Hi Guys. Just last month I developed a large air leak. Had it smoke tested & was one of the breather tubes. Had this repaired, checked again - no leaks. I had been getting a P0193 code. Purchased new fuel rail pressure sensor, fitted it, did a hard reset & car ran fine - definitely improved with new sensor, no more surging when cold etc. After a week or so I thought it was abit down on power so did another reset (neg cable off all night). Reset all the settings went to drive it & got CEL & RP. Codes listed as per above. Strange thing, when first started car runs fine, just as it hits full operating temp the RP kicks in, stays on for a few kms then goes away again...? Cleaned MAF & it appears fine. As mentioned just checked for vacuum leaks & besides that it was running fine until reset - no lean codes. I did the reset again just in case something went haywire, same result. I've had real problems replacing sensors on this car, seems really fussy & only wants direct OEM parts - tried 2x different MAFS last year neither of which would run so ended up refitting the original, so I'm wondering if it doesn't like the new pressure sensor? Really clutching at straws as I haven't got a clue. The RP when it comes on never seems to stay for very long - could it just be the fuel trims readjusting? Any ideas folks?

 

Stop resetting.

Let trims settle over a few drives and then do the usual tests to see if you've yet another air leak.

Also see which OBD monitors haven't set (if any).

If you keep getting P0193 check for the other possible causes - see workshop manual etc (free download).

 

Thanks JagV8. I spoke with the Euro specialist who fixed the vacuum leak. He thinks it will either be a wiring issue or a problem with the ECU. I plan to take it on a long drive over the weekend and see how it goes although have driven it 7 or 8 times since reset and the problem has a been consistent. Might be wishful thinking to hope that it will just go away....

 

Problem Solved!
When I fitted the new fuel rail pressure sensor I was careful to ensure that the vacuum line that goes from the sensor to the supercharger was properly attached at both ends.
I had forgotten that, for no good reason that I can see, this vacuum line has a joiner in the middle. When going over the wiring, connectors & looking for new vacuum leaks I found that this in-line connector had become disconnected...!
Plugged it back in, problem solved.

 

Hooray!