is this the behaviour of a bad AFPR?

Fast4Ward

Well-Known Member
Joined
Mar 27, 2005
before you view it, i've gotten lazy and have not checked for line kinks front to back.
changed the fuel pump (aem 320) guage still does the same ...the vid shows more than what it is set at. I can only adjust it to 39-40 with line on. expected with such a pump.
has a lean dip about 24-2700 rpm but quickly recovers before any major boost
 
I'd check voltage to the pump first. A dying pump will do goofy things. However, alot of times if the pump is bad it will fail to supply under boost. But as your video showed, pressure dropped as RPM rose or was sustained. To me that means a bad pump.
 
In tank hose connection can be fubar....Did you use the hose in the kit, or re-use the pulsator connector from the original pump??
 
this thing hits past 60's very fast when boosting, in tank rubber hose is new and clamped. remember it did this with the last pump too.
 
this thing hits past 60's very fast when boosting, in tank rubber hose is new and clamped. remember it did this with the last pump too.
Just putting it out there, but have you tried a different gage? Being that it is acting as before & now you have same issue, only thing not tried is another gage & would at least rule out the gage.
 
Use an air compressor to check 1:1 rise in pressure on your regulator. It might have a sticky spot internally where it sticks until it gets higher pressure and helps overcome the internal bind. Easy check before going further.
 
yeah i'll try the air injection and guage change...does it matter when to do the air test..like let it relieve of the pressure to nil?
 
Should be able to do the air pressure test with the engine off, and hot wire the pump to run.

If you still have the old pump check the sock on it. See if it has been crushed flat, it may be that there isn't any clearance between the bottom of the pump assembly and the bottom of the fuel tank.

RemoveBeforeFlight
 
before you view it, i've gotten lazy and have not checked for line kinks front to back.
changed the fuel pump (aem 320) guage still does the same ...the vid shows more than what it is set at. I can only adjust it to 39-40 with line on. expected with such a pump.
has a lean dip about 24-2700 rpm but quickly recovers before any major boost
You say that your pressure rises 1 to 1 with boost. Does your Scanmaster ever show spark retard?
 
I don't see any problem. Mine does that too.
funny i was going to ask to see if other memebers are seeing the same with their gauge?
up top (15#) the guage inside does not go backwards...just between 2-2700 and the idle test in video.
i put the stock one back on but it leaked so had to take it back out. got a new one on order.
 
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