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Radix issue....fuel pressure question..

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Old 06-27-2004, 02:29 AM
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im not sure how the wiring is done witht he inlines on the radix but when i first put my inline pump on i ended up tapping into the worng wire on the fuse box...my pump would turn on and (you could hear it) but under a load it wouldnt get enough of a power source and the fuel pressure would drop dramaticly just like you described...i would the check the wiring on your fuel pump. just cuz it turns on doesnt mean it does its job....
Old 06-27-2004, 11:06 PM
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Flyer, good call on checking the fuel preasure without running the truck. The fuel system is not staying pressurized...unless the pump constantly runs. As soon as the pump stops after 3 seconds the pressure goes right to 0 psi. Did same test on my buddies truck and the system stays pressurized to 45 psi. My truck won't even get to 45 psi unless the pump runs constantly.

Where should I look for the problem.

OUt working on the truck right now, so if you get ambitious...(360) 223-4758

Thanks!!
Old 06-27-2004, 11:16 PM
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Originally Posted by Hoover87
Flyer, good call on checking the fuel preasure without running the truck. The fuel system is not staying pressurized...unless the pump constantly runs. As soon as the pump stops after 3 seconds the pressure goes right to 0 psi. Did same test on my buddies truck and the system stays pressurized to 45 psi. My truck won't even get to 45 psi unless the pump runs constantly.

Where should I look for the problem.

OUt working on the truck right now, so if you get ambitious...(360) 223-4758

Thanks!!
Pull the FPR out of the little manifold they gave you. Check for both O-rings, one is messed up, I am pretty sure.
Old 06-27-2004, 11:22 PM
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Sure there isn't a leak somewhere? If its dropping back down its either leaking, or maybe the injectors are leaking? or maybe the pump isn't holding the line closed properly (I'm guessing the system is supposed to stay pressurized after the pump, and not before it, so maybe the pump "valve" isn't closing and its leaking pressure back towards the tank - not sure how all that works exactly?)

I am just thinking out loud here, I'm wanting you to get this problem fixed so if I run into the same problem this week we'll know the cure - to me it sounds like you need to try a different pump and at least eliminate that possibility
Old 06-27-2004, 11:23 PM
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Originally Posted by retsell
Pull the FPR out of the little manifold they gave you. Check for both O-rings, one is messed up, I am pretty sure.
btw, take his advice before mine
Old 06-27-2004, 11:25 PM
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THe fuel block on the side of the blower ... pull the pressure regulator out and replace that O-ring ... the itty bitty one in there. THe only place I can find one that size is a bearing supply store that does hydraulic lines and stuff too. Don't try fixing it cause if it has a hairline crack in it ... you will be pissing in the wind. That's your problem though. That little bitty o-ring is either cracked or in there sideways. That should clear things up once it gets fixed. When you get it ... make sure it will hole pressure. You might try putting a little vasoline on the o-ring to make it slide in easier. Make sure it will hold pressure, if it doesn't pull it out and try again.

After that, replace your plugs and wires cause chances are they will be burnt up.
Old 06-28-2004, 12:32 AM
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Lube up the o-ring with vasaline...Dont be shy with it.
Old 06-28-2004, 12:55 AM
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LOL ... Blown likes Vasoline ....
Old 06-28-2004, 02:00 PM
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First of all....BIG thanks to Retsell for the phone call last night to give me some clarification of what I was looking for. Great help. Thanks to all of you guys for your support!

Hahahaha........anyway, I found the little O-ring in the old manifold. I didn't have any vasaline handy and was freash out KY so I just dipped it in oil before putting it together. It seemed to do the trick 'cause the system is now holding pressure at about 50 psi when the pump turns off. Oh!...and the pinging is gone now too

Boy, that booster pump with this kit must be one heck of a pump...we removed the O-ring from my buddies stock truck to simulate the problem on his and his truck would barely idle. My truck even without the O-ring was still totally drivable as long as you kept your foot out of it. Interesting...I guess the pumps are working

Tonight I'm going to do a couple runs with the fuel pressure guage in the truck to make sure it's maintaining pressure.

Flyer, you mentioned new plugs. What is the favorite for Radix trucks?

Blown, I'm going to take another look at the boost also. I don't hear the pinging anymore, and after some tests on Saturday it looks like it's only kreeping up to 8 lbs when is gets up to about 5000-5500 RPM. I'll let you know what the outcome is and then we can decide on the pulley.

One last question, if the boost is not too rediculous, would there be any plus to putting my K&N FIPK back on? Any opinions? Good idea bad idea?

Thanks again guys for the priceless help. For the record, I'm very happy with the Radix kit...just working out a few self-induced bugs.
Old 06-28-2004, 02:21 PM
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Originally Posted by bigguy75inches
when i installed my whipple kit, they said the fuel pressure should be around 50 psi at idle with the vaccum hose disconnected. and it should run at 62 psi minimun at full throttle. (vaccum line connected) aslo, radix supergers send a inline fuel pump to keep pressure up. im sorta thinking your inline pump isnt working, so your having a loss of fuel pressure. your stocker is having to push fuel through a non workin pump thus causing hard starting from lack of fuel. Of course, i dont own a radix kit, and this is all just speculation. hope it helps!

haha its nice to know i was actually right about something for a change. it sounded too much like lack of fuel pressure than a stopped up exaust.


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