Isx oil pressure drops when let off throttle

[Rawze]

(12-14-2017 )Kevinb3373 Wrote:  A friend of mine did the tune on ecm. Per what rawse said on his delete video.


On the valve cover it just say isx 435st.

I don't recall ever making a delete video. In fact, I would never make a delete video.


=====

next,.... 18-20 psi at idle is normal for an ISX with 34-38 above 1000 rpm depending on oil temps. cummins spec is anything above 15 psi at idle.

If your oil pressure has fallen off then change the oil a second time and the filters. It very well may be all the carbon and crap from 700+k miles loosening up and clogging the filter. If that does not help, then its time to pull the rod and main bearings and replace them anyways at that age. Just some suggestions there.

=======
Making such drastic changes to an old engine with 700+k miles on it is very very risky.It is like asking grandma to suddenly run faster on the tread-mill and start breathing pure oxygen when she is already tired and worn down. The oxygen may help but will do likely her in much quicker. Some people get away with it but some just don't when they are old and you do that stuff. 700+k with EGR is like 1.2 mil without and all the carbon packing, soot-clogged cross channels, soot-packed components, soot-packed pistons, etc. can hide a lot of underlying problems. Doing such things to older equipment should be done by someone who can compensate for its age so that any kind of drastic changes like that are kind to the engine. Things like NOT turning up the power, replacing old sensors, re-adjusting the valve train, replacing rod/main bearings, testing the fuel system and injectors, + going through the engine to ensure there will be no problems from other worn out components.

=====

- I would suggest you have BOTH the engine AND the programming looked at professionally. Any kind of instructions your friend may have used is likely A. - out of date, and B. - Though it somewhat works for some trucks, any instructions that someone has used that I have ever seen was meant for people just trying to learn tuning and is no kind of final solution.

Getting it to Unilevers, Mr. Hag, or Gearhead to get it dialed in correctly for your specific model and make of truck would be the proper thing to do. Then also having the engine and truck inspected etc. to ensure there aren't any underlying problems about to cause a failure. Those ISX engines only last so long and some do, but very few actually make it much past 800 or 900k miles from what most people are reporting.