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Hi there, my cayenne won't drive as long i have the relay placed at 1/6 (the 404 relais) functioning. Once I take it out the car runs perfectly on one pump but once I put it back in the car stops working although I hear both fuel pumps working. What to do?
Thanks for your response.
Hello Porsche experts, I recently purchased a used 911 Carerra, 2003 and had the fuel pump fail. So I looked around in Orange County to find a Porsche mechanic and ended up taking it to Hergesheimer. They replaced the fuel pump but a few days latter I experienced something very troubling. The car would start but idle was somewhat rough. Revving the engine was a challenge in the lower RPM 1000-3000 then it became a bit smoother when driving with load on the engine in the 3000-4000 RPM range. Alarmed by this I called the shop to bring the car in, but this was the day before the Rennsport Reunion in Laguna Seca so I dropped by another mechanic who brought up these error codes on a generic diagnostics tool: P0134 Sensor Circuit No Activity Detected (Bank I Sensor 1) P0101 Mass Airflow Sensor / Circuit range issue Performance problem P0154 O2 Sensor no activity detected (Bank 2 post CAT ) P2098 Post Catalyst Fuel Trim System Too Lean Bank 2 P2096 O2 Sensor no activity detected Post Catalyst Fuel Trim System Too Lean (Bank 1) P0156 O2 sensor circuit malfunction (Bank 2 Sensor 2 post CAT) Initially I thought this was related to the fuel pump replacement. So I called the shop who did the work and they said bring it over. Their analysis identified similar codes and they suggested a few hours to review the harness and sensors in order to asses the problem. A week later i am still trying to resolve this and wondered if I should replace the O2 sensors myself. I have done brakes and other minor maintenance. What is the opinion of the forum here on next steps? I can provide further detail
First time post... hope to start contributing to the forum now!
09 GTS with 93k and excellent maintenance history, recently getting long cranking times and sometimes rough idle at startup. Starter is working properly so we can rule that out - not sure what to tackle first, coils? fuel pumps? HPFP?
1023 Ignition Coil D Primary/Secondary circuit - upper limit value exceeded
1026 Fuel high pressure implausible - value below lower limit value
The 1023 keeps coming back when cleared but never throws a CEL, the 1026 has been very intermittent but will throw a CEL.
I swapped coils 3 and 4 (assuming D is coil 4 and coil 4 is rear-passenger side of engine?) and still get the 1023 code for "D" but no misfire codes.
I tried pulling fuses 13 and 14, independently, and truck starts on both fuel pumps (with long crank).
Logged with Durametric the fuel setpoint vs. actual pressure and I get 40bar at idle and it seems to keep up OK while driving up to 120bar at WOT.
Plugs were changed at 80k but I believe to be on original coils and fuel pumps.
So before I start throwing parts at this, any advice on what to troubleshoot next? Still fairly new to the Durametric so anythink I'm missing there with respect to data logging?
By Reid Mayer
So recently had a fuel pump go out on my C4. Conveniently way far from home. Got a local shop to repair, and they put the fuel pump in from the C2. The car runs, but doesn't feel quite right. Does anyone know the difference between the two pumps, apart from the part number of course? Wondering how far to push this.