According to your symptoms, upon startup the Motronic brain is providing cold start enrichment via the cold start valve which means more gas. The car runs ok. After the initial start up period 15-20 sec it goes to normal running mode and car runs like crap. Not enough gas. Have you performed the cold start enrichment test procedures? Also, I think that disconnecting the DPR is not a valid troubleshooting procedure and may be leading you to believe in other possibilities that may be off track. Connecting a meter to the DPR and checking it's operation is certainly valid, a pulsating meter movement means your O2 sensor is working, steady needle means O2 is probably bad (must have ANALOG meter to see this). Completing all the electrical tests of the ECU and cleaning connectors should be done also. Connecting a fuel pressure guage to your system and verifying the pressure specifications is also a valid procedure but requires special equipment. Maybe the shop wrote down the readings they got when they said it was good? A vaccuum leak would cause the car to run crappy all the time regardless of temperature or start up enrichment. Good luck.
Rich Blake -----Original Message----- From: Patrick Austin <[email protected]> To: [email protected] <[email protected]> Date: Wednesday, August 22, 2001 3:37 PM Subject: Going insane: car still runs like crap. >OK...revised list of what's going on: > >Car makes fine power RIGHT after startup, for maybe 15-25 seconds or until >the car is warm (when starting from cold). After that 15-25 seconds, it >has absolutely no power. None at all. > >If I unplug the DPR, the car runs like a champ. It pulls to redline. This >makes me think that it's not a fuel pump issue, as it's getting enough fuel >to make lots of power up at high RPM when the DPR is unplugged. Also, it >seems to run just as bad with a full tank of gas as with a near-empty one. > >If I unplug the air mass sensor (other side of airbox from DPR) and the O2 >sensor, this has no effect whatsoever on how the car runs, with or without >the DPR. > >The DPR is BRAND NEW. It was doing this very same thing before the DPR was >replaced. However, immediately after replacement, the car didn't have this >problem. So something they did cured it very temporarily. About three >days. It sat for two weeks before I picked it up...maybe the cure had >something to do with sitting around a long time? > >I thought it might be the TT chip I installed, but I just re-installed the >stock one, and it made no difference. > >Could someone explain how a transfer pump could cause these symptoms? I'm >also curious about the time sensitivity of the running problems. Why does >it run OK immediately after startup, even if it's only turned off for a >second or two? The O2 sensor wouldn't have a chance to get cold in that >time period. A vacuum leak wouldn't cause a time-sensitive running >problem, would it? > > ************** > Patrick Austin > [email protected] > (617)782-9115 > ************** >_____________ >List Sponsor: http://www.netsville.com >To remove yourself from this list, send mail to [email protected] with 'unsubscribe a2_16v' in the body of your message >See us on the web at http://www.a2-16v.com >Visit the 16V Homepage at http://www.gti16v.org > _____________ List Sponsor: http://www.netsville.com To remove yourself from this list, send mail to [email protected] with 'unsubscribe a2_16v' in the body of your message See us on the web at http://www.a2-16v.com Visit the 16V Homepage at http://www.gti16v.org
