CS injector - CIS-E3 & Injector replacement & fuel testing [Re: Audi 100 Won't Start: Finally Starts !!!!!!!]

[Ben Swann]

A lot of CIS-EIII info here!

As I reported yesterday, the CIS-EIII CS injector port is different from the other five as best as I can tell.  Although it looks the same at first glance, and can be easily mixed up with the others, I took a closer inspection at a spare CIS-E3 fuel distributor I have.  There is a definate difference between the CS port ( pictures I've looked at showing where the CS injector goes to identify which one it is).  Also, the thing that really implied to me that it was different is this is the port that is supposed to be used for fuel pressure testing, according to a factory service training manual specifically for CIS-EIII systems ( not Bentley).    

According to the manual, when the correct guage assembly( I don't have)  is hooked up, it is a passthru to the test port which is on the lower chamber - differential pressure port - and the guage is in between with a valve that can be shut off - guage on test port side - to show diff. pressure, or when valve is open, supposedly system pressure.  

I would have thought when the guage is open, it really shows system pressure - diff. pressure.  I suppose in the procedure with fuel pump running and ignition turned off, differential pressure is so negligable that it is essentially system pressure.

Anyway,  I'm just mentioning all this, as before I was under the impression the the CS injector port was just another (6'th) injector port, and the lines could be installed any which way.  NO!  this apparently is not the case and I'm reporting what I feel is an error that I've helped propagate.

I am now trying to nail down what is specifically the problem with starting the engine after it has been shut down for over an hour.  Engine will only start after fuel pump relay jumpered, airflow plate raised to introduce fuel through injectors - then it starts and runs fine.    I replaced the injectors, but now believe, the injectors may only have been contributing to make the problem worse, but not the root of the problem - I have not put everything back together yet, so I don't know if the injectors helped or not.  At least one injector was dribbleing fuel after shutoff, causing a definative fuel leak, but again, I don't think this was the only problem. 

I am beginning to believe that the CS injector is not firing, and the ISV is not triggering properly if at all.   I have not been able to run the ouput tests, as I need to make the wiring corrections. This is a complete NG transplant including wiring harness, but some things did not interface seamlessly.  Now that I have a correct manual, I have more info. to getting everything sorted properly.

As I have been working this problem  it seems Marcs 100 non-start issue is being worked.  His appears to be the other way around.  Starts momentarily and can be made to run on the CS injector.  That tells me he is not getting fuel to his main injectors.  Sensor plate not rising,  Diff. Pressure way off ,  system pressure low ???  

Notes for Marc et. al:  CIS-E and E3 are way different than CIS - don't even look at CIS testing procedures - they are similar in principle only - where CIS uses warm-up reg. to control pressure, CIS-E's use a differential pressure regulator.  I have found on at least one instance on CIS-E, when there is no fuel to injectors when sensor plate is lifted, the DPR may be clogged and can be removed for cleaning (o-rings, etc - rebuild kit from dealer, gumout, light scuff pad/very fine emory(1000) if rusty) - I don't recall if you had done the injector spray test, so don't know if you have narrowed it down to no fuel to injectors - there are tiny holes to/fro DPR that become clogged if system was setting.  

Note 2 - even with brand new injector sleeves, I am replacing them as I messed them up a little as injectors became stuck inside.  I had to remove each line and force injector from sleeve on a vice.  It may be a good idea to have new ones on hand when R&R injectors/seals $3 ea. from dealer.  I could have re-used mine, but since I have the engine pretty with all this new stuff on it, I figured get new ones.  I can envision if injectors that have been in for a long time the sleeves might have to be cut off the injector just to be  able to get a wrench on the line fittings to remove old injector.

Looks like I may need to source a proper fuel pressure tester, but first need to square away my wiring in order to properly run I/O tests.  It would be much easier to troubleshoot a factory wired car, but my intention is to duplicate the factory wiring setup.  Now that I have a correct manual - lots of new info.  I am more prepared, as most of this information was not in the Bentley - at least not in a concise organised manner specific to CIS-EIII.  The wiring diagram varies slightly on this one, and it looks like the temp switch arrangement may be a little different as manual is more for 100 NF than 87.5 GT  NG configuration.

Ben
NG engine with CIS-EIII tranplanted into '87 4000 quattro


[Date: Thu, 29 Jan 2004 21:13:40 -0500 (EST)
From: "Doug Yoder" <yoderw at msoe.edu>
Subject: Re: Audi 100 Won't Start: Finally Starts !!!!!!!
To: "Marc Boucher" <mboucher70 at hotmail.com>
Cc: "Kurt W. Deschler" <desch at WPI.EDU>, quattro at audifans.com
Message-ID: <3088.151.144.149.70.1075428820.squirrel at www.msoe.edu>
Content-Type: text/plain;charset=iso-8859-1

As another note, the CIS-E3 fuel distributors do not "meter" fuel to the
cold start valve.  The CSV is a 6th injector, essentially, but it is
electronically controlled (so I *do* have EFI!), so the fuel distributor
doesn't need to control the pressure in that fuel line.  So Kurt is on the
right track with monitoring the injector spray while manually controlling
the fuel distributor.

Good luck,
-Doug]