CTDinMT

Thanks, for a bit there I was cornfused.

Duallydog

Now that we've got that settled, what about the fuel pressure? I take it Quads away from the internet.

Duallydog

Phew, thought I had another problem in the works on my way home. The fuel pressure was reading 203psi and the injection pressure was reading 3776 the whole way home. Looked at the connection under the dash and apparently my foot movement unplugged it. But it's still reading 4psi.

XLR8R

With the lift pump mounted on the fuel filter housing (you have an '04, right?) your fuel pressure should vary between 3-7 psi depending on engine load.
Certainly not read 4psi whether idling or pulling hard.

qzilla

Well, I am not exactly sure what to tell you. Typically you will run in the 7-8psi range at idle. Although it seems that every pump is slightly different?

I actually thought I had mine on my truck act up on me as it would start at 7psi and then work its way down to 2psi and sort of stick there. From time to time it would come back up and then work its way back down. I searched high and low and was sort of irritated and wondering if my sensor had gone bad? We tested them forever and they are said to be rubber mounted on the inside so that vibration does not affect them?

Well after making no headway and swapping sensors out with the same results I finally just slapped a fuel filter in. Now it is normal and my filter only had about 6K on it? That was several thousand miles ago and I never had any more issues since.

I have no idea how many miles are on your filter but, maybe it is time for a change.

Also someone mentioned testing it with an analog gauge. This is a good idea but, I am yet to find any analog gauges that do fuel pressure worth a flip. I have been pretty shocked and pretty disappointed in how bad some of them are. I am sure there are good ones too they are just not very sensitive. With the digital you can actually watch the pump ramping up and down slightly with the a/c kicking on and off at idle! Th ECM likes to fluctuate the CP3 a lot and you can watch the pressure slightly fall and then rise back up 1-2 psi! If you get a really expensive test gauge you can hook them up in line and watch them and it constantly moves!

So let us know what you come up with. I would start with your filter unless you already did that! I guess step 2 would be to let us send you another sending unit and see if the one you have is bad?

XLR8R

FYI - the AutoMeter mechanical fuel pressure gauge I use is pretty sensitive, it's easy to see 1/2 psi fluctuations with varying engine load. I plumbed mine w/o an isolator from the filter housing to the top of the cowl.

It's neat how you can watch the reversion pulse spike the needle up to 10psi when you back out of the throttle and the CP3 suddenly doesn't want the same fuel column rushing into it.

Duallydog

My filter has around 2K miles on it, but who knows could've been something already in the line and plugged it. Quad I'm gonna try to be by your place Friday (everything permitting). So at least the shipping can be saved and one of your guys can look at it and go "you hooked it up wrong".

Duallydog

Ok just changed my fuel filter and it didn't change just idleing we'll see if it changes when I drive tommorow.