All, I'm new at posting to this forum. I have a 2003 XKR 4.2L supercharged coupe SAJDA41B233A33059 I purchased with a blown engine for peanuts. Acquired a 'good, used' long block. Got the broken engine out, the replacement installed with new gaskets, hoses, new oil filter, new fuel filter, fresh oil and a new battery. The engine started right up, rough, wouldn't idle, oil pressure light went out immediately. Shut everything down, disconnected the battery and started looking for the problem(s). Manifold pressure line to the ECM was reversed with what I believe is the fuel pressure regulator signal line. Restarted the engine, smooth idle, good throttle response and a normal warm up. Took the Jag out for a maiden voyage. Excited and pleased until it began to throw the P0171 lean bank 1 code. A propane search for an air leak was futile and the code continues to pop up so I cant get over to the emissions station for that part of the registration process. Could sure use some help here, like a vacuum tube/signal tube diagram or some verbal path finding to get this very nice Jaguar back on the road.
TGman (Bob Grossman)

 

Offhand I would check the partlload breather pressure (vacuum) circuit for leaks. I am sure someone more knowledgeable will chime in. Good luck and welcome.

 

Did you drain the gas from the tank and fill with fresh? as people have had problems with "Restricted Performance" being given from old/stale gas. Though it does usually give codes P0171 and P0174 lean on both banks.
Can you check your short/long fuel trims?

 

You must be getting fairly close. Even quite a small air leak can cause a lean code and after the work done probably just a pest to find.

Engine hot, and if the car's had a chance to learn its own fuelling, LTFTs at idle then at about 2500rpm will reveal if you have a fairly typical air (vacuum) leak or something else (exhaust leak or whatever).

Some leaks (if it is one!) are a bit awkward to find due to their position (such as not where you're looking) or that they occur at odd times (valve that opens when you're not checking or a hose that flexes, etc).

If you need to, you can also get the "freeze frame" data i.e. what else was doing what at the time.

 

I can Daryl. I believe the last STFT trims were 25%. I don't recall the LTFT #s but I will get them sometime today. Thanks for the response.

 

If an engine's is reasonably consistent (but perhaps not within the designed specs) then STFTs migrate into LTFTs. The car keeps multiple values, for various speeds/loads, so it's usually best to let the values settle before paying too much attention.

Otherwise you have to kind of mentally figure where the STFTs & LTFTs are going.

 

You folks are awesome. I'll upgrade my post as soon as STFT and LTFT stabilize. Getting the XKR working was primarily air leak detection and repair. Three majors, full load vent tube (two severe cracks), MAF to inlet elbow not connected correctly (switched with fuel pressure regulator signal) and a biggie, one of the rubber doughnut seals between supercharger inlet and the throttle body got sucked into the passage. Correcting the above got the engine working nicely. I have two other issues (both electrical) that need resolution but will post under a new title later.