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-   -   5.7 MAP sensor (http://www.jeepgarage.org/f183/5-7-map-sensor-33888.html)

dmsfun 01-11-2012 10:58 AM

5.7 MAP sensor
 
I just recieved a new MAP sensor and PCV valve from Rockauto, and got the earlier 5.7 MAP sensor, same length as the OEM and without the lip. Trying to remove the OEM one, it is supposed to unscrew 1/4 turn, but there is a vertical post in the way. ?? I can't see what the function of this post would be, and why it is even there. Is there some sort of trick to removing the sensor, as the manual just says to unscrew it. I asked the dealer and they said they don't now, and they only have a larger than OEM replacement sensor which requires modifying the intake to fit.

Escape 01-11-2012 03:56 PM

Re: 5.7 MAP sensor
 
Oh man I know your pain!

Remove the post on the far back NOT the one on the passenger side of it, it's still a PIA to get out but it makes it a little better and actually possible. Best if the plastic is warm also.

Pics below.

Back tab removed MAP out.
http://i41.photobucket.com/albums/e2...F/IMG_0147.jpg

MAP inserted
http://i41.photobucket.com/albums/e2...F/IMG_0146.jpg

MAP inserted
http://i41.photobucket.com/albums/e2...IMG_0144-1.jpg

Map turned into position and good to go
http://i41.photobucket.com/albums/e2...F/IMG_0143.jpg

mrtosh 01-11-2012 05:42 PM

Re: 5.7 MAP sensor
 
There is a revision and instructions on the newer one's from the dealer where it states to cutoff both the rear tab and side tab. The aide tab needs to be made flush with the MAP mount. Also be prepared to give some elbow grease to get the sensor to snap/turn into place. The new OEM sensor has a considerably bigger head and has to squeeze past the rear intake runner and snap into place.

dmsfun 01-12-2012 10:00 AM

Re: 5.7 MAP sensor
 
Quote:

Originally Posted by mrtosh (Post 550657)
There is a revision and instructions on the newer one's from the dealer where it states to cutoff both the rear tab and side tab. The aide tab needs to be made flush with the MAP mount. Also be prepared to give some elbow grease to get the sensor to snap/turn into place. The new OEM sensor has a considerably bigger head and has to squeeze past the rear intake runner and snap into place.

The dealer only sells the newer, larger MAP sensor that required the modifications; Rockauto and other sources sell both the early, smaller ones (which I bought) and the larger later ones.

dmsfun 01-12-2012 10:05 AM

Re: 5.7 MAP sensor
 
THanks for the pics, Escape; so to remove the drivers side post, did you just cut if off, and the sensor will then twist in and out of place ?

Escape 01-12-2012 02:49 PM

Re: 5.7 MAP sensor
 
Quote:

Originally Posted by dmsfun (Post 551076)
THanks for the pics, Escape; so to remove the drivers side post, did you just cut if off, and the sensor will then twist in and out of place ?

Just snap it off. It's still quite a PIA to twist into place though. You will become very fluent in profanity while doing this repair!

There is a lot of stuff back there you don't want to hunt so becareful (fuel line, engine harness, vac line, ect)

dmsfun 01-16-2012 03:10 PM

Re: 5.7 MAP sensor
 
OK, so I wAs able to remove the OEM MAP sensor by prying the drivers side post back with a large screwdriver while turning it. THe replacement one is a Wells unit from Rockauto, and it is slightly longer on both ends, so ended up having to cut both plastic vertical posts off to get it on. Results are well worth it. THe hemi idles smoother; there was a small vibration felt in the steering wheel at idle which is gone; also runs quieter and throttle response is immediate with no delay now. When MDS kicks on, it is much smoother and quieter now.
So, I replaced a number of things one at a time, to see whcih one made a difference and here are the results. There were no codes thrown, which the dealer and most mechanics will tell you you don't need anything and they can do nothing unless you see one, which it BS.

First, replaced the EGR; $40 from Advanced auto; made for an improvement in dirvavbilily, smoother operation, better idle and tip in throttle response.

Second, replaced the PCV valve; $23 Rock Auto; also improved throttle response, and the catch can barely gathers any fluid now; about on eounce in a month (wintertime), where it was collecting much more with the orignal one.

Third, replaced the MAP sensor; $24 Rock Auto, and she really hums now.

I have 72k on the OD, and would highly recommend replacing all these at the 60k mark for the Hemi; total cost for parts was under $100.

ChrisWk 01-16-2012 05:21 PM

Re: 5.7 MAP sensor
 
So what did the old one look like, was it bad looking? What did you cut to make it fit.

Thanks

dmsfun 01-16-2012 06:25 PM

Re: 5.7 MAP sensor
 
Quote:

Originally Posted by ChrisWk (Post 553964)
So what did the old one look like, was it bad looking? What did you cut to make it fit.

Thanks

It looked like new with no dirt or oil anywhere. You have to cut off the two vertical posts made of plastic that surround it. It is a PITA to reach; I'm 6'7 so could reach it standing on the ground, but most will need a stool or something.

greenwayer 08-07-2013 04:57 PM

Re: 5.7 MAP sensor
 
Quote:

Originally Posted by dmsfun (Post 554002)
It looked like new with no dirt or oil anywhere. You have to cut off the two vertical posts made of plastic that surround it. It is a PITA to reach; I'm 6'7 so could reach it standing on the ground, but most will need a stool or something.

I removed mine today just to see how it looked and also couldn't understand why the hell I couldn't remove it until I saw this thread. I snapped of the tab like you did with a screw driver, I'm a bit shorter than you 6'4" but didn't need a stool either, but it wasn't dirty at all. Should I replace it anyways?
My jeep has 105k miles on it

johngreen1234 01-04-2014 03:08 PM

Re: 5.7 MAP sensor
 
I just did this, and thanks to this thread and a couple others, didn't break anything except for the bits I meant to break. I drove her around for an hour, checked for codes, and it looks like it really helped!

As the OP said (and I have disagreed with some of the OP's claims in the past), the hemi idles smoother and accelerates with much less hesitation. Moreover, when I checked for codes I noticed that a nagging P-code for incorrect oil viscosity had cleared.

Here are my tips:

1. Plan on breaking BOTH tabs. The sensor needs to rotate just past 90 degrees to clear its internal threading, and life is just too short to fight with the little tab. It doesn't need to be a clean break because the sensor will have risen up on its threading. As said, a little pry with a screwdriver will do it.

2. My experience was 100% curse-free, which really scared me once I had finished. What was it I had forgotten? Apparently nothing. And believe me I've got huge hands, and the dexterity of an angry elephant. If I could do it anyone can!

3. Take some time to scout out the workplace. The pix in this thread REALLY helped, as well as everybody ranting about what an asterisked-up task it was. I went slowly and was done in twenty minutes, and all but 30 seconds was spent going "really? really?" until I'd gotten the courage up to go ahead and break the back tab.

4. Once you find the tabs, carefully lift the vacuum hose up and over the tabs before you got at them. The back tab is fairly high, maybe 2 inches, which isn't clear in the pix. I went at it from the Passenger side, using a long screwdriver to lead the sensor around. The tab broke just under the screwdriver.

5. Once I'd broken the first tab, I lowered the hose down below the snsor so I could rotate it and see that the other tab had to go, or else my sanity would. Once that tab was broken the thing popped out like a used gerbil, and it was easy enough to replace.


I haven't driven enough to give an MPG report, but over the last month I'd noticed my mpg's falling, and wasn't sure if the dealer had messed something up. Finding the oil visc code only raised the paranoia level. But as I said, I noticed IMMEDIATE benefits, and I am optimistic regarding mpg's. We'll see!

johngreen1234 01-07-2014 05:44 PM

Re: 5.7 MAP sensor
 
UPDATE:

Got my first early feedback on MPG since the MAP service, and I am +2 MPG since doing the service. Immediately prior to the swap I was getting right around 14 mpg driving a rural mix, low enough to be alarming. 144 miles since the service and I put in 8.852 gallons, for an avg MPG of 16.27, much more typical for this driving.

With that in mind, I would expect to get around 18 mpg on my highway roadtrips. Again, based on gallons at the pump and not the EVIC.

BOTTOM LINE: I would recommend swapping the MAP sensor to anyone experiencing a sudden drop in MPG. For me, it was so sudden as to suspect a brake was dragging. Also, when waming up in the morning I was smelling a VERY rich mix coming out the exhaust.

Thanks to all!


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