Need a diagnosis
- Thread starter dracing70
- Start date
Fuel filter(s), FPRV, bad injectors with horrible return rates, bad CP3 - there are quite a few possibilities. Where did you "have this CP3 done"? Was it just remanned or was it a modded one, who said it "should hold 26K all day" (with enough PW it would take a very modded CP3 to do that)?
well it is not reman it is modded. all my work is done through fast track enterprises i can t remember the gentlemans name however this is my second one done by him and the one in my lly holds 26000 no problem and never flinches . as far as filters they r new injectors r new regulator is ruled out so it is either the cp3 or the fprv is poppin so i figure try to plug it and go from there?
the FPRV can be shimmed or plugged up, and both are reversible. shimming it only takes 18 cents but its a little more work to get the fprv off.
so what does everyone think?? with the cp3 bein a fresh mod does the fprv sound like the probable culprit??
Adding more fuel into the rails will increase the pressure causing it to pop open more easily, so I would say yes, that may have caused your little problem
yeah this lil problem has caused piss poor fuel mileage and a slight shudder at about 1500 rpm with a load other than that and now smoke at all it runs not to bad.
use your dvt function to command 160mpa at idle on the efi live scan tool and see if it holds. see how that works out for you.
No offense to them but I have never heard of them so I don't know what kind of mods he is doing to pumps. Modded pressure regulators that don't get cleaned up enough before being put back together can stick and cause low (or high) rail pressure. I doubt he is boring or stroking the CP3 itself (or we would have heard of him), so there shouldn't be any problem there as long as the pump was good to begin with and if it wasn't you should have noticed as soon as you installed it. Plug the FPRV and see how it does.
well i rand the dvt function and commanded 23000 and only got a lil over 11000. so does this sound like the prv poppin or the cp3 failing? also i read the forum on plug the fprv it is a 1/2 npt threaded plug correct? i just want to make sure cause that just seems a bit large???
i searched and only found one that said 1/2 inch plug i dont know if that is npt or just a measurement because 1/2 npt is quite big
Well there is two ways you can go about it. and still have it be reversible, welding it its a little hard to make it normal again
plugging it: http://www.dieselbombers.com/lb7-bombs-aftermarket/21777-plugging-lb7-fprv.html
or shimming it: http://www.dieselbombers.com/lb7-bombs-aftermarket/34726-lb7-fprv-shim-mod.html
there was a lb7 shim mod thread on here but it must of been moved.
plugging it: http://www.dieselbombers.com/lb7-bombs-aftermarket/21777-plugging-lb7-fprv.html
or shimming it: http://www.dieselbombers.com/lb7-bombs-aftermarket/34726-lb7-fprv-shim-mod.html
there was a lb7 shim mod thread on here but it must of been moved.
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the diesel bomber thread is the one i read and it said 1/2 plug but it was not real specific i was just tryin to have all the parts before i took it apart
i cant remember what size threads it was but it was a 1/2 steel plug. i took it out and went to ace and got what i needed. tap and plug
That set screw idea is pretty nifty, I like it... Seems easier than shimming it also
Just to be clear, this is completely different on your LBZ.