So I took on cleaning the throttle body and MAFS tonight, not a big deal, good write up in the FAQ, went just as it should, was very deliberate and careful, both were pretty dirty, used CRC throttle body and MAFS cleaners. Cleaned the MAFS first let it hang out on the work bench for 15-20 minutes while I did the rest to dry good. Put her all back together, fired her up, check engine light glaring at me. No amber or red warning light, running great, gauges are all on the money, just that glaring light! So after the speech from the wife about shouldn't #$%@ with it, pulled the negative battery cable hoping the computer would reset, put it back on and then drove it a little. Drives better than ever, but that light just glows. Does it just freak the system out when you clean everything up and it takes a few drive cycles to line out? I really think everything is closed up tight as far as air leaks and such, nothing broke or cracked coming apart, the snorkle and seals are all in great shape, oring on mafs etc.

Second issue is the part load breather, was going to see if it was cruded up, the other items indicate it probably is, but I wasn't sure about the catch/latch on it, not the "squeezer" I've seen in posts but rather a horseshoe looking slide, i think it's unlatched now, but wasn't sure so I didnt attempt to remove it for fear of breaking it, does the picture look like its ready to be removed, if not, how do you unlock it? This is how it was when I got to it

 

Maybe there was some residue that needed to evaporate off the MAFS. Try clearing the code with an OBDII scanner and see if it comes back. If it persists, read the code and let us know what it is.

 

Well happy to report it cleared itself just now after 4, 5? cycles of driving.

Any thoughts on the breather clip, I assume pushing in locks it on so it's ready to come off in the picture.....

I'm really confused on code readers, I want to buy one, I know OBDII but would like to be able to read trims etc, have seen something about a bluetooth/phone app combo but haven't found anything about where to get the hardware portion of it. What do you guys recommend?

 

Not familiar with that clip...my car does not have it.

The bluetooth scanners are on ebay:
obdii bluetooth | eBay

Also see the scanner thread:
https://www.jaguarforums.com/forum/g...-%2A%2A-33347/

 

I ran across the same situation after changing my aux. pump on the S/C intercooler. I took the air cleaner enclosure out along with the MAFS. Got a CEL and found codes P0102 (MAF) and P0102 (Air flow circuit-low input).CEL reset after driving a couple of times. I didn't have to clear the codes for the CEL to reset. All is good.

 

I was going to suggest letting a few drive cycles determine if the CEL would clear, as out of parameter fuel trims will clear themselves if corrected and 'adjusted' over time. The sudden cleaning through off what the ECM was used to seeing as far as air was concerned, and probably went the total opposite direction on the short term trims (probably went RICH if you were monitoring it live upon starting) and triggered that temporary CEL. Feels good to make an improvement with your own two hands doesn't it?

Be sure to let the wife know she should have a little more faith in your repair skills..lol. Give her the technical reasons why it happened, and maybe she'll be impressed - good things happen when women are in the presence of an apparent genius. <- wink x2

not sure about the horseshoe on that breather stub...have not seen that before, but I've only see one other 4.0 engine to compare it with. Is it integral with the 'squeezer' connector, or is it just wedged in there to keep a tight seal of the connector to the stub?

 

The bigger breather on the air cleaner side is the typical squeezer, but the load breather on drivers side has the horseshoe clip, it is able to slide in and out, would think it lokcs in and would be in a groove to hold the hose on, but the stem it is sliding on is smooth, doesnt look like it does anything, but it has to have a purpose! Guess I'll have a little liquid courage and go out to the garage and pull it off, worst case, I can get the wife's key cut while Im at the dealer buying the new fitting!

Question on the throttle body, when I had her full open, down on the floor if you will of the throttle body/intake, there was a small amount of what looked like new motor oil, not much, not sure it was oil, but thats what it looked like, is it possible to have oil there or is it just stray fuel gum or something?

 

The horseshoe clip is a bit tricky. You would think that with it loose as it is in your pic that the breather tube is ready to come off. It is exactly oposite of that. Push in on the clip very hard using your thumb & gently pull up on the breather tube when it is pushed in as far as you can & it should come right off off. And you will need to push on it again when putting it back on. Hope this helps before you had a chance to break it

 

I can tell you that my TB lower surface is covered in what looks like my mom's bbq chicken - charbroiled! I think on the 4.0, if there isn't any oil in your air pipe leading to the TB, that won't be oil in the TB. I may be wrong though, my driver side manifold leads back to the top of the TB on the air pipe, my passenger side, off the positive crankcase valve...that goes to the TB below the butterfly. I also couldn't really rub off any of the charcoal, and didn't want to 'chip' anything off, so cleaned what I could on the butterfly and sides, and moved on.

good tip on the horseshoe clip...hope it wasn't too late! Logically, who would push it IN to release? not me!

 

Didnt get around to it last night, laziness set in, so will try tonight. It seems the o-ring or whatever it sits in is very brittle, you can see in the pic that a little oil is able to seep around this thing, can it be changed without taking the valve cover off? I hate that the end of the bank looks so greasy and ghetto.....