Just replaced my 77K engine (tensioners...) with a 31K engine (replaced the tensioners,water pump, etc.). Drove it about 200 miles, let it set for a week and drove it 20 miles and got the 072 trouble code (still ran fine). Local auto shop that read the code said I had a bad MAF sensor and dirty Air filter and wanted $801 to fix it. Having done some homework on this site I asked if they had cleaned the MAF sensor and they said it was really complicated and basically couldnt be cleaned. I picked up the car, drove it home 3 miles in fairly heavy rain (constant "Check Engine"), and changed the filter and sprayed the CRC MAF cleaner for about 5-6 seconds in both sides of the MAF sensor (removed from car). I let it dry for an hour and then reinstalled it. I noticed a crack in the vacuum(?) tube that ran from just downstream of the MAF unit to the top front of the valve cover, and taped it up carefully (and temporarily) with some high heat tape. I noticed a small amount of water inside on the bottom of my air cleaner housing (maybe a 1/4 cup) and then I noticed that the intake for the air cleaner could be reached from inside the wheel well opening through a softball sized opening in the fender liner. My car actually has two softball sized holes above one another in the front of the fender liner (??) that would seem to allow a lot of water and dirt to head straight up into the air cleaner intake! Are there supposed to be some filters or covers for these access holes? I cleaned out the canister, inside the MAF wasnt dirty to the eye - reassembled and the car runs great - maybe my imagination but ever so slightly better than before. I havent run it outside the garage as it is still raining heavily. My questions are?

1. Isnt 072 more likely a bad O2 sensor? Should I replace all 4 from a 77K engine that destroyed itself? ($400 minimum if I do it...)

2. The filter I replaced seemed a little damp - are those holes supposed to be there? Can I just rivet some plastic over them or are one or both necessary for air flow? How tough is it to replace the fender liner?

3. Just the MAF sensor without the cannister is $130 after core charge at O'Reilys. Should I avoid the remanumactured ones? Should I proactively replace it if my 072 code doesnt clear itself? How long should I wait or should I have it cleared?

Sorry to write a book but I'm not sure what isnt relevant. Really appreciate any thoughts!

 

I can't answer most of your questions, but the wheel well liner is EASY to remove and reinstall. There are a few different types of fasteners around the edge (plastic nuts, rivet screws, a torx screw, and two plastic rivets). Take out the fasteners and the liner will pop right out.

Mine is a few years newer than yours, but on mine there is a plastic "pipe" that goes from the "dirty" side of the filter box, protrudes through the wall of the engine bay and into the wheel well in front of the liner directly behind the headlight. I think it would be very difficult for anything to get sucked up into the pipe. Every time I open my filter box there are a few small leaves underneath the filter, but I've never seen water in there.

 

My "dirty" air intake is in the same place behind the headlight, which would seem a great place if not for the two gaping holes in my fender liner... I am going to see if I can find a liner that isnt outrageous $.

Thanks again!

 

I am not sure if your code is correct, do you mean P0172? If I am correct you can read what that code means on the attached Codes http://www.gusglikas.com/images/Auto...J27%201999.pdf Before you go any further you need to know the correct code. It is hard to troubleshoot on the internet and do not wish send you on the wrong direction.

 

Code PO172 - bank 1 too rich. Sorry I didnt mean to be inaccurate...

Thanks for the clarification!

 

Use the chart and look up your code and to the right you will see possible causes

 

MAF SENSOR

First check air cleaner and clean the MAF. You've done that. With engine up to normal operating temperature, turn the key all the way off, engine not running. Unplug the MAF and restart the engine. If the idle gets better, the MAF is bad. With the engine at idle, take your fingers and give the MAF a sharp rap, if the engine stumbles, the MAF is bad.

Look for codes like P0068 and P0100 through P0104.

 

From recent experience my suggestion would be to get the air filter and intake system straightened out first.

My car was throwing rich codes (both A and B Banks) and I experimented with a replacement MAFS but the problem turned out to be simply a clogged air filter. Once that was replaced the codes cleared and I tested the old MAFS and it worked just fine with the new filter.

If you can read the Gm./sec. output of the MAFS compare it to the chart in this thread:

https://www.jaguarforums.com/forum/s...ad.php?t=50607

IF you end up replacing the MAFS, my suggestion would be to replace the sending unit ($125) and not the entire assembly ($350). The A1/Cardone rebuilt unit carries the same warranty (12 Mos.) as the new ones that come with the intake assembly. (I couldn't find a new sending unit, only rebuilt ones.)

 

OH!!! I know what you're talking about now! I didn't realize that the holes were in the ACTUAL WHEEL WELL LINER. I thought you were talking about holes between the fender well and the engine bay. Look at the picture below. If those holes are the same as the holes in your liner, then you're missing a plastic cover that is inserted into the holes. Go look at the other wheel well. it should be there.

 

You also mentioned that the filter was damp. That is going to do unpredictable things to the fuel/air ratio, all bad. Replacement would be better than drying.

 

Thanks guys! I ordered a used fender liner headlight access cover which must have come off. I will try the idle at temp with MAF unplugged / sharp rap technique, but I cant imagine my idle being any smoother than it is now. I think the filter got wet through the access holes. Still wondering how much driving is necessary for the code to reset itself...

Thanks again!!!

99 XK8 77K/31K miles

 

Yeah... if that access cover was missing I can easily see how the road spray could be sucked right into the intake tube.

Replace the filter and cover the holes with duct tape until you get your access cover.

A wet air filter is going to greatly restrict your airflow. In fact, if the air filter is an older paper air filter and it is saturated with fuel and oil it can break apart and get sucked into the intake causing a blockage which then causes the engine to die. Then your airplane will crash into the trees and you'll end up in the hospital for a month. Trust me on this one... Oh! Never mind! We're talking about cars!

Still, get a new air filter and cover those holes. Take it to your shop and have them reset the code. If it comes back then you know you have a different problem. By the way, just about any auto parts store will reset the codes for free. Don't pay anyone to do that.

 

Who in their right mind would be that much of a tightwad and not change their air filter ?

 

I'd guess 3-5 drive cycles are required to reset the code. That doesn't mean start and stop cycles, a drive cycle requires specific parameters to be fulfilled in order to reset, like cold engine, warm engine, time above xx speed in x gear, etc. A quick stop by a cheezy parts store (i.e. stores like NAPA don't usually do this because they aren't trying to peddle low quality parts) to have it cleared might be easier.

And do yourself a favor, don't replace your filter with K&N or similar. They're no better than an oily t-shirt.

 

Ouch! https://www.jaguarforums.com/forum/s...ghlight=Survey

 

I suppose the fact that almost every OEM has issued TSBs against their usage means nothing?

I guess peeps still buy magnets to place around their fuel lines, even though they more than likely have an electric fuel pump in their tank that generates a stronger magnetic field. (but not for the same purpose)

Oh well, to each their own...

 

If paper filters are better, it seems like mammals would have evolved with paper filters in their sinuses. Instead, we have fine hairs covered with a sticky fluid. Just like K&N filters...

 

True, but we release the fluids every day so it stays clean!!

 

The access covers are available from these folks:

Direct JPLV Porsche Parts.com

$30 brand new. Good people to deal with.