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NebularMan 01-31-2010 09:49 PM

5.7 Hesitation MDS
I have been finding that when the MDS goes from 4cyl to 8cyl it sometimes hesitates for a second when depressing the gas pedal as if the engine was going to shut off. It does not happen all the time but seems it could break something when it clunks. Any thoughts on what this may be or a fix? Thanks!

Scottina06 01-31-2010 09:58 PM

Re: 5.7 Hesitation MDS
are you using 5w-20 oil?

Marlin 01-31-2010 10:05 PM

Re: 5.7 Hesitation MDS
It won't break anything, it's just an annoyance.
As Scoott says, you need to be using the correct oil for it to work most efficiently, mine specifies 0W/20, but with it only available genuine here in Oz (too expensive) I've been using 5W/20 with only slightly less responsive MDS function

NebularMan 01-31-2010 10:28 PM

Re: 5.7 Hesitation MDS
Well since I am on a Jeep dealer oil change I am not certain since I just picked up my WK last week (bye bye WJ). I will make sure it is 5/20 when I get the oil changed then see how it goes. It almost feels as it the engine is going to shut off, kind of annoying especially when you want to show what the hemi can (can't?) do.

eerattler 01-31-2010 10:31 PM

Re: 5.7 Hesitation MDS
I've noticed it too, and there is a whine that goes along with it when I think it flips back and forth from 4 to 8...

Marlin 01-31-2010 11:44 PM

Re: 5.7 Hesitation MDS
I think both of you may have issues besides the MDS delay......

08Hemi 02-01-2010 10:38 AM

Re: 5.7 Hesitation MDS

So what speeds are we talking here? I know that when i am going 50-60 and have been in FSM for a couple minutes there is def a delay when I punch it, but it doesnt feel like it is going to shut feels like 4 more cylinders are engaging.

If you ever want to show what the HEMI CAN do, then drive in will eliminate MDS while showing off :)

jeepgcoman 02-01-2010 07:40 PM

Re: 5.7 Hesitation MDS
Many, many dealers use bulk 10W-30 or 10W-40 unless you specify. I think one of their motives (beside it being cheaper for them) is that it will cause problems like you're having and then you'll take it back for them to screw something else up and charge you for it. Sorry, I am not a big fan of dealers, although I know there are some good ones out there....just not many from what I've heard/seen. If you didn't specify or watch them, bet that's what they did. I bought my WK GCO about 4 months ago and the dealer was proud to announce that they had done an oil change for me. After looking at the paperwork, they had put 10W-30 in it. As soon as I ordered and received my Fumoto Drain Valve I changed the oil/filter and put the right stuff in it. Works much better, but be aware, as said above, it will still have the "bump" coming out of MDS sometimes. Also, the WK MDS doesn't work near as well as it does on my LX Magnum. Much more sensitive on the WK, but I think some of that is caused by wind and drivetrain drag. A Superchips tuner will do a lot to make it quite a bit better.

Marlin 02-01-2010 08:11 PM

Re: 5.7 Hesitation MDS
What I meant was neither of your problems sound truly MDS related to me, especially not when you start mentioning abnormal noises etc....... I wasn't being cheeky ;)

HemiJeep4x4 02-02-2010 05:40 AM

Re: 5.7 Hesitation MDS
Use Royal Purple 5/20 weight motor oil and not only will you Jeep Engine love it but you should see about a mile and a half increase in you fuel economy over that crap oil at the dealership.

LTrainGC 02-02-2010 07:50 AM

Re: 5.7 Hesitation MDS
Get a superchips or predator and disable that garbage.

NebularMan 02-02-2010 09:32 PM

Re: 5.7 Hesitation MDS
It kind of reminded me of when my crank/cam sensor went on my 99 but only for a split second. It has not happened since and I have stomped the pedal real good. Damn that 5.7 goes! I bet the 6.1 is amazing, was drooling over them at the dealer today.

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