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-   -   MDS in and out? EGR valve suspect? (http://www.jeepforum.com/forum/f67/mds-out-egr-valve-suspect-1825962/)

kookoo102 11-25-2013 02:43 AM

MDS in and out? EGR valve suspect?
 
So just got my XK not too long ago, and did almost all the basic maintenance. (all fluids/filters, plugs, pcv, o2 sensors) think thats all...
Was not till I did all this that I now notice the MDS goes in and out every 2-3 seconds... quite annoying. (on flat level surface)
Been reading on here that the EGR valve could potentailly cause this problem, Would this seem likely? No CEl or anything like that. Is there anything I can do to rule it out? Other then the MDS being annoying, jeep is running great.
Just put in the correct weight oil in, and everything to spec.

If I was to change this out... how in depth of a swap is this? I have no problem doing this, but because of my work schedule, I only have time to do this RIGHT before we leave for NY to visit family.
Thank you

kookoo102 11-25-2013 03:26 AM

Also, would anyone say no to getting a EGR valve from Advanced auto? Or is this a "stick with OEM" type of part?

And after an EGR swap, Do I need to do anything for learning purpose? Like disconnect the battery or anything of that nature, or just drive it?

90grandoneer 11-25-2013 09:17 AM

Yes, the EGR could cause the MDS to hunt. Do you have any of the MDS symptoms......erratic, (sometimes almost stalling) idle, surging at ~35-45 mph, and/or poor fuel economy and performance? Sometimes the EGR will be going bad and it will not throw a code. Before purchasing one, just make sure it's not a Chinese unit. A couple years ago, I bought mine from O'Reilly's and it's been fine. In addition to an EGR Valve tester, I also have a way to monitor mine onboard to insure proper function. Let us know what you find.

There is no learning process for the new valve and the job is not too bad. If you cut about 3/16 in. off the bolt that is hardest to get out (as I recall it is the inner one that hits the alternator), next time it'll be even easier.

Remember, among other things, the MDS is very load sensitive, so anything that causes additional drag (brakes dragging, low tire pressure, wheel bearings, racks, a lift, etc.) will have some affect on its operation. On the highway, mine is normally on in excess of 90%, but then mine is modified quite a bit.

msfulcher77 11-25-2013 11:31 AM

You said no check engine light, but you can have a code without throwing the light. Check codes with key dance or go by advance and let them do it. I would recommend advance since the key dance doesn't always show everything.

I replaced my EGR not long ago and it was pretty easy aside from cutting a bolt with a Dremel but still easy. Make sure they give you the gaskets with the valve.

I also replaced the MAP sensor. Pretty cheap and worth replacing...

kookoo102 11-25-2013 02:47 PM

I'm outside now, no access to a dremel... Therfore I guess can't be done without taking the alternator out? This sux. Just this one bolt left.
:(

msfulcher77 11-25-2013 03:13 PM

Quote:

Originally Posted by kookoo102
I'm outside now, no access to a dremel... There fore I guess can't be done without taking the alternator out? This sux. Just this one bolt left. :(

You can take one bolt out of alternator and loosen the pivot bolt and swing it out of the way I believe. I thought it was easier to cut the bolt but it can be done by moving the alternator. Remove the belt first...

90grandoneer 11-25-2013 05:33 PM

Quote:

Originally Posted by msfulcher77 (Post 18008586)
You can take one bolt out of alternator and loosen the pivot bolt and swing it out of the way I believe. I thought it was easier to cut the bolt but it can be done by moving the alternator. Remove the belt first...

When I did mine, I lucked out and didn't have to do anything to the alternator. Guess I just found the correct angle to get that bolt out. I did cut about 3/16 in. off the bolt and ground the small collar off the head of the bolt. Next time (if there is a next time) it'll be a super easy swap.

msfulcher77 11-25-2013 06:09 PM

Quote:

Originally Posted by 90grandoneer
When I did mine, I lucked out and didn't have to do anything to the alternator. Guess I just found the correct angle to get that bolt out. I did cut about 3/16 in. off the bolt and ground the small collar off the head of the bolt. Next time (if there is a next time) it'll be a super easy swap.

I did the same thing on the bolt I put back, but there was no angle that could allow the bolt to be removed on mine without cutting or moving the alternator. I could never be so lucky... :-/

kookoo102 11-25-2013 06:35 PM

Quote:

Originally Posted by 90grandoneer (Post 17997826)
Yes, the EGR could cause the MDS to hunt. Do you have any of the MDS symptoms......erratic, (sometimes almost stalling) idle, surging at ~35-45 mph, and/or poor fuel economy and performance? Sometimes the EGR will be going bad and it will not throw a code. Before purchasing one, just make sure it's not a Chinese unit. A couple years ago, I bought mine from O'Reilly's and it's been fine. In addition to an EGR Valve tester, I also have a way to monitor mine onboard to insure proper function. Let us know what you find.

There is no learning process for the new valve and the job is not too bad. If you cut about 3/16 in. off the bolt that is hardest to get out (as I recall it is the inner one that hits the alternator), next time it'll be even easier.

Remember, among other things, the MDS is very load sensitive, so anything that causes additional drag (brakes dragging, low tire pressure, wheel bearings, racks, a lift, etc.) will have some affect on its operation. On the highway, mine is normally on in excess of 90%, but then mine is modified quite a bit.

No other issues other then MDS going on /off like crazy. just figured this could be the origianl one.. and there really is not much else to potentially fix this. MPG has not been too great, but not expecting it too. 12mpg mix HWY/City. Was hoping for better, espcially after all new 02 sensors and everything else I just did.

I have a dremal... just dont have en extension cord.:thumbdown: I know what I need next.


Quote:

Originally Posted by msfulcher77 (Post 18008586)
You can take one bolt out of alternator and loosen the pivot bolt and swing it out of the way I believe. I thought it was easier to cut the bolt but it can be done by moving the alternator. Remove the belt first...

I will have to go for round 2 when I get back home. Unless it drives me completely crazy on the drive I may do it when I get to NY. (if I can find a warm place to do it)
If I had more time I might have gone as far as to swing the alterantor out of the way, but I had to get ready for work. I had enough time to only swap the EGR, if it was to cooperate.
We will see what my MPG will be before the swap on only HWY useage.

msfulcher77 11-25-2013 07:08 PM

Quote:

Originally Posted by kookoo102
No other issues other then MDS going on /off like crazy. just figured this could be the origianl one.. and there really is not much else to potentially fix this. MPG has not been too great, but not expecting it too. 12mpg mix HWY/City. Was hoping for better, espcially after all new 02 sensors and everything else I just did. I have a dremal... just dont have en extension cord.:thumbdown: I know what I need next. I will have to go for round 2 when I get back home. Unless it drives me completely crazy on the drive I may do it when I get to NY. (if I can find a warm place to do it) If I had more time I might have gone as far as to swing the alterantor out of the way, but I had to get ready for work. I had enough time to only swap the EGR, if it was to cooperate. We will see what my MPG will be before the swap on only HWY useage.

Try running 89 octane if you aren't already. Mine likes that better and seems to run better.

I know putting it in tow/haul mode disables MDS but I think only 05 WKs can still go in 5th in tow/haul whereas later models are limited to 4th...

Good luck.

Also, when did you last reset the computer with some of your maintenance? Mine seems to take a day or two depending on how much I drive to get the MDS dialed in again. You may find that it gets better as you go...

kookoo102 11-25-2013 10:04 PM

Quote:

Originally Posted by msfulcher77
Try running 89 octane if you aren't already. Mine likes that better and seems to run better. I know putting it in tow/haul mode disables MDS but I think only 05 WKs can still go in 5th in tow/haul whereas later models are limited to 4th... Good luck. Also, when did you last reset the computer with some of your maintenance? Mine seems to take a day or two depending on how much I drive to get the MDS dialed in again. You may find that it gets better as you go...

I have not reset the computer ( you mean unplugging the batt? ) I can give that a try.
I will fill it up with 89 and give that a go tomorrow, heading out for NY right as I get out if work.

90grandoneer 11-25-2013 10:25 PM

Quote:

Originally Posted by kookoo102 (Post 18014338)
MPG has not been too great, but not expecting it too. 12mpg mix HWY/City. Was hoping for better, espcially after all new 02 sensors and everything else I just did.

That's really not where it should be for mixed driving, especially with all the new stuff on it. Mixed should get you ~15-16 mpg and highway should bring ~17-19 mpg, stock. Let us know how you do on your trip, and figure the mileage using the calculator, not the EVIC.

Doing a reset may help, but I can't help thinking it's something else if it's that bad. I've never reset the PCM/TCM on either of my Hemi vehicles (over 9 years [60K] on my LX and over 4 years on the WK [87K]), and have never had any issues that would warrant doing it. How many miles are on your XK? Have you checked tire pressures/alignment and rolling resistance? How is the performance....does it run like a Hemi, especially now that you've done so much work on it?

One other thing....do you have the most current Calibration (CALID) files for your PCM/TCM?

kookoo102 11-25-2013 10:40 PM

Quote:

Originally Posted by 90grandoneer (Post 18021322)
That's really not where it should be for mixed driving, especially with all the new stuff on it. Mixed should get you ~15-16 mpg and highway should bring ~17-19 mpg, stock. Let us know how you do on your trip, and figure the mileage using the calculator, not the EVIC.

Doing a reset may help, but I can't help thinking it's something else if it's that bad. I've never reset the PCM/TCM on either of my Hemi vehicles (over 9 years [60K] on my LX and over 4 years on the WK [87K]), and have never had any issues that would warrant doing it. How many miles are on your XK? Have you checked tire pressures/alignment and rolling resistance? How is the performance....does it run like a Hemi, especially now that you've done so much work on it?

One other thing....do you have the most current Calibration (CALID) files for your PCM/TCM?


My calculation for MPG was not based off EVIC. XK has just under 85k and runs well. Had a 4.7 WJ prior, and it pulls harder then that. So I assume its where it should be power wise. Not to mentions its got some more lbs on it compared to the WJ. Tire pressure now as its 19 degrees outside is sitting at about 32 psi all around, was at 34psi for most that thet last tank full. I am looking to do an alignment when I get new tires right after the winter. Rolling resistance... no clue. I have no idea if it has the most up to date calibration loaded, I want to make a trip to the dealer for that, just have not had the time yet. im assuming there is a charge for it?

thanx for all the info fellas:thumbsup:

msfulcher77 11-26-2013 08:32 AM

Good luck on the trip. Report back your experience. I too am taking a road trip today. Hope all goes well. I've done a lot of work on it recently with little miles put on it... I'm taking tools just in case....

Btw, mixed driving I recently got a little over 14mpg and the city driving was a lot of stop and go. If it's mostly city like that, I'll get around 11, so far... But it's hilly here in the mountains... Kills mileage.

90grandoneer 11-26-2013 09:04 AM

Have you checked the throttle body/intake manifold plenum cleanliness? If it's real bad (which it probably will be if you haven't), you may also need to change the MAP Sensor. It is one of the primary inputs to the PCM for engine calibration. Also, I would highly recommend you get a catch can for it.


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