Huh???

[matuva]

Hi,

something I don't understand :

I have a Walbro FRB-5 lift pump to install.

At the moment, I'm using an Airtex HO stock lift pump (the one for a 1993 K3500)

At WTS cycle, my gauge is usually showing ~10 PSI fuel pressure, wich drops around 2 PSI at iddle, almost nothing at WOT.

So, I installed the FRB-5, and my gauge shown.... no PSI. I manually powered the pump, prime everything, still nothing.
I opened the bleeder, plenty of fuel. I opened the T-valve, plenty of fuel.
I started the engine, opened the T-valve, plenty of fuel, no stalling----

I put back the Airtex... and could read no pressure onthe gauge. Did the same test, still no pressure shown on the gauge, though plenty of fuel is flooding---

I took out the airtex and put the FRB-5 again : no luck :mad2:

Finally, I go back to the Airtex.

The truck runs fine, accelerates hard, and run perfect.

Now, at WTS, I can barely read that the gauge is showing about 2~4 PSI at WTS, and almost nothing at iddle.

I don't understand : I didn't touch anything, except I did the lift pumps swap---

Any thought? Just bad luck and the gauge failed as I swap the pumps? plugged lines ( lot of fuel flooding...) anything else?

 

[NVW]

Try a different gauge just to be sure it's working. Leo

 

[JMJNet]

Are you sure the Walbro is functioning, may be it is defective.

 

[North Maine]

if its pumping plenty of fuel, then its functioning.

 

[matuva]

Yes, it pumps a lot of fuel, so I assume it works fine.

I bought it second hand at a guy who was using it for bio diesel/veg oil. The pump was clean but could it be possible that a kind of "plug" built inside the pump and then was pushed inside the lines, clogging the fuel pressure sensor?

After driving a while, it seems that the gauge is slowly recovering and shows again signs of life.----

I will try to find some time this week end to install my new gauges.

 

[guybb3]

Did you clean the built in filter on the Walbro? I don't think that's your problem but you should do it anyway.

 

[matuva]

Well,
I put on my new "glow shift" gauges, including a new fuel pressure gauge in that serie.

Here is what I read for the Airtex (supposed to be a HO at 10~14 PSI according what's written on the pump)
- at WTS : 12 PSI
- at iddle : 7 PSI
- at WOT : 3~4 PSI.

Sounds good :thumbsup:

Next step, putting back the FRB-5. But I'm less in a hurry now, as it seems this Airtex is doing almost fine.

BTW, I recommend you the Glow Shift gauge series. They work great, are easely readable, the 7 colours features is awesome--- and they are cheap

Really they are worth the money

 

[dur0maxx]

I hope that is what my airtex is puting out. If not I will have to upgrade later to the walbro.