Date: Thu, 17 Apr 2003 21:41:49 -0400
Reply-To: Steve Gough <vw@EMRIVER.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Steve Gough <vw@EMRIVER.COM>
Subject: Help diagnose POSSESSED 2.1L Vanagon engine
Content-Type: text/plain
If you can solve this, you're a genius and I owe you one. Please
help me drive the demons out of my van. Some very smart vanagon
guys have looked at this van and are stumped. I've spent maybe 20 hours
on it.
1986 Westy (2.1). Symptoms: Won't respond to throttle, backfires,
sputters. Idles very well, and runs pretty good at highway cruise.
O2 sender shows it gets very lean under throttle when it sputters
and backfires, so probably not getting enough fuel. When engine is
turned off for even a second (hot or cold), it starts hard, sputtering and
not
responding to throttle as if it is gas-starved. It starts better,but
not good, if the pump is allowed to run for the full 5 seconds or so
when I do this. Once it gets past the lean acceleration point, will
run pretty good with good power.
History: Did find some water in gas this spring, was causing poor
running. Have since drained and rinsed tank with gas, replaced
fuel filter. Used double filter for a while to make sure all gunk
was out of tank. Now running some Techron through the system with
premium gas. Gas came from a very busy station.
Checked/replaced:
Injectors are all firing and pattern looks good. Injectors <2 yrs old.
Fuel pump <2 years old. Checked pressure with engine running -- 30psi,
rises to 35psi under throttle. Output per Bentley test 650ml in 30 seconds.
(Was 450 before I changed waterlogged fuel filter.) So fuel pump must be
good, though symptoms sure point to inadequate fuel delivery under
open throttle as the problem. Pump has been noisy since new.
All ignition connections good. Swapped distributor with no change, ruled
out timing and Hall sender problems. All plugs brand new, properly
gapped. All grounds double checked and cleaned. Strong spark at
distributor for all plugs. Timing triple checked per Bentley. Checked
advance, OK. Number two plug gets a little blackish for some reason.
Swapped AFM, no change.
Per Digitool, everything runs completely to specs except for lean
O2 readings (near zero) under hard throttle (when it's sputtering/backfiring).
So Temp II, AFM check out OK. Injector pulses and fuel pump look good.
Swapped ignition switch, no effect.
Compression checked, good. No vacuum leaks.
I did swap ECU's with someone else. We only checked at idle, but didn't
seem
to be a problem. I suspected ECU (by default), but have been told by those
who know that it is almost certainly not the problem (digitool readings look
fine).
Could the injectors be blocked somehow even though pattern looks good?
Any help will be greatly appreciated. I am at wit's end and have bugged my
vanagon gurus too much already.
Steve Gough
Carbondale, Illinois
'86 Westy, shortly to be named "Spooky"
