Date: Wed, 23 Apr 2003 20:27:50 -0400
Reply-To: Steve Gough <vw@EMRIVER.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Steve Gough <vw@EMRIVER.COM>
Subject: 2.1L Vanagon engine still possessed by demons
Content-Type: text/plain
I posted on this last week. After lots of advice and another
10 hours (maybe 40 total) or so of troubleshooting, I've gotten nowhere.
Please help:
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. Once it gets
past the lean acceleration point, at about 2Krpm will run pretty
good with fair power. But you can barely get the van moving in first
gear.
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.
Checked/replaced:
Injectors are all firing and pattern looks good. Injectors <2 yrs old.
Fuel pump <2 years old. Checked pressure with engine running and also under
load (driving) -- 30psi, rises to 38psi 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. Checked voltage at pump under
load and replaced pump ground wire/cleaned contacts.
I pulled all injectors and cleaned by pumping "Sea Foam" through them in
both directions while cycling them. Didn't see any gunk come out. Both
pump and regulator check valves tested OK.
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. Checked
advance, OK.
Swapped AFM, no change. Throttle switch set correctly. Have checked for
vacuum leaks with a microscope. There are none. Have tried adjusting
AFM spring, doesn't seem to help.
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. Also swapped Temp II, just to double
check, no improvement.
Replaced O2 sensor and have verified all grounds and signals at ECU.
All grounds cleaned. (Except tranny strap, which checks OK)
Compression checked, good. No vacuum leaks. Did leakdown test and found
intake valve too tight, but fixing that only slightly improved things.
Have tried 4 different ECU's now. Pulled O2 sensor and ran to check for
blocked cat. The cat is OK.
Diagnostics: If I pinch the fuel return line and manually keep pressure
at about 50psi, the van runs fine. It usually runs great in open loop when
first started cold, even under power.
Any help will be greatly appreciated.
Steve Gough
Carbondale, Illinois
'86 Westy, shortly to be named "Spooky"
