starkey

A freind of mine is having the hard start-no start problem on his 03. Its completely stock... we put another lift pump on her, new fuel filter, new crankshaft position sensor... nothin. So before we put new injectors in it, i wanna check the fuel pressure relief valve... i've read on here that sometimes it gets clogged up and stays stuck open, not lettin the rail build enough pressure.... so where is it located???

P.S. This truck start completely fine if push started, but not by the starter... maybe that'll help diagnose the prob a little more...

these CR's are different than my 2nd gen!

Thanks

starkey

so nobody knows where the fuel pressure relief valve is??

Rpainter

top of the rail beside the rail sensor

starkey

towards the back end of the rail?

staarma

Yes, towards the back. You can just get a metric bolt to replace it and plug it off to diagnose the problem. I forget what size though.

starkey

thanks. gotta get this thing on the road

cwoodall

It's 14mm fine thread pitch.......(1.5 or 1.25 thread pitch).

If you don't mind a little mess, just pull the banjo bolt from the top of thr CRPRV and move the line off to the side (it will leak fuel). The relief valve should not leak anything while cranking and idling......good luck.

jballou

I am trying to diagnose a similar problem. cwoodall- question if you remove the banjo bolt with the truck off and there is fuel there could it possibly also be comming from the fuel filter cannister? gonna try the messy method I guess. I am trying to diagnose a possible bad rail pressure relief valve.

MikeyB

There could be some fuel in the line. But you want to watch and see if fuel is dribbling out of the relief valve while the engine is running.

MikeyB

starkey

Well, we tested it last night... the PRV was good. So i'm thinking its a couple injectors gone bad. Funny thing.... if you take the BHAF off, and put your hand over the intake tube while cranking, it'll start up.... this thing has got me so turned around i don't know what to think. Thanks for the help about that PRV!

cwoodall

Yea, my truck has voodoo. I get my hard start prob all diagnosed in my head and go out to do something and it runs fine. Then I go somewhere and when I go to start I have to use ether. Get home and grab a tool, and it starts fine. Try to leave the bar, and yep, ether again. I did the chicken sacrifice, sold two small children, and drank tea with a witch.........................what next???

skynyrd

mine is starting to do the same thing now didn't want to start this morning then when it did start it was a really rough idle going to swap out my crank sensor when i get home.

starkey

cwoodall... thats what we're doin... umm except the chickens.... lol! We've sacrificed one 3/4" wrench, many many Lone Star Light beers, and our sanity!

tesla440

Starkey,

Does it start everytime when you have the bhaf off & your hand over the intake? It might be one of the two map/temp sensors going bad. I'm assuming that you have the same setup as my '05. One sensor at/by the bhaf & one on the intake manifold near the PRV. I'm going to guess that it might be the one by the bhaf since when you covered the intake up it started.

Just out of curriousity is there any codes? You don't have to have a MIL light to have them. Try the key on & off three times with the last being on. This will bring a code "Pxxx" up at the odometer & say "done" when all are listed. You can find the codes here on TDR.

Jeff

skynyrd

starkey try taking the sensor out of the tube at the air filter and cleaning it sometimes it gets dirty and starts to act up.