I recently had the transmission in my 1999 XJR rebuilt at a local shop. I picked up the car after the repair and everything seemed normal; the car ran great and the transmission shifted great. I drove the car for two days (no more than 20-25 miles) with no problems. However, the next time I got in the car, it was very difficult to start (felt almost like it was flooding) and once started, it would barely run. The car would not idle at all, and could only be kept running by feathering the throttle at higher RPMs. I managed to get it home (about 2 miles) and checked for codes with my OBD scanner, which gave the following codes: P0172 (System too Rich, Bank 1) and P0175 (System too Rich, Bank 2). I then drove the car (with difficulty) to my shop (about 2 miles) and put it up on my lift to check for anything that may have been misconnected during the transmission repair, but didn’t find anything obvious. I called the transmission shop and they said they would be glad to look and see if they had inadvertently hooked up something wrong or pinched a wire, etc., but I would appreciate any feedback regarding the next things to check before I try driving it to their shop again, as I am concerned that an over-rich condition may damage my catalytic converters. Ideas or thoughts, please?????

 

sounds stupid, but check that your mass airflow sensor is plgged in fully. when they took out the intake tubing and put it back in , then may not have snapped it in fully.

 

Also check the O2 sensor connections on top of the gearbox - they most likely got them crossed over or not connected.

 

Found the problem. Somehow the transmission shop broke off the rear resonance chamber that is molded into the air intake tube between the mass air meter and the throttle body. They taped it back on with black electrical tape, which worked fine on the short trips I made after I picked up the car. However, the last trip I made was apparently lengthly enough to create underhood temperatures sufficiently warm enough to cause the tape to come loose, thereby letting the broken part fall off and leaving a 1" diameter hole in the back of the tube. However, that part of the intake tube is normally hidden underneath the engine compartment trim panels, so the damage was not visible from above. Of course, the computer only saw a very lean condition with the extra air coming in through the hole, and added more and more fuel until the engine literally flooded itself out. For a temporary fix, I siliconed a plastic plug into the hole and let it set overnight. After reinstalling everything, the car started up first try and ran normally. I have ordered a new tube to replace the patched one.

I have come to this forum numerous times and always found other Jag enthusiasts who are willing to offer their time and experience to help me with various issues on my cars (I have three Jags at present). Thanks again for your responses and advice. I hope to be able to return the favor to yet another Jag lover.

 

not sure if this is my problem but have same codes after replacing the upstream o2 sensor on driver side...do you have a picture of the part you are talking about?

 

Have a read of this article-seems the problem was not the MAF sensor or even dirty connections. The guy found that the pins of the MAF were not actually properly touching the connector, so he bent the pins slightly to make a stronger electrical contact.

Running Rich - P0172 & P0175 | Jeeves and the Jaguar