Cant get fuel pressure down with new 420 walbro

[bpman1234]

So i put the pump in changed the return to 6an and my fp is topped at 100psi turn the fpr counter clock fp stays at 100 .i did use the original return on the sender .did i have to cut that thin part on the sender? anyone thanks.
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[pacecarta]

you have a restriction on the return side ,
are you certain you're connected on the return and not the larger vent tube at the sender?
how did you handle going from the regulator to the 6AN line ?

is your gauge connected with a schrader in the rail , does the gauge drop back to zero after pump has been off

 

[bpman1234]

I hooked up the return from the regulator with the 90 degree fitting 6 an line to the middle of the sender

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[pacecarta]

any kinks in the hose ?

 

[bpman1234]

it's an electric fuel gauge tapped into the rail it bleeds down after a while

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[pacecarta]

the walbro420assume is the 420lph pump
have to ask why a 420lph pump
moving on the stock mounted regulator should be able to handle the 420lph with a 6an line and plumbed into tank without any mod to sender .
i have 2 340lph pumps and i'm able to get to 3opsi with bothpumps on , with two 340lph being fed to stock rail with -08 , accufab reg , 90* 6an elbow out of reg , 6an to tank just shoved over sender tube and double clamped . the way i have it set base i'm ~45psi with one ..48 with both pumps

 

[pacecarta]

if you run a hose from regulator fitting into a bucket (jug ) and run pump briefly see if the pressure drops
if it does reconnect and disconnect at tank and run in bucket and see if you get same results

i usually install with a disconnect at front of tank to make it easier to test pump flow without having to drop tank

 

[bpman1234]

yes i did that yesterday i was trying ti get on the site all day but it was having problems the server i guess. its crazy cause i did hook it up with a disconnect right in front of the tank . so i did do that yesterday i stuffed the return right to the fill neck it went down to 60 just with key on but the car stopped running when i went to the regulator to bring it down some. this is my first start with the e85 .so anyway i read your post before typing and i went to look the pump is a 450lph .you asked why soooo why do you ask why what are you about to tell me to much pump?

 

[pacecarta]

asked because if you were on 93 it probably would be overkill
like i said i tested my setup again yesterday and posted the results using an accufab reg on the stock rail , turning the adjuster until pressure would no longer go down i was able to get down to 30psi with two rtx purple 340lph pumps running , rail fed with a -8 line and stock hanger (atr modified with alum y block inside )

check your fitting at the regulator for blockage

 

[pacecarta]

if it stopped running at 60psi have to question whether your fuel gauge is accurate

 

[NY_GN]

upgrade the return line, I went through this headache and the only thing that worked was larger fuel line. If you do upgrade it, go with PTFE / Teflon with stainless steel. I went with regular stainless steel and the fumes are killing me.

 

[NY_GN]

oh and yes cut that fitting on the sending unit first and see if that helps.

 

[dvernst]

upgrade the return line, I went through this headache and the only thing that worked was larger fuel line. If you do upgrade it, go with PTFE / Teflon with stainless steel. I went with regular stainless steel and the fumes are killing me.

Doesn't his first post already say he upgraded the return line?

 

[bpman1234]

ok been trying to get on here for about a day .now i can so yes i startted from the tank and i cut the thin part of the return on the sender and it went down to 80 lbs so the only other thing that i did was i put a oring in the regulator before i put the 90 elbom in to the 6an going to thye tank so i took it apart and it sure was stopping flow took it out put it all back together and yes it flowed alot better and could get the fp down to where it should be 42 line off vac line on it drops to 36-38 dont remember one of those to so went to get more gas and was running fine but then stalled kept blowing the 30 fuse on my hot wire so i unpluged the sender it it didnt blow when i hit the key as soon as i plug the sender back in it blows right away .so have to drop the tank again and see whats going on in there ,any ideas ?thanks for all that chimed in .

 

[NY_GN]

Tank grounded?

Exposed wire leading to relay up front?

Change fuse in relay at tank.

Not sure what else, good luck.

 

[bison]

Check for short to ground on harness first. Unplug harness at tank and use ohm setting and one end on hot wire and other on a good ground. Should be infinite resistance if it's unhooked. Then check the sender the same way. Orange with white tracer on the sender


BPE2013@hotmail.com

 

[bpman1234]

took the tank down and looked at all the wires nothing looked out of whack so I put it back together with the tank on the ground let it idle for a while everything seemed all good. so I bolted tank back up and running around ever since for about 2 days now . been talking to Eric about my tune. every now and then it seems like it has a miss and wants to stall but it doesn't. and at first. Up when its cold its really rough but then it clears up. thanks for all your replies

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[dynoman]

You could have pinched the positive wire on the intermediate harness going up to the sending unit when you first installed the new pump , and moved the harness when you installed the tank a second time . Glad you got it working.

 

[bpman1234]

yes I think that's what probably happened I made sure this time not to pinch anything so far so good thanks again for everyone that Chimed.in.

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