Baselined My CIS

[1982911SCTarga]

Used my CIS gauge for the first time today. No problems led me to do so, I just wanted to baseline my system to see how it stacks up to specifications. The results are pretty good.

Ambient temp: 60 degrees F; 15.55 C

System pressure: 70 PSI/5 bar (so far, so good)

Residual system pressure at 10 minutes: 25 PSI/1.75 bar

Residual system pressure at 20 minutes: 24 PSI/ 1.6 bar

Residual system pressure at 30 minutes: 24 PSI/1.6 bar (looking real good)

Now let's bring in the dreaded WUR/control pressure regulator.

Control pressure: 28 PSI/1.75 bar (right in the heart of the band for temp/control pressure for an '82 SC).

These stats and chart (with the date) will go into my notebook for future reference.

[hbkramer]

did you make the gauge or buy it ??
I am making one and am in need of us to metric fittingd and the 3 way valve
anyone .

Thanks
bruce

[1982911SCTarga]

Hey, Bruce. I bought mine from JC Whitney a year or so ago for something like $50 or $60. It's a decent unit that comes with several adapters for Porsche and other Bosch-equipped CIS cars.

You could theoretically get by without the switching valve, but it's really nice being able to switch to test system and control pressures from the basic hook-up (going between the control pressure regulator and the fuel distributor).

Brian

[Dan in Pasadena]

Brian,
Is there somewhere here on the board, an "Idiot's Guide" to how to use this test setup? Besides the obvious where-to-connect-what-to-what, how is this done - the car is not running, right? - like I said, "idiot's guide"!

Once you have the pressure readings, what do you do with the results, assuming they are NOT as good as yours? Does the setup come with clear instructions?

[ianc]

Hey Dan,

The Bentley SC manual would be a pretty handy thing for you to have, as it goes over all this stuff in pretty good detail. Alot of other details would be applicable to your car as well; it's really worth it.

For some info on CIS, including pressure testing and troubleshooting, see Jim Williams' very excellent and painstaking site at http://members.rennlist.com/jimwms/CIS/CIShome.html. Read the 'Testing' link on the left for some stuff to get you started,

ianc

[hbkramer]

Dan,
pm me if you want the Bently manual 90.00 shipped to your door.
I wound up with two . Tes they are indespensible as a learning tool .

Bruce

[1982911SCTarga]

Dan, Ian beat me to it on the Bentley SC book and Jim Williams' info (with a good pic of the test hook-up). Don't forget the search function on this site. There's no lack of stuff written about Porsche fuel injection systems around here.

Another source for 911 CIS information is here.

Brian

[1982911SCTarga]

Once you have the pressure readings, what do you do with the results, assuming they are NOT as good as yours? Does the setup come with clear instructions?

The sources listed above and this board provide information regarding what a particular out-of-spec reading could possibly mean and how to remediate it. The CIS test gauge is a diagnostic tool that is only as good as its operator.

Used properly it can point you in the right direction and keep you from straying off on random throw-money-at-it tangents in solving starting/drivability problems.

Identify the problem. Fix the problem. Don't guess. CMA, with an emphasis on the C and M.

[Dan in Pasadena]

Thanks guys. Bruce, special thanks for that second link...it is one I had not seen before. I'll read through it with interest. On another thread someone made reference to a CIS test setup available at Harbor Freight for $50. Anyone know if it is a decent tool or junk, as opposed to more pricey test setups available elsewhere?

Yes, I've already done several searches here and gotten back literally hundreds of threads - hard to sort through them all. I have read through the Williams site too.

Even though I have a mid year car I suppose I SHOULD buy a Bentley Manual too...I imagine most systems are similiar if not identical. Thanks again everyone, Dan.

P.S. My car runs great, no hesititation, no hot start issues at all, nothing. My only issue is cold start. Gotta hold the key to Start a few extra cranks for it to "catch", then it will sputter to life, pop slightly a few times - just a little, momentarily idle up to 1600-1700 then immediately drop back to 900-1000. At the point - may 10 seconds after starting it, it idles fine. You can even blip the throttle (as long as you don't attempt to blip hard) and it runs fine. I can drive off just fine. It is really only a problem right at start up and the lack of a sustained elevelated idle for ....well, however long it is supposed to idle up.

[1982911SCTarga]

Dan, I haven't seen the Harbor Freight CIS test unit. The key thing is that you'll need certain adapters to correctly fit the set-up to your system. The J.C. Whitney test gauge comes with several adapter fittings for different CIS systems. I'm guessing the Harbor Freight set is similar.

Brian

[Dan in Pasadena]

Thanks Brian, I'll keep that in mind. I've got a HF near me, I'll run over and take a look.

[Paulporsche]

Dan,

Since your cold control pressure is OK, sounds like your AAR is not functioning correctly. It's also possible you have a small air leak. You do have one, and not the hand throttle, right?
Lots of info available on this via a search and in the Bentley.

I am assuming your points, plugs, rotor, wires and cap are good and mixture is correct.

[Dan in Pasadena]

Actually Paul, I do NOT know that my cold control pressure is OK. Yes, the plugs, points, rotor, etc are good. I suspect my mixture MIGHT be running slightly rich.

[Tim Hancock]

Here is a link and a pic from the unit I made. DIY CIS Tester

[1982911SCTarga]

Tim can out-cheap anyone when it comes to P-car maintenance.

[Tim Hancock]

Originally posted by 1982911SCTarga
Tim can out-cheap anyone when it comes to P-car maintenance.

Thanks (I think )

[1982911SCTarga]

Tim, while the rest of us mortals will go and buy the proper tool (after, of course, finding the best deal possible), you'll make your own and it will be of like or better quality. While we're all money ahead (avoiding the professional wrench like the plague while better understanding our cars), you set the cost of maintenance standard absurdly low. I like it!

Brian

[Tim Hancock]

Unfortunately, I just bought an Audi 2.7 bi turbo and I had to break down and buy a Vag-com diagnostic tool and software to hook my laptop up to the car. (I was pretty p!ssed when I opened my $200 package and looked at a 5' long cable with a serial port plug on one end and special plug on the other to fit the audi diag. port! I guess it is coded somehow to keep cheapskates like me from duplicating it!)

I have begun to get revenge by modifying a leaking transmission cooler (that Audi wants over $600 for by cutting off the leaking thermostat portion and machining and adding pipe plugs to the holes leading to the thermostat portion.... leak free now for $0.00 + 1.5 hrs of head scratching and machining. Ha!

Good idea on the baselining idea, it will be very valuable info later if you develop CIS issues!

[Paulporsche]

Sorry Dan,

I confused you with the Pelican who started the thread. His pressures were good.

Well, you know what that means--you should probably get those pressures checked. My guess is that your ccp is too high, causing the idle to be too lean @ startup. As I mentioned, it also sounds like your AAR might not be keeping the idle up long enough, although I admit, in Pasadena that may not be for very long anyway. And there is also the possibility of an air leak somewhere, like (I hpoe not) a pulled or broken head stud. If it were my car, I would try knocking the plug slightly on the WUR in order to lower the ccp, but to be safe, you should really get the pressures checked first. Then you'll have that baseline.

[1982911SCTarga]

Dan, any luck in finding a gauge set?

Brian