1G Low Fuel Pressure

[Dsmpagan]

I replaced by fuel pump, the fuel pressure is supposed to be like 40-43psi correct? After changing to the Walbro 450 my FPR gauge now reads like 25psi and even when I adjust it never climbs much higher than that. Could I possibly have installed it incorrectly?

Also there is an ever so slight leak at where the hard line coming out of the fuel pump assembly meets the fuel line and i can't seem to get it to stop. I am worried that if i tighten any more i will bend the hard line. I know i can't use Teflon tape because of the fuel but is there something similar?

Does anyone make an aftermarket single pump hanger that loses the breakable hard like on the assembly?
Thanks in advance.

John

 

[1990TSIAWDTALON]

John, there is something up with not being able to stabilize the fuel pressure to 43.5 and hold it. You may have to check the oring at the top of the fuel pump to make sure it is sealing, I know you don't want to hear that. Hopefully others will chime in with some idea's for you to try so you can get the pressure back to where it needs to be.

 

[Dsmpagan]

So I used the two o-ring method suggested by one of the guys who did the 450 fuel pump write ups. Are you saying that the o-ring needs to be packed in better? I had to cut the white tip off of the fuel pump to make it not bottom out on the tank. Any advice on how to make it seal better I tried pushing the o-rings up with a screw driver. Also any advice on how to make the hard pipe seal better with the fuel lines. I will have another chance to tighten down everything to make it stop leaking.

 

[mattp_65]

its probably your stock return line. It is too small. I had to switch my stock return line with the stock feed line and used an aftermarket feed line back to the pump.
Another thing you can check is the FPR internal spring is broken or the seal itself.

 

[Dsmpagan]

So the fuel pump is not just a drop in upgrade I need to upgrade the fuel lines too? So does anyone make a fuel pump assembly with AN fittings so I can just upgrade everything?

 

[1990TSIAWDTALON]

John, is this in your 91? I replaced the pump in my 92 and I ended up cutting the "bell" off of the pickup tube and running a rubber line from the pump to the "new" delivery line with 2 hose clamps on both the pump and the part I cut the "bell" off of. Just something I had to do on mine, don't know if the 450 will work that way, mine was a 255.

 

[pauleyman]

I replaced by fuel pump, the fuel pressure is supposed to be act a like 40-43psi correct. After changing to the walbro 450 my FPR gauge now reads like 25psi and even when i adjust it never climbs much higher then that, could i possibly have installed it incorrectly? Also there is an ever so slight leak at where the hard line coming out of the fuel pump assembly meets the fuel line and i can't seem to get it to stop. I am worried that if i tighten any more i will bend the hard line. I know i can't use Teflon tape because of the fuel but is there something similar? Do anyone make an aftermarket single pump hanger that loses the breakable hard like on the assembly?
THanks in advance.

John

You must fix any leaks. No you don't need to upgrade stock return unless you get too much pressure. You have at least one obvious problem and possibly another intank if this was your only change

 

[boostdawd]

Dont use the orings. Cut the pickup tube like mentioned and run a hose from the tube to the pump. Secure with 2 worm clamps. Can u post a pic of where the leak is coming from?

 

[Dsmpagan]

I figured it out! Thanks for everyone who helped!

It was the o-rings not seated the correct way that limited the fuel pressure. I then used the advice of a member and cut the hard line going into the top of the pump and replaced it with fuel line and clamps. I attached pictures of both.

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[Vegas Smith]

BTW, you shouldn't need to upgrade your lines unless the stock line broke etc. If you want, you can buy the SS lines from most DSM vendors.

 

[1990TSIAWDTALON]

Wasn't that much easier?
I was WAY OVERTHINKING my problem when my 255 "drop in" didn't have the offset outlet nipple, so that's what I did to make mine work. Been that way for a year now and doing just fine. Very glad you got the problem solved. Those 450's can be finicky!