Losing prime over night... Injector issue?

Kronic_187

Kronic_187

Mekanical injection junky
First and foremost my fuel system is entirely not stock.

I have a drawstraw, 1/2 feed lines and 3/8 return... Fuel lab brushless pump and two fleetgaurd filter heads with an FS1212 and a FF5320, p-pump is dual fed.. And pressure is set with a by-pass fuel regulator. System holds a steady 40 pounds...

After truck has sat for longer then an hour its a bish to start and seems to run on 5 cylinders for awhile till it catchs prime and runs good till it sits again. No loss of power or more smoke.. Nothing.

I just replaced all my feed fuel hose, no leaks, freah filters.

I recently had a set of 5x.014 sac nozzles put on a set of bodies i had in the shop by a local injection business....

Is there anyway this could be an injector or delivery valve issue? Maybe sumthing in the pump letting it leak by?

There are no visible fuel leaks, everything is dry...

Starting to gt pissed off...

Might pull these injectors and stuff my stockers back in later just to make sure....


Any ideas?
 
If you don't have any excessive smoke at initial start up I doubt a nozzle is leaking by into a cylinder. Sounds to me like a check valve issue. Park on an incline with the tank being at the lowest elevation in the fuel system and see if it makes it worse. If it does you definitely have fuel bleeding back into the tank and I would try a new overflow valve. If it has a bad seat or spring it could cause fuel to bleed back into the tank and cause the symptoms you are describing.
 
If you read what i posted.... I dont have an overflow valve...


Not stock, using a by-pass regulator

About A week ago this all started happening and my #3 dv holder was leaking fuel... I took it apart and cleaned everything and it has stopped leaking... Still loaing prime though, dunno whats goin on. Can the injector bodies wear to the point of allowing fuel out the return line back to the tank? Here for losing prime?
 
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If the delivery valve holder O-ring was leaking, I'd suggest replace it. I cleaned one of mine that were leaking fuel, and it quit leaking fuel "physically". BUT it was still bleeding out prime. Went back to that exact same DV O-ring, replaced it, and the issue went away. I've had this EXACT same issue a few times, and each time resulted in a DV holder O-ring.
 
Only other time I've had the same type issue is when I had some copper return washers leaking on the injectors. But it'd struggle to start immediately after being shut off. Not after it sat for awhile.
 
Check the fuel return line at the back of the head drivers side. My 95 did the same and fuel leak. It was letting air in which caused the loss of prime.
I simply slid the hose on it farther, and it stopped the issue.
This line is a welded line which cracked over time.
 
overflow valve...

if that don't do it, the return line, if its the original will start to crack, replace the rubber section of it.. better yet, buy enough, eliminate that steel part, and run solid rubber lines to the tank..

worked great on my 12 valve.. and simpler to replace the hose in its entirety instead of fiddling with limited area with that steel hose
 
murphy41 said:
If the delivery valve holder O-ring was leaking, I'd suggest replace it. I cleaned one of mine that were leaking fuel, and it quit leaking fuel "physically". BUT it was still bleeding out prime. Went back to that exact same DV O-ring, replaced it, and the issue went away. I've had this EXACT same issue a few times, and each time resulted in a DV holder O-ring.
Click to expand...


I've had this happen to me too with DV o ring being bad. This may sound dumb but check your fuel filter one i had starting issues with mine and someone told me to try a new filter and it solved the problem
 
You guys really need to read what i posted originally or go back to cumminsforum.....

This is pathetic

MY FUEL SYSTEM IS NOT STOCK
IM NOT USING AN OVERFLOW VALVE
I MADE MY OWN FUEL LINES BOTH FEED AND RETURN AND JUST REPLACED ALL THE FEED LINE AS WELL AS CHANGED MY FILTERS

wow.....

Leaking return o-rings show fuel... Everything is dry

Either my aeromotive by-pass regulator has manages to wash-out sumhow and not holding pressure anymore... Somehow letting air replace the fuel in the lines from the tank baxk to the injection pump leading me to think maybe its an injector body or dv issue in the pump itself... Cuz air is going along way up if thats the case
 
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The regulator or an injector pop pressure issue. check exhaust manifold for a cold/dead cylinder on start up.
 
Your system is not stock. I read that part. :)

I would look at all of your connections on your fuel lines. Perhaps a clamp is loose causing an air leak. This sounds like a normal air leak issue.

There is also a possibility that in your modded system you have an anti-flow back valve that is leaking internally. Over time it could drip enough to let the system lose its fuel back into the tank.
 
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