CIS-e problems

[Ben Swann]

What you say is relevant for the CIS and CIS-E systems, which have full pressure to CSV when fuel pump is running.  On the other hand, from what I understand, the CSV on the CIS-E3 systems operates at the same pressure as the other 5 injector lines.  They only get pressurized when the air plate is lifted, even if the pump is running.  Just cranking the engine over is not enough flow to lift the plate - there needs to be residual pressure.

Someone correct me if I'm wrong.  My experience in getting this car started when cold and has been sitting for indefinate amount of time supports this.  For example, car has been sitting for a couple weeks now.  I jumpered the pump to run, lifted the plate(using 3mm allen) for about 1 sec to pressurize the lines.  Put FP relay back in place of jumper wire.  Get in car, turn key and engine starts - some fooling with accel pedal used as I don't have everything dialed in correctly yet, and I suspect ISV may not be working properly either.

Car will restart just after shutdown  and up to about an hour without re-priming injector lines.  Over time there seems to be a leakdown - question is where?  I will start by replacing injectors and the accumulator.

I should also probably perform pressure tests and run some other diagnostics, and may well do, but I feel I should have put in new injectors when I rebuilt the engine, and will do this now since I built this engine up and didn't really want to cut corners anyway.   Hindsight is 20/20 and I've learned a few things since I did the job, and have experienced similar hard start problems due to injectors - CIS in 5000 turbo quattro(s) and CIS-E in 4000Q.  Difference there was the CSV is fed directly off system pressure and the car would eventually start after cranking for about 7 sec.  New injectors briough the time down to 1 turnover of the crank in 5ktq or pretty much immediately, and all you need to do in the 4kq is bump the starter and VROOM.

Ben
  ----- Original Message ----- 
  From: Brian Sims 
  To: Ben Swann 
  Sent: Thursday, January 01, 2004 11:46 AM
  Subject: Re: CIS-e problems


  Hi Ben, Food for thought on the CSV,If it's cold and not squirt'in you may want to think signal.I believe the problem with pressure leakdown is directly related with engine temperature.It is my interpretation that any sort of leakdown and residual pressure drop on a stone cold engine causes minimal concerns.My reasoning being that once the fuel pump is energized and the pressure is regained, there is no problem because this happens before the motor turns over.On a hot engine,any drop in pressure would allow the fuel remaining to boil and create a vapor lock,therefore,creating excessive cranking time to start.Good luck,
    ----- Original Message ----- 
    From: Ben Swann 
    To: Brian Sims 
    Cc: quattro at audifans.com ; Ben Swann 
    Sent: Wednesday, December 31, 2003 11:24 AM
    Subject: Re: CIS-e problems


    1) Brand new fuel pump for NG engine installed (actually transplanted after feew months of successful running on other car that started with a bump of the key)  Rule out the pump.  

    2) System is undoubtedly getting full pressure, but may be a leakdown somewhere in the distributor itself, so leakdown test in order. I had thoroughly cleaned the fuel distributor prior to installation.

    3) Yeah - removal of CS injector would tell me it is firing or not.  I suspect it isn't, because of suspected leakdown, but need to confirm.

    I don't think I'll be able to do any of this before next week.

    Ben
      ----- Original Message ----- 
      From: Brian Sims 
      To: Ben Swann 
      Sent: Wednesday, December 31, 2003 12:08 PM
      Subject: Re: CIS-e problems


      Some quick tests you can do would be a fuel pressure residual pressure check( if the pressure stays up) that clears the injectors and if you still have a Bosch fuel pump, the check valve.You can check the CSV quickly by removing it from the manifold (leave it plugged in)and stick a plug(cork) in its place.Place it in a jar while you crank the motor.If you get gas you can scratch that.
        ----- Original Message ----- 
        From: Ben Swann 
        To: Brian Sims 
        Cc: quattro at audifans.com 
        Sent: Wednesday, December 31, 2003 10:49 AM
        Subject: Re: CIS-e problems


        [----- Original Message ----- 
        From: Brian Sims 
        To: benswann at comcast.net 
        Sent: Wednesday, December 31, 2003 10:49 AM
        Subject: CIS-e problems
          Hello Ben, I have been watching the conversations going on about the injection problems. One of my cars had some issues lately that caused me to do a fairly comprehensive investigation into the system to correct.Could you briefly describe to me the system tests you have done?Perhaps I can help you out.

                      Brian]

          Brian,

          I have not really done a great deal of troubleshooting so far.  After I did the CIS-E-3 transplant, I had so much work left to do on the car, I set it aside to work on my Ur Quattro.  I finally have complete diagnostics manual for NG/NF engines, and just need the time to work through. I plan to resume this project in few weeks, and then can devote the time to do more methodical trouble-shooting  I've only needed to start the car to move it around every so often, so I just prime the injectors as described below.

          In my experience, this is likely injectors leaking down, or some other leakdown.  After sitting for an undetermined length of time, over 10 minutes, the engine will not start even after continuous cranking.  If I jumper the Fuel-Pump to run, and lift the airflow plate to "prime" with fuel for a few seconds, the engine starts and runs.  This tells me that there was no fuel in the lines, and there was a leakdown somewhere. If I just jumper the fuel pump to run, the engine will not start - that indicates the system is pressurized, but since the airflow plate was not lifted, no fuel got in the lines.  I think that just cranking the engine is not enough to lift the plate and charge the injector lines.  Once the engine is started, it can be turned off and re-started.

          From what I understand, the Cold Start injector line would be the same pressure as the other injector lines, and therefore, it is not pressurized either.  This would be different than the setup on the CIS-E and CIS systems, which are full system pressure - correct me if I'm wrong.

          Perhaps I'm overlooking something else.  I have installed a NG fuel pump in the 4000 Quattro that the engine transplanted.  Complete CIS-E3 wiring and AFAIK everything is hooked up properly.

          I'd be glad to hear of any other ideas i may have missed.  At present I intend to buy injectors and install them to rule this out.  

          Ben

          Overly detailed writeup on the swap:
          http://www.homestead.com/ben_swann/files/GTQswap.txt

          and the wiring:
          http://www.homestead.com/ben_swann/NGwiring.html