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I have a bad fuel relief valve and in researching it its said that you have to have a special bolt... seen a guy on ebay that makes them and sells for like $25... also heard of people re-tapping there stuff so they could run a different thread bolt and all this crazy stuff... i got mine for like $2.00 at autozone... i went everywhere else... lowes, home depot, Ace, everywhere and of course they didnt have them short and fat enough... well i walked by the Oil section at autozone one day and saw what was needed! a M14 1.5 oil plug bolt... it was actually slightly shorter then the banjo bolt... you can also get new copper seals here too... same size and everything... Its alittle tight going through the return line and i had to turn mine through it but its copper and weaker so it went in fine without hurting anything... I just wanted to start this thread so that if anyone else is searching they would no its not that big of a deal... This for some with a rail pressure gauge means maybe alittle more power... this for me let me know that i have a bad injector and its not JUST the relief valve leaking... :banghead:
 

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I have a bad fuel relief valve and in researching it its said that you have to have a special bolt... seen a guy on ebay that makes them and sells for like $25... also heard of people re-tapping there stuff so they could run a different thread bolt and all this crazy stuff... i got mine for like $2.00 at autozone... i went everywhere else... lowes, home depot, Ace, everywhere and of course they didnt have them short and fat enough... well i walked by the Oil section at autozone one day and saw what was needed! a M14 1.5 oil plug bolt... it was actually slightly shorter then the banjo bolt... you can also get new copper seals here too... same size and everything... Its alittle tight going through the return line and i had to turn mine through it but its copper and weaker so it went in fine without hurting anything... I just wanted to start this thread so that if anyone else is searching they would no its not that big of a deal... This for some with a rail pressure gauge means maybe alittle more power... this for me let me know that i have a bad injector and its not JUST the relief valve leaking... :banghead:
that's cool for found something to work for that cheap. I personally don't think it's a good idea though. You have to realize there's 20K psi + in the rail and that can cause problems with weaker metals. The last thing you'd need is rust to form on the screw, psi cutting into the cheaper screw or having to force the screw into place if it's not the exact size you need.

Cummins and/or Floor It sells the actually cap which is known as a test cap. Floor Its is stainless and the Cummins one is grade #8 metal
 

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Discussion Starter #3
you dont have to "force" it... it just screws through... its the same size and thread as the banjo bolt... Also my relief valve was only leaking alittle... it would just bubble out... not shoot all over the place like some... the psi wont cut the bolt because in order for it to do that it has to bounce off and go somewhere else... the most it would do is strip the threads off and shoot the bolt out... but i seriouly doubt it would ever do that... hasnt on mine... im not a fan of it either unless you have a gauge to monitor your pressure so you dont kill your injectors... but for testing it works great... and i think even if it was left in (with a gauge) i think it would work fine... since i dont have a programmer yet im honestly not to worried about the rail getting anywhere close to max psi... actually mines been in there for like a month now... no problems... no rust either but i honestly dont know the metal grade...anyone who reads this post take it as you would like i guess... im just sticking the information out there!
 

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you dont have to "force" it... it just screws through... its the same size and thread as the banjo bolt... Also my relief valve was only leaking alittle... it would just bubble out... not shoot all over the place like some... the psi wont cut the bolt because in order for it to do that it has to bounce off and go somewhere else... the most it would do is strip the threads off and shoot the bolt out... but i seriouly doubt it would ever do that... hasnt on mine... im not a fan of it either unless you have a gauge to monitor your pressure so you dont kill your injectors... but for testing it works great... and i think even if it was left in (with a gauge) i think it would work fine... since i dont have a programmer yet im honestly not to worried about the rail getting anywhere close to max psi... actually mines been in there for like a month now... no problems... no rust either but i honestly dont know the metal grade...anyone who reads this post take it as you would like i guess... im just sticking the information out there!

I didn't realize you were using it just to check for issues. I see no problem with that. Some, like myself have them capped for good. I was just saying if that's what you were doing... a cheaper price and grade bolt might not be the best idea. :thumbsup:
 

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Discussion Starter #5
yeah thats all im doing right now... its still in there because between the leaky relief valve AND the bad injector my truck wont ever start without ether and im not liking that idea...right now i still have to keep it plugged in over night so itll start in the morning... between the two it cost alot so im trying to get it together... of course my drivers hub fell apart Sat (pass fell apart in Jan)... so had to fix that first... not cheap either... i dont have alot of power so i havent really been dogging it so im not worried about hurting anything by anymeans... just a temp fix... I wont leave one in mine unless i had a rail gauge to watch... ive got all the other gauges but that ones high and i gotta fix things first... lol... then i may upgrade... of i can be the guy that test it and lets everyone know if itll work and last forever or not... lol...
 

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I wouldn't worry bout it since it appears your running stock tuning. FYI there cant be any amount of pressure ever put against the bolt. If you follow the line that comes off the relief valve you'll notice that it tee's into the fuel canister and joins the return line for the cp3 pump. Between the cp3 and that tee is a rubber line about 10in. long and uses plain old factory hose clamps... therefore the pressure coming out of the valve cannot be very high or it would blow the rubber line off or blow it apart
 

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And the bolt should not ever rust internally because diesel is an oil after all
 

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Does anyone have a picture of this mod?
 

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Hey man id just thought id let you know ive been there done that!! i was at that point this winter with my truck and i was/am on a college student with no job budget haha but my lift pump went out in the fall and i didnt have the money right away to fix it so over time driving it, it took out the CP3 so i finally got the lift pump changed(got a fass for it) then i had the CP3 to worry about... would not start without ether at all!! so finally i changed that and i had run so much air through the injectors that i had ruined them as well, so i had to change them all, but i ran that Stainless Steel plug you were talking about from Ebay and it made a little differance with starting but with bad injectors, it just couldnt atomize the fuel so it was just pooring it in vs spraying it in so it wouldnt start without eether, but i changed the injectors(from a used truck with 40,000 miles) and she fires right up first time everytime!! but i have the rail cap pulled out for now because i dont need it and it was tripping a check engine code and it bugged me so i just said hell with it and pulled it out

I have a bad fuel relief valve and in researching it its said that you have to have a special bolt... seen a guy on ebay that makes them and sells for like $25... also heard of people re-tapping there stuff so they could run a different thread bolt and all this crazy stuff... i got mine for like $2.00 at autozone... i went everywhere else... lowes, home depot, Ace, everywhere and of course they didnt have them short and fat enough... well i walked by the Oil section at autozone one day and saw what was needed! a M14 1.5 oil plug bolt... it was actually slightly shorter then the banjo bolt... you can also get new copper seals here too... same size and everything... Its alittle tight going through the return line and i had to turn mine through it but its copper and weaker so it went in fine without hurting anything... I just wanted to start this thread so that if anyone else is searching they would no its not that big of a deal... This for some with a rail pressure gauge means maybe alittle more power... this for me let me know that i have a bad injector and its not JUST the relief valve leaking... :banghead:
 

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pics of the bolt in the truck

Does anyone have a picture of this mod?
here are some pics

<a href="http://s593.photobucket.com/albums/tt14/waterfreak08/?action=view&current=Img_1960.jpg" target="_blank"><img src="http://i593.photobucket.com/albums/tt14/waterfreak08/Img_1960.jpg" border="0" alt="Rail from truck"></a>

<a href="http://s593.photobucket.com/albums/tt14/waterfreak08/?action=view&current=1874B.jpg" target="_blank"><img src="http://i593.photobucket.com/albums/tt14/waterfreak08/1874B.jpg" border="0" alt="Rail Plug"></a>
 

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the second picture is the plug in the rail when i had the rail out of my truck to do injectors, the first one is the the plug in the rail in the truck... its kinda faintly circled
 

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ok i`m lost....why did you have to put a plug/cap on ur fuel rail... i saw where u said it was bubbling out but why not just fix the problem...or is the bolt the fix...IDK
 

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ok i`m lost....why did you have to put a plug/cap on ur fuel rail... i saw where u said it was bubbling out but why not just fix the problem...or is the bolt the fix...IDK

Capping the fuel rail allows it to have higher rail pressure... it replaces the banjo bolt for the return line to the pump, and so with no return it forces all fuel into injectors vs allowing fuel and potential power escape the rail and return to the tank..... but if you have a weak CP3 it helps with starting a little bit because it will help build the 1,400 PSI of rail pressure required to fire the injectors, but i wouldnt leave it on for prolonged periods of time becasuse it can and will ruin stock injectors if you have a chip and have the rail pressure turned up, the stock injector nozzles will crack under high pressure, but you asked why not just fix the problem?? well a stock CP3 is $700, new stock injectors are $395 a pieces so a $20 bolt is a cheap fix for the time being until you have enough cash to buck up and fix the problem the real way :redneck:
 

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I used a lug bolt for an '03 volkswagon jetta, the threads are the same and the bolt is hardened with a tapered head, I've had it on for about 3yrs, $1.50 at autozone.:thumbsup:
 

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so is this the same banjo bolt that i would hook a FP gauge up too..? or do i need a "tapped banjo bolt" as i have been told....what is a tapped banjo bolt? sorry 4 silly questions.

Now i understand the need for a $ 21 bolt..i`m with you all the way.
 

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so is this the same banjo bolt that i would hook a FP gauge up too..? or do i need a "tapped banjo bolt" as i have been told....what is a tapped banjo bolt? sorry 4 silly questions.

Now i understand the need for a $ 21 bolt..i`m with you all the way.

No the rail gauge hooks to the rail sensor. You do NOT want to hook a gauge to the actual rail itself with fuel running to a gauge at 20k+ psi of pressure... not a very safe thing to do.:doh:
 

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Discussion Starter #19
Yeah its suckin right now... i also have 2 piece steel H1 humvee wheels on it and at the time when i got them and had them sandblasted and powdercoated i didnt know that the 8 stud style doesnt work with the radial hummer tires... only the bias ply tires... i need the 12 stud style cause there stronger... so just about ever day im replacing a stud and lug nut on the outer studs to keep wheels together... sucks... for new ones its $250 plus shipping and then paint/powdercoat or whatever else i do to them... ive got 1/2 grade 8 bolts in there now and it still pops them like there nothing... sucks... so i think thats gonna be next... and closing on a house friday... money money money... also the reason id rather run a rail cap instead of replacing my relief valve is cause im told that it can only be gotten at dodge and you have to buy the whole rail... and its like $400... i found one on ebay the other day and it was like $10... but in the last 10 seconds it went to $200 somethin... wasnt expecting that... i stuck my max in at like $150 in the last 10 secs and got beat by somebody else with i guess more money then ive got... lol... so for now its fine... Lots of reason too though...

andrew allen... how did you find out you had a bad CP3?? i did the CP3 mod on mine myself and its worked great but now you got me wondering... lol... Garmons diesel up the road said he dont even have to look at it and knows its a injector and he pretty much knows his junk since he runs low 6's in his cummins without meth/propane/nos or anything... just motor power...
 

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Yeah its suckin right now... i also have 2 piece steel H1 humvee wheels on it and at the time when i got them and had them sandblasted and powdercoated i didnt know that the 8 stud style doesnt work with the radial hummer tires... only the bias ply tires... i need the 12 stud style cause there stronger... so just about ever day im replacing a stud and lug nut on the outer studs to keep wheels together... sucks... for new ones its $250 plus shipping and then paint/powdercoat or whatever else i do to them... ive got 1/2 grade 8 bolts in there now and it still pops them like there nothing... sucks... so i think thats gonna be next... and closing on a house friday... money money money... also the reason id rather run a rail cap instead of replacing my relief valve is cause im told that it can only be gotten at dodge and you have to buy the whole rail... and its like $400... i found one on ebay the other day and it was like $10... but in the last 10 seconds it went to $200 somethin... wasnt expecting that... i stuck my max in at like $150 in the last 10 secs and got beat by somebody else with i guess more money then ive got... lol... so for now its fine... Lots of reason too though...

andrew allen... how did you find out you had a bad CP3?? i did the CP3 mod on mine myself and its worked great but now you got me wondering... lol... Garmons diesel up the road said he dont even have to look at it and knows its a injector and he pretty much knows his junk since he runs low 6's in his cummins without meth/propane/nos or anything... just motor power...
hey, well after you test the injectors and they are all good and you still dont have sufficient rail pressure you know its the CP3, when you hook an OBD2 computer up to it and crank it over and if you dont hit 1,400 PSI in the rail on start up you either have 1 or more bad injectors or the CP3 is bad....
 
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