theskyisoutthere
Junior Member
Could a higher pressure oil pump cause issues with the MDS deactivation or reactivation and throw a code? 5.7 
So I posted on this before with the weird MDS deactivation issue code but it's not specific to one cylinder it was originally and we had a problem with a head gasket on that side It had a misfire on that cylinder anyway engine was cleaned up head gasket was addressed combustion chambers were checked all that stuff was done in the groundwork for making sure this thing's going to go back to work.
However there didn't seem to be any noticeable damage on the lifter and that misfire side one either intake or exhaust. Cam lobe looked great on that cylinder too and in fact it was moving properly It had the same movement as all the rest of them but it ended up being a head gasket leak a crack that was actually venting to crankcase down the lifter valley as well but just kind of a bullseye situation where it didn't go into the water jacket.
Machine shop I had look at it to see if we needed to do any major work I said they've seen the exact same thing happen before.
After having him check my heads over and check everything else and remove some broken studs from the heads this since he had them he said put it back together and run it.
Only when it's cold I randomly get a deactivation MDS code everything seems to be running fine but I get this deactivation.
I've talked with the machine shop guy who actually has built a lot of these engines of the late Mopar hemi, And he was kind of baffled so it's got to be electronic It's got to be something with the computer can you turn it off which if I turn it off everything's great If I run it and it throws the code it's still runs great because I think it turns off MDS at that point.
But I don't get a misfire or anything that would be detrimental to the engine.
Now here's the interesting part I was down at the machine shop with another engine, And the machine shop owners buddy was there and we got talking about my weird issue on this ram, specifically how it seems like it's healing as it's getting less and less frequent even when it's cold. He asked me if I've changed the oil pump. Of course it's got the same oil pump in it that was on the engine when I got it and we do know the engine's been replaced.
He had told me that he had some information personal information of using a different oil pump caused issues with the MDS. He had said it wasn't in a ram but it was in a Magnum or charger I forget which one but anyway it was in a car 5.7 hemi he said he ended up changing an oil pump cuz he suspected his oil pump was going bad and then his MDS system kept throwing codes on and off and on and off until his oil got to a certain age then it would almost go away.
He then asked me have I closely monitored my oil pressure gauge and of course I've always made sure it looks like it's in the center when I'm driving it You know to make sure it's not running out of oil pressure or starving for oil.
He said I need to pay attention to it when I start it up when it's cold just at idle see if the oil pressure seems really high because it's using that 5 20 oil anyway it should not be very high when it's cold because it doesn't get too much thicker. I'm going to include a running picture. It's not hot yes just starting to warm. But it's higher in cold start. Side note there's no crazy additives in the oil and the oil was changed about 300 or so miles ago by me with the proper oil I even sprung for some nicer grade I leave it with the Pennzoil platinum or ultra Platinum or something like that It was on sale at the local auto parts store but it was the higher end oil they had on sale. Also I'm running the Mopar filter.
Could there be any truth to his assertion that if I had too much oil pressure it could be allowing the MDS system to act funny and possibly either not deactivate or not activate or whatever is causing the code.
So I posted on this before with the weird MDS deactivation issue code but it's not specific to one cylinder it was originally and we had a problem with a head gasket on that side It had a misfire on that cylinder anyway engine was cleaned up head gasket was addressed combustion chambers were checked all that stuff was done in the groundwork for making sure this thing's going to go back to work.
However there didn't seem to be any noticeable damage on the lifter and that misfire side one either intake or exhaust. Cam lobe looked great on that cylinder too and in fact it was moving properly It had the same movement as all the rest of them but it ended up being a head gasket leak a crack that was actually venting to crankcase down the lifter valley as well but just kind of a bullseye situation where it didn't go into the water jacket.
Machine shop I had look at it to see if we needed to do any major work I said they've seen the exact same thing happen before.
After having him check my heads over and check everything else and remove some broken studs from the heads this since he had them he said put it back together and run it.
Only when it's cold I randomly get a deactivation MDS code everything seems to be running fine but I get this deactivation.
I've talked with the machine shop guy who actually has built a lot of these engines of the late Mopar hemi, And he was kind of baffled so it's got to be electronic It's got to be something with the computer can you turn it off which if I turn it off everything's great If I run it and it throws the code it's still runs great because I think it turns off MDS at that point.
But I don't get a misfire or anything that would be detrimental to the engine.
Now here's the interesting part I was down at the machine shop with another engine, And the machine shop owners buddy was there and we got talking about my weird issue on this ram, specifically how it seems like it's healing as it's getting less and less frequent even when it's cold. He asked me if I've changed the oil pump. Of course it's got the same oil pump in it that was on the engine when I got it and we do know the engine's been replaced.
He had told me that he had some information personal information of using a different oil pump caused issues with the MDS. He had said it wasn't in a ram but it was in a Magnum or charger I forget which one but anyway it was in a car 5.7 hemi he said he ended up changing an oil pump cuz he suspected his oil pump was going bad and then his MDS system kept throwing codes on and off and on and off until his oil got to a certain age then it would almost go away.
He then asked me have I closely monitored my oil pressure gauge and of course I've always made sure it looks like it's in the center when I'm driving it You know to make sure it's not running out of oil pressure or starving for oil.
He said I need to pay attention to it when I start it up when it's cold just at idle see if the oil pressure seems really high because it's using that 5 20 oil anyway it should not be very high when it's cold because it doesn't get too much thicker. I'm going to include a running picture. It's not hot yes just starting to warm. But it's higher in cold start. Side note there's no crazy additives in the oil and the oil was changed about 300 or so miles ago by me with the proper oil I even sprung for some nicer grade I leave it with the Pennzoil platinum or ultra Platinum or something like that It was on sale at the local auto parts store but it was the higher end oil they had on sale. Also I'm running the Mopar filter.
Could there be any truth to his assertion that if I had too much oil pressure it could be allowing the MDS system to act funny and possibly either not deactivate or not activate or whatever is causing the code.
