I've stumbled into something I could use some advice on. The engine is still slipping into Engne Failsafe Mode and there are pending codes indicating a long term fuel trim "too rich" condition for both banks. Could be the Mass Air Sensor.

I see that there are Mass Air Sensors (Rebuilt, A1-Cardone P/N 642-05080114 interchanges with Subaru and Mazda) for about $100. It appears to be the sensing unit only:

http://www.partsgeek.com/catalog/200...ss_sensor.html

Then there are Mass Air Meters (OES Genuine P/N W0133-1598418) for about $300. It appears to be the sensing unit and housing.

http://www.partsgeek.com/catalog/200...ass_meter.html

What's the story here? Does the sensing unit separate from the housing easily? Anyone have experience with rebuilt sensing units?

Thanks!

 

Yes the sensors come out of the housings with 2 screws, and no info on remanned. But why dont you be the first and report back

 

I'm going to reseal the MAF sensor housing just to make sure that's not the problem. It it persists I'll replace the sensor.

I used to be in the remanufacturing buisness (old school carburetors) and it was pretty straight forward when there were springs to replace, orifices to clean and bushings to press.

What the heck is there to remanfacture on a MAF sensor? There are some fragile connections I guess, and some sort of coating that could perhaps be reapplied...

There must be something because they want a core in return.

If I didn't mention it, the Jag part (sensor only) interchanges with a couple of late model Subaru and Mazda engines.

 

I wouldnt try 1 from another car, theyre calibrated to what they supposed to be on. Like putting a quadrajunk off a 454 onto a 350. Yeah theyll bolt and and run, but not right. Sealing that housing does nothing, if it leaked it would be a lean code not rich, look at the fuel regualtor or the vacuum line that goes to it. The lines tend to break when old and that will give a rich condition cause it ups fuel rpressure like your foot is in it. Thats where i would start

 

Hmmmm...good point avbout the leak and lean vs. rich. I replaced the FPR a few months ago with a new OEM one, it's probably not that. BUT, I intended to replace the vaccum line because it was dry but forgot about it until now...

Once again, 6" of 10-cent hose might save hundreds of dollars in sensors. I'll report back.

About the sensor, the same part number is called for in all the vehicles...but I agree with you in prinicpal.

 

Have you tried cleaning it with electronic spray cleaner? See the FAQ on that. Just spary the tiny wires inside..don't touch them. Maybe if it's dirty it's not reading all the air coming in and telling the computer to richen the mixture as a result...just a guess.

 

Scott, do you know what NEW means?
N ever
E ver
W orked

I just got burned on a new door module after programming took out 1, and then the NEW one was bad out of the box and exhibited the same faults. But made me doubt my own diag the first time and I wasted lots of time checking everything else out, and when in doubt I believe in using known good parts from another car. Something that Jaguar has recently last year sent out bulletins and said under NO circumstances are we to swap modules or parts.....So after I spent days, was told by hotline that I had a wiring issue( I doubted cause everything worked fine before programming) finally our field engineer came in and spent 4-5 hours with me, and in the end we swapped a known good door module in and voila' worked perfectly again....lots of wasted time....

 

Yep, it's clean. Thanks

 

Brutal -

Ouch! Swapping with known good parts works fine. Just find the exact replacement. I would expect a lot of electric components look and fit the same but are internally different.

My guess is that Jaguar isn't making the MAF sensor themselves, they are buying them from Delphi or some other electronics manufacturer and putting them into their hose fitting assembly. Oddly, I can't find new sensors in my casual online search, only remanufactured ones, even though the P/N is also specified for late model cars...

Meanwhile, I'm going to replace the vacuum hose on the FPR and hope for the best there. Simple things first, thanks for the advice.

 

This is interesting. The OEM new product offers a 12 month warranty. The A1 Cardone remanufactured product offers a 12 month/18,000 mile warranty.

http://www.cardone.com/English/Club/...assAirflow.asp

I guess they are pretty confident. It's an interesting website to poke around on.

I removed the FPR vaccum hose - dry but not split. I'll replace it today. When the snow around here gets below waist high I'll give it a try.

 

Update - cleaned the MAF, checked the plenum for tight fit, looked at the brake booster seals, replaced the FPR vaccum hose, and checked the full andn part load breather hoses - all OK. Still get the Failsafe message BUT NO CODES ARE CURRENT OR PENDING.

As a thank you for all this, it gives me a Restricted Performance message with a P0351 code: Ignition (A1) primary/secondary circuit malfunction.

I'm going to leave this thread and open a new one with that issue...

 

P0351 is bank 1, cylinder 1 coil failure, thats front coil passenger side u.s.
and that does give restricted performnce too

 

Ah Ha! Let me go down that path for a bit...I'll report in later.

 

Well, while you guys are on the topic

I have a 99 XK8 Conv and have both rich codes (PO172, PO175) as well as P1637. I also have not confirmed whether I have a MAF issue or a bad FPR but hope to troubleshoot soon (it's crazy cold here in VA). One thing that is interesting is that most each morning lately (cold weather) I start the car and it sputters for a couple minutes, stalls out, etc. Chokes, smells like gas. Once I warm it up for a bit and drive away, it settles down and runs great for the rest of the day. Then, on occasion (every few days) the CEL will come back on, same 3 codes and restricted performance. Then the RP status will go away on it's own, CEL still on, then that goes away too. I'm not sure if the randomness of the "coming and going" of those issues, along with the "cold start" issues in the morning shed any light on my particular issue, but I know this is the place to get some solid input! I'm thinking the fuel pressure regulator may be the root cause, but who knows. Thanks in advance....

 

Blast20 - Changing out the FPR is probably a good idea, I had similar issues that resolved themselves whan I replaced mine. It's kind of pricey at $140 as I recall, shop around.

While you're at it, change the vaccum hose as well. $3 worth of hose is all it takes.

Good luck

 

Will do Scott - I figure with the age of the car and the fact that many say the FPR goes bad at some point, it's good to do either way. I'll replace that hose as well. Did you ever have the P1637 code by chance when you had issues? Some sort of CAN BUS fault....I understand by viewing other posts that it could be a number of things, but just curious if you had that come up as well. Thanks -

 

Blast 20 -

P1637 = CAN Link ECM/ABS Control Module Circuit/Network

Probably unrelated to the FPR issue. It's some sort of communications issue between the EM and ABS Control Module. Start with the easy stuff - is your battery 100% what with the cold weather and all? (I get ABS/TRAC warnings when my battery is a little low fron sitting for days. They go away after it gets a good charge to it.)

The early CAN/BUS system on 10 year old cars is pretty primitive and sensitive to less than perfect conditions. When it's unhappy it will trip a lot of codes and gets people chasing their tails.

Separately, the ABS unit seems to have a definate lifetime which both you and I are probably at the end of - there are great threads on the forum about repairing it. In the absence of anything else, I don't think P1637 is telling you that, yet.

Changing the FPR is easy, a 10 year old Girl Scout could do it. It's easy to reach and you can do it in the cold if need be. Get to the hose later...