually quite different to the later 3.3 WUR graphs. If the number on the WUR matches, these would be the ones to use.

My manual doesn't have any graphs for the 930/52, sorry. Excuse the camera phone pics...

http://forums.pelicanparts.com/uploa...1177676097.jpg http://forums.pelicanparts.com/uploa...1177676138.jpg

Can't seem to upload a new images into the first post, so adding a close-up of the graph, hopefully easier to see that the first major vertical division is 0.5 bar on this graph, rather than 1.0 bar like it is on the 112 diagram...

http://forums.pelicanparts.com/uploa...1177676670.jpg

It's hard to read but it looks like if you pick 20*C from both graphs the ranges overlap. That is what I was refering to with my comment above.

I would expect the stock factory specs for cold pressure and system pressure might be significantly different but I do not know that for a fact and cannot read it from the pictures.

Engine modifications will have an impact on optimal static settings. The factory specs may no longer apply. If you list your present settings and your mods we can take a look at Spuggie's data and figure out where you're at.

Brian, they sure were pretty hard to read.

The 930/5[13] and 930/66 graphs are quite close at some temperatures, but the slope's different - they give different values elsewhere.

You'd be roughly .4 bar too high @ 10 degrees using a 930/66 graph for a 930/51 or 53 WUR, for example, and at 35 degrees, you'd be .2 bar too low using the 930/66 graph.

Admittedly, they're pretty close around the middle of that range - guess it all depends where you live how significant that is...

Here's the data anyway:

Pump Delivery: min 1170 cm^3 per 30 seconds (both pumps together).

Cold Control Pressures for Part # 911.606.105.02 and 930.606.105.00

Bosch part # 0 438 140 016 and 0 438 140 022


Deg: Min Max

10: 0.45 0.825
15: 0.75 1.125
20: 1.05 1.45
25: 1.375 1.75
30: 1.675 2.075
35: 2.0 2.375

Control Pressure Warm: 2.6 - 3.0 bar (atm)

System Pressure: 6.0 - 6.7 bar (atm)

Leak Test:

Min after 10 minutes: 1.7 bar (1.8 atm)
Min after 20 minutes: 1.5 bat (1.6 atm)

Injector Opening Pressure: 2.1 - 3.2 bar (atm)

Idle Adjustments

Idle Speed: 900 - 950 RPM
950-1000 RPM (1977 model)

CO Level:

930/51 1 - 3 %*
930/53 2 - 4 %*

* air pump disconnected

Well, the WUR checks ok. The issue appears to be the Fuel distributor unit. My guess is that the plunger that controls fuel flow is just worn out after 30 years. That or the slits have worn in that area and are just passing way to much fuel under heavier throttle demand.

Switching to EFI. Case closed.

Thanks for the help guys!:)

You make it sound so easy :D.

Time to start another thread on your new project!

There was a rebuilt fuel head in the classifieds recently for $400.
A LOT cheaper and easier to install than EFI.
Could it be that you have some dirt in your fuel system that has impacted the fuel head? If so you can clean it.
Unless you are looking for any reason to go EFI you might kick yourself if it ends up being an easy fix.

Kind of looking for this to go to EFI but if I can buy myself a couple more months that would be much better! How can I clean it?

Thanks!

Bump for my last post. Any answer would help. Just lookin to get a couple more months.

Thanks again!

Chris,

Here is another option...

I have used this company in the past to rebuild my fuel dist. I believe others on this board have used them as well. Actually, if I recall correctly, the PP board is where I initially got the info.

Check it out...They even do the full enrichment mod.

http://specialtauto.com/porsche-parts/index.html

hope this helps

David

If you are just wanting to buy a few months you can (carefully) dis-assemble the fuel head and clean everything with carb cleaner and a soft tooth brush. Put it back together using the red/rust colored adhesive made for the application (I forget the name off hand). that's what I did years ago and it still works perfectly.