Big metal fuel filter after the pump.
Fuel pressure in spec at idle, regulator is working.
No pressure under load, restricted filter, defective pump, or tank is
loaded with crud. I would suspect the tank. If the filter is clogged, also
sign of a bad tank.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
mordo
Sent: Saturday, March 31, 2007 6:00 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Surging between 1700 and 3000 rpm

Yes, o2 sensor has no effect, connected or not. Checked distributor - it
looks good. I put a new eye on the ground for good measure.

I measured fuel pressure at the T both with and without vacuum connected.
Both are at spec. However, under load, both with and without vacuum
connected, the pressure drops precipitously to almost ZERO.

So, FPR, fuel pump or restricted filter? I will start with the inexpensive
and easy filter because I am already suspicious of this one.

Would the FPR malfunction both with and without vacuum connected?

Also, I know this has been debated but what's the consensus? Filter before
AND after the pump or just before the pump?

ciao,

mordo

---------- Forwarded message ----------
From: Benny boy <huotb@videotron.ca>
Date: Mar 31, 2007 1:54 PM
Subject: Re: Surging between 1700 and 3000 rpm
To: VANAGON@gerry.vanagon.com, Mark Mordhorst <helmut.blong@gmail.com>

It can be any following items:
-AFM
-Fuel regulator, pump, tank
-Temp sender (the blue one mostly)
-Distributor (yea, i'm having a lot of trouble with those lately, check
inside, remove dust cap, check wires/hall sender), check the cap, inside,
the center pin should spring OUT, easily, check also the ground on the
same
harness (top of left head)that goes to the distrubutor, check the plug
aslo.

OS could do that but you said it's ok?

Ben

--
mordo
1990 Carat