My 98 Jag XK8 is running rich with check engine light and restricted performance message. Saw a video to suggest disconnect of the Mass Air Flow sensor as a test. If car quits running the sensor is running properly. If it keeps running, it is the problem. Anyone have experience with that test?

 

Thank you.

 

My plan is to install Genuine Air Mass Meter from Parts Geek and replace the air filter and replace the 8 seals on the Manifold and clean the throttle body. Will report results in a couple of weeks.
Part Number: W0133-1597921
Brand: Genuine
Notes: 100% New - Chas: -031302

• OEM Quality Direct fit Application
• Utilizes the factory style mounts, connectors and fittings
• Provides exceptional reliability
• Is the same product supplied by the automotive dealer
• Guarantees the same performance and quality provided by the vehicle manufacturer
• Guarantees OE quality performance, durability and fitment
• Is provided in the vehicle manufacturers original branded packaging

Condition: New
Shipping Options: Ground, Overnight, 2 Day
OEM

 

Do the earlier model XJ8's, have the same type intake manifold set up, & issues?
The 04 XJ8 has a different engine than the 1998 XJ8 does.
Don't know if they act the same, do check into this first

 

Hi wss25,

I have moved your posts from a thread in the X350 forum on lean running to start your own thread, since you have a different engine with different symptoms.

Before you spend any money on parts, please post all of the diagnostic trouble codes you scanned on your car, and if possible the fuel trims, and the knowledgeable members here in the X100 forum will try to help.

Note that leaking intake manifold seals will cause lean running, so replacing them is unlikely to resolve your rich condition.

Cheers,

Don

 

Have the obvious items been checked ? Like the air clearer element, etc ?

The shop manual lists the items needing to be checked for every trouble code. One can save a lot of time (and aggravation) by following the shop manual list of probable issues in the order given.

The manuals are available for download on this forum.

Z

 

I know this on a NA 4.0 2002 XK8... Initially, if the car is running, and you disconnect the MAF, the car will stall, pretty quick, pretty dramatically. Then, leaving plug disconnected, turn off the key completely and restart. It will start hard at first but go back to a rough broad factory setting and the car will run. It's not a fun or the right way to drive the car at all. Thing is, if it runs better than with the MAF sensor connected, then it tells ya you have a bad MAF. Replace it.

Also, carefully check the wiring of the MAF plug, both sides.

Please don't spend your good money on a generic MAF. It is a major information input into the ECU and running. Spend the money and get a good Denso sensor. I have had luck with doing a search for a MAF naming one of the many cars that use the same Denso sensor to save a buck or two (there is a list on the forum somewhere) but one ah the cheap generic alternatives is not your friend here...

 

1998 Jag xk8 99,000 miles.

My error codes are P0172 and P0175
Have replaced all four oxygen sensors, the tube from the air filter box to the throttle body, the air filter. Went from running lean on bank 1 to running rich on both banks 1 & 2.
My plan as announced is to replace the MAS, another air filer and clean the throttle body. Which I now believe I should have done when I did the above work. My check engine and abs lights come on. Engine starts and runs fine. after 20 min restricted performance and yellow light comes on.

And tips.

 

Denso search did not produce a MAS for a 98 jag xk8. Went to Parts Geek who said the Genuine OEM model MAS was the best currently on the market.
Part Number: W0133-1597921
Brand: Genuine
Notes: 100% New - Chas: -031302

• OEM Quality Direct fit Application
• Utilizes the factory style mounts, connectors and fittings
• Provides exceptional reliability
• Is the same product supplied by the automotive dealer
• Guarantees the same performance and quality provided by the vehicle manufacturer
• Guarantees OE quality performance, durability and fitment
• Is provided in the vehicle manufacturers original branded packaging

Condition: New
Shipping Options: Ground, Overnight, 2 Day
OEM

 

98 jag xk8 99,000 miles.
By the way, I have been a member since 2015, One of my posts in 2016 on the ABS problem had 3,000 hits..

Found this repair option on eBay. Sent my abs out to Module Repair Pro, 5911 Lemona Ave., Van Nuys, CA 91411,

Alex Shenderovich

(818) 235-1095

www.modulerepairpro.com
He gives a lifetime warranty.
Cost $49 at the time to rebuild at 73,000 miles. Can be expensive to pull out of the car and shipping both ways but still far less than the money they want for a new one.

 

Rich running can be caused by many issues, or a combination of issues. A stuck fuel pressure regulator, leaking fuel injectors, a stuck-open coolant thermostat, a failed or open Coolant Temperature Sensor (ECTS), weak ignition (how are your spark plugs?), a stuck-open purge valve, etc. Here are the listings from the DTC Summaries:





If your scan tool can view Live Data and you can see the coolant temperature, it's worth monitoring the coolant temp while driving the car to see if the temperature is getting as high as it should and to confirm that the thermostat is opening and closing. Also check the signals from the MAFS, IATS and TPS for plausibility.

Throwing parts at these kinds of problems can get very expensive.

BTW, many of us have repaired our own ABS modules by opening them up and re-flowing and supplementing the solder joints. Lots of info about this in the forums.

Cheers,

Don

 

Upon opening the air filter box, I found the filter off the proper location to interrupt the normal flow of air. It was a new filter, put it back in the holder properly and installed a new Mass Air Flow Sensor. Do not know which move corrected the problem, but in my opinion it was the air filter. Mass Air Flow Sensor had not been replaced for over 50,000 miles so it was due anyway. No more lights on dash. Should they reappear I will post again.