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New Lift, Still Biting, Splash of Air

Big T

Big T

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Fullerton, CA
Installed the new Raptor lift pump on the ‘99 K2500 Suburban It is very quiet, like I have to crawl under the truck to hear it working.

IMG_0363.jpegIMG_0364.jpegIMG_0365.jpeg
Took it for a spin and it’s biting/stuttering badly. Got a video of the clear line and I can see periodic pulses of air:


It gets worse the higher the rpm. I checked all connections for leaks. The filter had a drip coming off it, so I torqued it down further. Took it for another spin and it’s still biting/stuttering, which is when I took the video above.

I suspect a leak in the connection of the hardline at the tank sender, similar to what I experienced on the ‘94. If I brim the tank with fuel to the top of the fuel fill, I will get fuel spilling off the top of the tank.
 
OK, went back at it. Fuel filter had fuel dripping off it and it was coming from the fittings. I torqued the fittings in further and the leak seemed to stop. Tightened the fitting to the rear feed hard line, but there was not much more to go there. Started the truck and the fish bite seemed to be gone. Shut it down to put steak on the grill for a reverse sear and came back to do a test drive, but now it’s not starting and I’m getting full on bubbling in the clear line with just the lift pump going (the slight whirr noise in the background).


I ordered a new fuel tank and feed line from the tank, but they won’t arrive until after I leave next weekend. I will try to drain the tank and drop it tomorrow to inspect the seals.
 
Yes but do not get the tape near the end of the fitting. Some leave the first thread bare to be sure. I go to the edge then trim it back with a razor blade. 4 wraps is target. Plumbing code is 3 to 5 wraps- and npt threads is the same wether in your house or truck.
 
I don't know if it makes a difference but when wrapping fittings that could have contact with fuel or oil I use the yellow teflon tape that's made for gas lines. Apparently the gas can degrade regular teflon tape so I use the stuff that's supposed to better withstand hydrocarbon exposure.
 
You can also get a small can of that Indian head sealant to put on the threads. it's good at not degrading with fuel exposure and stays mallable. I also have heard guys talk about that stuff that is used on aviation fuel fittings. I can't think of the name if it but it's some goop that is approved to be used by the FFA or somesuch folks used that stuff in the race cars.

how far are the fittings threading into the housing. I had an issue with my fuel filter housing where the brass fittings were going in so far that the nut was bottoming on the housing. only fix for that was extra Teflon tape.
 
dbrannon79 said:
You can also get a small can of that Indian head sealant to put on the threads. it's good at not degrading with fuel exposure and stays mallable. I also have heard guys talk about that stuff that is used on aviation fuel fittings. I can't think of the name if it but it's some goop that is approved to be used by the FFA or somesuch folks used that stuff in the race cars.

how far are the fittings threading into the housing. I had an issue with my fuel filter housing where the brass fittings were going in so far that the nut was bottoming on the housing. only fix for that was extra Teflon tape.
Click to expand...
They are NPT so no seals. Not bottoming out, but tightening out.
 
Will L. said:
Yes but do not get the tape near the end of the fitting. Some leave the first thread bare to be sure. I go to the edge then trim it back with a razor blade. 4 wraps is target. Plumbing code is 3 to 5 wraps- and npt threads is the same wether in your house or truck.
Click to expand...
Depends on the tape. I like the thicker yellow tape. I also start 2 threads back and dope the ends with fuel compatible dope
 
The rain has backed off as expected, so I should be able to get on these fittings this am.

Tank is 1/2 full and when I undo the fittings, it's a constant flow of fuel coming out. I collected over a gallon in a bucket while doing the install yesterday and that includes plugging the line to the old lift pump with hose and the lock pin to a receiver hitch shoved in. I'm wonder if jacking up the front of the truck would stop the flow?

In addition to the fittings, I also probably need to wrap the plugs with tape.
 
Big T said:
The rain has backed off as expected, so I should be able to get on these fittings this am.

Tank is 1/2 full and when I undo the fittings, it's a constant flow of fuel coming out. I collected over a gallon in a bucket while doing the install yesterday and that includes plugging the line to the old lift pump with hose and the lock pin to a receiver hitch shoved in. I'm wonder if jacking up the front of the truck would stop the flow?

In addition to the fittings, I also probably need to wrap the plugs with tape.
Click to expand...
If you Jack it high enough that the area is higher than the tank
 
@ak diesel driver yes the yellow tape I'm referring to is for propane/ natural gas fittings. I know it's not apples to apples with propane/ gas to diesel fuel but just seemed logical to me to use the stuff designed for hydrocarbon exposure. If there is a diesel specific tape/ dope even better, just doubt the hardware store where @Big T is would stock anything other than the white and yellow stuff
 
DieselAmateur said:
@ak diesel driver yes the yellow tape I'm referring to is for propane/ natural gas fittings. I know it's not apples to apples with propane/ gas to diesel fuel but just seemed logical to me to use the stuff designed for hydrocarbon exposure. If there is a diesel specific tape/ dope even better, just doubt the hardware store where @Big T is would stock anything other than the white and yellow stuff
Click to expand...
I have several brands of dope. I called all the manufacturers to see which was compatible with diesel. I only had one that was.
And I don't remember which one.
 
No!! Do not roll the tape and fill the thread valleys. You are just making a weaker physical connection. Any work done like that would fail inspection immediately and the inspector would require the entire plumbing system disassembled and reassembled properly- thats just for water - imagine in an industrial setting for flammable materials. I have seen inspectors demand new pipe rather than accept improper threaded fittings. That guy teaching people that needs his ass kicked.

Technically- the proper stuff to use is the green pipe dope, most commonly known as gasoila. This is what is used in tank farms/ dispensaries and refineries. Regular teflon or the natural gas is fine (also available in blue as “blue monster”. The regular tape will fail in about 50 years. The yellow will make it about 60 years. The actual dope -yes only this composition- DONT USE JUST ANY PIPE DOPE, will last well over 100 years. But it is crazy dangerous to use for oxygen or NOS- spontaneous combustion.
I didn’t mention it because BigT doesn’t like to buy top shelf items for a one time use- he is more about reasonable prices for descent results instead of top $ for top performance.

If a guy is constantly doing fuel systems like N8in8or, or only wants the very best like Chris(TSP)- then this is the answer.

 
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Will L. said:
No!! Do not roll the tape and fill the thread valleys. You are just making a weaker physical connection. Any work done like that would fail inspection immediately and the inspector would require the entire plumbing system disassembled and reassembled properly- thats just for water - imagine in an industrial setting for flammable materials. I have seen inspectors demand new pipe rather than accept improper threaded fittings. That guy teaching people that needs his ass kicked.

Technically- the proper stuff to use is the green pipe dope, most commonly known as gasoila. This is what is used in tank farms/ dispensaries and refineries. Regular teflon or the natural gas is fine (also available in blue as “blue monster”. The regular tape will fail in about 50 years. The yellow will make it about 60 years. The actual dope -yes only this composition- DONT USE JUST ANY PIPE DOPE, will last well over 100 years. But it is crazy dangerous to use for oxygen or NOS- spontaneous combustion.
I didn’t mention it because BigT doesn’t like to buy top shelf items for a one time use- he is more about reasonable prices for descent results instead of top $ for top performance.

If a guy is constantly doing fuel systems like N8in8or, or only wants the very best like Chris(TSP)- then this is the answer.

Click to expand...
Hey I just installed a Raptor lift pump. Also ordered new fuel tank and feed line. I also bought lower steering shaft and all aluminum Champion Radiator from Twisted Steel. I do put in good stuff, but I don’t go crazy with it.
 
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Did some damage shopping in Missoula while letting the rain pass. Got all the filter fittings and plugs taped up, installed and no leaks (jacking it up stopped the flow from the tank). I got one rough light of the engine, then died. Still getting massive air bubbles through the clear return line. Wondering if I need to tape the fitting to the hard line on both sides of this set-up?


 
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