Good morning everyone, I pray all is well. I have a few issues that I need assistance with and I would greatly appreciate any help given. Okay issue number one..... Most often when I crank the vehicle there are no lights on in the dash, but when I start driving, a few moments later the check engine light comes on. No change in how the car drives or runs but the light comes on and I get the following codes.....P0101-00 Mass or Volume Air Flow-Circuit Range/performance, P0171-00 System to Lean (Bank 1) and P0174-00 System to Lean (Bank 2). The second Issue is this....... Before my uncle gave me this car, he said it was leaking water around the driver side door. He had the leaks repaired before giving it to me. Now that it has been repaired, the windows are no longer operating. The red indicator light on the window switch cluster lights up red as it supposed to so it is getting power to the switch. I changed the window switch and the door control module but the windows will not operate at all. Any assistance with either or both of these issues would be greatly appreciated.

 

Hi Jag Dog,

I'm traveling and typing on my phone, so my reply will not be as detailed as I would like.

The most common cause of lean codes is one or more leaks in the air intake plumbing between the Lass Air Flow Sensor and the intake manifold gaskets or in the crankcase breather system. Look for oil leaks since anywhere oil can leak out, air that is unmetered by the MAFS will be inhaled under Engine vacuum.

Regarding the windows, it would be worth checking all the fuses, since the windows regulator motors may run on different power circuits from the switch indicator lights. You can download the Electrical Guide at jagrepair.com

Cheers,

Don

 

Good evening Don. First off I pray you made it to your destination safely. I want to say as it relate to the windows, I did check all fuses. I will try this again to be sure I didn't miss anything. As for air leak in the plumbing from the mass airflow, I tried this also. Are you aware of any place that I might be able to purchase a new one?

 

Hi Jag Dog,

We made it home safely - thank you for your prayerful thoughts.

Regarding the windows, you stated that they stopped working after the driver's door water leaks were repaired. Is it only the driver's door window that is now inoperative, or all of the windows?

You can download the wiring schematics here:

Jaguar XJ Electrical Guide 2006

Regarding intake air leaks, there is not just one component you could replace. Any leak in the system between the MAFS and the intake manifold gaskets can cause lean running. Common leak points include the main plastic air intake pipe from the MAFS to the aluminum intake tube, which can develop cracks in the accordion folds and the Helmholtz resonators, especially the cylindrical resonator on the underside of the pipe where it is ultrasonically welded on. Other leak points include the aluminum intake tube gasket at the throttle body, the throttle body gaskets, the supercharger gaskets, the induction manifold gaskets, the intake manifold gaskets, the camshaft cover main gaskets and spark plug tube gaskets, the oil filler neck and cap gaskets, the breather tubes and the O-rings inside their Norma connectors, the crankcase vent valve itself ("PCV valve") and the two O-rings on its stem that fit into the cam cover, the oil dipstick tube gasket and dipstick gasket, the brake booster vacuum pipe, etc. A knowledgeable technician will inject smoke into every available access point to locate leaks. As I mentioned, anywhere you can see oil seeping out, unmetered air is getting in.

You can view exploded parts diagrams at parts.jaguarlandroverclassic.com to see parts related to the air intake. You'll have to view several different diagrams to see all the parts and gaskets.

Other possible causes of lean codes in both banks include a failing MAFS or a weak fuel pump. Contaminated fuel can cause lean codes but will usually also cause misfire codes. Possible causes that are bank-specific include obstructed fuel injectors and an exhaust manifold gasket leak. It would be unusual to have these occur on both sides of the engine simultaneously.

P.S. I edited your thread title so other members will know the nature of the assistance you are seeking.

Cheers,

Don

 

If you have lean codes you have leaks... except if the MAF is not sending an accurate signal to ECM. So I would first resolve the P0101 codes and make sure that the MAF is sending an accurate signal. Once you know that is correct, if you still get lean codes you're next step is to perform a smoke test. You'll need something like this:


You should search the forum for threads on how to properly do the smoke test, and you'll save yourself from "throwing parts at the problem" which is easy to do. Warning, you may have more than one leak, and smoke will appear at the path of least resistance first. So once you fix one o-ring, gasket, etc., you'll want to again perform a smoke test to make sure you have everything buttoned up.

 

Good afternoon Moderator Don, thank you for updating my thread topic. Also thanks for all the suggestions to assist. As for the windows, none of them work. The Sun roof is the only thing that opens to provide some fresh air. I have a buddy who is a mechanic and he has one of those smoker things that you can put the smoke in it. So I will get up with him and try the smoke test. Thanks once again.

 

Thank you Mac Allan, I will get with my buddy who has one of those smokers and put smoke in and see what we find out.

 

One thing to be aware of is that some smoke machines are regulated to an output pressure of just 1 psi for use in testing Evaporative Emissions Systems, which can be damaged by excessive pressure. But to test the engine air intake components, higher pressure is better. I typically use at least 10 psi, and sometimes as much as 20 psi.

Your mechanic friend will probably know this, but you do not want to subject the MAFS to the smoke, so remove it and plug or seal its port with duct tape held down with your hand as you pressurize the system. Also, when injecting smoke into the main air intake pipe, be sure to first prop open the throttle butterfly plate with a plastic trim tool or some other object that won't scratch the throttle body or fall into the intake manifold.

I inject smoke at the main air intake pipe with a large rubber cone adapter, then also inject smoke at the crankcase vent ("PCV valve") port, each end of all breather hoses, the brake booster vacuum hose, the oil filler neck, the oil dipstick tube, etc.

Cheers,

Don

 

Not a suggestion, but commiseration. I, too, had lean codes on both banks of my 03 XJ8, and eventually had to replace just about all of the airflow pieces as well as the MAF (twice). The first MAF was an aftermarket one that turned out not to be good enough despite being rated for the car. It took almost a year and numerous smoke tests before all the leaks were found and fixed.