CoolumConst

I was driving home tonight and turned up the mp8 just a bit to see how timeing 2 was working. I did WOT once to compare and when I got off the throttle the rail pressure was staying up around 24k. Under light throttle, overdrive off at 1500rpm and 45 mph up a small grade the rail pressure was between 24k and 25k. I do not remember it ever being that high. A little more throttle to up speed to 50 and rail pressure went to 26k.
This does not sound right. It seems I am normally under 20k.
Smarty rail on #2

CoolumConst

It is doing it again. 9k at idle and very light throttle will get up to 22k at 1000rpm. Any ideas? Could this have anything to do with overfueling?

soulezoo

Where is your MP-8 set at? Sounds more like MP-8 than smarty.

soulezoo

7-8k @ idle is normal for 04.5 and up. With smarty on #2rp, 9k sounds just slightly high. Going straight to 22K with a touch of the throttle is no bueno.

CoolumConst

MP8 is maybe turned 10% usinge it more for boost fueling to keep the cel off. Not real sure what is wrong. 1500rpm at 40 mph rail is sitting at 24k.

RamWheelsBy4

What rail pressure gauge?? I have seen mine react somewhat like that, a few times over the year. After I shutdown and restart goes back to normal. Don't know whether mine is dorked EZ/TST/Smarty or gauge glitch.

BTW mine is a DiPricol. One of the first sold, so been on for a good while.

Spooler

Either a bad MP8 or your rail pressure sensor is on the fritz.

2007 5.9

Does the truck feel any different she you are getting high readings?
With RP that high, you're throttle should be über sensetive. Also with high RP at low RPMs you should get injector rattle.

If you have none of these, unplug the MP-8, and see what happens!

I am inclined to think you RP gauge my be on the fritz!

PhilR

My MP-8 will do the same thing. The adjustment seems pretty linear for the first 40% of the dial or so, and then it's like an on-off switch for max rail pressure at all times.

CoolumConst

Sometimes the truck runs great and other times it is very laggy and blows tons of smoke. I tried to do a boosted launch(could not get over 4psi) and burn out and had no luck just tons of smoke. Other times you barely touch the pedal around a corner and it spins out very easy. I will see if it happens again and what effect it is having. I do not get much rattle at all.

homewrecker

What kind of gauge? If it is 22k at 1000rpm there will be some crazy rattle.You say theres no rattle so I would think the gauge is not reading acurately.If the RP sensor is going out you should have a code.

CoolumConst

It is the Quad recon gauge.

homewrecker

Don't read alot of the quad threads but I think there were alot of issues with it messing up the RP sender.Maybe someone else will chime in or do a search.Have you tried removing it and driving the truck?

homewrecker

https://www.dieseltruckresource.com/...highlight=quad

CoolumConst

It happened again today and the only difference in the way it run is it overfuels under light throttle. If I am going 60 in overdrive I have to take overdrive off to accel or it just smokes.