Fuel Pressure, Rail Pressure Gauges
From : craig christian
Q: mounting will be a 3 pod dash mount. i want a tranny temp pyro and i thought a fuel pressure gauge. however the guy doing the install feels that i would be better served with a rail pressure gauge since the pump issue in my model ram is no longer an issue at all. would like opinions ... i thought about a boost gauge but cant really think of what that gauge gives me that i cant tell without it. first while its true the 3rd gen trucks lift pumps were more reliable than previous years and the cp3 pump is much more tolerant of lower fuel pressures dc felt that the lift pump was still enough of an issue that they re-designed the low-pressure side of the fuel system and re-located the fuel pump inside the tank. there have still been reports of lift pumps failing even on the 3rd gen trucks. while this doesnt automatically trash the injection pump like it used to in the vp44 days its still not a good thing for the cp3. yes the cp3 has its own small gerotor lift pump built in which in other applications draws straight from a fuel source no aux. lift pump but thats just it - its not trying to suck fuel through a locked-up electric lift pump in those applications. imo a fuel pressure gauge is still useful. i use mine all the time to judge when its time to change fuel filters i notice the drop-off in pressure meaning the filters getting more loaded up with gunk. a rail pressure gauge is really just a gee-whiz kind of gauge unless youre planning on playing around with your fuel pressure to get more power out of the engine. thats a whole nother story then - and in that case yes a rail pressure gauge could be useful. i personally am against cranking up fuel pressure much beyond stock the pictures ive seen of worn injectors sold me on that one. i currently have an edge ez box hooked up that i run on level 1 mildest setting just to give a little more fuel way down low. as for the boost gauge again - not all that useful if youre running a stock truck. it can be helpful in diagnosing problems for instance a blown or even leaking intercooler boot is going to be easily noticable on your boost gauge. for reference i currently run 7 gauges - pre-and-post-turbo egts pre-turbo being read by my tst box boost fuel pressure tranny temp oil pressure and water temp needed to fill the last hole and i never trust the factory idiot lights in the shape of gauges. .
Replies:
From : roy
dido for us motorcycle riders! bonehenge b a r r y wrote ive ridden bicycles over lots of them and seen a wide variety of traction. think a slippery grate is scary in a truck try the slippery slightly downsloped examples on a 25 mph bicycle with a car 20-30 feet behind. on the bike i can even see a huge difference were the tires usually travel and where they dont. im scared everytime i ride across one on my motorcycle. ive screwed around before on thenm and nearly go road rash. .
From : mike simmons
ok now i am getting in to the little stuff that drives me nuts. the ram is awesome and i will never go back to gas again. i am a diesel head forever. but i cant shut off the stupid horn chirp when i am locking the doors. i have asked the dealer and all he said was to rtfm. brilliant................ it says to stand outside the vehicle hold the lock button for 4 seconds but less then 10 then press the panic button and then to let go of both at the same time. the wife and i have both tried it at least a dozen times. we have reread the manual probably that many times as well. no luck. i am thinking the manual is wrong but i have no idea what key combination will shut off the chirp. i did it in my 92 dakota my 02 ram and my 04 ram with no problems. any ideas wayne i kept going on google and finally got a hit at http//www.dieseltruckresource.com/dev/showthread.phpt=149133 it seems that this is a feature that cannot be disabled like the manual describes. i hope i find the guy who told me to read the manual. if anyone does know of a fix. let me know. thanks wayne .
From : craig christian
this is the justification from the mechanic i have been dealing with after asking him why a rail pressure gauge is preferred over the fuel pressure all of what he says is correct - however all that information is available to any tech diagnosing the truck by simply hooking up the drb3 will operating the truck. so having a rail pressure gauge is only going to be of use to you to indicate that yep theres a problem - better take it to the dealer. however the truck having little to no power is going to be an even bigger indicator of the same problem. i highly doubt that my truck will ever be anything but stock. i like it just the way it is. okay - then that narrows things down a bit. in your case then id say the most important gauge is the tranny temp gauge followed by the pyro followed by fuel pressure and heres the reasoning in stock form its much more likely to kill your tranny from overheating it pulling heavy at slow speeds no torque converter lock-up building lots of heat in the transmission than it is to burn up your engine. when towing with my truck and with the power dialed down to more sane levels i could see 230f+ on my tranny temp before i would hit 1300f on the pyro. now that doesnt mean that the engine is immune from melting itself... the 3rd gens do run hotter than the previous 24vs and with the right combination of power and load its possible to see 1350f+ on your pyro - and thats not something you want to do for an extended period of time. at that point its time to slow down downshift get the engine rpms and thereby boost up to help cool those egts a bit. and lastly from our previous discussions a failed/failing lift pump can still cause damage to your injection pump... not nearly as quickly as the older 24vs but the possibility is still there. other gauges - rail pressure boost and others are simply informational.... youre not going to kill your engine if you loose boost but youre going to know it right away because power will be down and egts will be up. youre also not going to damage anything if your fca breaks and you lose rail pressure. again youre sure going to know it because power will be low-to-non-existant - but again no damage can come of it. .
From : craig christian
does this sound correct well.... no back in ye olden days when there were only two valves per cylinder there was a mechanical lift pump mounted on the back of the engine that sucked fuel from the tank and fed it up to the p7100 injection pump. the p7100 was lubricated by engine oil and if for some strange reason the mechanical lift pump failed and stopped feeding fuel to the p7100 the extent of the damage done was probably a sore toe from you kicking the truck because it stopped running not to mention all the fun of re-priming the fuel system and getting it running again... but still no permanent damage done. with the introduction of the 24v isb engine came electronics. with that the mechanical lift pump was replaced with an electric pump still mounted on the left-rear of the engine still sucking fuel from the fuel tank but now delivering it to a vp44 injection pump. the vp44 no longer used engine oil to lubricate itself as the p7100 did... it relied on diesel fuel for lubrication. you can see where this is going.... when not if but when the electric lift pump failed it starved the vp44 of fuel which in very short order would gawl itself all up and you were then the proud owner of two broken pumps.... one relatively cheap the electric lift pump and one really expensive the vp44. the 3rd gen trucks with their new isbe also called the hpcr high-pressure common rail engine use a different version of the same electric lift pump and a newer higher-pressure yet still fuel-lubricated cp3 pump. the cp3 is cheaper to produce than the vp44 as there are no electronics the vp44 contained electronics to control injection timing - all the injection timing is now done at the injectors themselves. however the cp3 is still an expensive unit and not something you want to fail and believe me starve anything that spins around and around of lubrication and thats exactly what will happen. starting in model year 05 dc decided that pulling fuel 12 or so feet through a tiny little tube probably wasnt the best use of a pump designed to push rather than pull - and re-re-re-designed the fuel system with an in-tank pusher pump that would now feed fuel directly to the cp3 still going through the stock fuel filter canister however. guess what sometimes those pumps fail too. of course now you have the added fun of dropping the tank and removing the fuel module to replace the pump - something that old 24v guys could do by feel on the side of the road on a moonless night inside of 10 minutes. .
From : tom lawrence
tom lawrence wrote does this sound correct well.... no thanks for the lesson. as usual your explanation is easy to understand even for those of us that have the random retard gene floating about. - craig c. .
From : craig christian
ill be taking regular 5 mile trips to work and back everyday. the manual has 2 sets of maintenance guides depending on the mileage you put on it on daily basis. one glaring difference is changing the lube in the rear axle much more often for low mileage daily driving. she says shes never had it changed. whats up with that regarding the axle lube stuff moisture in the air condenses as the air cools and will eventually lead to some water contamination in the rear end lube. low mileage daily driving prevents the lube from reaching a temperature that allows the trapped water to cook off therefore more frequent lube changes are recommended. .
From : chris thompson
chris thompson wrote why not do both. install a srt apillar trim and mount your piro there thats where mine is and then your tranny and fuel pressure gauges up on the dash.. or you could do the steering column mount this mount comes in both dual and single gauge. ive got a dual on mine but still only the boost gauge i have yet to buy the fuel pressure gauge i considered the steering mount but it blocks part of the dash. im a no-clutter kinda guy. ill email ya a pic of my setup if ya want. yes please. i personally still want to monitor the lift pump but i have yet to install the capability lol remember i am not a mechanic so what im about to say might be worded incorrectly ... or worse yet just downright wrong. - my understanding is that the issue on the older rams was that they had two pumps. when the fuel pump in the tank failed it caused the lift pump to work harder and eventually fail. which is why the fuel pressure gauge was necessary to detect the failure of the cheap pump in the tank and get it fixed before the expensive lift pump failed. in my ram there is now just a single more powerful lift pump. therefore the fuel pressure gauge really serves no purpose. however the rail pressure gauge can be useful in detecting a faulty fca. does this sound correct if i ever decide to add a boost gauge ill probably put it on the a-pillar with the srt mount. thanks! craig c. .
From : tom lawrence
tom lawrence wrote first while its true the 3rd gen trucks lift pumps were more reliable than previous years and the cp3 pump is much more tolerant of lower fuel pressures dc felt that the lift pump was still enough of an issue that they re-designed the low-pressure side of the fuel system and re-located the fuel pump inside the tank. this is the justification from the mechanic i have been dealing with after asking him why a rail pressure gauge is preferred over the fuel pressure on the rail pressure low or fluctuating rail pressure dont necessarily equate to a dead cp3 injection pump. its use is to give the operator a base line of rail operating pressures at given load and engine rpms. out of the norm for same driving conditions could help diagnose the concern with the high pressure side of the fuel system. ie. the fuel control acuator fca sticking or cycling improperly low to no rail pressure or a bad rail pressure sensor or fuel valve. both would cause performance concerns and could asst. dodge or other diesel techs in more accurate diagnosis of the concern. for example the cp3 could be failing causing a low rail pressure if the tech did troubleshooting and found the fca rail sensors and low pressure side volumes to be up to par the ecm engine control module or cp3 would be the obvious culprit. note i am not trying to pit anyone against anyone. i trust this guy hes a great mechanic. what i am trying to overcome is my own personal ignorance on the matter. id like to understand better why one is better than the other. or ... if id be better served with scrapping the fuel gauges altogether and just put in two gauges tranny temp and pyro. a rail pressure gauge is really just a gee-whiz kind of gauge this is what i am trying to avoid. having a gauge for the sake of having a gauge doesnt excite me at all. unless youre planning on playing around with your fuel pressure to get more power out of the engine. thats a whole nother story then - and in that case yes a rail pressure gauge could be useful. i personally am against cranking up fuel pressure much beyond stock the pictures ive seen of worn injectors sold me on that one. i currently have an edge ez box hooked up that i run on level 1 mildest setting just to give a little more fuel way down low. i highly doubt that my truck will ever be anything but stock. i like it just the way it is. for reference i currently run 7 gauges - pre-and-post-turbo egts pre-turbo being read by my tst box boost fuel pressure tranny temp oil pressure and water temp needed to fill the last hole and i never trust the factory idiot lights in the shape of gauges. okay ... you *might* need to calm down a little. - craig c. .
From : tom lawrence
tom lawrence wrote okay - then that narrows things down a bit. in your case then id say the most important gauge is the tranny temp gauge followed by the pyro followed by fuel pressure and heres the reasoning thanks. just what i needed and wanted to hear. craig c. .
From : craig christian
it is made by a pump company so hopefully they know what theyre doing plus for pennies a fill-up i get to avoid costly pump rebuilds. ymmv. .
From : chris thompson
on wed 30 may 2007 162841 -0700 sbgirl11 wrote i have a 2001 dodge dakota with a v8 engine. on my way to work today it started to over heat and spit radiator fluid. does anyone know what this could be list of things it could be..... bad radiator cap bad thermostat bad radiator clogged radiator or a/c condensor fins blown head gasket cracked head cracked block bad fan clutch bad water pump improper mix of coolant to water should be 50 - 50 mix id start with a pressure test of the system including the cap a cap and or the thermostat would be prime suspects and are the cheapest. -- chris 05 ctd 06 liberty crd .