CD in NM

I also have one of the first gauges that were produced, NO mods on my truck other than intake and intake horn. I got mine because I was having the P0191 code too frequently and wanted to watch the rail pressure. After I have been driving a while it starts to act up, reading real high, then low, never the same problems repeatedly. At idle the pressure is at about 5K, crusing around at about 2K rpm's the pressure is at 15K, this is on average. Then after a few hours of travel at idle the pressure drops to 3-4K and the 2K rpm's is right at 12-12.5K. Sometimes at idle it fluctuates from 4K down to 2K intermittently. I have also noticed a lot of deflection back and forth from 12-15K while driving with the cruise on at 2K rpm's. If I stop, shut down, then restart, it will be back up to 5K at idle and 15K at 2K rpms. I have yet to call and see if I could get a new gauge, trying a new gauge might be the route to go, but I am certainly not buying another one.

It could be that there is some kind of RFI/EFI taking place, I have never really noticed my proximity to high tension electrical stuff or cell towers, nor have I watched the gauge while using my cell phone in the cab. All the times that my truck threw the P0191 code I WAS passing my local electric company and they DO have those remote meters they check via some kind of transmiting/receiving devices, so, it could even be something like that affecting the rail pressure sensors themselves, causing RFI to the main computer system of the truck. Plus, going down the road there are many using CB radios with linear amplifiers. That stuff affects our trucks computers too. I have a lot more issues happening with my RP gauge when on interstates than when out on local roads/highways.

CD

metal_miner

I finally broke down and bought a DiPricol rail pressure gauge thinking that the problem with them and modded CP3's would finally be resolved by now. Well, it's not resolved yet...

For the most part the gauge works fine, especially interstate driving. However, driving in city stop-and-go traffic the past week the gauge acted up as others reported.

When the problems occurred I was, and still am, running a stock FCA on my modded pump after the modded FCA went on the fritz about 2 months ago.

metal_miner

I guess everyone else got their DiPripol RP issue resolved?

cquestad

UM...not me....irregular readings...at cruise is the worst. WOT seems to work.

gus's 03

for those of you that are having emi problems.....

i installed a rail gauge in my truck last week, due to the high rf energy in my truck i have learned to start twisting all pairs of wires on my truck, i have 0 issues....

for those that dont know what a twisted pair is, take a bunch of wires have some one hold one end , chuck the other end up in a drill, then spin it till its tight.

gus's 03

oh, and as far as presures on my truck...
idle 5500
70 mph cruise 10-11k
wot 22k solid up to 3500rpm

this is on beta 4.4

i have noticed a dip in presure from about 2k-2200 rpm, this corisponds with a dip in every dyno curve i have.....

metal_miner

Gus, I'm listening! can you please explain EMI and specifically how a modded CP3 could cause it? How can you measure with a meter to know you have an EMI problem?

I've had 0 issues at first too, then it goes to hell usually when driving stop-and-go. Could it be that the FCA cycles less during stop-and-go with a modded pump so it builds up energy? Which wires on the harness did you twist? The entire harness from the sensor to the gauge?

-Thanks-

Dieselhed

Mine worked fine with the stock cp3. I installed Flux 2's a week ago and had the low rail pressure at idle immediatly. 5500psi. down from 7,000psi. Go figure.

gus's 03

EMI= Electro Magnetic Inerferance
to mesure EMI you need a field strength meter.

most EMI issues are intermitant, the field can generate small amounts of current by twisting the leads it helps to counteract the field. that can cause voltage fluctuations that the computer interpis and causes wierd things.

a mod'd pump doesnt cause it. but the diy pump mod can compound the issue. the computer thinks theres a gradual ramping up of fuel flow, bu slotting the shuttle valve, it see's a sudden spike in volume, so it trys to back it off, this causes a sudden drop as it closes.and so the surgeing cycle begins.

stop and go traffic cycles the fca more than a steady speed.

as far as wires, the one from the sensor to the gauge would be the one id be most concerned with, tho i do it to all connections, power, ground, signal etc.

http://en.wikipedia.org/wiki/Twisted_pair
http://en.wikipedia.org/wiki/Electromagnetic_shielding
http://en.wikipedia.org/wiki/Electro...c_interference
http://en.wikipedia.org/wiki/Electromagnetic_radiation
http://en.wikipedia.org/wiki/Electric_field