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JFP in PA

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Posts posted by JFP in PA

  1. If your VarioCam system was not functional, the car should code indicating that.  With the Durametric system, you can activate the solenoids one at a time while it is running and see the cam position change in real time, plus the car should stumble a bit if you do this while the car is at idle.  Unfortunately, due to the size of the cam deviation on bank 2, my guess would be it is probably out of position due to the recent installation.

  2. It is sounding more like the fets in he DME are not functioning properly.  Again, the way the solenoids are supposed to function is one wire carries battery voltage to the solenoid when the car is running, the second wire runs to the fet in the DME which functions as a gate or switch that changes at a fixed RPM.  In my experience, the wire going to the fet reads low (~3 volts DC) until the RPM target is reached, at which that wire turns into ground and the solenoid activates.  You are indicating battery voltage on both solenoid harness wires, which will never activate the solenoids. 

     

    As for the misfiring cylinder #3, electrically there are only three possibles: the plug is bad, the coil is bad, the coil harness connection is bad.  So if you have power at the coil harness connector, and the connector is fully seated, you are left with the coil or plug.  Pulling and replacing the plug is simple enough, and the coil pack can be tested by moving it to another cylinder to see if the fault code reappeared there.

  3. The Durametric system can see every value the DME sees, but it cannot create values that are not part of the DME's PID file.  As for spec values, or explanations of what those values mean, that is not Durametric's prevue; if you want to know what the car's specs are, or an explanation of the codes it reports,  you need either the factory OBD II manual for the car (about $2,000.00 when it was still in print, which it no longer is), or the vehicle's factory service manual (13 volumes, but also no longer in print, but available online with either a monthly or annual subscription of around $5,000.00, depending upon what you ask to see).  Your other choice to get everything you want, you can lease the current PIWIS III (lease only, not for sale), starting with an opening annual lease cost of $20,000.00.

     

    "Speed cost money; how fast do you want to go?"

    • Sad 1
  4. Remember, both solenoids are electrically "hot" when the car is running, regardless of the cam activation, which happens when the DME active position conditions are met (read RPM levels), and the fets create a path to ground, which is what causes the solenoid to move and the cam positions to change, so there can be common wire colors to both that are carrying battery voltage.

  5. And ten seconds after I posted that, I realized I have to be wrong on that point as the Durametric can activate either one independent of the other, so there has to be separate circuits, at least for diagnostic purposes, and the DME can by throwing different codes tell you that one specific bank is not assuming an active position.  There has to be two circuits.

  6. This may start out sounding weird, but bear with me.  You have two pin connectors on the harness coming from the DME to the solenoid, using a multimeter set to at least 12V DC, you should read around 3V on one pin, and battery voltage on the other (engine running).  The low voltage pin is seeing the transistor or fet in the DME that is the ground (yes, I know grounds do not normally show voltage, but in this case it does because of the electronic device the DME uses, it has a low voltage DC signal on it).  The second pin should show battery voltage (~13V DC) when the engine is running.  Obviously, that is not what you are seeing, and as a 9V battery can trigger the solenoid, it looks like the solenoid is good, but the voltage on the harness is low and wavering with RPM's, which it should not be doing.  That wire gets its power from the ECM relay, left side of the engine bay (if memory serves), which may be going south.

  7. The way the system works is that the DME supplies a ground to the  always hot solenoid at the appropriate RPM level, allowing the solenoid to assume the active position; so it is beginning to sound like you have either (1) a harness fault between the solenoid and the DME (high resistance causing a voltage drop), (2) a breach in the harness itself, or (3)an internal failure in the DME.

     

    I would disconnect the solenoid harness at the cam cover, and using a wiring diagram, check the harness from the cam cover connector to the appropriate DME harness pin for resistance, which would cause a voltage drop and stall the solenoids.  If the harness is fine, you have a DME issue.

  8. If the car was in my shop, I would be testing the harness between the sensor and the DME for continuity, resistance, etc.

     

    The codes are specific to banks: P0140 is bank# 1, cylinders 1-3; P1121 is for bank # 2, cylinders 4-6.  As both are signal interruption related, I would be checking the harness, both electrically, and visually for any damage.

     

    These kinds of faults can be a pain to locate the problem, as it can be anywhere along the harness (rodent damage, wire insulations becoming brittle and splitting, etc).

  9. 12 hours ago, weegogs said:
    Hi I'm a newbie to the forum and would like to share the journey to fix my 2000 986 which was suffering from rough idle/limp mode issues. The car was diving great the night before and was parked in the garage as usual. The next morning when i tried to take her out the Idle was all over the place and I couldn't get over 2000revs so I jumped onto google looking for answers. The general opinion was to replace the coils and plugs to cure the rough idle, I never drive her in the rain but I had got caught in the rain the night before and thought that it was possible if there were hairline cracks in the coils water may have got into the coils causing the rough idle so I replaced both the coils and the plugs. Still no change, so back onto forums I went, If you disconnect the MAF sensor and the car runs better then you need a new MAF sensor, I tried cleaning the sensor but still no change. A new MAF sensor was ordered and in the meantime I ordered an iCarsoft POR 3.0 to see if there were any codes as the CEL hadn't come on. I fitted the new MAF sensor but STILL NO CHANGE. By now I'm getting a bit frustrated and thinking the solution might be a gallon of petrol and a box of matches but on I pushed. The scan tool arrived and I was able to get a code from it, P1502 Throttle jacking unit,spring test-above limit. Google is my friend, turn ignition on for 1 min, turn off for 10secs, turn ignition on. Yeah you've guessed it still no change. Next cab of the rank is to remove and clean the throttle body which was done with no improvement so now I'm trawling all the forums, you tube video's, witch doctors, clairvoyants anything to try and solve the problem. Then I stumbled on a forum where someone had exactly the same issues I was and he traced the fault to his ignition switch, he realized he couldn't hear the throttle move when he turned on his ignition and instead of troubleshooting the throttle body he concentrated on his ignition switch. His solution was to turn the ignition on and off quickly 20 times and then start the car. Surely not but hey I'm willing to try just about anything by now so off I trot and would you believe it I've got my baby back and she's running as smooth as a swiss watch. I hope that this helps anyone else who finds themselves in the same situation.
     

     

    Welcome to RennTech :welcomeani:

     

    I don't know where you got that definition for P1502, but that is not the code for the throttle jacking spring, it is the code for faulty fuel pump relay, so I would start there.....

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